— Not Recommended for New Designs — PT7720 Series 17A, 12-V Input “Big-Hammer II” Programmable ISR SLTS048B (Revised 5/21/2002) Features • +12V Bus Input • 5-bit Programmable: 1.3V to 3.5V or 4.5V to 7.6V • High Efficiency • Differential Remote Sense • 27-pin SIP Package • Parallelable with PT7748 17A current booster Description Ordering Information The PT7720 series is a +12-V input, 17-A output, high-performance Integrated Switching Regulator (ISR), housed in a 27-pin SIP package. The 17A capability allows easy integration of the latest highspeed, low-voltage microprocessors and bus drivers into +12V power systems. The output voltage is programmable using a 5-bit code. The output voltage range and code for the PT7721 is compatible with Intel’s Pentium II processor. The PT7720 series has been designed to work in parallel with one or more of the PT7748 current boosters, allowing the output load current capacity to be increased in increments of 17A. A differential remote sense is provided to compensate for voltage drop between the ISR to the load. A 1200µF of output capacitance is required for proper operation. PT7721H PT7722H PT7748H Pin-Out Information = 1.3 to 3.5 Volts = 4.5 to 7.6 Volts = 17-A Booster PT Series Suffix (PT1234 x ) Case/Pin Configuration Order Suffix Package Code * N A C Vertical Horizontal SMD (EJE) (EJF) (EJG) * Previously known as package styles 1000/ 1010. (Reference the applicable package code drawing for the dimensions and PC board layout) Pin Function 1 2 3 4 5 6 7 8 9 10 11 12 13 14 VID0 VID1 VID2 VID3 STBY # VID4 Vin Vin Vin Vin Vin Sense Gnd GND GND Pin 15 16 17 18 19 20 21 22 23 24 25 26 27 Function GND GND GND GND GND Vout Vout Vout Vout Vout Vout Sense Vout Sync Out # For further information, see application notes. Standard Application PROGRAMMING PINS VID0 VID1 VID2 VID3 VID4 VIN REMOTE SENSE (+) 6 4 3 2 1 L1 PT7720 7 - 11 1µH CIN + 26 27 13 - 19 5 V OUT 20 - 25 12 COUT + LOAD SYNC OUT GND STBY* GND REMOTE SENSE (-) Cin = Required 560µF electrolytic (See input filter note) Cout = Required 1200µF electrolytic L1 = Optional 1µH input choke For technical support and more information, see inside back cover or visit www.ti.com PT7720 Series 17 A, 12-V Input “Big-Hammer II” Programmable ISR Programming Information PT7721 VID3 VID2 VID1 VID0 1 1 1 1 1 1 1 0 1 1 0 1 1 1 0 0 1 0 1 1 1 0 1 0 1 0 0 1 1 0 0 0 0 1 1 1 0 1 1 0 0 1 0 1 0 1 0 0 0 0 1 1 0 0 1 0 0 0 0 1 0 0 0 0 VID4=1 Vout 2.0V 2.1V 2.2V 2.3V 2.4V 2.5V 2.6V 2.7V 2.8V 2.9V 3.0V 3.1V 3.2V 3.3V 3.4V 3.5V VID4=0 Vout 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 PT7722 VID4=1 Vout 4.5V 4.6V 4.7V 4.8V 4.9V 5.0V 5.1V 5.2V 5.3V 5.4V 5.5V 5.6V 5.7V 5.8V 5.9V 6.0V VID4=0 Vout 6.1V 6.2V 6.3V 6.4V 6.5V 6.6V 6.7V 6.8V 6.9V 7.0V 7.1V 7.2V 7.3V 7.4V 7.5V 7.6V Logic 0 = Pin 12 potential (remote sense gnd) Logic 1 = Open circuit (no pull-up resistors) VID3 and VID4 may not be changed while the unit is operating. Specifications (Unless otherwise stated, Ta =25°C, V in =12V, Cin =560µF, C out =1200µF, and Io =Iomax) PT7720 SERIES Characteristics Symbols Conditions Min Output Current Io T a = +60°C, 200 LFM, pkg N, T a = +25°C, natural convection, Vo ≤5V Vo ≤5V 0.1 0.1 Output Power Po T a = +60°C, 200 LFM, pkg N, T a = +25°C, natural convection, Vo ≥5V Vo ≥5V — — Input Voltage Range V in 0.1A ≤ Io ≤ 17A Output Voltage Tolerance ∆Vo 0°C ≤ Ta ≤ +60°C Line Regulation Reg line 11V ≤ Vin ≤ 14V (with remote sense) — ±5 ±10 mV Load Regulation Reg load 0.1 ≤ Io ≤ 17A (with remote sense) — ±5 ±10 mV Vo Ripple/Noise Vn — — 50 100 — — mVpp Transient Response with Cout = 1200µF t tr Vos I o step between 7.5A and 15A V o over/undershoot — — 100 200 — — µSec mV Efficiency η I o = 10A — — — — 90 88 85 78 — — — — % 300 350 400 kHz (PT7721) (PT7722) (PT7721) (PT7722) Vo =5.0V Vo = 3.3V Vo = 2.5V Vo = 1.5V Typ (1) (1) Max Units — — 17 (2) 17 (2) A — — 85 85 W 11.0 — 14.0 V Vo–0.03 — — ±1 Vo+0.03 ±2 V %Vo ƒs 11V ≤ Vin ≤ 14V 0.1A ≤ Io ≤ 17A Operating Temperature Range Ta — 0 — +85 (3) °C