MCP6441T-E/LT - MICROCHIP

MCP6441/2/4

Features:

• Low Quiescent Current: 450 nA (typical)

• Gain Bandwidth Product: 9 kHz (typical)

• Supply Voltage Range: 1.4V to 6.0V

• Rail-to-Rail Input and Output

• Unity Gain Stable

• Slew Rate: 3V/ms (typical)

• Extended Temperature Range: -40°C to +125°C

• No Phase Reve rsal

• Small Packages

Applications:

• Port ab le Equi pm ent

• Battery Powered System

• Data Acquisition Equipment

• Sensor C onditioning

• Battery Current Sensing

• Analog Active Filters

Design Aids:

• SPICE Ma cr o Models

•FilterLab

® Software

• Microchip Advanced Part Selector (MAPS)

• Analog Demonstration and Evaluation Boards

• Application Notes

Description:

The MCP6441/2/4 device is a single nanopower

operational amplifier (op amp), which has low

quiescent current (450 nA, typical) and rail-to-rail input

and output operation. This op amp is unity gain stable

and has a gain bandwidth product of 9 kHz (typical).

These devices operate with a single supply voltage as

low as 1.4V. These features make the family of op

amps well suited for single-supply, battery-powered

applications.

The MC P6441/2/4 op amp is designed with Mic rochip’ s

advanced CMOS process and offered in single

(MCP6441), dual (MCP6442), and quad (MCP6444)

configurations. All devices are available in the

extended temperature range, with a power supply

range of 1.4V to 6.0V.

Typical Application

Package Types

VDD

IDD

100 kΩ

1MΩ

1.4V VOUT

Battery Current Sensing

10Ω

6.0V

IDD

VDD VOUT

–

10 V/V()10

()

⋅

------------------------------------------=

To load

MCP6441

VDD

VIN–

VIN+

VSS

VOUT

MCP6441

SC70-5, SOT-23-5

VDD

VIN–

VIN+

VSS

VOUTA

MCP6442

SOIC, MSOP MCP6444

SOIC, TSSOP

6VOUTB

4VINB+

VINA–

VDD

VIND+

VIN+VSS

VOUTA

6VOUTC

VINB+

VINA–

VINB–

VOUTB VINC–

VINC+

VIND–

VOUTD

MCP6442

2x3 TDFN *

VIN+

VIN–

VSS

VOUTB

VINB–

5VINB+

VDD

VOUTA EP

* Includes Exposed Thermal Pad (EP); see Table 3-1.

450 nA, 9 kHz Op Amp

MCP6441/2/4

NOTES:

MCP6441/2/4

1.0 ELECTRICAL CHARACTERISTICS

1.1 Absolute Maximum Ratings †

VDD – VSS ........................................................................7.0V

Current at Input Pins.....................................................±2 mA

Analog Inputs (VIN+, VIN-)†† .......... VSS – 1.0V to VDD + 1.0V

All Other Inputs and Outputs ......... VSS – 0.3V to VDD + 0.3V

Difference Input Voltage ...................................... | VDD – VSS|

Output Sh o rt-Circuit Cu r ren t ................................Continuous

Current at Output and Supply Pins ............................±30 mA

Storage Temperature ................................... .-65°C to +150°C

Maximum Junction Temperature (TJ)..........................+150°C

ESD Protection on All Pins (HBM; MM)............... ≥ 4 kV ; 200V

† Notice: Stresses above those listed under “Absolute

Maximum Ratings” may cause permanent damage to

the device. This is a stress rating only and functional

operatio n of the devic e at those or an y other con ditions

above those indicated in the operational listings of this

specification is not implied. Exposure to maximum rat-

ing conditions for extended periods may affect device

reliability.

†† See Section 4.1.2 “Input Voltage Limits”.

DC ELECTRICAL SPECIFICATIONS

Electrical Characteristics: Unless otherw ise in dicat ed, VDD = +1.4V to +6 .0V, VSS= GND, TA= +2 5°C, VCM = VDD/2,

VOUT ≈VDD/2, VL = VDD/2 and RL = 1 MΩ to VL. (Refer to Figure 1-1).

Parameters Sym Min Typ Max Units Conditions

Input Offset

Input Offset Voltage VOS -4.5 — +4.5 mV VCM = VSS

Input Offset Drift with Temperature ΔVOS/ΔTA—±2.5—µV/°CT

A= -40°C to +125°C,

VCM = VSS

Power Supply Rejection Ratio PSRR 65 86 — dB VCM = VSS

Input Bias Current and Impedance

Input Bias Current IB—±1—pA

—20—pAT

A = +85°C

—400—pAT

A = +125°C

Input Offset Current IOS —±1—pA

Common Mode Input Impedance ZCM —10

13||6 — Ω||pF

Differential Input Impedance ZDIFF —10

13||6 — Ω||pF

Common Mode

Common Mode Input Voltage Range VCMR VSS-0.3 — VDD+0.3 V

Common Mode Rejection Ratio CMRR 60 76 — dB VCM = -0.3V to 6.3V,

VDD = 6.0V

Open-Loop Gain

DC Open-Loop Gain

(Large Signal) AOL 90 110 — dB VOUT = 0.1V to VDD-0.1V

RL = 10 kΩ to VL

Output

Maximum Outp ut Voltage Swi ng VOL, VOH VSS+20 — VDD–20 mV VDD = 6.0V, RL = 10 kΩ

