LT1630 Linear Technology, LT1630 Datasheet - Page 11

• Manufacturer Part Number: LT1630
• Description: 30MHz/ 10V/us/ Dual/Quad Rail-to-Rail Input and Output Precision Op Amps
• Manufacturer: Linear Technology

APPLICATIONS
TYPICAL PERFORMANCE CHARACTERISTICS
Rail-to-Rail Input and Output
The LT1630/LT1631 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
input common mode voltages V
supply to approximately 1.4V below the positive supply.
As V
–100
–100
–20
–40
–60
–80
–20
–40
–60
–80
0
0
100
100
CM
Harmonic Distortion vs Frequency
Harmonic Distortion vs Frequency
V
A
V
V
A
V
S
V
IN
S
V
IN
= 5V, 0V
= 1
= 5V, 0V
= –1
moves closer toward the positive supply, the
= 2V
= 2V
R
R
R
R
L
L
L
L
= 150
= 1k
= 150
= 1k
P-P
P-P
200
200
FREQUENCY (kHz)
FREQUENCY (kHz)
3RD
U
3RD
2ND
3RD
2ND
INFORMATION
500
500
2ND
U
3RD
2ND
W
CM
1630/31 G30
1630/31 G31
U
1000
1000
1000
1000
W
between the negative
V
A
R
5V Small-Signal Response
V
A
R
U
S
V
L
S
V
L
15V Small-Signal Response
= 5V, 0V
= 1
= 1k
= 15V
= 1
= 1k
transistor Q5 will steer the tail current I
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.
1630/31 G26
1630/31 G28
5V Large-Signal Response
V
A
R
V
A
R
S
V
L
S
V
L
15V Large-Signal Response
= 5V, 0V
= 1
= 1k
= 15V
= 1
= 1k
LT1630/LT1631
1
to the current
11
1630/31 G27
1630/31 G29