Storage Temperature Ts — -40 — +125 °C Mechanical Shock Per Mil-STD-883D, Method 2002.3 , 1 msec, Half Sine, mounted to a fixture — TBD — G’s Mechanical Vibration Per Mil-STD-883D, Method 2007.2, 20-2000 Hz, Soldered in a PC board Switching Frequency Weight — Vertical Horizontal — TBD — G’s — — 53 66 — — grams Notes: (1) The ISR will operate down to no load with reduced specifications. Please note that this product is not short-circuit protected. (2) The PT7720 series can be easily paralleled with one or more of the PT7748 Current Boosters to provide increased output current in increments of 17A. (3) See Safe Operating Area curves or contact the factory for the appropriate derating. Output Capacitors: The PT7720 series requires a minimum output capacitance of 1200µF for proper operation. Do not use Oscon type capacitors. The maximum allowable output capacitance is (57,000 ÷ Vout)µF, or 15,000µF, whichever is less. Input Filter: An input inductor is optional for most applications. The input inductor must be sized to handle 7ADC with a typical value of 1µH. The input capacitance must be rated for a minimum of 4 Arms of ripple current when operated at maximum output current and maximum output voltage. Contact an applications specialist for input capacitor selection for applications at other output voltages and output currents. For technical support and more information, see inside back cover or visit www.ti.com Typical Characteristics PT7720 Series 17 A, 12-V Input “Big-Hammer II” Programmable ISR PT7721/PT7722 @Vin =12V Safe Operating Area, Vin=+12V (See Note A) PT7721, Vout=+3.3V, Pkg N) Efficiency vs Output Current 90 Efficiency (%) 90 Vout 80 5.0V 3.3V 2.5V 1.5V 70 60 50 Ambient Temperature (°C) 100 80 0 2 4 6 8 10 12 14 Output Current (A) 16 18 200LFM 60 120LFM 60LFM 50 Nat conv 40 30 0 20 2 4 6 8 10 12 14 16 18 20 Output Current (A) Output Ripple vs Output Current PT7722, Vout=+5.0V, Pkg N) 16 Vout 12 5.0V 3.3V 2.5V 1.5V 10 8 6 4 2 0 Ambient Temperature (°C) 90 14 Ripple (mVpp) Airflow 70 20 40 80 70 Airflow 200LFM 60 120LFM 60LFM 50 Nat conv 40 30 20 0 2 4 6 8 10 12 14 16 18 0 20 Output Current (A) 2 4 6 8 10 12 14 16 18 Output Current (A) Power Dissipation vs Output Current 16 14 Vout 12 Pd (Watts) (See Note B) 5.0V 3.3V 2.5V 1.5V 10 8 6 4 2 0 0 2 4 6 8 10 12 14 16 18 20 Output Current (Amps) Note A: Characteristic data has been developed from actual products tested at 25°C. This data is considered typical data for the Converter. Note B: SOA curves represent the conditions at which internal components are at or below the manufacturer’s maximum operating temperatures For technical support and more information, see inside back cover or visit www.ti.com 20 Application Notes PT7721/22, PT7748 Using the PT7748 17-A Current Booster with the PT7720 Series Programmable ISRs The PT7748 is a 17-A “Current Booster” module for the PT7720 series of regulators. The booster is controlled directly by the regulator, and effectively adds a parallel output stage. This allows the system to run sychronously, providing a low noise solution. Up to four booster modules can be connected to a single regulator. Each booster increases the available output current by 17A. Combinations of a regulator and booster modules can supply power for virtually any multi-processor application. the respective input/output filter notes in the PT7720 product data sheet. 2. The 1-µH filter choke located at the input of each regulator and booster module (Lin) is optional for most applications. If specified, each inductor must be sized to handle 7ADC at full output load. 3. The pin-out of the current booster modules include a number pins identified, “No Connect” (see Table 1). These pins are not connected internally to the module but must be soldered to a pad to preserve the unit’s mechanical integrity. A current booster is not a stand-alone product, and can only operate with a regulator. It is housed in the same package as its compatible regulator, and shares the same mechanical outline. Except for an increase in output current, the overall performance of a PT7720 regulator/booster combination is identical to that of a stand-alone regulator. Refer to the appropriate data sheet for the performance specifications. 