®
VFC101
Synchronized
VOLTAGE-TO-FREQUENCY CONVERTER
FEATURES
DESCRIPTION
● FULL-SCALE FREQUENCY SET BY
The VFC101 voltage-to-frequency converter uses the
proven charge-balance technique with internal digital
logic to control the critical reference integration pe-
riod. Reference timing is derived from an external
clock signal which accurately sets the full-scale fre-
quency. This technique eliminates the errors and drift
from external timing components which are required
with other VFCs.
SYSTEM CLOCK
● MULTIPLE INPUT RANGES:
5V, 8V, 10V Full Scale
● ACCURATE 5V REFERENCE VOLTAGE
● LOW NONLINEARITY:
0.02% max at 100kHz FS
● LOW GAIN DRIFT: 40ppm/°C
Internal resistors provide accurate full-scale input
ranges of 5V, 8V or 10V inputs without external
resistors or trimming. An accurate 5V reference volt-
age output is useful for bridge or sensor excitation.
With simple pin interconnections, it can provide half-
scale offset to allow bipolar input voltages.
APPLICATIONS
● INTEGRATING A/D CONVERTER
● MULTICHANNEL DATA ACQUISITION
● FREQUENCY-TO-VOLTAGE CONVERSION
● VOLTAGE ISOLATION
The open-collector frequency output interfaces easily
to CMOS or TTL circuitry. Output one-shot circuitry
may be used to optimize the output pulse width for
optical couplers or transformers.
The VFC101 is packaged in a surface-mount 20-pin
PLCC (plastic leaded chip carrier) package.
+VCC
2
8
5
4
17
13
14
10kΩ
10kΩ
Integrator
Comparator
Clocked
Logic
Output
One-Shot
7
9
15
16kΩ
4kΩ
1mA
I1
10
6
5V
Reference
–VCC
18
11
–VCC
16
20
12
International Airport Industrial Park
•
Mailing Address: PO Box 11400
Cable: BBRCORP
•
Tucson, AZ 85734
•
Street Address: 6730 S. Tucson Blvd.
• Tucson, AZ 85706
Tel: (520) 746-1111 Twx: 910-952-1111
•
•
•
Telex: 066-6491
•
FAX: (520) 889-1510
•
Immediate Product Info: (800) 548-6132
© 1988 Burr-Brown Corporation
PDS-779B
Printed in U.S.A. October, 1993