Application examples
power-on, short voltage fluctuations do not repetitively reset the system. Delay times of 10 to 20ms or
even up to 500 ms will usually avoid these problems. Owing to an internal limitation of discharge current of
the timing capacitor Ct, there is no upper limit for the size of this capacitor.
3. Application examples
Five versions of this circuit are available:
- TL7705A, TL7705B (Vt = 4.55 V): Application in TTL-systems and micro-
computer systems which require a 5 volt supply (e.g. TMS7000)
- TL7709A (Vt = 7.6 V): Application in microcomputer systems using the
TMS1XXXNLL.
- TL7712A (Vt = 10.8 V): Application in CMOS, microprocessor, and memory
circuits with a 12 volt supply.
- TL7715A (Vt = 13.5 V): Application in circuits which operate with a supply voltage
of 15 V, as is found often in analog circuits.
- TL7702A, TL7702B (Vt = 2.5 V): Application in systems where other supply
voltages are used. The required trigger level my be adjusted with an external
resistor divider at the SENSE input.
Since for most applications the circuits are already adjusted to the appropriate voltage levels, these
devices are easy to use. Figure 5 shows the initialization circuit diagrams for TMS7000 microcomputer
system with supply voltage V = 5 V. The external components required are the decoupling capacitor C
cc
ref
for the reference voltage and the timing capacitor C. The outputs of the TL77xx are open collector outputs.
t
In figure 5 therefore a pull-up resistor is shown at the RESET output to ensure the correct High level.
Figure 5. TL7705A in 5 Volt Microcomputer Applications
Supply voltage Supervisor TL77xx Series
5
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