0.5V input overdrive

Output Short -Circ uit Curren t ISC —±3—mAV

DD = 1.4V

—±22—mAV

DD = 6.0V

Power Supply

Supply Voltage VDD 1.4 — 6.0 V

Quies cen t Curr ent per Amp lif ier IQ250 450 650 nA IO = 0, VDD = 5.0V

MCP6441/2/4

1.2 Test Circuits

The circuit used for most DC and AC tests is shown in

Figure 1-1. This circuit can independently set VCM and

VOUT (see Equation 1-1). Note that V

CM is not the

circuit ’s Comm on Mode volt age ((VP+V

M)/2), and that

VOST includes VOS plus t h e e ffects ( on t he i n pu t o ffset

error, VOST) of the temperature, CMRR, PSRR and

AOL.

EQUATION 1-1:

FIGURE 1-1: AC and DC Test Circuit for

Most Spe cific ations.

AC ELECTRICAL SPECIFICATIONS

Electrical Characteristics: Unless otherwise indicated, TA = +25°C, VDD = +1.4V to +6.0V, VSS = GND,

VCM = VDD/2, VOUT ≈VDD/2, VL = VDD/2 , RL = 1 MΩ to VL and CL = 60 pF. (Refer to Figure 1-1).

Parameters Sym Min Typ Max Units Conditions

AC Response

Gain Bandwidth Product GBWP — 9 — kHz

Phase Margin PM — 65 — ° G = +1 V/V

Slew Rate SR — 3 — V/ms

Noise

Input Noise Voltage Eni — 5 — µVp-p f = 0.1 Hz to 10 Hz

Input Noise Voltage Density eni —190—nV/√Hz f = 1 kHz

Input Noise Current Density ini —0.6—fA/√Hz f = 1 kHz

TEMPERATURE SPECIFICATIONS

Electrical Characteristics: Unless otherwise indicated, VDD = +1.4V to + 6.0V and VSS = GND.

Parameters Sym Min Typ Max Units Conditions

Temperature Ranges

Operati ng Tempe ratu r e Range TA-40 — +125 °C Note 1

Storage Temperature Range TA-65 — +150 °C

Thermal Package Resistances

Thermal Resistance, 5L-SC70 θJA — 331 — °C/W

Thermal Resistance, 5L-SOT-23 θJA —220.7—°C/W

Thermal Resistance, 8L-MSOP θJA —211—°C/W

Thermal Resistance, 8L-SOIC θJA —149.5—°C/W

Thermal Resistance, 8L-2x3 TDFN θJA —52.5—°C/W

Thermal Resistance, 14L-SOIC θJA —95.3—°C/W

Thermal Resistance, 14L-TSSOP θJA — 100 — °C/W

Note 1: The internal junction temperature (TJ) must not exceed the absolute maximum specification of +150°C.

GDM RFRG

⁄

VCM VPVDD 2

⁄

+()2

⁄

VOUT VDD 2

⁄

()VPVM

–()VOST 1G

+()++=

Where:

GDM = Differential Mode Gain (V/V)

VCM = Op Amp’s Common Mode

Input Voltage (V)

VOST = Op Amp’s Total Input O ffset Voltage (mV)

VOST VIN– VIN+

–=

VDD

RGRF

VOUT

CB2

CB1

100 kΩ

RGRF

VDD/2

VP100 kΩ

100 kΩ

60 pF1MΩ

1µF100 nF

VIN–

VIN+

6.8 pF

MCP6441

MCP6441/2/4

2.0 TYPICAL PERFORMANCE CURVES

Note: Unless otherwise indicated, TA = +25°C, VDD = +1.4V to +6.0V, VSS = GND, VCM = VDD/2 , VOUT ≈VDD/2,

VL = VDD/2, RL = 1 MΩ to VL and CL = 60 pF.

FIGURE 2-1: Input Offset Voltage.

FIGURE 2-2: Input Offset Voltage Drift.

FIGURE 2-3: Input Offset Voltage vs.

Common Mode Input Voltage with VDD = 6.0V.

FIGURE 2-4: Input Offset Voltage vs.

Common Mode Input Voltage with VDD = 1.4V.

FIGURE 2-5: Input Offset Voltage vs.

Output Voltage.

FIGURE 2-6: Input Offset Voltage vs.

Power Supply Voltage.

Note: The gra phs and tab les prov ided fo llow ing this note are a sta tistic al sum mary b ased on a limit ed numb er of

samples and are provided for informational purposes only. The performance characteristics listed herein

are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified

operating range (e.g., outside specified power supply range) and therefore outside the warranted range.

