PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 1.5-A, WIDE-INPUT ADJUSTABLE SWITCHING REGULATOR FEATURES APPLICATIONS * * * * * * * * * * * 1.5-A Output Current Wide-Input Voltage (7 V to 36 V) / (15 V to 36 V) Wide-Output Voltage Adjust (2.5 V to 12.6 V) / (11.85 V to 22 V) High Efficiency (Up to 95%) On/Off Inhibit Undervoltage Lockout Output Current Limit Overtemperature Shutdown Operating Temperature: -40C to 85C Surface Mount Package Available General-Purpose, Industrial Controls, HVAC Systems, Test and Measurement, Medical Instrumentation, AC/DC Adaptors, Vehicles, Marine, and Avionics DESCRIPTION The PTN78000 is a series of high-efficiency, step-down Integrated Switching Regulators (ISR), that represent the third generation in the evolution of the popular 78ST100 series of products. In new designs it should be considered in place of the 78ST100, PT78ST100, PT5100, and PT6100 series of single in-line pin (SIP) products. The PTN78000 is smaller and lighter than its predecessors, and has either similar or improved electrical performance characteristics. The case-less, double-sided package, also exhibits improved thermal characteristics, and is compatible with TI's roadmap for RoHS and lead-free compliance. Operating from a wide-input voltage range, the PTN78000 provides high-efficiency, step-down voltage conversion for loads of up to 1.5 A. The output voltage is set using a single external resistor. The PTN78000W may be set to any value within the range, 2.5 V to 12.6 V, and the PTN78000H from 11.85 V to 22 V. The output voltage of the PTN78000W can be as little as 2 V lower than the input, allowing operation down to 7 V, with an output voltage of 5 V. The output voltage of the PTN78000H can be as little as 3 V lower than the input, alowing operation down to 15 V, with an output voltage of 12 V. The PTN78000 has undervoltage lockout and an integral on/off inhibit. The modules are suited to a wide variety of general-purpose applications that operate off 12-V, 24-V, or 28-V dc power. STANDARD APPLICATION VI 1 2 PTN78000 (Top View) 3 CI* Ceramic (Required) Inhibit GND VO 5 4 RSET# 0.05 W, 1% (Required) CO* 100 mF Electrolytic (Required) GND * See the Application Information section for capacitor recommendations. The minimum input capacitance is 2.2 mF for PYN78000W, and 9.4 mF (2 x 4.7 mF) for PTN78000H. # RSET is required to adjust the output voltage higher than 2.5 V for PTN78000W, and 11.824 V for PTN78000H. See the Application Information section for values. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright (c) 2004-2005, Texas Instruments Incorporated PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. ORDERING INFORMATION PTN78000 (Basic Model) Output Voltage 2.5 V - 12.6 V Part Number Description Package Designator PTN78000WAH Horizontal T/H EUS Horizontal SMD EUT Horizontal T/H EUS Horizontal SMD EUT PTN78000WAS (1) (2) PTN78000WAZ (3) (2) PTN78000HAH 11.85 V - 22 V (1) (2) (3) PTN78000HAS (1) (2) PTN78000HAZ (3) (2) Standard option specifies Sn/Pb solder pin material. Add a T suffix for tape and reel option on SMD packages. Lead (Pb) - free option specifies Sn/Ag solder pin material. ABSOLUTE MAXIMUM RATINGS (1) over operating free-air temperature range unless otherwise noted all voltages with respect to GND (pin 1), UNIT TA Operating free-air temperature Over VI range Solder reflow temperature Surface temperature of module body or pins Tstg Storage temperature VI Input surge voltage, 10 ms maximum VINH Inhibit (pin 3) input voltage PO Output power (1) -40C to 85 C Horizontal SMD (suffix AS) 235 C Horizontal SMD (suffix AZ) 260 C -40 C to 125 C 38 V -0.3 V to 5 V VO 15 volts 22.5 W Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. RECOMMENDED OPERATING CONDITIONS VI Input voltage TA Operating free-air temperature MIN MAX PTN78000W 7 36 PTN78000H 15 36 -40 85 UNIT V C PACKAGE SPECIFICATIONS PTN78000x (Suffix AH, AS, and AZ) Weight 2 grams Flammability Meets UL 94 V-O Mechanical shock Per Mil-STD-883D, Method 2002.3, 1 ms, 1/2 sine, mounted Mechanical vibration Mil-STD-883D, Method 2007.2, 20-2000 Hz (1) 2 Qualification limit. 