MAX44241 Ver la hoja de datos (PDF) - Maxim Integrated

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MAX44241

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

Maxim Integrated 

MAX44246

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

The MAX11211 ADC operates from a single 2.7V to 3.6V

analog supply, offers 18-bit noise-free resolution and

0.86mW power dissipation. The MAX11211 also offers

> 100dB rejection at 50Hz and 60Hz. This ADC is part of

a family of 16-, 18-, 20-, and 24-bit delta sigma ADCs with

high precision and < 1mW power dissipation.

The low input offset voltage and low noise of MAX44246

allows a gain circuit to precede the MAX11211 without

losing any dynamic range at the ADC. See the Typical

Operating Circuit.

Precision Low-Side Current Sensing

The ICs’ ultra-low offset voltage and drift make them

ideal for precision current-sensing applications. Figure 1

shows the ICs in a low-side current-sense configuration.

This circuit produces an accurate output voltage, VOUT

equal to ILOAD x RSENSE x (1 + R2/R1).

Layout Guidelines

The MAX44246 features ultra-low offset voltage and

noise. Therefore, to get optimum performance follow the

following layout guidelines.

Avoid temperature gradients at the junction of two dis-

similar metals. The most common dissimilar metals used

on a PCB are solder-to-component lead and solder-to-

board trace. Dissimilar metals create a local thermo-

couple. A variation in temperature across the board can

cause an additional offset due to Seebeck effect at the

solder junctions. To minimize the Seebeck effect, place

VSUPPLY

ILOAD

RSENSE

R1

MAX44246

OUT

R2

Figure 1. Low-Side Current Sensing

the amplifier away from potential heat sources on the

board, if possible. Orient the resistors such that both

the ends are heated equally. It is a good practice to

match the input signal path to ensure that the type and

number of thermoelectric junctions remain the same. For

example, consider using dummy 0Ω resistors oriented

in such a way that the thermoelectric sources, due to

the real resistors in the signal path, are cancelled. It is

recommended to flood the PCB with ground plane. The

ground plane ensures that heat is distributed uniformly

reducing the potential offset voltage degradation due to

Seebeck effect.

Maxim Integrated

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