10%

15%

20%

25%

30%

35%

-4.5

-3.5

-2.5

-1.5

-0.5

0.5

1.5

2.5

3.5

4.5

Input Offset Voltage (mV)

Percentage of Occurences

1700 Samples

VCM = VSS

10%

15%

20%

25%

30%

-10

-8

-6

-4

-2

Input Offset Voltage Drift (µV/°C)

Percentage of Occurences

1700 Samples

VCM = VSS

TA = -40°C to +125°C

-500

500

1000

1500

2000

2500

3000

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

Common Mode Input Voltage (V)

Input Offset Voltage (µV)

VDD = 6.0V

Representative Part

TA = +125°C

TA = +85°C

TA = +25°C

TA = -40°C

-500

500

1000

1500

2000

2500

3000

3500

4000

-0.3

-0.1

0.1

0.3

0.5

0.7

0.9

1.1

1.3

1.5

1.7

Common mode input voltage (V)

Input Offset Voltage (µV)

VDD = 1.4V

Representative Part

TA = +125°C

TA = +85°C

TA = +25°C

TA = -40°C

-1000

-800

-600

-400

-200

200

400

600

800

1000

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Output Voltage (V)

Input Offset Voltage (µV)

VDD = 6.0V

VDD = 1.4V

Representative Part

-2000

-1600

-1200

-800

-400

400

800

1200

1600

2000

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

Power Supply Voltage (V)

Input Offset Voltage (µV)

Representative Part

TA = +125°C

TA = +85°C

TA = +25°C

TA = -40°C

MCP6441/2/4

Note: Unless otherwise indicated, TA = +25°C, VDD = +1.4V to +6.0V, VSS = GND, VCM = VDD/2 , VOUT ≈VDD/2,

VL = VDD/2, RL = 1 MΩ to VL and CL = 60 pF.

FIGURE 2-7: Input Noise Voltage Density

vs. Frequency.

FIGURE 2-8: Input Noise Voltage Density

vs. Common Mode Input Voltage.

FIGURE 2-9: CMRR, PSRR vs.

Frequency.

FIGURE 2-10: CMRR, PSRR vs. Ambient

Temperature.

FIGURE 2-11: Input Bias, Offset Current

vs. Ambient Temperature.

FIGURE 2-12: Input Bias Current vs.

Common Mode Input Voltage.

100

1,000

0.1 1 10 100 1000 10000

Frequency (Hz)

Input Noise Voltage Density

(nV/Hz)

0.1 1 10 100 1k 10k

100

150

200

250

300

350

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

Common Mode Input Voltage (V)

Input Noise Voltage Density

(nV/Hz)

f = 1 kHz

VDD = 6.0 V

100

0.1 1 10 100 1000

Frequency (Hz)

CMRR, PSRR (dB)

CMRR

PSRR-

PSRR+

Representative Part

100

-50 -25 0 25 50 75 100 125

Ambient Temperature (°C)

CMRR,PSRR (dB)

PSRR (VDD = 1.4V to 6.0V, VCM = VSS)

CMRR (VDD = 6.0V, VCM = -0.3V to 6.3V)

CMRR (VDD = 1.4V, VCM = -0.3V to 1.7V)

100

1000

25 45 65 85 105 125

Ambient Temperature (°C)

Input Bias and Offset Currents

(pA)

Input Bias Current

VDD = 6.0V

Input Offset Current

100

1000

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Common Mode Input Voltage (V)

Input Bias Current (pA)

VDD = 6.0V

TA = +125°C

TA = +85°C

MCP6441/2/4

Note: Unless otherwise indicated, TA = +25°C, VDD = +1.4V to +6.0V, VSS = GND, VCM = VDD/2 , VOUT ≈VDD/2,

VL = VDD/2, RL = 1 MΩ to VL and CL = 60 pF.

FIGURE 2-13: Quiescent Current vs.

Ambient Temperature.

FIGURE 2-14: Quiescent Current vs.

Power Supply Voltage.

FIGURE 2-15: Open-Loop Gain, Phase vs.

Frequency.

FIGURE 2-16: DC Open-Loop Gain vs.

Power Supply Voltage.

FIGURE 2-17: DC Open-Loop Gain vs.

Output Voltage Headroom.

FIGURE 2-18: Gain Bandwidth Product,

Phase Margin vs. Ambient Temperature.

