LTC1559-3.3/LTC1559-5 Backup Battery Controller with Fixed Output DESCRIPTION FEATURES The LTC 1559 is a backup battery controller that provides all the functions necessary to implement a backup 3.3V or n Complete Battery Backup System in an SO-8, 5V power supply using a single NiCd cell. It includes a 1.2V 16-Pin GN or SO Package to 3.07V/4.63V boost converter, an intelligent 2-stage n Generates Fixed Backup Voltage (3.07V/4.63V) from battery charger, automatic backup switching and a micro- a Single 1.2V NiCd Button Cell processor reset generator. The boost converter uses a n Automatic Main Supply to Backup Switching synchronous switching architecture to achieve a typical n Minimum 100mW Output Power efficiency of 70%, ensuring maximum backup lifetime n Automatic Fast Recharge of NiCd Battery from a small NiCd cell. n Programmable NiCd Trickle Charge Current n The on-chip NiCd charger uses an internal gas gauge to Smart NiCd Charger Minimizes Recharge Time and minimize fast recharge time and prevent overcharging of Maximizes System Efficiency After Backup n the backup cell, thereby improving system efficiency and Onboard Power-Up and Push-Button Reset extending the life of the backup cell. The LTC1559 also Generator n provides a user programmable trickle charge current to Performs V Supervisory Functions CC n compensate for self-discharge losses in the backup cell. Reset Assertion Guaranteed at V = 1V CC n Short-Circuit Protection The LTC1559s automatic backup switching scheme n Thermal Limiting requires minimum intervention from the host system and provides feedback to the host to minimize system loading U APPLICATIONS in the backup state. Its internal V fault detector and reset CC generator eliminate the need for a separate microproces- n Notebook Computers sor supervisory chip in most applications. n Palmtop Computers/PDAs n Portable Instruments The LTC1559 is available in an SO-8, 16-pin GN or SO n Battery-Powered Systems package. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATION Backup Time vs *L1 V Output Load Current BAK 22m H 800 **BACKUP + 1 8 C1 V = 3.07V BATTERY R1 BAK V 700 1m F SW + NiCd CELL = P-11AAH 1.2V 68k BAK 7 2 C2 GND V (110mA Hrs) NiCd CC 1F 600 3 CTL R2 LTC1559-3.3 100k 500 S1 6 BACKUP SYSTEM RESET 400 4 5 P PS RESET 300 LTC1435 MAIN SYNCHRONOUS 200 Q1 C3 BATTERY BUCK P-MOSFET 100F 4.5V TO 28V REGULATOR Si9424DY 100 V OUT 10V 3.3V AT NORMAL MODE * SUMIDA CD54-22H 3A 0 V BAK 0 510 15 20 25 30 35 ** PANASONIC P-11AAH 33mA (3.07V) AT BACKUP MODE CONSULT LTC1435 DATA SHEET FOR >33mA (3.3V) AT NORMAL MODE V LOAD CURRENT (mA) BAK APPLICATION CIRCUIT INFORMATION 1559 TA01 1559 TA02 1 BACKUP TIME (MINUTES) + U ULTC1559-3.3/LTC1559-5 ABSOLUTE MAXIMUM RATINGS (Note 1) V Output Current ................... Short-Circuit Protected Terminal Voltages BAK Operating Ambient Temperature Range ....... 0 C to 70 C V ........................................................................ 6V CC Junction Temperature .......................................... 125 C V .................................................................... 12V BAK Storage Temperature Range .................. 65 C to 150 C SW ...................................................................... 14V Lead Temperature (Soldering, 10 sec)................... 300 C All Other Pins .............................. 0.3V to V + 0.3V CC SW Input Currents ............................................. 500mA PACKAGE/ORDER INFORMATION TOP VIEW ORDER PART ORDER PART SW 1 16 V NUMBER NUMBER BAK TOP VIEW SW 2 15 V BAK LTC1559CS8-3.3 LTC1559CGN-3.3 PGND 3 14 V SW 1 8 V CC BAK LTC1559CS8-5 LTC1559CGN-5 GND 4 13 BACKUP GND 2 7 V CC LTC1559CS-3.3 CTL 5 12 RESET CTL 3 6 BACKUP LTC1559CS-5 SHDN 6 11 RESET PS 4 5 RESET PS 7 10 NC S8 PART MARKING S8 PACKAGE NC 8 9 LOBAT 8-LEAD PLASTIC SO 155933 T = 125 C, q = 130 C/ W JMAX JA GN PACKAGE S PACKAGE 15595 16-LEAD PLASTIC SSOP 16-LEAD PLASTIC SO T = 125 C, q = 110 C/ W (GN) JMAX JA T = 125 C, q = 110 C/ W (S) JMAX JA Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS V = 1.2V, T = 0 C to 70 C unless otherwise noted. BAT A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Battery Backup Switching V Operating Voltage Range LTC1559-3.3 l 2.900 3.5 V CC LTC1559-5 l 4.400 5.5 V V Backup Battery Cell Voltage l 1.0 1.2 1.5 V BAT I Quiescent Supply Current (Note 2) l 155 250 m A VCC I Peak Inductor Current (Backup) Boost Converter in Low Current Mode (Note 7) l 80 165 225 mA BAT Boost Converter in High Current Mode (Note 7) l 225 330 445 mA I Battery Standby Current V = 0V l 0.1 15 m A BAT(SHDN) CC I Supply Current During Shutdown (Note 3) l 50 m A VCC(SHDN) V V Backup Request/Booster Assertion LTC1559-3.3 l 3.011 3.070 3.127 V BAK(ON) CC Trip Point (Note 4) LTC1559-5 l 4.475 4.625 4.775 V V V Backup Deassertion Trip Point LTC1559-3.3 l 3.061 3.119 3.176 V BAK(OFF) CC (Note 4) LTC1559-5 l 4.550 4.700 4.850 V V Low V Detect (Note 3) l 0.95 1.00 1.05 V LOBAT1 BAT V V UVLO Trip Voltage (Note 4) LTC1559-3.3 l 2.904 3.003 3.102 V UVLO(ON) CC LTC1559-5 l 4.400 4.550 4.700 V V V UVLO Trip Voltage (Note 4) LTC1559-3.3 l 3.061 3.119 3.176 V UVLO(OFF) CC LTC1559-5 l 4.550 4.700 4.850 V 2 U W U W U WW