S1011 Datasheet, PDF (23/43 Pages) Seiko Instruments Inc – BUILT-IN DELAY CIRCUIT (EXTERNAL DELAY TIME SETTING) VOLTAGE DETECTOR

HIGH-WITHSTAND VOLTAGE BUILT-IN DELAY CIRCUIT (EXTERNAL DELAY TIME SETTING) VOLTAGE DETECTOR
Rev.1.2_00
S-1011 Series
3. Delay circuit
The delay circuit has a function that adjusts the detection delay time (t_RESET) from when the power supply voltage
(V_DD) or SENSE pin voltage (V_SENSE) reaches the detection voltage (−V_DET) or lower to when the output from OUT
pin inverts.
It also has a function that adjusts the release delay time (t_DELAY) from when the power supply voltage (V_DD) or
SENSE pin voltage (V_SENSE) reaches the release voltage (+V_DET) to when the output from OUT pin inverts.
t_RESET is determined by the delay coefficient, the delay capacitor (C_N) and the detection delay time when the CN pin
is open (t_RESET0), and the t_DELAY is determined by the delay coefficient, the delay capacitor (C_P) and the release
delay time when the CP pin is open (t_DELAY0). They are calculated by the equation below.
t_RESET [ms] = Delay coefficient × C_N [nF] + t_RESET0 [ms]
t_DELAY [ms] = Delay coefficient × C_P [nF] + t_DELAY0 [ms]
Operation
Temperature
Ta = +85°C
Ta = +25°C
Ta = −40°C
Min.
2.41
2.41
2.40
Table 19
Delay Coefficient
Typ.
2.85
2.86
2.83
Max.
3.32
3.30
3.25
Operation
Temperature
Ta = −40°C to +85°C
Table 20
Detection Delay Time
when CN Pin is Open (t_RESET0)
Typ.
0.35 ms
Release Delay Time
when CP Pin is Open (t_DELAY0)
Typ.
0.35 ms
Caution 1.
2.
3.
Mounted board layout should be made in such a way that no current flows into or flows from
the CN pin or CP pin since the impedance of the CN pin and CP pin are high, otherwise correct
delay time cannot be provided.
There is no limit for the capacitance of C_N and C_P as long as the leakage current of the
capacitor can be ignored against the built-in constant current value (approximately 300 nA).
The leakage current may cause error in delay time. When the leakage current is larger than the
built-in constant current, no detect or release takes place.
The above equation will not guarantee successful operation. Determine the capacitance of C_N
and C_P through thorough evaluation including temperature characteristics in the actual usage
conditions.
When using an X8R equivalent capacitor, refer to the "2. Detection delay time (t_RESET) vs.
Temperature (Ta)", "3. Detection delay time (t_RESET) vs. Power supply voltage (V_DD)", "5.
Release delay time (t_DELAY) vs. Temperature (Ta)" and "6. Release delay time (t_DELAY) vs.
Power supply voltage (V_DD)" in " Reference Data" for details.
Seiko Instruments Inc.
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