200

250

300

350

400

450

500

550

600

-50 -25 0 25 50 75 100 125

Ambient Temperature (°C)

Quiescent Current

(nA/Amplifier)

DD = 6.0V

VDD = 1.4V

100

200

300

400

500

600

700

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

Power Supply Voltage (V)

Quiescent Current

(nA/Amplifier)

TA = +125°C

TA = +85°C

TA = +25°C

TA = -40°C

-20

100

120

1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05

Frequency (Hz)

Open-Loop Gain (dB)

-210

-180

-150

-120

-90

-60

-30

Open-Loop Phase (°)

Open-Loop Gain

Open-Loop Phase

VDD = 6.0V

1m 10m 0.1 1 10 100 1k 10k 100k

100

110

120

130

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Power Supply Voltage (V)

DC Open-Loop Gain (dB)

RL = 10 kΩ

VSS + 0.1V < VOUT < VDD - 0.1V

120

130

)

= 6.0V

110

120

in (d

100

op G

VDD = 1.4V

pen-L

LSilA

RL= 10k

arge

gna

0.00 0.05 0.10 0.15 0.20 0.25

-50 -25 0 25 50 75 100 125

Ambient Temperature (°C)

Gain Bandwidth Product

(kHz)

Phase Margin (°)

Gain Bandwidth Product

Phase Margin

VDD = 6.0V

MCP6441/2/4

Note: Unless otherwise indicated, TA = +25°C, VDD = +1.4V to +6.0V, VSS = GND, VCM = VDD/2 , VOUT ≈VDD/2,

VL = VDD/2, RL = 1 MΩ to VL and CL = 60 pF.

FIGURE 2-19: Gain Bandwidth Product,

Phase Margin vs. Ambient Temperature.

FIGURE 2-20: Output Short Circuit Current

vs. Power Supply Voltage.

FIGURE 2-21: Output Voltage Swing vs.

Frequency.

FIGURE 2-22: Output Voltage Headroom

vs. Output Current.

FIGURE 2-23: Output Voltage Headroom

vs. Ambient Temperature.

FIGURE 2-24: Slew Rate vs. Ambien t

Temperature.

-50 -25 0 25 50 75 100 125

Ambient Temperature (°C)

Gain Bandwidth Product

(kHz)

Phase Margin (°)

Gain Bandwidth Product

Phase Margin

VDD = 1.4V

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Power Supply Voltage (V)

Output Short Circuit Current

(mA)

TA = -40°C

TA = +25°C

TA = +85°C

TA = +125°C

0.1

10 100 1000 10000

Frequency (Hz)

Output Voltage Swing (VP-P)

VDD = 1.4V

VDD = 6.0V

10 100 1k 10k

0.1

100

1000

10 100 1000 10000

Output Current (mA)

Output Voltage Headroom (mV)

VDD - VOH @ VDD = 1.4V

VOL - VSS @ VDD = 1.4V

VDD - VOH @ VDD = 6.0V

VOL - VSS @ VDD = 6.0V

RL = 10 kΩ

0.01 0.1 1 10

-50 -25 0 25 50 75 100 125

Ambient Temperature (°C)

Output Voltage Headroom

VDD - VOH or VOL - VSS (mV)

VDD - VOH @ VDD = 1.4V

VOL - VSS @ VDD = 1.4V

VDD - VOH @ VDD = 6.0V

VOL - VSS @ VDD = 6.0V

-50 -25 0 25 50 75 100 125

Ambient Temperature (°C)

Slew Rate (V/ms)

Falling Edge, VDD = 6.0V

Rising Edge, VDD = 6.0V

Falling Edge, VDD = 1.4V

Rising Edge, VDD = 1.4V

MCP6441/2/4

Note: Unless otherwise indicated, TA = +25°C, VDD = +1.4V to +6.0V, VSS = GND, VCM = VDD/2 , VOUT ≈VDD/2,

VL = VDD/2, RL = 1 MΩ to VL and CL = 60 pF.

FIGURE 2-25: Small Signal Non-Inverting

Pulse Response.

FIGURE 2-26: Small Signal Inverting Pulse

Response.

FIGURE 2-27: Large Signal Non-Inverting

Pulse Response.

FIGURE 2-28: Large Signal Inverting Pulse

Response.

FIGURE 2-29: The MCP 644 1/2/4 Device

Shows No Phase Reversal.

FIGURE 2-30: Closed Loop Output

Impedance vs. Frequency.

Time (200 µs/div)

Output Voltage (20 mv/div)

VDD = 6.0V

G = +1 V/V

Time (200 µs/div)

Output Voltage (20 mv/div)

VDD = 6.0V

G = -1 V/V

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Time (2 ms/div)

Output Voltage (V)

VDD = 6.0V

G = +1 V/V

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Time (2 ms/div)

Output Voltage (V)

VDD = 6.0V

G = -1 V/V

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Time (2 ms/div)

Input,Output Voltage (V)

VDD = 6.0V

G = +2 V/V

VOUT

VIN

100

1000

10000

100000

1000000

1 10 100 1000 10000

Frequency (Hz)

Closed Loop Output

Impedance (Ω)

1 10 100 1k 10k

100

10k

100k

GN:

101 V/V

11 V/V

1 V/V

MCP6441/2/4

Note: Unless otherwise indicated, TA = +25°C, VDD = +1.4V to +6.0V, VSS = GND, VCM = VDD/2 , VOUT ≈VDD/2,

VL = VDD/2, RL = 1 MΩ to VL and CL = 60 pF.

