MAXIM MAX4490, MAX4491, MAX4492 Technical data

General Description

The MAX4490/MAX4491/MAX4492 single/dual/quad,
low-cost CMOS op amps feature Rail-to-Rail®input and
output capability from either a single 2.7V to 5.5V sup­ply or dual ±1.35V to ±2.75V supplies. These amplifiers
exhibit a high slew rate of 10V/µs and a gain-bandwidth
product of 10MHz. They can drive 2kΩ resistive loads
to within 55mV of either supply rail and remain unity­gain stable with capacitive loads up to 300pF.

The MAX4490 is offered in the ultra-small, 5-pin SC70
package, which is 50% smaller than the standard 5-pin
SOT23 package. Specifications for all parts are guaran­teed over the automotive (-40°C to +125°C) tempera­ture range.

Applications

Battery-Powered Instruments

Portable Equipment

Audio Signal Conditioning

Low-Power/Low-Voltage Applications

Sensor Amplifiers

RF Power Amplifier Control

High-Side/Low-Side Current Sensors

Features

♦ 2.7V to 5.5V Single-Supply Operation

♦ 10V/µs Slew Rate

♦ Rail-to-Rail Input Common-Mode Voltage Range

♦ Rail-to-Rail Output Voltage Swing

♦ 10MHz Gain-Bandwidth Product

♦ Unity-Gain Stable with Capacitive Loads

Up to 300pF

♦ 50pA Input Bias Current

♦ Ultra-Small, 5-Pin SC70 Package (MAX4490)

MAX4490/MAX4491/MAX4492

Low-Cost, High-Slew-Rate,

Rail-to-Rail I/O Op Amps in SC70

________________________________________________________________ Maxim Integrated Products 1

19-1525; Rev 2; 4/01

PART

MAX4490AXK-T

MAX4490AUK-T

MAX4491AKA-T

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C

TEMP RANGE

PIN­PACKAGE

5 SC70-5

5 SOT23-5

8 SOT23-5

Capacitive-Load Stability

Ordering Information

Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.

MAX4492AUD

-40°C to +125°C 14 TSSOP

MAX4492ASD -40°C to +125°C 14 SO

TOP

MARK

AAB

ADKQ

AADB

—
—

Pin Configurations/

Functional Diagrams

Pin Configurations continued at end of data sheet.

MAX4491AUA -40°C to +125°C 8 µMAX —

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

6000

5000

4000

3000

2000

CAPACITIVE LOAD (pF)

1000

0

100 100k10k1k

UNSTABLE

STABLE

RESISTIVE LOAD (Ω)

TOP VIEW

MAX4490

15V

IN+

2

V

SS

- +

34

SOT23-5/SC70-5

DD

OUTIN-

MAX4490/MAX4491/MAX4492

Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC70

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= 5V, VSS= 0, VCM= 0, V

OUT

= VDD/2, RL= 100kΩ connected to VDD/2, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical

values are at T

A

= +25°C.) (Note 1)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

Supply Voltage (VDDto VSS)....................................................6V

All Other Pins ...................................(V

SS

- 0.3V) to (VDD+ 0.3V)

Output Short-Circuit Duration .................................................10s

Continuous Power Dissipation (T

A

= +70°C)

5-Pin SC70 (derate 2.5mW/°C above +70°C)............ 200mW

5-Pin SOT23 (derate 7.1mW/°C above +70°C).......... 571mW

8-Pin SOT23 (derate 5.26mW/°C above +70°C)........421 mW

8-Pin µMAX (derate 4.1mW/°C above +70°C) ........... 330mW

14-Pin TSSOP (derate 8.3mW/°C above +70°C) ....... 667mW

14-Pin SO (derate 8.3mW/°C above +70°C).............. 667mW

Operating Temperature Range ........................ -40°C to +125°C

Junction Temperature..................................................... +150°C

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

Lead Temperature (soldering, 10s) ................................ +300°C

A

V(CL)

= 1, no sustained oscillations

ƒ = 10kHz

TA= +25°C

ƒ = 10kHz

Measured from 10% to 90% of 4V

P-P

step

(Note 2)

