S-8351/8352 Series STEP-UP, BUILT-IN / EXTERNAL FET PFM CONTROL SWITCHING www.ablic.com REGULATOR / SWITCHING REGULATOR CONTROLLER ABLIC Inc., 2002-2018 Rev.3.1 00 The S-8351/8352 Series is a CMOS step-up switching regulator controller which mainly consists of a reference voltage source, an oscillation circuit, a comparator and PFM control circuit. The PFM control circuit allows the duty ratio to be automatically switched according to the load (at light load : 50%, at high output current : 75%), enabling products with a low ripple over a wide range, high efficiency, and high output current (A, B, and D type). Products with a fixed duty ratio of 75% are also available (C type). The S-8351 Series can configure a step-up switching regulator with an external coil, capacitor, and diode. A protection circuit turns off the built-in MOS FET when the voltage at the CONT pin exceeds the limit to prevent it from being damaged. In addition to the above features, the small package and low current consumption, makes the S-8351 Series ideal for applications such as the power supply unit of portable equipment. The S-8352 Series, which features an external transistor, is suitable for applications requiring a high output current. Features Low voltage operation : Startup at 0.9 V min. (I = 1 mA) guaranteed OUT Low current consumption : During operation 23.2 A (V = 3.3 V, typ.) OUT During shutdown 0.5 A (max.) Duty ratio : 50 % / 75 % built-in auto-switching-type PFM control circuit (A, B, and D type) 75 % built-in fixed-type PFM control circuit (C type) External parts : Coil, capacitor, and diode Output voltage : Selectable in 0.1 V steps between 2.0 V to 6.5 V (A, B, and C type) Selectable in 0.1 V steps between 1.5 V to 6.5 V (D type) Output voltage accuracy : 2.4% Shutdown function (A type) V / V separate type (D type) DD OUT External transistor type available (S-8352 Series) *1 Lead-free, Sn 100%, halogen-free *1. Refer to Product Name Structure for details. 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 SOT-23-3 SOT-23-5 SOT-89-3 1 STEP-UP, BUILT-IN / EXTERNAL FET PFM CONTROL SWITCHING REGULATOR / SWITCHING REGULATOR CONTROLLER Rev.3.1 00 S-8351/8352 Series Block Diagrams 1. S-8351 Series (1) A Type (With shutdown function) CONT VOUT IC internal power supply Protection circuit V REF PFM + control circuit VSS ON/ OFF Figure 1 (2) B and C Types (Without shutdown function, V / V non-separate type) DD OUT CONT VOUT IC internal power supply Protection circuit V REF PFM + control circuit VSS Figure 2 (3) D Type (V / V separate type) DD OUT CONT VDD VOUT IC internal power supply Protection V REF circuit PFM + control circuit VSS Figure 3 2