500 Gs (1) Horizontal T/H (suffix AH) 20 Gs (1) Horizontal SMD (suffix AS and AZ) 15 Gs (1) PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 ELECTRICAL CHARACTERISTICS operating at 25C free-air temperature, VI = 20 V, VO = 5 V, IO = IO (max), CI = 2.2 F, CO = 100 F (unless otherwise noted) PARAMETER PTN78000W TEST CONDITIONS MIN TYP IO Output current TA = 85C, natural convection airflow VI Input voltage range Over IO range Set-point voltage tolerance TA = 25C Temperature variation -40C to +85C Line regulation Over VI range 10 Load regulation Over IO range 10 Total output voltage variation Includes set point, line, load -40C < TA < 85C VO VO Adj 0 7 (1) UNIT 1.5 A 36 (2) V 2% (3) 0.5% 20 MHz bandwith Current limit threshold VO = -50 mV mV (3) VI < 12 V 2.5 VI - 2 12 V VI 15.1 V 2.5 VI - 2.5 15.1 V < VI 25 V 2.5 12.6 VI > 25 V 0.1 x VI V 12.6 VI = 24 V, RSET = 732 , VO = 12 V 91% VI = 15 V, RSET = 21 k, VO = 5 V 86% VI = 15 V, RSET = 78.7 k, VO = 3.3 V Output voltage ripple mV 3% Output voltage adjust range Efficiency IO (LIM) MAX 82% 1% VO V(PP) 3.2 A 1 A/s load step from 50% to 100% IOmax Transient response UVLO Undervoltage lockout Recovery time 100 s VO over/undershoot 2.5 %VO VI increasing 5.5 VI decreasing 5.2 Input high voltage (VIH) Inhibit control (pin 3) Input low voltage (VIL) 1 Pin 3 connected to GND FS Switching frequency Over VI and IO ranges CI External input capacitance Ceramic 2.2 (5) Nonceramic 100 (6) CO External output capacitance MTBF (1) (2) (3) (4) (5) (6) (7) Calculated reliability Per Telcordia SR-332, 50% stress, TA = 40C, ground benign 0.3 440 550 mA 660 (7) 8.9 kHz F 200 10 V mA 17 Ceramic Equiv. series resistance (nonceramic) (4) -0.25 Input standby current (STBY) Open -0.1 Input low current (IIL) II V F m 106 Hr For output voltages less than 10 V, the minimum input voltage is 7 V or (VO + 2) V, whichever is greater. For output voltages of 10 V and higher, the minimum input voltage is (VO + 2.5) V. See the Application Information section for further guidance. For output voltages less than 3.6 V, the maximum input voltage is 10 x VO . See the Application Information section for further guidance. The set-point voltage tolerance is affected by the tolerance and stability of RSET. The stated limit is unconditionally met if RSET has a tolerance of 1% with with 100 ppm/C or better temperature stability. This control pin has an internal pullup, and if left open circuit, the module operates when input power is applied. The open-circuit voltage is typically 1.5 V. A smal,l low-leakage (< 100 nA) MOSFET is recommended for control. See the Application Information section for further guidance. An external 2.2-F ceramic capacitor is required across the input (VI and GND) for proper operation. Locate the capacitor close to the module. 100 F of output capacitance is required for proper operation. See the Application Information section for further guidance. This is the typical ESR for all the electrolytic (nonceramic) capacitance. Use 17 m as the minimum when using maximum ESR values to calculate. 