© 2004 Fairchild Semiconductor Corporation

www.fairchildsemi.com

FAN4174/FAN4274 • Rev. 1.0.8

8

Application Information

General Description

The FAN4174 amplifier includes single-supply, general-

purpose, voltage-feedback amplifiers, fabricated on a bi-

CMOS process. The family features a rail-to-rail input

and output and is unity gain stable. The typical non-

inverting circuit schematic is shown in Figure 21.

Figure 21. Typical Non-inverting Configuration

Input Common Mode Voltage

The common mode input range extends to 300mV

operation. Exceeding these values does not cause

phase reversal; however, if the input voltage exceeds

the rails by more than 0.5V, the input ESD devices

begin to conduct. The output stays at the rail during this

(700mV beyond either rail) is exceeded, externally limit

the input current to ±5mA, as shown in Figure 22.

Figure 22. Circuit for Input Current Protection

Power Dissipation

The maximum internal power dissipation allowed is

directly related to the maximum junction temperature. If

the maximum junction temperature exceeds 150°C,

performance degradation occurs. If the maximum

junction temperature exceeds 150°C for an extended

time, device failure may occur.

Overdrive Recovery

Overdrive of an amplifier occurs when the output and/or

input ranges are exceeded. The recovery time varies

based on whether the input or output is overdriven and

by how much the range is exceeded. The FAN4174

typically recovers in less than 500ns from an overdrive

condition. Figure 23 shows the FAN4174 amplifier in an

overdriven condition.

Figure 23. Overdrive Recovery

Driving Capacitive Loads

Figure 9 illustrates the response of the FAN4174

output of the amplifier, illustrated in Figure 24, improves

were chosen to achieve maximum bandwidth with less

than 2dB of peaking. For maximum flatness, use a

Figure 24. Typical Topology for Driving a

Capacitive Load

Driving a capacitive load introduces phase-lag into the

output signal, which reduces phase margin in the

amplifier. The unity gain follower is the most sensitive

configuration. In a unity gain follower configuration, the

FAN4174 amplifier family requires a 300

series

resistor to drive a 100pF load.