Rev.1.4_00
STEP-UP, PWM CONTROL or PWM / PFM SWITCHABLE
BUILT-IN TRANSISTOR 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
control circuit (S-8353 Series) and a PWM / PFM switching control circuit
(S-8354 Series).
The S-8353/8354 Series can configure the step-up switching regulator with
an external coil, capacitor, and diode. In addition to the above features,
the small package and low current consumption make the S-8353/8354
Series ideal for portable equipment applications requiring high efficiency.
The S-8353 Series realizes low ripple, high efficiency, and excellent
transient characteristics due to its PWM control circuit whose duty ratio
can be varied linearly from 0 to 83% (from 0 to 78% for 250 kHz models),
an excellently 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: Startup at 0.9 V min. (IOUT = 1 mA) guaranteed
• 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 : Selectable in 0.1 V steps between 1.5 and 6.5 V (for VDD / VOUT separate types)
Selectable in 0.1 V steps between 2.0 and 6.5 V (for other than VDD / VOUT separate types)
• Output voltage accuracy : ±2.4%
• Oscillation frequency : 30 kHz, 50 kHz, and 250 kHz selectable
• 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, VCRs, and communication devices
• Power supplies for microcomputers
Packages
Drawing Code
Package Name 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