KM4110/KM4120

DATA SHEET

REV. 1A February 2001

7

General Description

The KM4110 is a single supply, general purpose, volt-

age-feedback amplifier fabricated on a complementary

bipolar process. The KM4110 offers 75MHz unity gain

bandwidth, 50V/

µs slew rate, and only 505µA supply

current. It features a rail-to-rail output stage and is

unity gain stable.

The design utilizes a patent pending topology that

provides increased slew rate performance. The common

mode input range extends to 300mV below ground

and to 1.2V below Vs. Exceeding these values will not

cause phase reversal. However, if the input voltage

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

devices will begin to conduct. The output will stay at

the rail during this overdrive condition.

The design uses a Darlington output stage. The out-

put stage is short circuit protected and offers “soft”

saturation protection that improves recovery time.

The typical circuit schematic is shown in Figure 1.

Figure 1: Typical Configuration

For optimum response at a gain of +2, a feedback resistor

of 1k

Ω is recommended. Figure 2 illustrates the

KM4110 frequency response with both 1k

Ω and 2kΩ

feedback resistors.

Enable/Disable Function (KM4120)

The KM4120 offers an active-low disable pin that can

be used to lower its supply current. Leave the pin

floating to enable the part. Pull the disable pin to the

negative supply (which is ground in a single supply

application) to disable the output. During the disable

condition, the nominal supply current will drop to

below 30

µA and the output will be at high impedance

with about 2pF capacitance.

Power Dissipation

The maximum internal power dissipation allowed is

directly related to the maximum junction temperature.

If the maximum junction temperature exceeds 150°C,

some reliability degradation will occur. If the maximum

junction temperature exceeds 175°C for an extended

time, device failure may occur.

The KM4110 is short circuit protected. However, this

may not guarantee that the maximum junction tem-

perature (+150°C) is not exceeded under all condi-

tions.

Follow the maximum power derating curves

shown in Figure 3 to ensure proper operation.

Figure 3: Power Derating Curves

Overdrive Recovery

For an amplifier, an overdrive condition 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 ranges are

exceeded. The KM4110 will typically recover in less

than 20ns from an overdrive condition.

Figure 4

shows the KM4110 in an overdriven condition.

+

-

KM4110

0.01

µF

6.8

µF

Out

In

+

Frequency (MHz)

0.1

1

10

100

G = 2

Ambient Temperature ( C)

-50

-30

-10

10

30

50

70

90

SOIC-8 lead

0

0.5

1.0

1.5

2.0

SOT23-5 lead