FIGURE 2-31: Measured Input Current vs.

Input Voltage (below VSS). FIGURE 2-32: Channel-to-Channel

Separation vs. Frequency (MCP6442/4 only).

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

-1.0 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0

Input Voltage (V)

-IIN (A)

100

10µ

1µ

100n

10n

100

10p

TA = -40°C

TA = +25°C

TA = +85°C

TA = +125°C

100

110

120

130

140

150

100 1000 10000

(

)

Frequency (Hz)

Input Referred

Channel to Channel Separation

(dB)

100 10k

MCP6441/2/4

3.0 PIN DESCRIPTIONS

Descrip tions of the pins are listed in Table 3-1.

3.1 Analog Output (VOUT)

The output pin is a low-impedance voltage source.

3.2 Power Supply Pins (VDD, VSS)

The pos iti ve po we r s upp ly (VDD) is 1. 4V to 6. 0V h igh er

than the negative power supply (VSS). For normal

operation, the other pins are at voltages between VSS

and VDD.

Typically, these parts are used in a single (positive)

supply configuration. In this case, VSS is connected to

ground and VDD is connected to the supply. VDD will

need bypass capacitors.

3.3 Analog Inputs (VIN+, VIN-)

The non-inverting and inverting inputs are high-

impedance CMOS inputs with low bias currents.

3.4 Exposed Thermal Pad (EP)

There is an internal connection between the Exposed

Thermal Pad (EP) and the VSS pin; they must be con-

nected to the same potential on the Printed Circuit

Board (PCB).

This pad can be connected to a PCB ground plane to

provide a larger heat sink. This improves the package

thermal res istance (θJA).

TABLE 3-1: PIN FUNCTION TABLE

MCP6441 MCP6442 MCP6444

Symbol Description

SC70-5,

SOT-23-5 SOIC,

MSOP 2x3 TDFN SOIC,

TSSOP

1111V

OUT, VOUTA Analog Output (op amp A)

4222V

IN–, VINA– Inverting Input (op amp A)

3333V

IN+, VINA+ Non-inverting Input (op amp A)

5884V

DD Positive Power Supply

—555V

INB+ Non-inverting Input (op amp B)

—666V

INB- Inverting Input (op amp B)

—777V

OUTB Analog Output (op amp B)

———8V

OUTC Analog Output (op amp C)

———9V

INC- Inverting Input (op amp C)

———10V

INC+ Non-inverting Input (op amp C)

24411V

SS Negative Power Supply

———12V

IND+ Non-inverting Input (op amp D)

———13V

IND- Inverting Input (op amp D)

———14V

OUTD Analog Output (op amp D)

— — 9 — EP Exposed Thermal Pad (EP);

must be connected to VSS

MCP6441/2/4

Notes:

MCP6441/2/4

4.0 APPLICATION INFORMATION

The MCP6441/2/4 op amp is manufactured using

Microc hip’s s tate-of-the -art CMOS proce ss, specifica lly

designed for low power applications.

4.1 Rail-to-Rail Input

4.1.1 PHASE REVERSAL

The MCP6441/2/4 op amp is designed to prevent

phase reversal, when the input pins exceed the supply

voltages. Figure 2-29 shows the input voltage

exceeding the supply voltage with no phase reversal.

4.1.2 INPUT VOLTAGE LIMITS

In order to prevent damage and/or improper operation

of the am plifie r, the circuit m ust li mit the volt a ges at th e

input pins (see Section 1.1, Absolute Maximum

Ratings †).

The Electrostatic Discharge (ESD) protection on the

inputs can be depicted as shown in Figure 4-1. This

structure was chosen to protect the input transistors

against many, but not all, over-voltage conditions, and

to minimize the input bias current (IB).

FIGURE 4-1: Simplified Analog Input ESD

Structures.

The input ESD diodes clamp the inputs when they try

to go more than one diode drop below VSS. They also

clamp any voltages that go well above VDD; their

breakdown voltage is high enough to allow normal

operation, but not low enough to protect against slow

over-voltage (beyond VDD) events. Very fast ESD

events that meet the spec are limited so that damage

does not occur.

In some applications, it may be necessary to prevent

excessive voltages from reaching the op amp inputs;

Figure 4-2 shows one approach to protecting these

inputs.

FIGURE 4-2: Protecting the Analog

Inputs.

A significant amount of current can flow out of the

input s when t he Common M ode volt age (VCM) is below

ground (VSS); see Figure 2-31.

4.1.3 INPUT CURRENT LIMITS

In order to prevent damage and/or improper operation

of the amplifier, the circuit must limit the currents into

the input pins (see Section 1.1 “Absolute Maximum

Ratings †”).

Figure 4-3 shows one approach to protecting these

inputs. The resistors R1 and R2 limit the possible

current s in or out of the input pin s (and the ESD dio des,

D1 and D2). The diode currents will go through either

VDD or VSS.

