Table of Contents

1.0 General Description ..................................................................................................................................... 1

2.0 Key Specifications ........................................................................................................................................ 1

3.0 Features ....................................................................................................................................................... 1

4.0 Applications .................................................................................................................................................. 1

5.0 Typical Application Circuit ............................................................................................................................ 1

6.0 Connection Diagrams and Package Marking .............................................................................................. 3

7.0 LM3655 Pin Description ............................................................................................................................... 3

8.0 Ordering Information .................................................................................................................................... 4

9.0 Operation Description .................................................................................................................................. 4

10.0 Pin Functions ............................................................................................................................................. 4

10.1 V

IN ............................................................................................................................................................ 4

10.2 CELL ........................................................................................................................................................ 4

10.3 RADIO_B+ ............................................................................................................................................... 4

10.4 V

DETECT

................................................................................................................................................... 5

10.5 DISABLE ................................................................................................................................................. 5

10.6 CHEMISTRY ............................................................................................................................................ 5

10.7 HIB_EN .................................................................................................................................................... 5

10.8 HIS_DIS ................................................................................................................................................... 5

10.9 BATT_DETB ............................................................................................................................................ 5

10.10 CHRG_STATE ....................................................................................................................................... 5

10.11 CHRG_DET ........................................................................................................................................... 5

10.12 CNTRL ................................................................................................................................................... 5

10.13 EXT_PWR_ON ...................................................................................................................................... 6

11.0 Charge Control Functions .......................................................................................................................... 6

11.1 GENERAL OPERATION .......................................................................................................................... 6

11.2 EXTERNAL POWER SUPPLY DETECT ................................................................................................. 6

11.2.1 V

DETECT Circuit

................................................................................................................................... 6

11.2.2 Debounce Function ............................................................................................................................ 7

11.2.3 Power Supply Test Pulses ................................................................................................................. 8

11.2.4 Low Cell Voltage Charging (Pre-Charging) ....................................................................................... 9

11.2.5 Full-Rate Charging ........................................................................................................................... 10

11.2.6 Trickle/Top-Off Mode ........................................................................................................................ 11

11.2.7 Peak Detector Function .................................................................................................................... 11

12.0 Discharge Control Functions .................................................................................................................... 12

12.1 GENERAL DESCRIPTION .................................................................................................................... 12

12.2 RADIO+ GENERATION ........................................................................................................................ 12

12.3 UNDER-VOLTAGE CUT-OFF ............................................................................................................... 13

12.4 POWER CUT OPERATION .................................................................................................................. 13

12.5 HIBERNATION MODE .......................................................................................................................... 13

13.0 Safety Functions ...................................................................................................................................... 13

13.1 INPUT OVER-VOLTAGE PROTECTION .............................................................................................. 13

13.1.1 Normal Operation (Q1 Control) ....................................................................................................... 13

13.1.2 Safety Shunt/Crowbar Operation ..................................................................................................... 14

13.1.3 Standby Shunt Mode ....................................................................................................................... 14

13.1.4 Thermal Crowbar Mode ................................................................................................................... 14

13.1.5 Fast Shunt Operation ...................................................................................................................... 14

13.1.6 Shunt Circuit Parametric Specifications .......................................................................................... 14

13.2 SCHOTTKY ELIMINATION MODE (CHARGER INPUT SHORT CIRCUIT/REVERSE CURRENT PRO-

TECTION) ...................................................................................................................................................... 15

13.3 REVERSE CHARGER PROTECTION .................................................................................................. 15

13.4 OUTPUT CURRENT OVERLOAD PROTECTION (“PTC” MODE) ...................................................... 15

13.5 OUTPUT SHORT CIRCUIT CURRENT PROTECTION ....................................................................... 15

14.0 Required External Components ............................................................................................................... 17

14.1 CHARGE PASS TRANSISTOR (Q1) ....................................................................................................17

14.2 DRIVER TRANSISTOR AND BIAS RESISTORS (R2, R3 AND R5) .................................................... 17

14.3 EXTERNAL CHARGER SENSE RESISTOR (R4) ................................................................................ 17

14.4 CAPACITORS ........................................................................................................................................ 17

14.5 FUSE (F1) ............................................................................................................................................. 17

15.0 Electrical Characteristics .......................................................................................................................... 17

15.1 GENERAL SPECIFICATION AND ABSOLUTE MAXIMUM RATINGS

................................................ 17

15.2 PASS DEVICE AND POWER SUPPLY RATINGS ............................................................................... 18

15.3 IC PIN ELECTRICAL CHARACTERISTICS ......................................................................................... 18

www.national.com

2