TC9402 TELCOM [TelCom Semiconductor, Inc], TC9402 Datasheet - Page 8

• Manufacturer Part Number: TC9402
• Description: VOLTAGE-TO-FREQUENCY/FREQUENCY-TO-VOLTAGE CONVERTERS
• Manufacturer: TELCOM [TelCom Semiconductor, Inc]

C
full-scale frequency (see "Input/Output Relationships"). Glass
film or air trimmer capacitors are recommended because of
their stability and low leakage. Locate as close as possible
to pins 5 and 3.
V
accuracy requirements, 0.05% line and load regulation and
0.1 F disc decoupling capacitors located near the pins are
recommended.
Adjustment Procedure
Full scale may be trimmed by adjusting R
Recommended procedure for a 10kHz full-scale frequency
is as follows:
If adjustments are performed in this order, there should be
no interaction and they should not have to be repeated.
3-294
TC9400
TC9401
TC9402
DD
REF
, V
The exact value is not critical and may be used to trim the
Power supplies of 5V are recommended. For high-
Figure 1 shows a circuit for trimming the zero location.
(1) Set V
(2) Set V
SS
obtain a 10Hz output frequency.
obtain a 10kHz output frequency.
500
400
300
200
100
0
Figure 3.
IN
IN
to 10V and trim either R
to 10 mV and trim the zero adjust circuit to
–1
–2
Recommended C
1 kHz
V REF (V)
–3
100kHz
–4
V DD = +5V
V SS = – 5V
R IN = 1M
V IN = +10V
T A = +25°C
–5
REF
IN
vs V
IN
, V
–6
, V
REF
REF
REF
–7
, or C
, or C
REF
REF
to
FREQUENCY-TO-VOLTAGE CONVERTERS
.
Improved Single Supply V/F Converter
Operation
variable power source is shown in Figure 5. This circuit uses
two Zener diodes to set stable biasing levels for the TC9400.
The Zener diodes also provide the reference voltage, so the
output impedance and temperature coefficient of the Zeners
will directly affect power supply rejection and temperature
performance.
input current. Trimming the reference voltage is not recom-
mended for high accuracy applications unless an op amp is
used as a buffer, because the TC9400 requires a low
impedance reference (see the V
for more information).
logic operating at 12V to 15V. TTL or 5V CMOS logic can be
accommodated by connecting the output pullup resistors to
the +5V supply. An optoisolator can also be used if an
isolated output is required.
A TC9400 which operates from a single 12 to 15V
Full scale adjustment is accomplished by trimming the
The circuit of Figure 5 will directly interface with CMOS
VOLTAGE-TO-FREQUENCY/
TELCOM SEMICONDUCTOR, INC.
REF
pin description section