3 PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 ELECTRICAL CHARACTERISTICS operating at 25C free-air temperature, VI = 24 V, VO = 12 V, IO = IO (max), CI = 2x 4.7 F, CO = 100 F (unless otherwise noted) PARAMETER IO Output current PTN78000H TEST CONDITIONS TA = 85C, natural convection airflow MIN VO = 12 V 0.1 VO = 15 V 0.1 VO = 22 V VI VO VO Adj 0.1 15 Set-point voltage tolerance TA = 25C Temperature variation -40C to +85C Line regulation Over VI range 10 Load regulation Over IO range 10 Total output voltage variation Includes set point, line, load -40C < TA < 85C (1) 1 (1) 36 2% UNIT A V (3) 0.5% mV mV 3% Output voltage adjust range (3) VI < 19 V 11.85 VI - 3 19 V VI 25 V 11.85 VI - 4 VI > 25 V 11.85 V 22 VI = 24 V, RSET = 383 k , VO = 12 V 91% VI = 24 V, RSET = 15 k, VO = 15 V 93% VI = 32 V, RSET = 95.3 , VO = 22 V Current limit threshold 1.5 (2) Over IO range Output voltage ripple MAX 1.5 Input voltage range Efficiency IO (LIM) TYP 94% 20 MHz bandwith VO = -50 mV, minimum VI 1% VO V(PP) 2 x IO A (MAX) 1 A/s load step from 50% to 100% IOmax Transient response UVLO Undervoltage lockout Recovery time 200 VO over/undershoot 1 VI increasing 12.2 VI decreasing Input low voltage (VIL) 1 Pin 3 connected to GND FS Switching frequency Over VI and IO ranges CI External input capacitance Ceramic 9.4 (5) Nonceramic 100 (6) External output capacitance CO MTBF (1) (2) (3) (4) (5) (6) (7) 4 Calculated reliability Per Telcordia SR-332, 50% stress, TA = 40C, ground benign 0.3 440 550 mA 660 (7) 8.9 kHz F 200 10 V mA 17 Ceramic Equiv. series resistance (nonceramic) (4) -0.25 Input standby current (STBY) Open -0.1 Input low current (IIL) II V 12 Input high voltage (VIH) Inhibit control (pin 3) s %VO F m 106 Hr The maximum output current is 1.5 A or the maximum output power is 22.5 W, whichever is less. For output voltages less than 19 V, the minimum input voltage is 15 V or (VO + 3) V, whichever is greater. For output voltages of 19 V and higher, the minimum input voltage is (VO + 4) V. See the Application Information section for further guidance. The set-point voltage tolerance is affected by the tolerance and stability of RSET. The stated limit is unconditionally met if RSET has a tolerance of 1% with with 100 ppm/C or better temperature stability. This control pin has an internal pullup, and if left open circuit, the module operates when input power is applied. The open-circuit voltage is typically 1.5 V. A small, low-leakage (< 100 nA) MOSFET is recommended for control. See the Application Information section for further guidance. Two external 4.7-F ceramic capacitors are required across the input (VI and GND) for proper operation. Locate the capacitor close to the module. 100 F of output capacitance is required for proper operation. See the Application Information section for further guidance. This is the typical ESR for all the electrolytic (nonceramic) capacitance. Use 17 m as the minimum when using maximum ESR values to calculate. PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 PIN ASSIGNMENT 1 2 5 PTN78000 (Top View) 4 3 TERMINAL FUNCTIONS TERMINAL NAME NO. I/O DESCRIPTION This is the common ground connection for the VI and VO power connections. It is also the 0 Vdc reference for the Inhibit and VO Adjust control inputs. GND 1 I/O VI 2 I The positive input voltage power node to the module, which is referenced to common GND. I The Inhibit pin is an open-collector/drain active-low input that is referenced to GND. Applying a low-level ground signal to this input disables the module's output and turns off the output voltage. When the Inhibit control is active, the input current drawn by the regulator is significantly reduced. If the Inhibit pin is left open-circuit, the module will produce an output whenever a valid input source is applied. Inhibit 