HT77S10_10 Datasheet, PDF (1/16 Pages) Holtek Semiconductor Inc – High Efficiency Synchronous Step-Up DC/DC Converter

HT77S10/HT77S11
High Efficiency Synchronous Step-Up DC/DC Converter
Features
· Low start-up voltage: 0.7V (Typ.)
· High efficiency: HT77S10: 91% (Typ.)
at I_OUT=200mA, V_IN=2.4V, V_OUT=3.3V
· High output voltage accuracy: ±4%
· Output voltage: 3.3V, 5.0V or Adjustable
Applications
· Battery-powered equipment power source
· Power source for cameras, camcorders, VCRs,
PDAs, pagers, electronic data banks, and
hand-held communication equipment
· Low ripple and low noise
· Ultra low supply current: 20mA (Typ.)
· Low shutdown current: 1mA (Max.)
· Built-in voltage detector
· 8-pin MSOP/SOP packages
· Power source for appliances, which require a higher
operating voltage than that of the application
batteries
General Description
The HT77S11 and HT77S10 are high efficiency PFM
synchronous step-up DC-DC converters. The two de-
vices although functionally similar are different in their
output drive current capabilities. Synchronous rectifica-
tion operation is used to increase device efficiency and
to reduce the external component resulting in reduced
product costs. The converter switching frequency, which
can have a value up to 500KHz, will vary according to
the load demands and according to the input voltage to
keep the output voltage at the required level.
The HT77S11 and HT77S10 have 0.7V start-up voltage,
and will consume a typical quiescent current of 20mA. A
shutdown mode is provided whereby the operating cur-
rent will be reduced a very low value. The output voltage
has two fixed voltages of 3.3V by setting FB to OUT pin
and 5V by setting FB to GND pin, but can also be ad-
justed between a value of 1.8V~5.5V using two external
resistors. With internal voltage detector function, the de-
tected voltage can be set by using dividing resistor.
Selection Table
Part No.
Current Limit
HT77S10
1.0A
HT77S11
0.55A
Package
8MSOP/SOP
Rev. 1.10
1
March 11, 2010