ADVANCED INFORMATION ADVANCED INFORMATION HIGH CURRENT STEP-UP CONVERTER WITH BATTERY MONITOR APPLICATIONS FEATURES ■ ■ ■ ■ ■ ■ ■ TK653xx Very Low Quiescent Current (10 µA) Extremely Low Operating Current (25 µA) Internal Battery Monitor Regulates Down to 1.8 V Short Circuit Protection Synchronous Rectification Up To 95% Efficient ■ ■ ■ ■ ■ ■ Battery Powered System Cellular Telephones Pagers Personal Communications Equipment Radio Controlled Systems Toys DESCRIPTION The TK653xx mid power step-down converter is designed for portable battery powered systems, capable of operating from single Li-ion battery cells or two NiCad battery cells. The TK653xx provides the power switch, synchronous rectifier, and the control circuit for a buck step-down converter. Only three external components are required to complete the step-down conversion. output. The TK653xx utilizes a proprietary control scheme, where the average amplitude of the current pulse is varied depending upon the current loads. The proprietary architecture allows fast transient response and minimal ripple while maintaining ease-of-use and low component count. The TK653xx is available in SOP-8 and DIP-8 packages. The TK653xx provides laser-trimmed output voltages ranging from 1.8 V to 3.3 V. The low resistance MOSFET switch and synchronous rectifier allow average currents up to 800 mA, while maintaining peak efficiencies up to 95%. A low-battery threshold and turn-off threshold can be individually programmed by the user, utilizing a single resistor divider connected to the Low Battery Input (LBI) pin. When the resistively-divided supply voltage on the LBI pin drops below approximately 1.25 V, the Low Battery Output (LBO) pin will become asserted. The dual-function LBI pin can alternatively be used as a Standby (SB) pin. Driving the SB pin low will disable the TK653xx and drop the quiescent current on the input supply to approximately 10 µA. TK653xxM VOUT VIN SW LBI/SB LBO GND PVIN PGND BLOCK DIAGRAM Pulse Burst Modulation (PBM) is used to regulate the voltage at the VOUT pin of the IC. When the output voltage of the TK653xx drops below the regulation threshold, a current pulse is transferred from the input supply to the VIN PVIN GND ORDERING INFORMATION CONTROL CIRCUIT VOUT TK653xxM PGND REF OFF Tape/Reel Code Voltage Code VOLTAGE CODE SW LBI/SB LBO BATTERY MONITOR LBO TAPE/REEL CODE TL: Tape Left January 1999 TOKO, Inc. Page 1 ADVANCED INFORMATION TK653xx PACKAGE OUTLINE Marking Information SOP-8 Marking 0.76 5 e1 8 5.4 1.27 TK653xx 3.9 e 1.27 Recommended Mount Pad 1 0.5 e 1.27 0.42 0.2 + 0.3 1.64 0 ~ 0.25 1.45 4.89 0 ~ 10 4 6.07 + 0.3 0.1 0.12 l Dimensions are shown in millimeters Tolerance: x.x = 0.2 mm (unless otherwise specified) Toko America, Inc. Headquarters 1250 Feehanville Drive, Mount Prospect, Illinois 60056 Tel: (847) 297-0070 Fax: (847) 699-7864 TOKO AMERICA REGIONAL OFFICES Midwest Regional Office Toko America, Inc. 1250 Feehanville Drive Mount Prospect, IL 60056 Tel: (847) 297-0070 Fax: (847) 699-7864 Western Regional Office Toko America, Inc. 2480 North First Street , Suite 260 San Jose, CA 95131 Tel: (408) 432-8281 Fax: (408) 943-9790 Eastern Regional Office Toko America, Inc. 107 Mill Plain Road Danbury, CT 06811 Tel: (203) 748-6871 Fax: (203) 797-1223 Semiconductor Technical Support Toko Design Center 4755 Forge Road Colorado Springs, CO 80907 Tel: (719) 528-2200 Fax: (719) 528-2375 Visit our Internet site at http://www.tokoam.com The information furnished by TOKO, Inc. is believed to be accurate and reliable. However, TOKO reserves the right to make changes or improvements in the design, specification or manufacture of its products without further notice. TOKO does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. No license is granted by implication or otherwise under any patent or patent rights of TOKO, Inc. January 1999 TOKO, Inc. Page 2 © 1999 Toko, Inc. All Rights Reserved IC-xxx-TK653xx 0798O0.0K Printed in the USA