S807 Series Seiko Instruments, Inc., S807 Series Datasheet - Page 27

• Manufacturer Part Number: S807 Series
• Description: Series High-Precision Voltage Detector
• Manufacturer: Seiko Instruments, Inc.

HIGH-PRECISION VOLTAGE DETECTOR
S-807 Series



26
Operation
1. Basic operation
(1) When power supply voltage V
(2) When power supply voltage V
(3) When V
(4) V
(5) When V
transistor ON, causing V
input voltage is (RB+RC)/(RA+RB+RC) V
long as V
transistor goes ON, the Pch transistor goes OFF, and V
(a) ON, the comparator input voltage is RB/(RA+RB) V
if a pull-up has been employed.
V
appears at the output.
SS
DD
V
SS
will again be output when V
surpasses -V
V
REF
DD
DD
DD
falls below the minimum operating voltage, the output becomes undefined. However, output will revert to V
rises above +V
remains above the detection voltage -V
RA
RB
RC
DET
-
+
, as long as it does not exceed the release voltage +V
(a)
Figure 13
DD
DET
(high) to appear at the output. With the Nch transistor of Figure 13 (a) off, the comparator
V
DD
DD
(B in Figure 14), the Nch transistor goes OFF, the Pch transistor goes ON, and V
DD
DD
goes below +V
rises above the minimum operating voltage. V
is greater than the release voltage +V
* Parasitic diode
Seiko Instruments Inc.
DD
Pch
Nch
.
DET
OUT
, the output continues to maintain the power supply voltage level, as
*
DET
DD
. When V
SS
.
appears at the output. With the Nch transistor of Figure 13
Hysteresis
width
(V
HYS
DD
)
V
DD
does fall below -V
(1)
V
SS
DET
DET
.
(2)
, the Nch transistor is OFF and the Pch
A
SS
Figure 14
(3)
will continue to be output even when
(4)
B
DET
(5)
(A in Figure 14), the Nch
V
Release voltage(+V
Detection voltage(-V
Minimum operating
voltage
V
Comparator
output
DD
SS
OUT
DET
DET
)
)
DD
DD