TK653XX Datasheet, PDF (1/2 Pages) TOKO, Inc – HIGH CURRENT STEP-UP CONVERTER WITH BATTERY MONITOR

ADVANCED INFORMATION
TK653xx
ADVANCED
INFORMATION
FEATURES
HIGH CURRENT STEP-UP CONVERTER WITH
BATTERY MONITOR
APPLICATIONS
s Very Low Quiescent Current (10 µA)
s Extremely Low Operating Current (25 µA)
s Internal Battery Monitor
s Regulates Down to 1.8 V
s Short Circuit Protection
s Synchronous Rectification
s Up To 95% Efficient
s Battery Powered System
s Cellular Telephones
s Pagers
s Personal Communications Equipment
s Radio Controlled Systems
s 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.
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.
Pulse Burst Modulation (PBM) is used to regulate the
voltage at the V_OUT 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
ORDERING INFORMATION
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.
TK653xxM
VIN
LBI/SB
LBO
PVIN
VOUT
SW
GND
PGND
BLOCK DIAGRAM
VIN
GND
VOUT
CONTROL
CIRCUIT
PVIN
SW
TK653xxM
Voltage Code
Tape/Reel Code
LBI/SB
REF
OFF
LBO
BATTERY
MONITOR
PGND
LBO
VOLTAGE CODE
January 1999 TOKO, Inc.
TAPE/REEL CODE
TL: Tape Left
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