TK65020 Datasheet, PDF (1/14 Pages) TOKO, Inc – STEP-UP VOLTAGE CONVERTER

ADVANCED INFORMATION
TK65020
ADVANCED
INFORMATION
STEP-UP VOLTAGE CONVERTER
FEATURES
APPLICATIONS
s Guaranteed 0.9 V Operation
s Very Low Quiescent Current
s Internal Bandgap Reference
s High Efficiency MOS Switching
s Low Output Ripple
s Laser-Trimmed Output Voltage
s Laser-Trimmed Oscillator
s Undervoltage Lockout
s Regulation by Pulse Burst Modulation (PBM)
s Battery Powered Systems
s Cellular Telephones
s Pagers
s Personal Communications Equipment
s Portable Instrumentation
s Portable Consumer Equipment
s Radio Control Systems
DESCRIPTION
The TK65020 low power step-up DC-DC converter is
designed for portable battery-powered systems, capable
of operating from a single battery cell down to 0.9 V. The
TK65020 provides the power switch and the control circuit
for a boost converter. The converter takes a DC input and
boosts it up to a regulated 2.5 V output .
taken to achieve reliability through the use of Oxide,
double Nitride passivation. The TK65020 is available in a
miniature 6-pin SOT-23L-6 surface mount package.
For other output levels, please refer to the TK651xx and
TK652xx Toko series of step-up converters.
The output voltage is laser-trimmed. An internal
Undervoltage Lockout (UVLO) circuit is utilized to prevent
the inductor switch from remaining in the “on” mode when
the battery voltage is too low to permit normal operation.
Pulse Burst Modulation (PBM) is used to regulate the
voltage at the V_OUT pin of the IC. PBM is the process in
which an oscillator signal is gated or not gated to the switch
drive each period. The decision is made just before the
start of each cycle and is based on comparing the output
voltage to an internally-generated bandgap reference.
The decision is latched, so the duty ratio is not modulated
within a cycle. The average duty ratio is effectively
modulated by the “bursting” and skipping of pulses which
can be seen at the SW pin of the IC. Special care has been
TK65020
VIN
20P
GND
SW
NC
GND
VOUT
BLOCK DIAGRAM
SW
VOUT
ORDERING INFORMATION
TK65020MTL
VIN
Tape/Reel Code
Vref
UVLO
CONTROL
CIRCUIT
NC
OSCILLATOR
January 1999 TOKO, Inc.
TAPE/REEL CODE
TL: Tape Left
GND
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