AD654JRZ Analog Devices Inc, AD654JRZ Datasheet - Page 9

• Manufacturer Part Number: AD654JRZ
• Description: IC V-F CONVERTER MONO 8-SOIC
• Manufacturer: Analog Devices Inc
• Type: Voltage to Frequencyr

Specifications of AD654JRZ

• Frequency - Max: 500kHz
• Full Scale: ±50ppm/°C
• Linearity: ±0.2%
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Frequency: 500kHz
• Linearity %: 0.03%
• Supply Voltage Range: ± 5V To ± 18V
• Digital Ic Case Style: SOIC
• No. Of Pins: 8
• Svhc: No SVHC (18-Jun-2010)
• Operating Temperature Max: 85°C
• Operating Temperature: RoHS Compliant
• Converter Function: VFC
• Full Scale Frequency: 500
• Power Supply Requirement: Single/Dual
• Single Supply Voltage (typ): 5/9/12/15/18/24/28V
• Single Supply Voltage (max): 36V
• Single Supply Voltage (min): 4.5V
• Dual Supply Voltage (typ): ±9/±12/±15V
• Dual Supply Voltage (min): ±5V
• Dual Supply Voltage (max): ±18V
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Package Type: SOIC N
• Full Scale Range: 0kHz To 500kHz
• Rohs Compliant: Yes
• Bandwidth: 0.5MHz
• Base Number: 654
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

REV. B
(0V TO 1V)
+
–
V
IN
1k
D
Figure 11. AD654 VFC as an ADC
A
825
1%
500
20pF
20pF
1
2
3
4
AD654
1 F
10k
6MHz
(0V TO 10V)
NC
V
8
7
6
5
IN
ALE PSEN PROG WR RD
XTAL1
XTAL2
RESET
EA
SS
INT
T0
T1
5V
8.06k
R1
1000pF
V
5V
CC
NC
2k
1k
R2
V
R3
DD
8048
NC
GND
V
R
1k
SS
NC = NO CONNECT
T
DB0
DB7
Figure 12. Frequency Doubler
P10
P17
P20
P27
AD654
TRANSISTOR
PORT 1
PORT 2
BUS
PORT
A
B
C
OFF
–9–
DRIVER
ON
500pF
OSC/
V
V
0
0
5
0
C
T
FREQUENCY DOUBLING
Since the AD654’s output is a square-wave rather than a pulse
train, information about the input signal is carried on both
halves of the output waveform. The circuit in Figure 12 converts
the output into a pulse train, effectively doubling the output
frequency, while preserving the better low frequency linearity of
the AD654. This circuit also accommodates an input voltage
that is greater than the AD654 supply voltage.
Resistors R1–R3 are used to scale the 0 V to +10 V input voltage
down to 0 V to +1 V as seen at Pin 4 of the AD654. Recall that
V
The timing resistor and capacitor are selected such that this 0 V
to +1 V signal seen at Pin 4 results in a 0 kHz to 200 kHz output
frequency.
The use of R4, C1 and the XOR gate doubles this 200 kHz
output frequency to 400 kHz. The AD654 output transistor is
basically used as a switch, switching capacitor C1 between a
charging mode and a discharging mode of operation. The voltages
seen at the input of the 74LS86 are shown in the waveform dia-
gram. Due to the difference in the charge and discharge time
constants, the output pulse widths of the 74LS86 are not equal.
The output pulse is wider when the capacitor is charging due to
its longer rise time than fall time. The pulses should therefore be
counted on their rising, rather than falling, edges.
IN
must be less than V
WAVEFORM DIAGRAM
5V
1000pF
R
2.87k
PU
C1
R4
1k
A
B
SUPPLY
74LS86
FS = 400MHz
V/F OUTPUT
–4 V, or in this case less than 1 V.
C
AD654