PT78ST200 Series 12V 2 Amp Positive Step-Down Integrated Switching Regulator SLTS060A (Revised 6/30/2000) Standard Application • High Efficiency > 87% • Wide Input Range • Aluminum Heatsink for Applications with Airflow • Self-Contained Inductor • Short Circuit Protection • Over-Temperature Protection • Pin Compatible with Linear 3-Terminal, “78” Series Regulators • Small Footprint The Power Trends’ PT78ST200 is a series of 3-terminal Integrated Switching Regulators (ISRs) that can supply up to 24 watts of regulated 12V power. With a surge capability of 3 Amps and an output voltage that is laser trimmed, it is ideal for inductive load applications such as disk drive motors. Pin-Out Information Ordering Information Pin Function 1 Vin 2 GND Vout 3 Vin 1 PT78ST200 C1 2 Y Output Voltage Package Suffix 12 = 12.0 Volts V = Vertical Mount Vout 3 C2 PT78ST2 XX + COM COM C1 = Optional 1µF ceramic C2 = Required 100µF electrolytic Pkg Style 600 Specifications PT78ST200 SERIES Characteristics (Ta = 25°C unless noted) Symbols Conditions Min Typ Max Units Output Current Io Over Vin range With forced air cooling 0.1* — 2.0 A Short Circuit Current Isc Vin = Vin min — 5.0 — Apk Input Voltage Range Output Voltage Tolerance Vin ∆Vo 0.1 ≤ Io ≤ 2.0A Over Vin range, Io= 2.0A Ta= 0°C to +60°C 16 — 28 V — ±1.0 ±2.0 %Vo Line Regulation Regline Over Vin range — ±0.4 ±0.8 %Vo Load Regulation Regload 0.1 ≤ Io ≤ 2.0A — ±0.2 ±0.4 %Vo Vo Ripple/Noise Vn Vin=17V, Io=2.0A, Vo=12V — 120 — mVpp Transient Response (with 100µF output cap) ttr 50% load change Vo over/undershoot — — 100 5.0 — — µSec %Vo Efficiency η Vin=17V, Io=2.0A — 87 — % Switching Frequency ƒo Over Vin and Io ranges 0.95 1.0 1.05 MHz Absolute Maximum Operating Temperature Range Ta — -40 — +65 °C Recommended Operating Temperature Range Ta Free Air Convection, (40-60LFM) at Vin= 24V, Io=2A -40 — +55** °C Thermal Resistance θja Free Air Convection, (40-60LFM) — 35 — °C/W Storage Temperature Ts — -40 — +125 °C Mechanical Shock — Per Mil-STD-883D, Method 2002.3 — 500 — G’s Mechanical Vibration — Per Mil-STD-883D, Method 2007.2, 20-2000 Hz, Soldered in a PC board — 10 — G’s Weight — — — 11 — Grams *ISR will operate down to no load with reduced specifications. **See Thermal Derating chart. Note: The PT78ST200 Series requires a 100µF electrolytic or tantalum output capacitor for proper operation in all applications. For technical support and more information, see inside back cover or visit www.ti.com/powertrends Typical Characteristics PT78ST200 Series 12V 2 Amp Positive Step-Down Integrated Switching Regulator PT78ST212 12.0 VDC (See Note 1) Efficiency vs Output Current 100 Efficiency - % 90 Vin 80 16.0V 18.0V 21.0V 24.0V 28.0V 70 60 50 40 0 0.5 1 1.5 2 Iout-(Amps) Ripple vs Output Current 100 Ripple-(mV) 80 Vin 28.0V 24.0V 21.0V 18.0V 16.0V 60 40 20 0 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 Iout-(Amps) Thermal Derating (Ta) (See Note 2) 45°C 2 1.8 55°C 65°C 1.6 Iout-(Amps) 1.4 1.2 1 0.8 0.6 0.4 0.2 0 16 18 20 22 24 26 28 Vin-(Volts) Power Dissipation vs Output Current 3.5 3 PD-(Watts) 2.5 Vin 28.0V 24.0V 21.0V 18.0V 16.0V 2 ‘ 1.5 1 0.5 0 0 0.5 1 1.5 2 Iout-(Amps) Note 1: All data listed in the above graphs, except for derating data, has been developed from actual products tested at 25°C. This data is considered typical data for the ISR. 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