FIGURE 4-3: Protecting the Analog

Inputs.

Bond

Pad

Bond

Pad

Bond

Pad

VDD

VIN+

VSS

Input

Stage Bond

Pad VIN–

VDD

MCP644X

VOUT

V1R1

VDD

min(R1,R2)> VSS –min(V

1, V2)

2mA

V2R2

MCP644X

VOUT

min(R1,R2)> max(V1,V2)–V

2mA

MCP6441/2/4

4.1.4 NORMAL OPERATION

The input stage of the MCP6441/2/4 op amp uses two

differential input stages in parallel. One operates at a

low Com mon Mode inpu t voltage (VCM), while the other

operates at a high VCM. With this topology, the device

operates with a VCM up to 300 mV above VDD and

300 mV below VSS. The input offset voltage is

measured at VCM =V

SS – 0.3V and VDD + 0.3V, to

ensure proper operation.

The transition between the input stages occurs when

VCM is near VDD –0.6V (see Figures 2-3 and 2-4). For

the best distortion performance and gain linearity, with

non-inverting gains, avoid this region of operation.

4.2 Rail-to-Rail Output

The output voltage range of the MCP6441/2/4 op amp

is VSS + 20 mV (minimum) and VDD – 20 mV (maxi-

mum) when RL=10kΩ is connected to VDD/2 and

VDD = 6.0V. Refer to Figures 2-22 and 2-23 for more

information.

4.3 Capacitive Loads

Driving large capacitive loads can cause stability

problems for voltage feedback op amps. As the load

capacitance increases, the feedback loop’s phase

margin decreases, and the closed-loop bandwidth is

reduced. This produces gain peaking in the frequency

response, with overshoot and ringing in the step

response. While a unity-gain buffer (G = +1 V/V) is the

most sensitive to the capacitive loads, all gains show

the same general behavior.

When driving large capacitive loads with the

MCP6441/2/4 op amp (e.g., > 100 pF when

G = +1 V /V), a small series resistor a t the ou tput (RISO

in Figure 4-4) improves the fe edback loop’s phase mar-

gin (stability) by making the output load resistive at

higher frequencies. The bandwidth will be generally

lower than the bandwidth with no capacitance load.

FIGURE 4-4: Output Resistor, RISO

Stabilizes Large Capacitive Loads.

Figure 4-5 gives th e rec om mende d RISO valu es for the

different capacitive loads and gains. The x-axis is the

normalized load capacitance (CL/GN), where GN is the

circuit 's noise gain. For non-inverti ng gains, GN an d the

Signal Gain are equal. For inverting gains, GN is

1+|Signal Gain| (e.g., -1 V/V gives GN = +2 V/V).

FIGURE 4-5: Recommended RISO Values

for Capacitive Loads.

After selecting RISO for your circuit, double-check the

resulting frequency response peaking and step

response overshoot. Modify RISO’s value until the

response is reasonable. Bench evaluation and

simulations with the MCP6441/2/4 SPICE macro

model are very helpful.

4.4 Supply Bypass

The MCP6 441 /2/ 4 op am p’s power s upp ly pin (VDD for

single-supply) should have a local bypass capacitor

(i.e., 0.01 µF to 0.1 µF) within 2 mm for good high

frequency performance. It can use a bulk capacitor

(i.e., 1 µF or larger) within 100 mm to provide large,

slow currents. This bulk capacitor can be shared with

other analog part s .

4.5 PCB Surface Leakage

In applications where low input bias current is critical,

Printed Circuit Board (PCB) surface leakage effects

need to be considered. Surface leakage is caused by

humidity, dust or other contamination on the board.

Under low humidity conditions, a typical resistance

betwee n nearby traces i s 1012Ω. A 5V dif ference would

cause 5 pA of current to flow, which is greater than the

MCP6441/2/4 op amp’s bias current at +25°C (±1 pA,

typical).

VIN

RISO VOUT

–

MCP644X

1000

10000

100000

1000000

1.E-11 1.E-10 1.E-09 1.E-08 1.E-07 1.E-06

Normalized Load Capacitance; CL/GN (F)

Recommended RISO (Ω)

GN:

1 V/V

2 V/V

≥ 5 V/V

10p 100p 1n 10n 0.1µ 1µ

10k

100k

MCP6441/2/4

The easiest way to reduce surface leakage is to use a

guard ring around se nsi tiv e p ins (or t rac es). The gua rd

ring is biased at the same voltage as the sensitive pin.

An example of this type of layout is shown in

Figure 4-6.

FIGURE 4-6: Example Guard Ring Layout

for Inverting Gain.

1. Non-inverting Gain and Unity-Gain Buffer:

a) Connect the non-inverting pin (VIN+) to the

input with a wire that does not touch the

PCB surface.

b) Connect the guard ring to the inverting input

pin (VIN–). This b iases th e g uard ri ng to the

Common Mode input voltage.

