REV. A
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otherwise under any patent or patent rights of Analog Devices.
a
Voltage-to-Frequency and
Frequency-to-Voltage Converter
ADVFC32
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 Fax: 617/326-8703
FEATURES
High Linearity
60.01% max at 10 kHz FS
60.05% max at 100 kHz FS
60.2% max at 500 kHz FS
Output TTL/CMOS Compatible
V/F or F/V Conversion
6 Decade Dynamic Range
Voltage or Current Input
Reliable Monolithic Construction
MIL-STD-883 Compliant Versions Available
PRODUCT DESCRIPTION
The industry standard ADVFC32 is a low cost monolithic
voltage-to-frequency (V/F) converter or frequency-to-voltage
(F/V) converter with good linearity (0.01% max error at
10 kHz) and operating frequency up to 0.5 MHz. In the V/F
configuration, positive or negative input voltages or currents can
be converted to a proportional frequency using only a few exter-
nal components. For F/V conversion, the same components are
used with a simple biasing network to accommodate a wide
range of input logic levels.
TTL or CMOS compatibility is achieved in the V/F operating
mode using an open collector frequency output. The pullup re-
sistor can be connected to voltages up to 30 volts, or to +15 V
or +5 V for conventional CMOS or TTL logic levels. This resis-
tor should be chosen to limit current through the open collector
output to 8 mA. A larger resistance can be used if driving a high
impedance load.
Input offset drift is only 3ppm of full scale per °C, and full-
scale calibration drift is held to a maximum of 100 ppm/°C
(ADVFC32BH) due to a low T.C. Zener diode.
The ADVFC32 is available in commercial, industrial, and ex-
tended temperature grades. The commercial grade is packaged
in a 14-pin plastic DIP while the two wider temperature range
parts are packaged in hermetically sealed TO-100 cans.
PRODUCT HIGHLIGHTS
1. The ADVFC32 uses a charge balancing circuit technique
(see Functional Block Diagram) which is well suited to high
accuracy voltage-to-frequency conversion. The full-scale
operating frequency is determined by only one precision re-
sistor and capacitor. The tolerance of other support compo-
nents (including the integration capacitor) is not critical.
Inexpensive ±20% resistors and capacitors can be used with-
out affecting linearity or temperature drift.
PIN CONFIGURATION
(TOP VIEW)
“N” Package
“H” Package – TO-100
NC = NO CONNECT
2. The ADVFC32 is easily configured to satisfy a wide range of
system requirements. Input voltage scaling is set by selecting
the input resistor which sets the input current to 0.25 mA at
the maximum input voltage.
3. The same components used for V/F conversion can also be
used for F/V conversion by adding a simple logic biasing net-
work and reconfiguring the ADVFC32.
4. The ADVFC32 is intended as a pin-for-pin replacement for
VFC32 devices from other manufacturers.
5. The ADVFC32 is available in versions compliant with MIL-
STD-883. Refer to the Analog Devices Military Products
Databook or current ADVFC32/883B data sheet for detailed
specifications.