CL= 10pF

CL= 10pF

RL= 100kΩ

2.7V ≤ VDD≤ 5.5V

CL= 10pF

VSS≤ VCM≤ V

DD

Inferred from CMRR test

TA= T

MIN

to T

MAX

(Note 3)

(Note 3)

Sourcing or sinking

RL= 2kΩ

CONDITIONS

pF300Capacitive-Load Drive

fA√Hz

1i

n

Current-Noise Density

nV/√Hz

12e

n

Voltage-Noise Density

V/µs10SRSlew Rate

dB10Gain Margin

degrees60Phase Margin

pF5C

IN

Input Capacitance

MHz10GBWPGain-Bandwidth Product

mA±50I

OUT(SC)

Output Short-Circuit Current

65 85

mV

±1.5 ±10

V

OS

Input Offset Voltage

mA0.8 2I

S

V2.7 5.5V

DD

Supply Voltage Range

Supply Current (per amplifier)

dB

110

A

V

Large-Signal Voltage Gain

dB65 100PSRRPower-Supply Rejection Ratio

dB54 75CMRRCommon-Mode Rejection Ratio

VV

SS

V

DD

V

CM

Input Common-Mode Range

16

nA±0.05 ±2.5I

B

Input Bias Current

nA±0.05 ±2.5I

OS

Input Offset Current

MΩ

1000R

IN

Input Resistance

UNITSMIN TYP MAXSYMBOLPARAMETER

Note 1: All units production tested at TA= +25°C. Limits over temperature guaranteed by design.
Note 2: Guaranteed by the Power-Supply Rejection Ratio (PSRR) test.
Note 3: Input Offset Voltage, Input Bias Current, and Input Offset Current are all tested and guaranteed at both ends of the common-

mode range.

(V

SS

+ 0.25V) ≤ V

OUT

≤ (V

DD

- 0.25V)

RL= 100kΩ

RL= 2kΩ

55 200

mV

1.5

V

OH

Output-Voltage Swing High

Specified as
VDD- V

OH

RL= 100kΩ

RL= 2kΩ

35 150

mV

1.5

V

OL

Output-Voltage Swing Low

Specified as
VOL- V

SS

(Note 3)

MAX4490/MAX4491/MAX4492

Low-Cost, High-Slew-Rate,

Rail-to-Rail I/O Op Amps in SC70

_______________________________________________________________________________________ 3

5

MAX4490 toc02

Typical Operating Characteristics

(VDD= 5V, VSS= 0, VCM= VDD/2, RL= 100kΩ to VDD/2, TA= +25°C, unless otherwise noted.)

SUPPLY CURRENT PER AMPLIFIER

vs. TEMPERATURE

850

800

750

700

650

SUPPLY CURRENT (µA)

600

550

500

VDD = 5V

VDD = 2.7V

-40 -10 5 20-25 35 50 65 80 95 110 125

TEMPERATURE (°C)

OUTPUT SWING HIGH

vs. TEMPERATURE

80

70

60

50

(mV)

OUT

40

- V

DD

30

V

20

10

0

-40 -10 5 20 35-25 50 65 80 95 110 125

VDD = 5V

= 2kΩ

R

L

VDD = 5V OR 2.7V

= 100kΩ

R

L

TEMPERATURE (°C)

VDD = 2.7V

= 2kΩ

R

L

GAIN AND PHASE

vs. FREQUENCY (WITH C

60

50

40

30

20

GAIN (dB)

10

0

AV = 1000

-10
C

LOAD

-20

100 1k 10k 100k 1M 10M

PHASE

= 200pF

FREQUENCY (Hz)

GAIN

LOAD

MAX4490 toc07

MAX4490 toc 01

MAX4490 toc04

)

180

135

90

45

0

-45
PHASE (DEGREES)

-90

-135

-180

SUPPLY CURRENT PER AMPLIFIER

vs. SUPPLY VOLTAGE

1000

900

800

700

600

500

400

300

SUPPLY CURRENT (µA)