3 VO Adjust 4 O A 1% resistor must be connected between this pin and GND (pin 1) to set the output voltage. If left open-circuit, the output voltage defaults to its minimum adjust value. The temperature stability of the resistor should be 100 ppm/C (or better). The PTN78000W set-point range is 2.5 V to 12.6 V. The PTN78000H set-point range is 11.85 V to 22 V. The standard resistor value for a number of common output voltages is provided in the application information. VO 5 O The regulated positive power output with respect to the GND node. 5 PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 TYPICAL CHARACTERISTICS (7-V INPUT) (1) (2) EFFICIENCY vs OUTPUT CURRENT OUTPUT VOLTAGE RIPPLE vs OUTPUT CURRENT 100 50 VO = 5 V V O - Output Voltage Ripple - mV PP VO = 3.3 V Efficiency - % 90 80 VO = 2.5 V 70 60 50 40 30 VO = 2.5 V 20 VO = 3.3 V 10 VO = 5 V 0 0 0.3 0.6 0.9 1.2 1.5 0 0.3 IO - Output Current - A 0.6 0.9 1.2 IO - Output Current - A Figure 1. Figure 2. POWER DISSIPATION vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT 1 1.5 90 Temperature Derating - C PD - Power Dissipation - W 80 0.8 VO = 2.5 V 0.6 0.4 VO = 5 V VO = 3.3 V 0.2 0.3 0.6 0.9 IO - Output Current - A Figure 3. (2) 6 50 40 20 0 1.2 1.5 Airflow: Nat conv 60 VO 5 V 30 0 (1) 60 LFM 70 0 0.3 0.6 0.9 1.2 1.5 IO - Output Current - A Figure 4. The electrical characteristic data has been developed from actual products tested at 25 C. This data is considered typical for the converter. Applies to Figure 1, Figure 2, and Figure 3. The temperature derating curves represent the conditions at which internal components are at or below the manufacturer's maximum operating temperatures. Derating limits apply to modules soldered directly to a 100 mm x 100 mm double-sided PCB with 2 oz. copper. Applies to Figure 4. PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 TYPICAL CHARACTERISTICS (15-V INPUT) (1) (2) EFFICIENCY vs OUTPUT CURRENT OUTPUT VOLTAGE RIPPLE vs OUTPUT CURRENT 100 V O - Output Voltage Ripple - mV PP VO = 12 V VO = 9 V Efficiency - % 90 80 VO = 5 V 70 VO = 3.3 V 60 VO = 2.5 V 1.5 80 60 VO = 9 V VO = 12 V VO = 5 V 40 20 VO = 3.3 V 0 0.3 0.6 0.9 1.2 VO = 9 V 0.9 0.6 VO = 2.5 V 0.3 0.3 VO = 12 V VO = 2.5 V 0.6 0.9 1.2 Figure 5. 0 0.3 0.6 0.9 1.2 1.5 IO - Output Current - A Figure 6. Figure 7. TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT 90 90 80 80 200 LFM Temperature Derating - C Temperature Derating - C 1.5 IO - Output Current - A IO - Output Current - A 120 LFM 70 60 LFM Nat conv 60 50 40 VO 5 V Airflow: Nat conv 70 60 50 40 VO = 12 V 30 30 20 VO = 3.3 V 0 0 1.5 VO = 5 V 1.2 0 50 20 0 0.3 0.6 0.9 IO - Output Current - A Figure 8. (2) PD - Power Dissipation - W 100 (1) POWER DISSIPATION vs OUTPUT CURRENT 1.2 1.5 0 0.3 0.6 0.9 1.2 1.5 IO - Output Current - A Figure 9. The electrical characteristic data has been developed from actual products tested at 25 C. This data is considered typical for the converter. Applies to Figure 5, Figure 6, and Figure 7. The temperature derating curves represent the conditions at which internal components are at or below the manufacturer's maximum operating temperatures. Derating limits apply to modules soldered directly to a 100-mm x 100-mm, double-sided PCB with 2 oz. copper. Applies to Figure 8 and Figure 9. 7 PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 TYPICAL CHARACTERISTICS (24-V INPUT) (1) (2) EFFICIENCY vs OUTPUT CURRENT VO - Output Voltage Ripple - mVPP VO = 15 V VO = 12 V 80 VO = 5 V 70 VO = 3.3 V 60 VO = 2.5 V 50 0 0.3 0.6 0.9 1.2 120 VO = 12 V 100 VO = 12 V 80 60 VO = 5 V 40 20 0 1.5 0.3 0.6 0.9 1.2 0.5 VO = 2.5 V 0 1.5 0 0.3 0.6 0.9 1.2 1.5 Figure 12. TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT 90 Temperature Derating - C 200 LFM Nat conv 60 LFM 70 120 LFM 60 50 40 VO = 3.3 V 30 80 0.3 0.6 0.9 1.2 IO - Output Current - A 60 LFM 120 LFM 50 40 VO = 5 V 30 0 0.3 0.6 0.9 1.2 IO - Output Current - A 80 Nat conv 70 60 LFM 120 LFM 60 50 40 VO = 12 V 30 20 1.5 0 0.3 0.6 0.9 1.2 IO - Output Current - A Figure 14. 