MAX44246AUA Просмотр технического описания (PDF) - Maxim Integrated

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MAX44246AUA

36V, Low-Noise, Precision, Single/Quad/Dual Op Amps

Maxim Integrated 

MAX44246

36V, Low-Noise, Precision, Dual Op Amp

Pin Configuration

TOP VIEW

+

OUTA 1

INA- 2

INA+ 3

GND 4

MAX44246 8 VDD

7 OUTB

6 INB-

5 INB+

µMAX/SO

Pin Description

PIN

NAME

FUNCTION

1

OUTA

Channel-A Output

2

INA-

Channel-A Negative Input

3

INA+

Channel-A Positive Input

4

GND

Negative Supply Voltage

5

INB+

Channel-B Positive Input

6

INB-

Channel-B Negative Input

7

OUTB

Channel-B Output

8

VDD

Positive Supply Voltage

Detailed Description

The MAX44246 is a high-precision amplifier that provides

below 5µV of maximum input-referred offset and low

flicker noise. These characteristics are achieved by using

a combination of proprietary auto-zeroing and chopper

stabilized techniques. This combination of auto-zeroing

and chopping ensures that these amplifiers give all the

benefits of zero-drift amplifiers, while still ensuring low

noise, minimizing chopper spikes, and providing wide

bandwidth. Offset voltages due to power ripple/spikes as

well as common-mode variation, are corrected resulting

in excellent PSRR and CMRR specifications.

Noise Suppression

Flicker noise, inherent in all active devices, is inverse-

ly proportional to frequency present. Charges at the

oxide-silicon interface that are trapped-and-released

by MOSFET oxide occurs at low frequency more often.

For this reason, flicker noise is also called 1/f noise. The

MAX44246 eliminates the 1/f noise internally, thus making

it an ideal choice for DC or sub-Hz precision applications.

Maxim Integrated

The 1/f noise appears as a slow varying offset voltage and

is eliminated by the chopping technique used.

Electromagnetic interference (EMI) noise occurs at higher

frequency, resulting in malfunction or degradation of elec-

trical equipment. The ICs have an input EMI filter to avoid

the output being affected by radio frequency interference.

The EMI filter composed of passive devices, presents sig-

nificant higher impedance to higher frequency.

Applications Information

ADC Buffer Amplifier

The MAX44246 has low input offset voltage, low noise,

and fast settling time that make this amplifier ideal for

ADC buffers. Weight scales are one application that often

requires a low-noise, high-voltage amplifier in front of an

ADC. The Typical Operating Circuit details an example

of a load cell and amplifier driven from the same ±10V

supplies, along with the MAX11211 18-bit delta sigma

ADC. Load cells produce a very small voltage change at

their outputs; therefore driving the excitation source with a

higher voltage produces a wider dynamic range that can

be measured at the ADC inputs.

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