S-19104N10H-M5T1U Datasheet, PDF (15/40 Pages) Seiko Instruments Inc – VOLTAGE DETECTOR WITH SENSE PIN

FOR AUTOMOTIVE 105°C OPERATION BUILT-IN DELAY CIRCUIT (EXTERNAL DELAY TIME SETTING) VOLTAGE DETECTOR WITH SENSE PIN
Rev.1.2_00
S-19104/19106 Series
3. Hysteresis width (V_HYS)
The hysteresis width is the voltage difference between the detection voltage and the release voltage (the voltage at
point B − the voltage at point A = V_HYS in "Figure 21 Timing Chart of S-19104/19106 Series N Type" and
"Figure 23 Timing Chart of S-19104/19106 Series C Type"). Setting the hysteresis width between the detection
voltage and the release voltage, prevents malfunction caused by noise on the input voltage.
4. Release delay time (t_RESET)
The release delay time is the time period from when the input voltage to the SENSE pin exceeds the release
voltage (+V_DET) to when the output from the OUT pin inverts. The release delay time changes according to the
delay capacitor (C_D).
V_SENSE
+V_DET
OUT
t_RESET
Figure 18 Release Delay Time
5. Feed-through current
The feed-through current is a current that flows instantaneously to the VDD pin at the time of detection and release
of a voltage detector. The feed-through current is large in CMOS output product, small in Nch open-drain output
product.
6. Oscillation
In applications where an input resistor is connected (Figure 19), taking a CMOS output (active "L") product for
example, the feed-through current which is generated when the output goes from "L" to "H" (at the time of release)
causes a voltage drop equal to [feed-through current] × [input resistance]. Since the VDD pin and the SENSE pin
are shorted as in Figure 19, the SENSE pin voltage drops at the time of release. Then the SENSE pin voltage
drops below the detection voltage and the output goes from "H" to "L". In this status, the feed-through current stops
and its resultant voltage drop disappears, and the output goes from "L" to "H". The feed-through current is then
generated again, a voltage drop appears, and repeating the process finally induces oscillation.
V_DD
R_A
V_IN
R_B
VDD
SENSE ^OUT
VSS CD
(CMOS output product)
GND
Figure 19 Example for Bad Implementation Due to Detection Voltage Change
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