ICL7650CTV View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'ICL7650CTV' PDF : 24 Pages View PDF
LTC1052/LTC7652
APPLICATIO S I FOR ATIO
OUTPUT CLAMP
If the LTC1052 is driven into saturation, the nulling loop,
attempting to force the differential input voltage to zero,
will drive CEXTA and CEXTB to a supply rail. After the
saturating drive is removed, the capacitors take a finite
time to recover—this is the overload recovery time. The
overload recovery is longest when the capacitors are
driven to the negative rail (refer to Overload Recovery in
the Typical Performance Characteristics section). The
overload recovery time in this case is typically 225ms. In
the opposite direction (i.e., CEXTA and CEXTB at positive
rail), it is about ten times faster (25ms). The overload
recovery time for the LTC1052 is much faster than com-
petitive devices; however, if a faster overload recovery
time is necessary, the output clamp function can be used.
When the output clamp is connected to the negative input
it prevents the amplifier from saturating, thus keeping
CEXTA and CEXTB at their nominal voltages. The output
clamp is a switch that turns on when the output gets to
within approximately 1V of either supply rail. This switch
is in parallel with the amplifier’s feedback resistor. As the
output moves closer to the rail, the switch on
resistance decreases, reducing the closed loop gain. The
output swing is reduced when the clamp function is used.
How much current the output clamp leaks when off
is important because, when used, it is connected to the
amplifier’s negative input. Any current acts like input bias
current and will degrade accuracy. At the other extreme,
the maximum current the clamp conducts when on deter-
mines how much overdrive the clamp will take, and still
keep the amplifier from saturating. Both of these numbers
are guaranteed in the Electrical Characteristics section.
LOW SUPPLY OPERATION
The minimum supply voltage for proper operation of the
LTC1052 is typically 4.0V (±2.0V). In single supply
applications, PSRR is guaranteed down to 4.7V (±2.35V).
This assures proper operation down to the minimum TTL
specified voltage of 4.75V.
TYPICAL APPLICATIO S
5V Powered Ultraprecision Instrumentation Amplifier
5V
4
+ IN
7
8
11
C1
1µF
12
– IN
5V
43k
13
14
LTC1043
6
5
1N914
2
C3
1µF
3
C2
1µF
R1
100
5V
3+ 7
LTC1052
2–
41
0.1µF
R2
100k
6
8
0.1µF
0.22µF
+ C4
1µF
10k
VOUT
18
15
0.0047µF
17
16
≈ – 0.5V
CIRCUITRY WITHIN DASHED LINES MAY BE DELETED IF OUTPUT
DOES NOT HAVE TO SWING ALL THE WAY TO GROUND
DRIFT = 50nV/°C
VOS = 3µV
GAIN =
R2
R1
+
1
CMRR = >120dB DC – 20kHz
BANDWIDTH = 10Hz
LTC1052/7652 • TA03
12
Fast Precision Inverter
10k*
10k*
INPUT
10k
8pF
1N4148
300pF
1000pF
5V
5V
2+ 7
2+ 7
6
LT318A
6
LTC1052
10k 3 –
8
4
10k
1
3– 4
–5V
0.1µF
0.1µF
OUTPUT
– 5V
*1% METAL FILM
FULL POWER BANDWIDTH = 2MHz
SLEW RATE = 40V/µs
SETTLING (10V STEP) = 12µs TO 0.01%
BIAS CURRENT DC = 30pA
OFFSET DRIFT = 50nV/°C
OFFSET VOLTAGE = 5µV
LTC1052/7652 • TA04
1052fa
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