Data Sheet

MAX74840

analog.com

Rev. 0

13 of 17

For higher input voltages, determine the resistor value by:

VIN − VSY

RS

≤ 10mA

(1)

where:

VIN is the input voltage.

VSY is the voltage of either the V+ pin or the V− pin.

RS is the series resistor.

With a very low input bias current of ±1.5nA maximum up to 125°C, higher resistor values can be used in series with

the inputs without introducing large offset errors. A 1kΩ series resistor allows the MAX74840 to withstand 10V of

continuous overvoltage and increases the noise by a negligible amount. A 5kΩ resistor protects the inputs from

voltages as high as 25V beyond the supplies and adds less than 10µV to the offset voltage of the amplifier.

EMI Rejection Ratio

Figure 27 shows the EMI rejection ratio (EMIRR) vs. the frequency for the MAX74840.

Figure 27. EMIRR vs. Frequency

Output Characteristics

The MAX74840’s unique bipolar rail-to-rail output stage swings within 10mV of the supplies with no external

resistive load.

The approximate output saturation resistance of the MAX74840 is 24Ω, sourcing or sinking. Use the output

impedance to estimate the output saturation voltage when driving heavier loads. As an example, when driving

5mA, the saturation voltage from either rail is approximately 120mV.

If the MAX74840 output drives hard against the output saturation voltage, it recovers within 1.2µs of the input,

returning to the linear operating region of the amplifier (see Figure 15 and Figure 16).

0

20

40

60

80

100

10M

100M

1G

FREQUENCY (Hz)

COMPETITOR 1

COMPETITOR 2

MAX74840