AD652SQ/883B Analog Devices Inc, AD652SQ/883B Datasheet - Page 9

• Manufacturer Part Number: AD652SQ/883B
• Manufacturer: Analog Devices Inc

Specifications of AD652SQ/883B

• Converter Function: VFC
• Full Scale Frequency: 2000
• Power Supply Requirement: Single/Dual
• Single Supply Voltage (max): 36V
• Single Supply Voltage (min): 12V
• Dual Supply Voltage (typ): ±15V
• Dual Supply Voltage (min): ±6V
• Dual Supply Voltage (max): ±18V
• Operating Temperature (min): -55
• Operating Temperature (max): 125C
• Operating Temperature Classification: Military
• Package Type: CDIP
• Lead Free Status / Rohs Status: Not Compliant

SVFC CONNECTION FOR DUAL SUPPLY, POSITIVE
INPUT VOLTAGES
Figure 8 shows the AD652 connection scheme for the
traditional dual supply, positive input mode of operation. The
As shown in Figure 8, three additional connections are required
The first connection is to short Pin 13 to Pin 8 (Analog Ground
to −V
Figure 21). The pull-up resistor is determined by the following
equation:
These connections ensure proper operation of the 5 V reference.
Tie Pin 16 to Pin 6 (as shown in Figure 21) to ensure that the
integrator output ramps down far enough to trip the
comparator.
The CERDIP-packaged AD652 accepts either a 0 V to 10 V or
0 mA to 0.5 mA full-scale input signal. The temperature drift of
±V
S
range is from ±6 V to ±18 V. When +V
R
S
) and add a pull-up resistor to +V
PULLUP
=
2
V
500
S
−
µA
5
V
V
+
–
IN
C
V
INT
–
+
C
IN
Figure 8. Standard V/F Connection for Positive Input Voltage with Dual Supply
–V
INT
S
S
+V
(as shown in
–V
+V
S
S
S
1
2
3
4
5
6
7
8
S
is lower than 9.0 V,
1
2
3
4
5
6
7
8
20kΩ
SYNCHRONOUS
20kΩ
VOLTAGE-TO-
FREQUENCY
CONVERTER
SYNCHRONOUS
VOLTAGE-TO-
FREQUENCY
CONVERTER
AD652
1mA
AD652
1mA
Figure 9. Negative Voltage Input
Rev. C | Page 9 of 28
REFERENCE
AND
REFERENCE
AND
5V
5V
D
SHOT
ONE
Q
Q
D
SHOT
ONE
Q
Q
FLOP
"D"
CK
the AD652 is specified for a 0 V to 10 V input range using the
internal 20 kΩ resistor. If a current input is used, the gain drift is
degraded by a maximum of 100 ppm/°C (the TC of the 20 kΩ
resistor). If an external resistor is connected to Pin 5 to establish
a different input voltage range, drift is induced to the extent that
the external resistor’s TC differs from the TC of the internal
resistor. The external resistor used to establish a different input
voltage range should be selected to provide a full-scale current
of 0.5 mA (i.e., 10 kΩ for 0 V to 5 V).
SVFC CONNECTIONS FOR NEGATIVE INPUT
VOLTAGES
Voltages that are negative with respect to ground may be used
as the input to the AD652 SVFC. In this case, Pin 7 is grounded
and the input voltage is applied to Pin 6 (see Figure 9). In this
mode, the input voltage can go as low as 4 V above −V
configuration, the input is a high impedance, and only the
20 nA (typical) input bias current of the op amp must be
supplied by the input signal. This is contrasted with the more
usual positive input voltage configuration, which has a 20 kΩ
input impedance and requires 0.5 mA from the signal source.
FLOP
"D"
CK
16
15
14
13
12
11
10
9
16
15
14
13
12
11
10
9
R
+V
L
ANALOG
GND
R
+V
L
S
ANALOG
GND
S
CLOCK
5V
CLOCK
5V
DIGITAL
GND
FREQ
OUT
DIGITAL
GND
FREQ
OUT
S
AD652
. In this