MITSMI MM1421 Datasheet

MITSUMI

Protection of Lithium-Ion Batteries MM1421

Protection of Lithium-Ion Batteries

Monolithic IC MM1421

Outline

This IC is used to protect single-cell lithium-ion batteries. It adopts an ultra-compact package and has the
functions of previous models, with functions for overcharge detection, overdischarge detection and
overcurrent detection. A dead time can be set externally.

Features

1. Overcharge detection voltage accuracy (0°C to 50°C) ±25mV/cell

2. Consumption current (Vcell=3.6V) 10.0µA typ.

3. Consumption current (Vcell=1.9V) 0.1µA typ.

4. Overcharge sensing dead time can be set externally

5. Overdischarge reset reset by charging

Package

SOT-26A

Applications

IC for protection of single-cell lithium-ion batteries.

MITSUMI

Pin Assignment

123

654

SOT-26A

1 VM

2 V

CC

3 TD

4 CO

5 GND

6 DO

MITSUMI

Protection of Lithium-Ion Batteries MM1421

Block Diagram

Note 1 : Overdischarge voltage
Note 2 : Overcharge voltage

Pin Description

Pin No.

Pin Name

Function

1 V

M

Overcurrent detection input pin. Detects discharge current by connection to charging control
FET source pin.
Discharge current = (voltage between V

M

and GND) / (FET 2 ON resistance)

2 VCC Positive power supply pin.
3 TD Overcharge detection dead time setting pin.

4 CO

Charging control FET (N-ch) gate connection pin. An external resistor (910kΩ) is required

between gate and source. Turns off charging control FET (N-ch) for overcharge mode
(during charging) and overdischarge mode. Also, overcharge mode (during discharge)
turns charging control FET (N-ch) ON, and suppresses FET power consumption.

5 GND

Negative power supply pin. Also, negative input pin for battery connected between V

CC and

GND.

6 DO

Discharge control FET (N-ch) gate connection pin. Turns gate OFF for overdischarge
mode and overcurrent mode. Turns gate ON for overcharge mode and normal mode.

(1) Overcharge mode: Battery voltage > overcharge detection voltage
(2) Normal mode: Overdischarge detection voltage < battery voltage <overcharge detection voltage

Discharge current < overcurrent detection level
(3) Overdischarge mode: Overdischarge detection voltage > battery voltage
(4) Overcurrent mode: Discharge current > overcurrent detection level, voltage between V

M and GND =

discharge current FET ON resistance

(discharge/charge control FET)

MITSUMI

Protection of Lithium-Ion Batteries MM1421

MITSUMI

Pin Assignment

Pin No.

Pin name

Equivalent circuit diagram Pin No.

Pin name

Equivalent circuit diagram

1 V

M 5 GND

6 DO

2 V

CC

4 CO

3 TD

Absolute Maximum Ratings

(Ta=25°C)

Item Symbol Ratings Unit

Storage temparature T

STG

-

40~+125 °C

Operating temparature T

OPR

-

20~+70 °C

Supply voltage V

CC max.

-

0.3~+18 V

CO pin voltage V

CO max.

V

CC

-

28~VCC V

V

M pin voltage VVM max.

Allowable loss Pd 200 mW

Recommended Operating Conditions

Item Symbol Ratings Unit

Operating temparature T

OPR

-

20~+70 °C

Power supply voltage V

OP +1.8~+10 V