Datasheet

TLC2654, TLC2654A
Advanced LinCMOS LOW-NOISE CHOPPER-STABILIZED
OPERATIONAL AMPLIFIERS
SLOS020G – NOVEMBER 1988 – REVISED APRIL 2001
23
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
theory of operation (continued)
The TLC2654 removes this restriction on ac performance by using a 10-kHz internal clock frequency. This high
chopping frequency allows amplification of input signals up to 5 kHz without errors due to intermodulation and
greatly reduces low-frequency noise.
THERMAL INFORMATION
temperature coefficient of input offset voltage
Figure 36 shows the effects of package-included thermal EMF. The TLC2654 can null only the offset voltage
within its nulling loop. There are metal-to-metal junctions outside the nulling loop (bonding wires, solder joints,
etc.) that produce EMF. In Figure 36, a TLC2654 packaged in a 14-pin plastic package (N package) was placed
in an oven at 25°C at t = 0, biased up, and allowed to stabilize. At t = 3 min, the oven was turned on and allowed
to rise in temperature to 125°C. As evidenced by the curve, the overall change in input offset voltage with
temperature is less than the specified maximum limit of 0.05 µV/°C.
– Input Offset Voltage –
– 12
– 15
4
– 18
0 3 6 9 12 15 18
– 4
– 8
0
t – Time – min
8
21 24 27 30
0.1 µF
0.1 µF
50 kΩ
5 V
–5 V
50 kΩ
100 Ω
V
O
V
IO
= V
O
/1000
0
– 0.04
0.04
+
–
V
IO
Vµ
aVIO – Temperature Coefficient of
Input Offset Voltage – uV/C
α
VIO
V/µ
C
°
IN–
IN+
4
5
OUT
10– 0.08
– 0.12
– 0.16
– 0.2
0.08
Pin numbers shown are for the D (14-pin), J, and N
packages.
Figure 36. Effects of Package-Induced Thermal EMF