11

LT1632/LT1633

5V Large-Signal Response

1632/33 G26

5V Small-Signal Response

163233 G25

Harmonic Distortion vs Frequency

FREQUENCY (kHz)

100

0

–20

–40

–60

–80

–100

1000

2000

1632/33 G29

200

500

2ND

3RD

2ND

3RD

Harmonic Distortion vs Frequency

±15V Large-Signal Response

1632/33 G27

±15V Small-Signal Response

FREQUENCY (kHz)

100

0

–20

–40

–60

–80

–100

1000

2000

1632/33 G30

1000

200

500

2ND

3RD

3RD

2ND

1632/33 G28

Rail-to-Rail Input and Output

The LT1632/LT1633 are fully functional for an input and

output signal range from the negative supply to the posi-

tive supply. Figure 1 shows a simplified schematic of the

amplifier. The input stage consists of two differential

amplifiers, a PNP stage Q1/Q2 and an NPN stage Q3/Q4

that are active over different ranges of input common

mode voltage. The PNP differential input pair is active for

supply to approximately 1.5V below the positive supply.

mirror Q6/Q7, activating the NPN differential pair and the

PNP pair becomes inactive for the rest of the input com-

mon mode range up to the positive supply.

The output is configured with a pair of complementary

common emitter stages Q14/Q15 that enables the output

to swing from rail to rail. These devices are fabricated on

Linear Technology’s proprietary complementary bipolar

process to ensure similar DC and AC characteristics.

Capacitors C1 and C2 form local feedback loops that lower

the output impedance at high frequencies.

Power Dissipation

The LT1632/LT1633 amplifiers combine high speed and

large output current drive in a small package. Because the