Battery Backup Switching IC
Description
Battery Backup Switching IC
NJU7287
GENERAL DESCRIPTION The NJU7287 is a battery backup system IC with three regulators, two voltage detectors, a battery switching system and their control circuit.
It switches the regulator output from main power supply source to the backup battery when it detects main power supply drop and also has two voltage detection outputs.
The NJU7287 employs an exclusive sequence on the battery switching system which reduces the battery operation.
Combining the special sequence and its low operating current, it is well-suited for battery backup systems of DSC, DVC and other portable devices.
The NJU7287 is available in small and thin packages of 8-lead MSOP (TVSP) and 12-lead PCSP12-C3.
PACKAGE OUTLINE
NJU7287xRB1 (MSOP8 (TVSP8))
FEATURES
z Low Quiescent Current
:13µA max.
/ Normal operation
:2.
1µA max.
/ Backup
z Low Dropout Voltage
:0.
06V max.
(IRO =3mA) / REG1
:0.
3V max.
(IOUT =23mA) / REG2
:0.
06Vmax.
(ICH=3mA) / REG3
z 3ch(REG1, REG2, REG3) Output Voltage :±2.
0%
———————
z 2ch(CS, RESET) Detection Voltage
: ± 2.
0%
z Exclusive Sequence
z Small Package NJU7287xRB1 : MSOP8 (TVSP8)*
*MEET JEDEC MO-187-DA / THIN TYPE
PIN CONFIGURATION
18 27 36 45
NJU7287xRB1
1.
VSS 2.
VCH
3.
VBAT 4.
CS
———————
5.
RESET 6.
VOUT 7.
VIN 8.
VRO
Ver.
2012-07-18
-1-
NJU7287
SELECTION GUIDE
Device Name
Output Voltage (V)
VRO
VOUT
VCH
CS Voltage (V)
-VDET1
+VDET1
—R—E—S——E—T— Voltage (V)
-VDET2
+VDET2
Switch Voltage (V) VSW1
NJU7287A
3.
000 3.
000 3.
100 4.
000
4.
129
2.
000
2.
096
+VDET1×0.
85
———————
Caution: CS voltage should be set up so that switch voltage (VSW1) may become more than RESET voltage (-VDET2).
Note: The selection range is as follows.
VRO, VOUT, VCH : 2.
3 to 5.
4V (0.
1V Step)
-VDET1
:2.
4 to 5.
3V (0.
1V Step)
-VDET2
:1.
7 to 3.
4V (0.
1V Step)
VSW1
:+VDET1X0.
85
ABSOLUTE MAXIMAM RATINGS
PARAMETER
Main Power Supply Input Voltage
Backup Power Supply Input Voltage
Output Voltage of Voltage Regulator
Output V...
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