SS6578 Datasheet, PDF (1/11 Pages) List of Unclassifed Manufacturers – HIGH EFFICIENCY STEP DOWN DC/DC CONTROLLER

SS6578
High-Efficiency, Step-Down DC/DC Controller
FEATURES
4V to 18V input voltage operation.
High-efficiency (up to 95%).
Low quiescent current at 90µA.
Pulse-skipping and pulse-frequency modulation.
Inputs-uncommitted current-sense comparator.
Duty-cycle adjustable.
90KHz to 280KHz oscillator frequency.
Power-saving shutdown mode (8µA typical).
Push-pull driver output.
APPLICATIONS
• Notebook 5V/3.3V Main Power
• Step-Down DC/DC Controller Modules.
• Constant-Current Source for Battery Chargers.
DESCRIPTION
The SS6578 is a high performance
step-down DC/DC controller, designed to drive
an external P-channel MOSFET to generate
programmable output voltages. Two main
schemes of Pulse-Skipping and Pulse-Frequency
Modulation are employed to maintain low
quiescent current and high conversion efficiency
under wide ranges of input voltage and loading
condition. The SS6578 delivers 10mA to 2A
of output current with 87%~93% efficiency at
V_IN=9V, V_OUT=5V condition. A current-sense
comparator with both inverting and non-inverting
inputs uncommitted is included to provide the
crucial function of either current-limit protection
or constant-output current control. When the
SS6578 is used in a high-side current-sensing
step-down constant-current source, the efficiency
is typically greater than 90%. Duty-cycle can be
adjusted to greater than 90% by connecting a
resistor from DUTY pin to V_IN. Quiescent current
is about 90µA and can be reduced to 8µA in
shutdown mode. The switching frequency range
of around 90 kHz to 280 kHz allows small size
switching components, which are ideal for battery
powered portable equipment.
ORDERING INFORMATION
PIN CONFIGURATION
SS6578CXXX
Packing
TR: Tape and reel
TB: Tubes
Packaging
S: SO-8
N: PDIP-8
SO-8
TOP VIEW
VIN 1
DUTY 2
SHDN ³
8 CS+
7 CS-
6 DRI
FB 4
Example: SS6578CSTR
à in SO-8 package, shipped in tape and reel packing
5 GND
(PDIP-8 is only available in tubes)
Rev.2.02 4/06/2004
www.SiliconStandard.com
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