High-Output-Drive, Precision, Low-Power, Single-

Supply, Rail-to-Rail I/O Op Amps with Shutdown

12

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Power-Up and Shutdown Modes

The MAX4166/MAX4168 have a shutdown option.

When the shutdown pin (SHDN) is pulled low, supply

amplifiers are disabled, and their outputs are placed in

a high-impedance state. Pulling SHDN high or leaving it

floating enables the amplifier. In the dual MAX4168, the

two amplifiers shut down independently. Figures 12

and 13 show the MAX4166’s output voltage and sup-

ply-current responses to a shutdown pulse. The

MAX4166–MAX4169 typically settle within 5µs after

power-up (Figure 14).

Power Supplies and Layout

The MAX4165–MAX4169 can operate from a single

+2.7V to +6.5V supply, or from dual ±1.35V to

±3.25V supplies. For single-supply operation, bypass

the power supply with a 0.1µF ceramic capacitor in

parallel with at least 1µF. For dual-supply operation,

bypass each supply to ground. Good layout improves

performance by decreasing the amount of stray capac-

itance at the op amps’ inputs and outputs. Decrease

stray capacitance by placing external components

close to the op amps’ pins, minimizing trace and lead

lengths.

1300

0

10

100k

100

200

300

400

1100

1200

RESISTIVE LOAD (k

Ω)

100

1k

10k

1000

900

800

700

600

500

STABLE REGION

UNSTABLE REGION

Figure 8. Capacitive-Load Stability

IN

(20mV/div)

OUT

(20mV/div)

TIME (1

µs/div)

Figure 9. Small-Signal Transient Response with Excessive

Capacitive Load

IN

(20mV/div)

OUT

(20mV/div)

TIME (1

µs/div)

Figure 10. Small-Signal Transient Response with Excessive

Capacitive Load with Isolation Resistor

Figure 11. Capacitive-Load-Driving Circuit