TC9400_06 MICROCHIP [Microchip Technology], TC9400_06 Datasheet - Page 18

• Manufacturer Part Number: TC9400_06
• Description: Voltage-to-Frequency/Frequency-to-Voltage Converters
• Manufacturer: MICROCHIP [Microchip Technology]

TC9400/9401/9402
8.0
In F/V mode, the TC9400 output voltage will occasion-
ally be at its maximum value when power is first
applied. This condition remains until the first pulse is
applied to F
cations, this is not a problem because proper operation
begins as soon as the frequency input is applied.
FIGURE 8-1:
DS21483C-page 18
F
IN
1 kΩ
F/V POWER-ON RESET
IN
. In most frequency measurement appli-
Power-On Operation/Reset
1000 pF
11
(a)
Threshold
Detector
TC9400
14
V
DD
100 kΩ
1 μF
V
DD
3
4
In some cases, however, the TC9400 output must be
zero at power-on without a frequency input. In such
cases, a capacitor connected from Pin 11 to V
usually be sufficient to pulse the TC9400 and provide a
Power-on Reset (see Figure 8-1 (a) and (b)). Where
predictable power-on operation is critical, a more
complicated circuit, such as Figure 8-1 (b), may be
required.
CLRA
A
V
CC
16
B
CD4538
5
V
SS
8
(b)
R
2
© 2006 Microchip Technology Inc.
C
1
Q
6
F
IN
To TC9400
DD
will