tc9400 Microchip Technology Inc., tc9400 Datasheet - Page 7

• Manufacturer Part Number: tc9400
• Description: Voltage-to-frequency / Frequency-to-voltage Converters
• Manufacturer: Microchip Technology Inc.

2.6
This output is an open-drain N-channel FET, which
provides a pulse waveform whose frequency is propor-
tional to the input voltage. This output requires a pull-
up resistor and interfaces directly with MOS, CMOS,
and TTL logic (see
2.7
The sources of both the FREQ/2 OUT and the PULSE
FREQ OUT are connected to this pin. An output level
swing from the drain voltage to ground, or to the V
supply, may be obtained by connecting this pin to the
appropriate point.
2.8
This output is an open-drain N-channel FET, which
provides a square-wave one-half the frequency of the
pulse frequency output. The FREQ/2 OUT output will
change state on the rising edge of PULSE FREQ OUT.
This output requires a pull-up resistor and interfaces
directly with MOS, CMOS, and TTL logic.
FIGURE 2-1:
© 2007 Microchip Technology Inc.
F
Amp Out
OUT
F
Note 1: To adjust F
OUT
/2
Pulse Freq Out
Output Common
Freq/2 Out
2: To adjust F
3: To increase F
4: For high performance applications, use high stability components for R
resistors and glass capacitors). Also, separate output ground (Pin 9) from input ground (Pin 6).
Figure
Output Waveforms.
MIN
MAX
2-1).
1/f
OUTMAX
, set V
, set V
IN
3 ms
Typ.
IN
to 100 kHz, change C
= 10 mV and adjust the 50 kΩ offset for 10 Hz output.
= 10V and adjust R
SS
IN
REF
or V
to 2 pF and C
2.9
In the V/F mode, this input is connected to the AMPLI-
FIER OUT output (Pin 12) and triggers a 3 µs pulse
when the input voltage passes through its threshold. In
the F/V mode, the input frequency is applied to this
input.
The nominal threshold of the detector is half way
between the power supplies, or (V
mV. The TC9400’s charge balancing V/F technique is
not dependent on a precision comparator threshold,
because the threshold only sets the lower limit of the op
amp output. The op amp’s peak-to-peak output swing,
which determines the frequency, is only influenced by
external capacitors and by V
2.10
This pin is the output stage of the operational amplifier.
During V/F operation, a negative going ramp signal is
available at this pin. In the F/V mode, a voltage
proportional to the frequency input is generated.
REF
for 10 kHz output.
TC9400/9401/9402
Threshold Detector Input
Amplifier Out
INT
to 75 pF.
IN
, C
REF
REF
.
. V
DD
REF
DS21483D-page 7
V REF
0V
+ V
(metal film
SS
C REF
C INT
)/2 ±400