PT7778—3.3V 32 Amp Programmable Integrated Switching Regulator SLTS115 (Revised 8/31/2000) Description ble with Intel’s Pentium II Processors. The 32A capability provides the ideal power source for the industry’s latest high-speed, low-voltage µPs, DSPs, and custom VLSI devices. For additional current, the PT7778 may be paralleled with up to two PT7740 32A current boosters. A differential remote sense is provided to compensate for voltage drop between the ISR and load. The PT7778 is a high-output 32A Integrated Switching Regulator (ISR), housed in a 27-pin SIP package, The PT7778 is the 3.3V-input bus version of the PT7779. It includes short circuit protection and requires only 330µF of output capacitance for proper operation. The output voltage of the PT7778 is programmable from 1.3V to 2.05V using a 4-bit input, which is compati- Pin-Out Information Standard Application PROGRAMMING PINS VID0 VID1 VID2 VID3 REMOTE SENSE (+) 4 3 2 1 26 SNS(+) VID3 - VID0 V IN L1 7-11 PT7778 Vin 1µH + SYNC OUT Pin Function 1 VID0 2 VID1 3 VID2 4 VID3 5 STBY*- Stand-by 6 N/C 7 Vin 8 Vin STBY Synch Out 5 27 C IN GND 13-19 Vo SNS(-) 12 V OUT 20-25 + LOAD COUT GND GND REMOTE SENSE (–) STBY* C in = Required 2400µF electrolytic C out = Required 330µF electrolytic L1 = Optional 1µH input choke 9 10 11 12 13 14 Vin Vin Vin Remote Sense Gnd (3) GND Pin Function 15 GND 16 GND 17 GND 18 GND 19 GND 20 Vout 21 Vout 22 Vout 23 Vout 24 Vout 25 Vout 26 Remote Sense Vout 27 Sync Out GND For STBY* pin; open = output enabled; ground = output disabled. Specifications PT7778 Characteristics (T a = 25°C unless noted) Symbols Conditions Min Output Current Io Ta = +60°C, 200 LFM, pkg N Ta = +25°C, natural convection 0.1 0.1 Input Voltage Range Vin 0.1A ≤ I o ≤ 32A Output Voltage Tolerance ∆Vo Vin = +3.3V, Io = 32A –40°C ≤ Ta ≤ +85°C Line Regulation Regline 3.1V ≤ V in ≤ 3.6V, I o = 32A Load Regulation Regload Vin = +3.3V, 0.1 ≤ I o ≤ 32A Vo Ripple/Noise pk-pk Vn Vin = +3.3V, Io = 32A Transient Response with Cout = 330µF ttr Vos Efficiency Switching Frequency Absolute Maximum Operating Temperature Range Storage Temperature Typ Max Units — — 32 31 A 3.1 — 3.6 V Vo-0.03 — Vo+0.03 V — ±10 — mV — ±10 — mV — 50 — mV Io step between 16A and 32A Vo over/undershoot — — 100 200 — — µSec mV η Vin = +3.3V, Io = 20A, Vo = 1.8V — 90 — % ƒo 3.1V ≤ V in ≤ 3.6V 0.1A ≤ I o ≤ 32A 300 350 400 kHz Ta Over V in Range –40 — +85 Ts — -40 — +125 Mechanical Vibration Weight — (1) (1) (2) °C °C Per Mil-STD-883D, Method 2007.2 20-20,000Hz, Soldered in a PC board — 10/15 — G’s Vertical/Horizontal — 53/66 — grams Notes: (1) ISR-will operate down to no load with reduced specifications. (2) Consult the Safe Operating Area curves, or contact the factory for the appropriate derating. (3) If the remote sense ground is not used, pin 12 must be connected to pin13 for optimum output voltage accuracy. External Capacitors: The PT7778 requires a minimum output capacitance of 330µF for proper operation. The PT7778 also requires an input capacitance of 2400µF, which must be rated for a minimum of 2.0Arms of ripple current. For transient or dynamic load applications, additional capacitance may be required. For further information, see the accompanying application note on capacitor selection for this product. Input Filter: An input filter inductor is optional for most applications. The input inductor must be sized to handle 32ADC with a typical value of 1µH. For technical support and more information, see inside back cover or visit www.ti.com/powertrends PT7778—3.3V 32 Amp Programmable Integrated Switching Regulator Ordering Information Programming Information Features • +3.3V Input VID3 VID2 VID1 VID0 • 32A Output (64A with PT7740 Booster) 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 • 4-bit Programmable: 1.3V to 2.05V • High Efficiency • Short Circuit Protection • Differential Remote Sense • 27-pin SIP Package 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 PT7778❏ ❏ = 1.3 to 3.5 Volts Vout For dimensions and PC board layout, see Package Style 1020 and 1030 1.30V 1.35V 1.40V 1.45V 1.50V 1.55V 1.60V 1.65V 1.70V 1.75V 1.80V 1.85V 1.90V 1.95V 2.00V 2.05V PT Series Suffix (PT1234X) Case/Pin Configuration N A C Vertical Through-Hole Horizontal Through-Hole Horizontal Surface Mount Logic 0 = Pin 12 potential (remote sense gnd) Logic 1 = Open circuit (no pull-up resistors) VID3 may not be changed while the unit is operating. T Y P I C A L Performance Characteristics, Vin =3.3V C H A R A C T E R I S T I C S Safe Operating Area Curves (See Note A) Efficiency Vs Output Current PT7778, VIN =3.3V, V O =1.8V 90.0 85.0 80.0 VOUT 75.0 1.8V 1.5V 70.0 65.0 60.0 Ambient Temperature (°C) 90.0 80.0 Efficiency - % (See Note B) 70.0 Airflow 400LFM 200LFM 120LFM Nat conv 60.0 50.0 40.0 30.0 55.0 50.0 20.0 0 4 8 12 16 20 24 28 0.0 32 Iout (A) 4.0 8.0 12.0 16.0 20.0 24.0 28.0 32.0 Iout (A) Output Ripple Vs Output Current 80.0 70.0 Ripple - mV 60.0 VOUT 50.0 1.5V 1.8V 40.0 30.0 20.0 10.0 0.0 0 4 8 12 16 20 24 28 32 Iout (A) Power Dissipation Vs Output Current 16.00 14.00 Pd - Watts 12.00 VOUT 10.00 1.8V 1.5V 8.00 6.00 4.00 2.00 0.00 0 4 8 12 16 20 24 28 32 Iout (A) Note A: Characteristic data has been developed from actual products tested at 25°C. This data is considered typical for the regulator. Note B: Safe Operating Area curves represent conditions at which internal components are at or beow manufacturer’s rated operating temperatures. For technical support and more information, see inside back cover or visit www.ti.com/powertrends IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. 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