200

100

0

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.
SUPPLY VOLTAGE (V)

OUTPUT SWING LOW

vs. TEMPERATURE

80

70

60

50

(mV)

SS

40

- V

OUT

V

30

20

10

VDD = 5V OR 2.7V

= 100kΩ

R

L

0

-40 -10 5 20 35-25 50 65 80 95 110 125

VDD = 5V

= 2kΩ

R

L

TEMPERATURE (°C)

VDD = 2.7V
R

LARGE-SIGNAL GAIN

vs. TEMPERATURE

130

120

110

100

LARGE-SIGNAL GAIN (dB)

90

80

-40 -10 5-25 20 35 50 65 80 95 110 125

TEMPERATURE (°C)

= 2kΩ

L

VDD = 5V

-0.2

-0.4

-0.6

-0.8

-1.0

-1.2

OFFSET VOLTAGE (mV)

-1.4

-1.6

-1.8

-2.0

MAX4490 toc05

GAIN (dB)

MAX4490 toc08

PSSR (dB)

-100

INPUT OFFSET VOLTAGE

vs. TEMPERATURE

0

-40 -25 -10 5 20 35 50 8065 95 125110

TEMPERATURE (°C)

OP AMP GAIN AND PHASE

vs. FREQUENCY

60

50

40

30

20

10

0

-10

-20

AV = 1000

= 10pF

C

L

100 1k

PHASE

10k

FREQUENCY (Hz)

GAIN

100k 1M 10M

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY

0

AV = 1

-10

-20

-30

-40

-50

-60

-70

-80

-90

10 1k 10k100 100k 1M 10M

FREQUENCY (Hz)

MAX4490 toc06

MAX4490 toc03

180

135

90

45

0

-45
PHASE (DEGREES)

-90

-135

-180

MAX4490 toc09

MAX4490/MAX4491/MAX4492

Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC70

4 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VDD= 5V, VSS= 0, VCM= VDD/2, RL= 100kΩ to VDD/2, TA= +25°C, unless otherwise noted.)

0.01

1

0.1

10

100

1k

1k 10k100 100k 1M 10M

OUTPUT IMPEDANCE vs. FREQUENCY

MAX4490 toc10

FREQUENCY (Hz)

OUTPUT IMPEDANCE (Ω)

AV = 1

0.040

0

10 100 1k 10k 100k

TOTAL HARMONIC DISTORTION PLUS

NOISE vs. FREQUENCY

0.005

0.010

MAX4490 toc11

FREQUENCY (Hz)

THD + NOISE (%)

0.015

0.020

0.025

0.030

0.035

AV = 1V/V
2Vp-p SIGNAL
500kHz LOWPASS FILTER

RL = 2kΩ

RL = 10kΩ

LARGE-SIGNAL TRANSIENT RESPONSE

(NONINVERTING)

AV = 1

IN

OUT

40µs/div

MAX4490toc12

LARGE-SIGNAL TRANSIENT RESPONSE

(INVERTING)

AV = -1

IN

OUT

2V/div

2V/div

40µs/div

MAX4490toc13

SMALL-SIGNAL TRANSIENT RESPONSE

(NONINVERTING)

AV = 1

40µs/div

IN

OUT

50mV/div

50mV/div

MAX4490toc14

SMALL-SIGNAL TRANSIENT RESPONSE

(INVERTING)

AV = -1

IN

OUT

40µs/div

MAX4490toc15

50mV/div

50mV/div

POWER-UP TRANSIENT RESPONSE

AV = 1, VIN CONNECTED TO VDD/2, RL = 2kΩ

V

DD

OUT

2V/div

1V/div

MAX4490toc16

4µs/div

0

4

2

8

6

10

12

2.5 3.5 4.03.0 4.5 5.0 5.5

SLEW RATE vs. SUPPLY VOLTAGE

MAX4490 toc17

SUPPLY VOLTAGE (V)

SLEW RATE (V/µS)

AV = 1
10% TO 90% STEP

0

-20

-40

-120

0.001 1 10 1000.01 0.1 1000

MAX4491/MAX4492

CROSSTALK vs. FREQUENCY

-60

-80

-100

MAX4492toc18

FREQUENCY (MHz)

CROSSTALK (dB)

MAX4490/MAX4491/MAX4492

Low-Cost, High-Slew-Rate,

Rail-to-Rail I/O Op Amps in SC70

_______________________________________________________________________________________ 5

NAME FUNCTION

MAX4490

1 IN+ Noninverting Input

PIN

2 V

SS

Negative Supply Input. Connect to ground for single-supply operation.

