Single/Dual/Quad, 10MHz

Single-Supply Op Amps

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9

______________________________________________________________Pin Description

Amplifier D Output

OUTD

14

—

—

Amplifier D Inverting Input

IND-

13

—

—

Amplifier D Noninverting Input

IND+

12

—

—

Amplifier C Noninverting Input

INC+

10

—

—

Amplifier C Inverting Input

INC-

9

—

—

Amplifier C Output

OUTC

8

—

—

MAX474

MAX475

PIN

INB+

OUT

INB-

OUTB

IN+

INA+

N.C.

INA-

IN-

OUTA

NULL

NAME

5

—

6

7

4

—

3

11

—

2

—

1

—

MAX473

Amplifier B Noninverting Input

5

—

Amplifier Output

—

6

Amplifier B Inverting Input

6

—

Amplifier B Output

7

—

Positive Power-Supply Pin. Connect to (+) terminal of power supply.

8

7

Noninverting Input

—

3

Amplifier A Noninverting Input

3

—

Negative Power-Supply Pin. Connect to ground or a negative voltage.

4

4

No Connect—not internally connected

—

5

Amplifier A Inverting Input

2

—

Inverting Input

—

2

Amplifier A Output

1

—

Offset Null Input. Connect to one end of 2k

Ω potentiometer for offset voltage

—

1, 8

FUNCTION

__________Applications Information

Power Supplies

The MAX473/MAX474/MAX475 operate from a single

2.7V to 5.25V power supply, or from dual supplies of

±1.35V to ±2.625V. For single-supply operation,

bypass the power supply with 0.1µF. If operating from

dual supplies, bypass each supply to ground. With

0.1µF bypass capacitance, channel separation

(MAX474/MAX475) is typically better than 120dB with

signal frequencies up to 300kHz. Increasing the

bypass capacitance (e.g. 10µF

channel separation at higher frequencies.

Minimizing Offsets

The MAX473’s maximum offset voltage is ±2mV

connect a 2k

Ω trim potentiometer between pins 1, 8, and

4 (Figure 1). Input offset voltage for the dual MAX474

and quad MAX475 cannot be externally trimmed.

The MAX473/MAX474/MAX475 are bipolar op amps

with low input bias currents. The bias currents at both

inputs flow out of the device. Matching the resistance

at the op amp’s inputs significantly reduces the offset

error caused by the bias currents. Place a resistor (R3)

from the noninverting input to ground when using the

inverting configuration (Figure 2a); place R3 in series

with the noninverting input when using the noninverting

configuration (Figure 2b). Select R3 such that the paral-

lel combination of R2 and R1 equals R3. Adding R3 will

slightly increase the op amp’s voltage noise.

Output Loading and Stability

The MAX473/MAX474/MAX475 op amps are unity-gain

stable. Any op amp’s stability depends on the configu-

ration, closed-loop gain, and load capacitance. The

unity-gain, noninverting buffer is the most sensitive gain

configuration, and driving capacitive loads decreases

stability.