2. Inverting Gain and Transimpedance Gain

Amplifiers (convert current to voltage, such as

photo detectors):

a) Connect the guard ring to the non-inverting

input pin (VIN+). This biases the guard ring

to the same reference voltage as the op

amp (e.g., VDD/2 or ground).

b) Connect the inverting pin (VIN–) to the inp ut

with a wire that does not touch the PCB

surface.

4.6 Application Circuits

4.6.1 BATTERY CURRENT SENSING

The MCP6441/2/4 op amp’s Common Mode Input

Range, which goes 0.3V beyond both supply rails,

supports their use in high-side and low-side battery

current sensing applications. The low quiescent current

(450 nA, typical) helps prolong battery life, and the

rail-to-rail output supports detection of low currents.

Figure 4-7 shows a high side battery current sensor

circuit. The 10Ω resistor is sized to minimize power

losses. The battery current (IDD) through the 10Ω

resistor causes its top terminal to be more negative

than the bottom terminal. This keeps the Common

Mode input voltage of the op amp below VDD, w hic h is

with in i ts al lowe d r ange. Th e ou tput of t he op am p wi ll

also be below VDD, within its Maxim um O utp ut Voltage

Swing specification.

FIGURE 4-7: Battery Current Sensing.

Guard Ring VIN–V

IN+ VSS

VDD

IDD

100 kΩ

1MΩ

1.4V VOUT

10Ω

6.0V

IDD VDD VOUT

–

10 V/V()10

()

⋅

------------------------------------------=

To load

MCP6441

MCP6441/2/4

4.6.2 PRECISION HALF-WAVE

RECTIFIER

The precision half-wave rectifier, which is also known

as a super diode, is a configuration obtained with an

operatio nal amplif ier in o rder to have a circuit beha vin g

like an ideal diod e and rectifier . It ef fectively cancels the

forward voltage drop of the diode in such a way that

very low leve l signa ls can still b e rectifi ed, with mini mal

error. This can be useful for high-precision signal

processing. The MCP6441/2/4 op amp has high input

impedance, low input bias current and rail-to-rail

input/output, which makes this device suitable for

precision rectifier applications.

Figure 4-8 shows a pre ci sio n ha lf-w a ve rect ifi er an d its

transfer characteristic. The rectifier’s input impedance

is determined by the input resistor R1. To avoid the

loading effect, it must be driven from a low-impedance

source.

When VIN is greater than zero, D1 is OFF , D2 is ON, and

VOUT is zero. When VIN is less than zero, D1 is ON, D2

is OFF, and VOUT is the VIN with an amplification of

-R2/R1.

The rectifi er ci rcuit sho wn in Figure 4-8 has the benef it

that the op amp never goes in saturation, so the only

thing affecting its frequency response is the

amplification and the gain bandwidth product.

FIGURE 4-8: Precision Half-Wave

Rectifier.

4.6.3 INSTRUMENTATION AMPLIF IER

The MCP6441/2/4 op amp is well suited for condition-

ing sensor signals in battery-powered applications.

Figure 4-9 shows a two op amp instrumentation

amplifier, using the MCP6441/2/4 device, that works

well for applications requiring rejection of Common

Mode noise at higher gains. The reference voltage

(VREF) is supplied by a low-impedance source. In sin-

gle supply applications, VREF is typically VDD/2.

FIGURE 4-9: Two Op Amp

Instrumentation Amplifier.

VOUT

VIN

VOUT

VIN

-R2/R1

Transfer Characteristic

Precision Half-Wave Rectifier

MCP6441

VOUT V1V2

–()1R1

------2R1

---------++

⎝⎠

⎛⎞

VREF

VREF R1R2R2R1VOUT

1/2 MCP6442 1/2 MCP6442

MCP6441/2/4

5.0 DESIGN AIDS

Microchip provides the basic design tools needed for

the MCP6441/2/4 op amp.

5.1 SPICE Macro Model

The latest SPICE macro model for the MCP6441/2/4

op amp is available on the Microchip web site at

www.microchip.com. The model was wr itten and teste d

in the official OrCAD (Cadence®) owned PSpice®. For

the other simulators, translation may be required.

The model covers a wide aspect of the op amp's

electric al speci fication s. Not onl y does the mod el cover

voltage, current and resistance of the op amp, but it

also covers the temperature and the noise effects on

the behavior of the op amp. The model has not been

verified outside of the specification range listed in the

op amp data sheet. The model behaviors under these

conditions cannot ensure it will match the actual op

amp performance.

Moreover, the model is intended to be an initial design

tool. Bench testing is a very important part of any

design and cannot be replaced with simulations. Also,

simulation results using this macro model need to be

validated by comparing them to the data sheet

specifications and characteristic curves.

