LTC1250 Linear Technology, LTC1250 Datasheet - Page 5

• Manufacturer Part Number: LTC1250
• Description: Very Low Noise Zero-Drift Bridge Amplifier
• Manufacturer: Linear Technology

TYPICAL PERFOR
Input Noise
The LTC1250, like all CMOS amplifiers, exhibits two types
of low frequency noise: thermal noise and 1/f noise. The
LTC1250 uses several design modifications to minimize
these noise sources. Thermal noise is minimized by rais-
ing the g
high bias levels and using large transistor geometries. 1/f
noise is combated by optimizing the zero-drift nulling loop
to run at twice the 1/f corner frequency, allowing it to
reduce the inherently high CMOS 1/f noise to near thermal
levels at low frequencies. The resultant noise spectrum is
quite low at frequencies below the internal 5kHz clock
A
TEST CIRCUITS
10
PPLICATI
–2
–3
–4
–5
–1
5
4
3
2
1
0
0.01
2
3
Output Swing vs Output Current,
Offset Test Circuit
5V Supply
+
–
V
S
LTC1250
M
= ±5V
100pF
100k
–5V
of the front-end transistors by running them at
5V
7
4
OUTPUT CURRENT (mA)
0.1
O
6
U
OUTPUT
S
1250 TC01
1
I FOR ATIO
U
W
LTC1250 G16
A
U
10
CE
10
W
2
3
C
–
+
HARA TERISTICS
LTC1250
100pF
100k
–5V
5V
5
4
2
1
0
6
3
0.01
7
4
Output Swing vs Output Current,
Single 5V Supply
U
V
S
= SINGLE 5V
C
6
0.02 F
OUTPUT CURRENT (mA)
800k
0.1
(for DC to 1Hz Multiply All Capacitor Values by 10)
2
3
LT1057
1
1/2
–5V
DC to 10Hz Noise Test Circuit
–
5V
+
4
8
LTC1250 G17
80
50
40
70
60
30
20
10
Figure 1. Voltage Noise vs Frequency
0
0.01
1
10
LTC1250
800k
OP-27
–40
–20
–30
–10
40
30
20
10
FREQUENCY (Hz)
0
–50
0.01 F
Short-Circuit Current
vs Temperature
800k
0.04 F
OP-07
0.1
–25
V
S
= ±15V
6
5
0
TEMPERATURE (°C)
–
+
V
R
LT1057
S
S
25
1/2
= ±5V
= 10
LTC1250 F01
LTC1250
50
1
V
V
OUT
OUT
7
75
= V
= V
–
+
100
LTC1250 G18
OUTPUT
1250 TC02
5
125