4. A similar PCB footprint and trace layout between the regulator and each booster will facilitate current sharing between all modules. Table 1-1; PT7748 Pin-Out Information Pin Function Notes: 1. Each booster requires the same amount of input and output capacitance as recommended for a stand-alone regulator. See the Standard Application schematic and Pin Function Pin Function 1 No Connect 10 Vin 19 GND 2 No Connect 11 Vin 20 Vout 3 No Connect 12 No Connect 21 Vout 4 5 No Connect No Connect 13 GND 14 GND 22 Vout 23 Vout 6 No Connect 15 GND 24 Vout 7 Vin 16 GND 25 Vout 8 9 Vin Vin 17 GND 18 GND 26 No Connect 27 Sync In Figure 1-1; Current Booster Application Schematic PROGRAMMING PINS VID0 VID1 VID2 VID3 VID4 VIN REMOTE SENSE (+) 6 4 3 2 1 Lin 7 - 11 PT7720 1µH CIN 27 + 26 13 - 19 5 VOUT 20 - 25 12 COUT + LOAD STBY* GND GND REMOTE SENSE (-) 27 Lin 7 - 11 1µH CIN + PT7748 20 - 25 13 - 19 COUT + To Additional Boosters For technical support and more information, see inside back cover or visit www.ti.com Application Notes PT7720 Series Pin-Coded Output Voltage Adjustment on the “Big Hammer II” Series ISRs ground (pins 13-19) can also be used for programming, doing so will degrade the load reglation of the product. 4. If active devices are used to ground the voltage control pins, low-level open drain MOSFET devices should be used over bipolar transistors. The inherent Vce(sat) in bipolar devices introduces errors in the device’s internal divider network. Discrete transistors such as the BSS138, 2N7002, or the IRLML2402 are examples of appropriate devices. Power Trends PT7720 series ISRs incorporate pin-coded voltage control to adjust the ouput voltage. The control pins are identified VID0 - VID4 (pins 1, 2, 3, 4, & 6) respectively. When the control pins are left open-circuit, the ISR will regulate at its factory trimmed output voltage. Each pin is internally connected to a precision resistor, which when grounded changes the output voltage by a set amount. By selectively grounding VID0-VID4, the output voltage of each ISR in the PT7720 series ISRs can be programmed in incremental steps over its specified output voltage range. The output voltage ranges offered by these regulators provide a convenient method of voltage selection for many applications. In addition, the program code and output voltage range of the PT7721 model is compatible with the voltage ID specification defined by Intel Corporation for voltage regulator modules (VRMs) used to power Pentium® II microprocessors. Refer to Figure 2-1 below for the connection schematic, and the PT7720 Data Sheet for the appropriate programming code information. Active Voltage Programming: Special precautions should be taken when making changes to the voltage control progam code while the unit is powered. It is highly recommended that the ISR be either powered down or held in standby. Changes made to the program code while Vout is enabled induces high current transients through the device. This is the result of the electrolytic output capacitors being either charged or discharged to the new output voltage set-point. The transient current can be minimized by making only incremental changes to the binary code, i.e. one LSB at a time. A minimum of 100µs settling time between each program state is also recommended. Making non-incremental changes to VID3 and VID4 with the output enabled is discouraged. If they are changed, the transients induced can overstress the device resulting in a permanent drop in efficiency. If the use of active devices prevents the program code being asserted prior to power-up, pull pin 5 (STBY) to the device GND during the period that the input voltage is applied to Vin. Releasing pin 5 will then allow the device output to execute a soft-start