AT1457

Features:

• Ideal for Single-Cell (4.1 V or 4.2 V) and Li-Ion or Li-Pol Packs
• Better Than ±1% Voltage Regulation Accuracy With Preset Voltages
• Optional Cell-Temperature Monitoring Before and During Charge
• Integrated Voltage and Current Regulation With Programmable Charge-Current and High or Low-Side Current Sensing
• Charge Status Output for Single or Dual Led or Host Processor Interface
• Automatic Battery-Recharge Feature
• Charge Termination by Minimum Current
• Automatic Low-Power Sleep Mode When VCC is Removed
•Requires Small Number of External Components
• Packaging: 8-Pin MSOP


Application

•1-Cell Lithium-Ion And Lithium-Polymer Charger
• DSC


Pinout

Specifications

Parameter	Symbol	Condition	Rated Value		Unit
			Min.	Max.
Power supply voltage	VCC	-	-0.3	+8	V
Imput voltage	V(BAT)	-	-0.3	VCC+0.3	V
	V(SNS)	-	-0.3	VCC+0.3	V
	V(TS)	-	-0.3	VCC+0.3	V
Sink current (STAT pin)	IOL	not to exceed PD	-	20	mA
Source current (STAT pin)	IOH	not to exceed PD	-	10	mA
Output current (CC pin)	IO(CC)	not to exceed PD	-	40	mA
Total power dissipation	PD	at 25	-	300	mW
Operating free-air temperature range	TA	-	-20	+85
Storage temperature range	Tstg	-	-40	+125
Lead temperature	TL	soldering, 10 s	-	300

Description

The AT1457 series Lithium-Ion (Li-Ion) and Lithium-Polymer (Li-Pol) linear charge ICs are designed for costsensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, and charge-status indication in a single 8-pin IC. MSOP package op-tions are offered to fit a wide range of end applications.

The AT1457 continuously measures battery temperature using an external thermistor. For safety, the AT1457 inhi-bits charge until the battery temperature is within user-defined thresholds.

The AT1457 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the AT1457 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. After conditioning, the AT1457 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the chargeregulation voltage. The AT1457 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating- temperature and supply-voltage ranges. For single cells, the AT1457 is offered in two fixed-voltage versions: 4.1 V, and 4.2 V. Charge stops when the current tapers to the charge termination threshold, I(TERM).The AT1457 automatically restarts the charge if the battery voltage falls below the V(RCH) threshold.