Micropower, SOT23, Rail-to-Rail,

Fixed-Gain, GainAmp/Open-Loop Op Amps

10

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Pin Description

_______________Detailed Description

Maxim’s GainAmp fixed-gain amplifiers combine a low-

cost rail-to-rail op amp with internal gain-setting resis-

tors. Factory-trimmed on-chip resistors provide 0.1%

gain accuracy while decreasing design size, cost, and

layout. There are two versions in this amplifier family:

single/dual/quad open-loop, unity-gain-stable devices

(MAX4076/MAX4077/MAX4078), and single/dual fixed-

gain devices (MAX4074/MAX4075). All amplifiers fea-

ture rail-to-rail outputs and drive a 10k

Ω load while

maintaining excellent DC accuracy.

Open-Loop Op Amps

The single/dual/quad MAX4076/MAX4077/MAX4078 are

low-power, open-loop op amps with rail-to-rail outputs.

These devices are compensated for unity-gain stability

and feature a GBW product of 230kHz. The common-

mode range extends from 150mV below the negative

rail to within 1.2V of the positive rail. These high-perfor-

mance op amps serve as the core for this family of

GainAmp fixed-gain amplifiers. Although the -3dB band-

width will not correspond to that of a fixed-gain amplifier

in higher gain configurations, these open-loop op amps

can be used to prototype designs.

Internal Gain-Setting Resistors

Maxim’s proprietary laser trimming techniques allow

gain configurations. These GainAmp fixed-gain ampli-

fiers feature a negative-feedback resistor network that

is laser trimmed to provide a gain-setting feedback

op amp pinouts allow the GainAmp fixed-gain ampli-

fiers to plug directly into existing board designs, easily

replacing op amps-plus-resistor gain blocks.

OUT

IN-

IN+

Figure 1. Internal Gain-Setting Resistors

FUNCTION

Positive Supply

5

No Connection. Not internally connected.

N.C.

—

Inverting Amplifier Input

IN_-

4

Noninverting Amplifier Input

IN_+

3

Negative Supply or Ground

2

Amplifier Output

OUT_

1

7

1, 5, 8

2

3

4

6

8

—

2, 6

3, 5

4

1, 7

4

—

2, 6, 9, 13

3, 5, 10, 12

11

1, 7, 8, 14

MAX4075

MAX4077

MAX4078

µMAX/SO

SO/TSSOP

SOT23

NAME

SO

PIN

MAX4074/MAX4076