power-up to the programmed voltage. Notes: 1. The programming convention is as follows:Logic 0: Logic 1: Connect to pin12 (Remote Sense Ground). Open circuit/open drain (See notes 2, & 4) 2. Do not connect pull-up resistors to the voltage programming pins. 3. To minimize output voltage error, always use pin 12 (Sense Ground) as the logic “0” reference. While the regular Figure 2-1 6 +12V 7-11 1µH (Optional) 4 3 2 1 VID4 - VID0 26 SNS(+) PT7720 Vin STBY 5 Synch Out 27 GND 13-19 Vo 20-25 SNS(-) 12 + Cin STBY COM For technical support and more information, see inside back cover or visit www.ti.com + Cout L O A D Application Notes continued PT7720 Series Using the Standby Function on the PT7720 “Big Hammer II” Programmable ISRs For applications requiring output voltage On/Off control, the PT7720 “Big Hammer” ISRs incorporate a standby function. This feature may be used for power-up/shutdown sequencing, and wherever there is a requirement for the output status of the module to be controlled by external circuitry. The standby function is provided by the STBY* control, pin 5. If pin 5 is left open-circuit the regulator operates normally, providing a regulated output whenever a valid supply voltage is applied to Vin (pins 7-11) with respect to GND (pins 13-19). Connecting pin 5 to ground 1 will set the regulator output to zero volts 2. This places the regulator in standby mode, and reduces the input current to typcially 30mA (50mA max). If a ground signal is applied to pin 5 prior to power-up, the regulator output will be held at zero volts during the period that input power is applied. The standby input must be controlled with an open-collector (or open-drain) discrete transistor (See Figure 3-1). Table 3-1 gives the threshold requirements. Table 3-1 Inhibit Control Threshold 1 Parameter Min Max Disable (VIL) –0.1V 0.3V Notes: 1. The Standby input on the PT7720 regulator series must be controlled using an open-collector (or open-drain) discrete transistor. Do Not use a pull-up resistor. The control input has an open-circuit voltage of about 1.5Vdc. To set the regulator output to zero, the control pin must be “pulled” to less than 0.3Vdc with a low-level 0.1mA sink to ground. Figure 3-1 6 4 3 2 1 26 VID4 - VID0 7-11 +12V Rem Sns (+) 20-25 PT7721 Vin Synch STBY Out 5 27 GND V o =3.3V Vo Rem Sns (–) 13-19 12 + + C in C out Q1 BSS138 Inhibit COM COM Turn-On Time: Turning Q1 in Figure 3-1 off, removes the low-voltage signal at pin 5 and enables the output. Following a brief delay of 5-15ms, the output voltage of the PT7720 series regulators rise to full regulation within 20ms3. Figure 3-2 shows the typical output voltage waveform of a PT7721, following the prompt turn-off of Q1 at time t =0 secs. The output voltage in Figure 3-1 is set to 3.3V by connecting VID0 (pin 1), VID2 (pin 3), and VID3 (pin 4) to the Sense Gnd (pin 12)*. The waveform in Figure 3-2 was measured with a 12-V input source voltage, and 15-A resistive load. Figure 3-2 Vo (2V/Div) 2. When placed in the standby mode, the regulator output discharges the output capacitance with a low impedance to ground. If an external voltage is applied to the output, it will sink current and possibly over-stress the part. 3. The turn-off time of Q1, or rise time of the standby input is not critical on the PT7720 series. Turning Q1 off slowly, over periods up to 100ms, will not affect regulator operation. However, a slow turn-off time will increase both the initial delay and rise-time of the output voltage. L O A D 0 5 10 15 20 t (milli - secs) * Consult the data sheet for details on other VID codes. For technical support and more information, see inside back cover or visit www.ti.com IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using TI components. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third–party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Mailing Address: Texas Instruments Post Office Box 655303 Dallas, Texas 75265 Copyright 2002, Texas Instruments Incorporated