5.2 FilterLab® Software

Microchip’s FilterLab software is an innova tive software

tool that simplifies analog active filter design using op

amp s. Availab le at no cost from the Mic roc hip we b si te

at www.microchip.com/filterlab, the FilterLab design

tool prov ides f ull sche matic diagra ms of th e filte r circu it

with component values. It also outputs the filter circuit

in SPICE format, which can be used with the macro

model to simulate the actual filter performance.

5.3 Microchip Advanced Part Selector

(MAPS)

MAPS is a software tool that helps semiconductor

professionals efficiently identify the Microchip devices

that fit a par tic ula r desig n re qui rem ent . Availab le at no

cost from the Microchip website at

www.microchip.com/ maps, the MAPS is an overall

selection tool for Microchip’s product portfolio that

includes Analog, Memory , MCUs and DSCs. Using this

tool, you can define a filter to sort features for a

parametric search of devices and export side-by-side

technical comparison reports. Helpful links are also

provided for Data Sheets, Purchase and Sampling of

Microchip parts.

5.4 Analog Demonstration and

Evaluation Boards

Microchip offers a broad spectrum of Analog

Demonstration and Evaluation Boards that are

designe d to h elp you a chieve f aster tim e to market. F or

a complete listing of these boards and their

correspo nding user’s guides and tech nical info rmatio n,

visit the Microchip web site at

www.microchip.com/analogtools.

Some boards that are especially useful are:

• MCP6XXX Amplifier Evaluation Board 1

• MCP6XXX Amplifier Evaluation Board 2

• MCP6XXX Amplifier Evaluation Board 3

• MCP6XXX Amplifier Evaluation Board 4

• Active Filter Demo Board Kit

• 5/6-Pin SOT-23 Evaluation Board, P/N VSUPEV2

5.5 Application Notes

The following Microchip Analog Design Note and

Application Notes are available on the Microchip web

site at www.microchip.com/appnotes, and are

recomm end ed as suppl em ental refer enc e reso urc es.

•ADN003 – “Sel ect th e Right Opera tional Ampli fier

for your Filtering Circuits”, DS21821

•AN722 – “Operational Amplifier Topologies and

DC Specifications”, DS00722

•AN723 – “Operationa l Amplifi er AC Specif ications

and Applications”, DS00723

•AN884 – “Driving Capacitive Loads With Op

Amps”, DS00884

•AN990 – “Analog Sensor Conditioning Circuits –

An Overview”, DS00990

•AN1177 – “Op Amp Precision Des ign: DC Errors”,

DS01177

•AN1228 – “Op Amp Precision Design: Random

Noise”, DS01228

• AN1297 – “Microchip’s Op Amp SPICE Macro

Models”, DS01297

• AN1332: “Current Sensing Circuit Concepts and

Fundamentals”’ DS01332

These application notes and others are listed in the

design guide:

•“Signal Chain Design Guide”, DS21825

MCP6441/2/4

NOTES:

MCP6441/2/4

6.0 PACKAGING INFORMATION

6.1 Package Marking Information

Example:

Legend: XX...X Customer-specific information

Y Year code (last digit of calendar year)

YY Year code (last 2 digits of calendar year)

WW Week code (week of January 1 is week ‘01’)

NNN Alphanumeric traceability code

Pb-free JEDEC designator for Matte Tin (Sn)

*This package is Pb-free. The Pb-free JEDEC designator ( )

can be found on the outer packaging for this package.

Note: In the event the full Microchip part number cannot be marked on one line, it

will be carried over to the next line, thus limiting the number of available

characters for customer-specific information.

Example:

5-Lead SOT-23 (MCP6441)

5-Lead SC70 (MCP6441)

Example:

DG25

XXNN

WU25

8-Lead MSOP (MCP6442)

6442E

211256

MCP6441/2/4

Legend: XX...X Customer-specific information

Y Year code (last digit of calendar year)

YY Year code (last 2 digits of calendar year)

WW Week code (week of January 1 is week ‘01’)

NNN Alphanumer ic trac eab il ity code

Pb-free JEDEC designator for Matte Tin (Sn)

*This package is Pb-free. The Pb-free JEDEC designator ( )

can be found on the outer packaging for this package.

Note: In the event t he full Mic roch ip p art numb er canno t be marked on one line, it wil l

be carried over to the next line, thus limiting the number of available

characters for customer-specific information.

14-Lead TSSOP (MCP6444)Example:

14-Lead SOIC ( 150 mil) (MCP6444)Example:

8-Lead SOIC (150 mil) (MCP6442) Example:

NNN

MCP6442E

SN^^ 1211

256

8-Lead TDFN (2x3x0.75 mm)(MCP6442)Example:

AAX

211

MCP6444

E/SL ^^

1211256

YYWW

NNN

XXXXXXXX

6444E/ST

1211

256

MCP6441/2/4



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AA2

   

MCP6441/2/4



5-Lead Plastic Small Outline Transistor (LT) [SC70]

MCP6441/2/4

 !

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  

  

    

    

    

    

    

    

    

    

   

    

    

123

A2 c

   

MCP6441/2/4