3 IN- Inverting Input

— INA- Inverting Input to Amplifier A

— INA+ Noninverting Input to Amplifier A

5 V

DD

Positive Supply Input

4 OUT Amplifier Output

— INC+, IND+ Noninverting Inputs to Amplifiers C and D

— OUTB Amplifier B Output

— INB- Inverting Input to Amplifier B

— INB+ Noninverting Input to Amplifier B

— OUTA Amplifier A Output

Pin Description

MAX4492

—

11

—

2

3

4

—

10, 12

7

6

5

1

MAX4491

—

4

—

2

3

8

—

—

7

6

5

1

— — 9, 13 INC-, IND- Inverting Inputs to Amplifiers C and D

— — 8, 14 OUTC, OUTD Amplifiers C and D Outputs

Detailed Description

Rail-to-Rail Input Stage

The MAX4490/MAX4491/MAX4492 CMOS operational
amplifiers have parallel-connected N- and P-channel
differential input stages that combine to accept a com­mon-mode range extending to both supply rails. The N­channel stage is active for common-mode input
voltages typically greater than (VSS+ 1.2V), and the P­channel stage is active for common-mode input volt­ages typically less than (VDD- 1.2V).

Rail-to-Rail Output Stage

The MAX4490/MAX4491/MAX4492 CMOS operational
amplifiers feature class-AB push-pull output stages that
can drive a 100kΩ load to within 1.5mV of either supply
rail. Short-circuit output current is typically ±50mA.

Figures 1a and 1b show the typical temperature depen­dence of output source and sink currents, respectively,
for three fixed values of (VDD- VOH) and (VOL- VSS).
For example, at VDD= 5.0V, the load currents that main­tain (VDD- VOH) = 100mV and (VOL- VSS) = 100mV at
TA= +25°C are 2.2mA and 3.3mA, respectively, when

the load is connected to VDD/2. Consistent resistive­drive capability is (2.5 - 0.1) / 2.2 = 1.1kΩ. For the same
application, resistive-drive capability is 2.2kΩ when the
load is connected to VDDor VSS.

Applications Information

Power-Supply Considerations

The MAX4490/MAX4491/MAX4492 operate from a sin­gle 2.7V to 5.5V supply or from dual ±1.35V to ±2.75V
supplies with typically 800µA supply current per ampli­fier. A high power-supply rejection ratio of 100dB
allows for extended operation from a decaying battery
voltage, thereby simplifying designs for portable appli­cations. For single-supply operation, bypass the power
supply with a 0.1µF ceramic capacitor placed close to
the VDDpin. For dual-supply operation, bypass each
supply to ground.

Input Capacitance

One consequence of the parallel-connected differential
input stages for rail-to-rail operation is a relatively large
input capacitance CIN(typically 5pF). This introduces a

pole at frequency (2πR′CIN)-1, where R′ is the parallel
combination of the gain-setting resistors for the invert­ing or noninverting amplifier configuration (Figure 2). If
the pole frequency is less than or comparable to the
unity-gain bandwidth (10MHz), the phase margin will
be reduced, and the amplifier will exhibit degraded
AC performance through either ringing in the step
response or sustained oscillations. The pole frequency is
10MHz when R′ = 3.2kΩ. To maximize stability, R′ <3kΩ
is recommended.

