Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - battery management Charge management Li-Ion SOT 23 6 Surface-mount

General Description

The MAX1736 is a simple, low-cost, single-cell lithium-

ion (Li+) battery charger for small hand-held applica-

tions. When accompanied by a current-limited voltage

source (such as a wall cube), the MAX1736 provides

simple, accurate charging and termination control for

single-cell Li+ batteries. The MAX1736EUT42 is preset

to a 4.2V battery regulation voltage, while the

MAX1736EUT41 is preset to 4.1V.

The MAX1736 initiates charging in one of four ways:

battery insertion, charger power-up, battery voltage

threshold, and by external manipulation of the EN pin.

The device features an internal precharge current

source that safely charges near-dead cells, as well as

input-supply detection that shuts down the MAX1736

when the supply is removed to minimize battery current

drain.

The MAX1736 accepts input voltages up to 22V, mak-

ing it compatible with a wide range of input supplies. It

has a single control input yet offers stand-alone and

microprocessor-controlled operation. The MAX1736 is

packaged in a small SOT23-6 package. An evaluation

kit (EV kit) is available to reduce design time.

________________________Applications

Single-Cell Li+ Portable Applications

Wireless Handsets

Personal Digital Assistants

Digital Cameras

Small Hand-Held Equipment

Self-Charging Battery Packs

Cradle Chargers

Features

♦ Small 6-Pin SOT23 Package

♦ Stand-Alone or µP-Controlled Operation

♦ 0.5% Voltage Set-Point Accuracy

♦ Lowest Power Dissipation

♦ Low 4.7V min Input Voltage

♦ Top-Off Charging to Achieve Full Battery Capacity

♦ No Inductor Required

♦ Safely Precharges Near-Dead Cells

♦ Automatic Power-Down when Input Power

Removed

Note: Requires special solder temperature profile

described in the Absolute Maximum Ratings Section.

MAX1736

SOT23, Single-Cell Li+ Battery

Charger for Current-Limited Supply

________________________________________________________________ Maxim Integrated Products 1

GATE

ENGND

16BATT

5 CT

MAX1736

SOT23

TOP VIEW

Pin Configuration

CURRENT-LIMITED

VOLTAGE SOURCE

GATE

BATT

BATTERY

GND

OFF

MAX1736

PFET

Typical Operating Circuit

19-1662; Rev 1; 10/00

EVALUATION KIT

AVAILABLE

Ordering Information

PART

TEMP.

RANGE

PIN-

PACKAGE

SOT

MARK

MAX1736EUT42-T -40°C to +85°C 6 SOT23-6 AAHO

MAX1736EUT41-T -40°C to +85°C 6 SOT23-6 AANC

For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

Summary of content (8 pages)

PAGE 1
9-1662; Rev 1; 10/00 KIT ATION EVALU E L B AVAILA SOT23, Single-Cell Li+ Battery Charger for Current-Limited Supply ________________________Applications Single-Cell Li+ Portable Applications Wireless Handsets Personal Digital Assistants Digital Cameras Small Hand-Held Equipment Self-Charging Battery Packs Cradle Chargers Features ♦ Small 6-Pin SOT23 Package ♦ Stand-Alone or µP-Controlled Operation ♦ 0.5% Voltage Set-Point Accuracy ♦ Lowest Power Dissipation ♦ Low 4.
PAGE 2
MAX1736 SOT23, Single-Cell Li+ Battery Charger for Current-Limited Supply ABSOLUTE MAXIMUM RATINGS IN, GATE to GND....................................................-0.3V to +26V Operating Temperature Range ...........................-40°C to +85°C BATT, EN, CT to GND ..............................................-0.3V to +6V Storage Temperature Range ..............................-65°C to +150°C GATE to IN................................................................-6V to +0.
PAGE 3
SOT23, Single-Cell Li+ Battery Charger for Current-Limited Supply (VIN = 10V, VBATT = 4.2V for MAX1736EUT42 or 4.1V for MAX1736EUT41, TA = 0°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) PARAMETER CONDITIONS CT Pullup Current MIN -12 TYP MAX -10 -8 UNITS µA Minimum On-Time CCT = 0.33µF 165 ms Minimum Off-Time CCT = 0.33µF 33 ms EN Pullup Resistance 175 350 725 kΩ ELECTRICAL CHARACTERISTICS (VIN = 10V, VBATT = 4.2V for MAX1736EUT42 or 4.
PAGE 4
Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) MINIMUM OFF-TIME 100 0.15 0.10 0.05 0.00 -0.05 -0.10 MAX1736-03 MAX1736-02 5.8 VBATT = 0 5.7 PRECHARGE CURRENT CURRENT (mA) (mA) PRECHARGE MINIMUM ON-TIME 1000 0.20 BATT VOLTAGE DEVIATION (%) MAX1736 toc01 10,000 PRECHARGE CURRENT vs. INPUT VOLTAGE BATT REGULATION VOLTAGE DEVIATION vs. TEMPERATURE MINIMUM ON/OFF-TIMES vs. CCT MINIMUM ON/OFF-TIME (ms) 5.6 VBATT = 1V 5.5 5.4 VBATT = 2V 5.3 5.2 -0.15 0.1 1 5.1 -0.
PAGE 5
SOT23, Single-Cell Li+ Battery Charger for Current-Limited Supply PIN NAME DESCRIPTION 1 IN 2 GATE Gate Drive for External PMOS Pass Element. The PMOS device should have a VGS threshold of 2.5V or less (see Selecting External Components). 3 GND Ground. Connect the battery’s negative terminal to GND. 4 EN Logic-Level Enable Input. Pull low to disable the MAX1736. EN is internally pulled up to VBATT + 100mV through 350kΩ, but draws no current from BATT. 5 CT Charge Time Control.
PAGE 6
MAX1736 SOT23, Single-Cell Li+ Battery Charger for Current-Limited Supply IN EN IN GATE IN VBATT + 100mV 6mA 350k 10µA 1.4V 4.2V (4.1V) STATE MACHINE CT BATT 0.4V 5V REF MAX1736EUT42 (MAX1736EUT41) 2µA GND Figure 1. Functional Diagram Once the switch turns off, it remains off for at least the minimum off-time. After the minimum off-time, the Pchannel MOSFET turns on if the cell voltage is lower than the BATT regulation voltage. A C CT value of 0.33µF sets a minimum off-time of 33ms.
PAGE 7
SOT23, Single-Cell Li+ Battery Charger for Current-Limited Supply MAX1736 CHARGER POWER REMOVED (FROM ANY STATE) (FROM ANY STATE) EN CHARGER POWER PRESENT SHUTDOWN FET: OFF PRECHARGE FET: OFF IOUT = -6mA DISABLED FET: OFF EVERY CYCLE CHARGER POWER PRESENT TOP-OFF FET: PULSED IN DETECTION INTERVAL VBATT > 4.2V VBATT < 2.5V FAST-CHARGE QUAL FET: OFF VBATT < 2.5V TOP-OFF QUAL FET: OFF VBATT ≥ 2.5V EN CHARGER POWER PRESENT FAST-CHARGE FET: ON Figure 2.
PAGE 8
further slow switching edges and prevent transient spikes. CCT sets the minimum on-time and off-time according to the following equations: tON(MIN) = 5 ✕ 105 x CCT CURRENT-LIMITED WALL CUBE (800mA) FDC638P PFET 100k 0.22µF tOFF(MIN) = 1 ✕ 105 x CCT GATE Layout Guidelines The MAX1736 controls the GATE slew rate; consequently, PC board layout is not as sensitive to noise as a high-frequency switching regulator.