Single/Dual/Quad, Wide-Bandwidth, Low-Power,

Single-Supply Rail-to-Rail I/O Op Amps

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13

TIME (5

µs/div)

OUT

Figure 11. Power-Up Output Voltage

SHDN

(1V/div)

TIME (2

µs/div)

OUT

(0.5V/div)

Figure 13. Shutdown Output Voltage

(1V/div)

TIME (5

µs/div)

(500

µA/div)

Figure 12. Power-Up Supply Current

SHDN

(1V/div)

TIME (2

µs/div)

(500

µA/div)

Figure 14. Shutdown Enable/Disable Supply Current

Power-Up and Shutdown Mode

The MAX4122–MAX4129 amplifiers typically settle with-

in 1µs after power-up. Using the test circuit of Figure

10, Figures 11 and 12 show the output voltage and

supply current on power-up.

The MAX4123, MAX4125, and MAX4127 have a shut-

down option. When the shutdown pin (SHDN) is pulled

low, the supply current drops below 25µA per amplifier

and the amplifiers are disabled with the outputs in a

high-impedance state. Pulling SHDN high or leaving it

floating enables the amplifier. In the dual-amplifier

MAX4129, the shutdown functions operate indepen-

dently. Figures 13 and 14 show the output voltage and

supply current responses of the MAX4123 to a shut-

down pulse.

Power Supplies and Layout

The MAX4122–MAX4129 operate from a single +2.7V

to +6.5V power supply, or from dual supplies of ±1.35V

to ±3.25V. For single-supply operation, bypass the

power supply with a 0.1µF ceramic capacitor in parallel

with at least 1µF. For dual supplies, bypass each sup-

ply to ground.

Good layout improves performance by decreasing the

amount of stray capacitance at the op amp’s inputs

and outputs. To decrease stray capacitance, minimize

trace lengths and resistor leads by placing external

components close to the op amp’s pins.