Applications that require rail-to-rail operation with mini­mal loading (for small VDD- VOHand VOL- VSS) will
typically require R′ values >3kΩ. To improve step
response under these conditions, connect a small

capacitor Cfbetween the inverting input and output.
Choose Cfas follows:

Cf= 5(R / Rf) [pf]

where Rfis the feedback resistor and R is the gain-set­ting resistor (Figure 2).

Figure 3 shows the step response for a noninverting
amplifier subject to R′ = 4kΩ with and without the C

f

feedback capacitor.

MAX4490/MAX4491/MAX4492

Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC70

6 _______________________________________________________________________________________

Figure 1a. Output Source Current vs. Temperature

Figure 1b. Output Sink Current vs. Temperature

Figure 2. Inverting and Noninverting Amplifier with Feedback
Compensation

6

5

VDD = 2.7V

4

3

2

OUTPUT SOURCE CURRENT (mA)

1

0

-40 -10-25 5 20 35 50 65 80 12595 110
TEMPERATURE (

VDD - VOH = 200mV

- VOH = 100mV

V

DD

- VOH = 50mV

V

DD

VDD = 5V

°C)

INVERTING

V

IN

R

C

R

MAX4490

f

f

V

OUT

R′ = R || R

f

RfCf = RC

IN

9

8

7

6

5

4

3

OUTPUT SINK CURRENT (mA)

2

1

0

VDD = 2.7V

-40 -10-25 5 20 35 6550 80 11095 125
TEMPERATURE (°C)

VDD - VOH = 200mV

- VOH = 100mV

V

DD

- VOH = 50mV

V

DD

VDD = 5V

NONINVERTING

R

V

IN

MAX4490

R

f

C

f

R′ = R || R
RfCf = RC

V

OUT

f

IN

Driving Capacitive Loads

In conjunction with op amp output resistance, capaci­tive loads introduce a pole frequency that can reduce
phase margin and lead to unstable operation. The
MAX4490/MAX4491/MAX4492 drive capacitive loads
up to 300pF without significant degradation of step
response and slew rate (Figure 4). Capacitive-Load
Stability (page 1) shows regions of stable and margin­ally stable (step overshoot <10%) operation for different
combinations of capacitive and resistive loads.

Improve stability for large capacitive loads by adding
an isolation resistor (typically 10Ω) in series with the
output (Figure 5). Note that the isolation resistor forms a
voltage divider with potential for gain error.

Chip Information

MAX4490 TRANSISTOR COUNT: 60
MAX4491 TRANSISTOR COUNT: 120
MAX4492 TRANSISTOR COUNT: 240
SUBSTRATE CONNECTED TO V

SS

MAX4490/MAX4491/MAX4492

Low-Cost, High-Slew-Rate,

Rail-to-Rail I/O Op Amps in SC70

_______________________________________________________________________________________ 7

Figure 4. Step Response With and Without Capacitive Loading

Figure 3. Step Response With and Without Feedback
Compensation

3a)

WITHOUT FEEDBACK COMPENSATION

AV = -1, RL = 4kΩ, Cf = 0

4a)

WITHOUT CAPACITIVE LOADING

AV = +1, RL = 100kΩ, CL = 0

3b)

WITH FEEDBACK COMPENSATION

AV = -1, RL = 4kΩ, Cf = 5pF

4b)

WITH CAPACITIVE LOADING

AV = +1, RL = 100kΩ, CL = 300pF

MAX4490/MAX4491/MAX4492

Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC70

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

Figure 5. Isolation Resistor for Large Capacitive Loads

Package Information

Pin Configurations/

Functional Diagrams (continued)

TOP VIEW

V

IN

OUTA

INA-

INA+

SS

MAX4490

R

S

C

V

LOAD

OUT

1

MAX4491

+ -

2

3

4

+ -

SOT23-8/µMAX

1

OUTA

2

V

DD

OUTB

INB-

INB+V

INA-

INA+

V

INB+

INB-

3

4

DD

5

6

7

8

7

6

5

+ -

MAX4492

+ -

+ -

+ -

OUTD

14

IND-

13

IND+

12

V

11

10

INC+

9

INC-

8

OUTCOUTB

TSSOP/SO

SC70, 5L.EPS

SS