S-8261ABSMD-G3ST2G Seiko Instruments, S-8261ABSMD-G3ST2G Datasheet - Page 18

IC LI-ION BATT PROTECT SOT23-6

S-8261ABSMD-G3ST2G

Manufacturer Part Number
S-8261ABSMD-G3ST2G
Description
IC LI-ION BATT PROTECT SOT23-6
Manufacturer
Seiko Instruments
Datasheet

Specifications of S-8261ABSMD-G3ST2G

Function
Over/Under Voltage Protection
Battery Type
Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
SOT-23-6
Output Voltage
4.28 V
Operating Supply Voltage
1.5 V to 28 V
Maximum Operating Temperature
+ 85 C
Minimum Operating Temperature
- 40 C
Mounting Style
SMD/SMT
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
18
LOW DROPOUT CMOS VOLTAGE REGULATOR
S-8261 Series
Operation
Remark Refer to “ Battery Protection IC Connection Example”.
1. Normal Status
2. Overcurrent Status (Detection of Overcurrent 1, Overcurrent 2 and Load Short-circuiting)
3. Overcharge Status
The S-8261 Series monitors the voltage of the battery connected between VDD pin and VSS pin and the voltage
difference between VM pin and VSS pin to control charging and discharging. When the battery voltage is in the
range from the overdischarge detection voltage (V
voltage is in the range from the charger detection voltage (V
turns both the charging and discharging control FETs on. This status is called the normal status, and in this status
charging and discharging can be carried out freely.
When a battery in the normal status is in the status where the voltage of the VM pin is equal to or higher than the
overcurrent detection voltage because the discharge current is higher than the specified value and the status lasts for
the overcurrent detection delay time, the discharge control FET is turned off and discharging is stopped. This status
is called the overcurrent status.
In the overcurrent status, the VM and VSS pins are shorted by the resistor between VM and VSS (R
However, the voltage of the VM pin is at the V
load is disconnected, the VM pin returns to the V
This IC detects the status when the impedance between the EB+ pin and EB− pin (Refer to Figure 10) increases and
is equal to the impedance that enables automatic restoration and the voltage at the VM pin returns to overcurrent 1
detection voltage (V
When the battery voltage becomes higher than the overcharge detection voltage (V
normal status and the detection continues for the overcharge detection delay time (t
turns the charging control FET off to stop charging. This status is called the overcharge status.
The overcharge status is released by the following two cases ((1) and (2)):
Caution
Caution
(1) When the battery voltage falls below the overcharge release voltage (V
(2) When a load is connected and discharging starts, the S-8261 Series turns the charging control FET on and
Caution 1. If the battery is charged to a voltage higher than the overcharge detection voltage (V
voltage (V
returns to the normal status. Just after the load is connected and discharging starts, the discharging current flows
through the parasitic diode in the charging control FET. At this moment the VM pin potential becomes V
voltage for the parasitic diode, higher than V
detection voltage (V
the S-8261 Series releases the overcharge status.
2. When a charger is connected after the overcharge detection, the overcharge status is not
When a battery is connected to the IC for the first time, discharging may not be enabled. In this
case, short the VM pin and VSS pin or connect the charger to restore the normal condition.
The impedance that enables automatic restoration varies depending on the battery voltage and the
set value of overcurrent 1 detection voltage.
battery voltage does not fall below the overcharge detection voltage (V
is connected, the detection of overcurrent 1, overcurrent 2 and load short-circuiting do not
function until the battery voltage falls below overcharge detection voltage (V
battery has an internal impedance of several dozens of mΩ, the battery voltage drops immediately
after a heavy load that causes overcurrent is connected, and the detection of overcurrent 1,
overcurrent 2 and load short-circuiting function.
released even if the battery voltage is below the overcharge release voltage (V
overcharge status is released when the VM pin voltage goes over the charger detection voltage
(V
HC
CHA
), the S-8261 Series turns the charging control FET on and turns to the normal status.
) by removing the charger.
IOV1
) or lower and the overcurrent status is restored to the normal status.
CU
) and provided that the VM pin voltage is higher than the overcurrent 1 detection voltage,
Seiko Instruments Inc.
DD
SS
potential due to the load as long as the load is connected. When the
SS
potential.
DL
level. When the battery voltage goes under the overcharge
) to the overcharge detection voltage (V
CHA
) to the overcurrent 1 detection voltage (V
CU
) − overcharge detection hysteresis
CU
CU
) or longer, the S-8261 Series
CU
) during charging under the
) even when a heavy load
CU
CU
). Since an actual
), and the VM pin
Rev.5.0
VMS
CU
IOV1
) in the IC.
CL
) and the
).
), the IC
f
_00
, the
The

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