Preliminary
RT9541
Li-Ion Battery Protector
Features
General Description
z Low supply current
The RT9541 Series are protection ICs for over-
charge/discharge of rechargeable one-cell Lithium-ion
(Li+) batteries by CMOS process.
− Supply current: TYP. 2.0µA
− Standby current (after detecting over-
discharge): Less than 0.2µA
The RT9541 Series can detect over-charge/discharge
of Li+ one-cell and excess load current and charge
current, further include a short circuit protector for
preventing large external short circuit current.
z High accuracy detector threshold
− Over-charge detector: 25mV
− Over-discharge detector: 2.5%
z Built-in protection circuit
− Excess current trip/Short circuit protector in
both charging and discharging direction
z Output delay of over-charge adjustable with
an external capacitor: 75mS at 0.01µF
z Ultra small package: SOT26
Each of these ICs is composed of four voltage
detectors, a reference unit, a hysteresis circuit, and a
bidirectional short circuit protector. Package of SOT-
26 is available.
Ordering Information
Applications
RT9541ꢀ ꢀ ꢀ ꢀ
z Over-charge / Over-discharge Protection for Li+
One-cell Pack
Package type
E : SOT-26 Type I
ER : SOT-26 Type II
z High Precision Protectors for Cellular Phones or
Instruments Using Li+ One-cell Battery
Operating temperature range
C: Commercial standard
See Table 1
Pin Configurations
Part Number
Pin Configurations
TOP VIEW
Typical Application Circuit
RT9541ꢀCE
1. COUT
2. CT
6
5
4
(Plastic SOT-26)
+
R1
3. VSS
4. DOUT
5. VDD
6. V-
100Ω
1
2
3
C1
VDD
0.1µF
TOP VIEW
RT9541
RT9541ꢀCER
CT
V-
C3
(Plastic SOT-26)
1. DOUT
2. V-
6
1
5
2
4
3
0.01µF
COUT
VSS
DOUT
3. COUT
4. CT
5. VDD
6. VSS
R2
C2
1KΩ
0.1µF
DS9541-05 August 2001
www.richtek-ic.com.tw
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