TLC770X Datasheet, PDF (14/27 Pages) Texas Instruments – BiCMOS SUPPLY VOLTAGE SUPERVISORS

input IN, then only one transistor will be conducting, and no lateral current flows through the circuit. With input levels
that are between the specified High and Low levels, a current flows between the supply voltage V_DD and Ground.
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voltage at CONTROL-input [V]
Figure 11. Dependence of the lateral current at the CONTROL input on the input voltage (V_DD=5V)
The typical current consumption of a TLC770X is only 10 µA, whereas the lateral current can be about 100x higher.
With some applications (see Section 5, Figure 21.) undefined levels may exists at the CONTROL input. In order to
prevent the CONTROL input from causing an increase of current consumption, it is inhibited as a result of internal
circuitry if the RESET − Output is active; that is, when a Low level is applied to the input RESIN , or the voltage at
the SENSE input is below the threshold voltage V_t .
In the quiescent state, the input RESIN must be at a High level, and the input CONTROL at Low.
With supply voltages of less than the threshold voltage V_t of the MOS transistors ( V_t ≈ 1V ), the device can not
operate, and in this situation it is not possible to say what the voltage level at the output will be. Although with this
order of voltage no definite function can be expected from the circuit being monitored, this does not mean any
restriction in practice. With a supply voltage above 1 V there will be a Low level at the RESET output, provided the
input conditions are fulfilled. With a supply voltage of more than 2 V, all parts of the circuit in the TLC770X operate
as specified in the Data Sheet.
In order that the circuit may recognize voltage reductions at the SENSE input, these voltages must be applied for a
certain time period. This time depends on the magnitude of the voltage reductions: the greater these are, the shorter
is the time period needed to start the RESET procedure. Figure 12. shows this relationship.
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