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. Note 2: Thermal derating graphs are developed in free air convection cooling of 40-60 LFM. (See Thermal Application Notes.) For technical support and more information, see inside back cover or visit www.ti.com/powertrends I MPORTANT NOTI CE Te xas Instrume nts and its subsidiarie s (TI) re se rve the right to make change s to the ir products or to discontinue any product or se rvice without notice , and advise custome rs to obtain the late st ve rsion of re le vant information to ve rify, be fore placing orde rs, that information be ing re lie d on is curre nt and comple te . All products are sold subje ct to the te rms and conditions of sale supplie d at the time of orde r acknowle dgme nt, including those pe rtaining to warranty, pate nt infringe me nt, and limitation of liability. TI warrants pe rformance of its se miconductor products to the spe cifications applicable at the time of sale in accordance with TI’s standard warranty. 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