Rev.1.2_00
ULTRA-SMALL PACKAGE PWM CONTROL, PWM/PFM
SWITCHING CONTROL STEP-UP SWITCHING REGULATOR
S-8353/8354 Series
Seiko Instruments Inc. 1
The S-8353/8354 Series is a CMOS step-up switching
regulator which mainly consists of a reference voltage
source, an oscillation circuit, a power MOS FET, an
error amplifier, a phase compensation circuit, a PWM
controller (S-8353 Series) and a PWM/PFM switching
controller (S-8354 Series).
Simply attaching a coil, capacitor, and diode externally
can configure the step-up switching regulator. In
addition to the above features, the small package and
low power consumption of this series make it ideal for
portable device applications requiring high efficiency.
The S-8353 Series realizes low ripple, high efficiency,
and excellent transient characteristics due to its PWM
controller, which can vary the duty ratio linearly from
0 % to 83 % (from 0 % to 78 % for 250 kHz models),
optimally-designed error amplifier, and phase
compensation circuits.
The S-8354 Series features a PWM/PFM switching
controller that can switch the operation to a PFM
controller with a duty ratio is 15 % under a light load to
prevent a decline in the efficiency due to the IC
operating current.
Features
• Low voltage operation: Start-up is guaranteed from 0.9 V (IOUT=1 mA)
• Low current consumption: During operation: 18.7 µA (3.3 V, 50 kHz, typ.)
During shutdown: 0.5 µA (max.)
• Duty ratio: Built-in PWM/PFM switching control circuit (S-8354 Series)
15 % to 83 % (30 kHz and 50 kHz models), 15 % to 78 % (250 kHz models)
• External parts: Coil, capacitor, and diode
• Output voltage: Can be set in 0.1 V steps between 1.5 and 6.5 V (for VDD/VOUT separate
types) or 2.0 and 6.5 V (for other than VDD/VOUT separate types). Accuracy
of ±2.4%.
• Oscillation frequency: 30 kHz, 50 kHz, and 250 kHz
• Soft start function: 6 ms (50 kHz, typ.)
Applications
• Power supplies for portable equipment such as digital cameras, electronic notebooks, and PDAs
• Power supplies for audio equipment such as portable CD/MD players
• Constant voltage power supplies for cameras, video equipment, and communications equipment
• Power supplies for microcomputers
Packages
Package name Drawing code
Package Tape Reel
SOT-23-3 MP003-A MP003-A MP003-A
SOT-23-5 MP005-A MP005-A MP005-A
SOT-89-3 UP003-A UP003-A UP003-A