1.5 Figure 15. TEMPERATURE DERATING vs OUTPUT CURRENT 90 Temperature Derating - C Temperature Derating - C 200 LFM 60 1.5 80 200 LFM 120 LFM 70 60 LFM 60 Nat conv 50 40 VO = 15 V 30 20 90 Nat conv 70 20 0 IO- Output Current - A 200 LFM 90 80 60 LFM 120 LFM 70 200 LFM Nat conv 60 50 40 VO = 18 V 30 20 0 0.3 0.6 0.9 1.2 IO- Output Current - A Figure 16. 8 VO = 5 V VO = 3.3 V Figure 11. TEMPERATURE DERATING vs OUTPUT CURRENT (2) 1 Figure 10. Figure 13. (1) VO = 9 V VO = 3.3 V VO = 2.5 V 0 1.5 IO- Output Current - A 80 20 2 VO = 15 V IO- Output Current - A 90 Temperature Derating - C 140 Temperature Derating - C Efficiency - % 90 POWER DISSIPATION vs OUTPUT CURRENT PD- Power Dissipation - W 100 OUTPUT VOLTAGE RIPPLE vs OUTPUT CURRENT 1.5 0 0.2 0.4 0.6 0.8 1 1.2 IO - Output Current - A Figure 17. The electrical characteristic data has been developed from actual products tested at 25 C. This data is considered typical for the converter. Applies to Figure 10, Figure 11, and Figure 12. The temperature derating curves represent the conditions at which internal components are at or below the manufacturer's maximum operating temperatures. Derating limits apply to modules soldered directly to a 100-mm x 100-mm, double-sided PCB with 2 oz. copper. Applies to Figure 13 through Figure 17. PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 TYPICAL CHARACTERISTICS (32-V INPUT) (1) (2) EFFICIENCY vs OUTPUT CURRENT OUTPUT VOLTAGE RIPPLE vs OUTPUT CURRENT 100 70 60 VO = 5 V 50 40 VO = 3.3 V 30 20 0 0.3 0.6 0.9 1.2 VO = 22 V 200 VO = 9 V 150 VO = 12 V 100 VO = 5 V VO = 3.3 V 50 0 0 1.5 IO - Output Current - A VO = 12 V 1.5 1 VO = 5 V VO = 3.3 V 0.5 0 1.5 0.3 0.6 0.9 1.2 IO - Output Current - A 1.5 Figure 19. Figure 20. TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT Temperature Derating - C Temperature Derating - C 2 0 0.3 0.6 0.9 1.2 IO - Output Current - A 90 90 80 200 LFM 120 LFM 70 60 LFM 60 Nat conv 50 40 VO = 3.3 V 30 200 LFM 80 120 LFM 70 Nat conv 60 LFM 60 50 40 VO = 5 V 30 0 VO = 15 V VO = 22 V Figure 18. 90 20 PD - Power Dissipation - W VO = 12 V 80 2.5 250 0.3 0.6 0.9 1.2 IO - Output Current - A Temperature Derating - C Efficiency - % VO = 15 V VO -Output Voltage Ripple - mVPP VO = 22 V 90 POWER DISSIPATION vs OUTPUT CURRENT 200 LFM 70 120 LFM 60 60 LFM Nat conv 50 40 VO = 12 V 30 20 20 1.5 80 0 0.3 0.6 0.9 1.2 IO - Output Current - A 0 1.5 0.3 0.6 0.9 1.2 IO - Output Current - A 1.5 Figure 21. Figure 22. Figure 23. TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT 90 90 90 80 120 LFM 70 60 LFM 60 Nat conv 50 40 VO = 15 V 30 0.3 0.6 0.9 1.2 IO- Output Current - A Figure 24. (2) 120 LFM 60 LFM 60 Nat conv 50 40 VO = 18 V 20 0 200 LFM 70 30 20 (1) 80 Temperature Derating - C Temperature Derating - C Temperature Derating - C 200 LFM 1.5 80 200 LFM 120 LFM 70 60 LFM 60 Nat conv 50 40 VO = 22 V 30 20 0 0.2 0.4 0.6 0.8 1 IO - Output Current - A Figure 25. 1.2 0 0.2 0.4 0.6 0.8 1 IO- Output Current - A Figure 26. The electrical characteristic data has been developed from actual products tested at 25 C. This data is considered typical for the converter. Applies to Figure 18, Figure 19, and Figure 20. The temperature derating curves represent the conditions at which internal components are at or below the manufacturer's maximum operating temperatures. Derating limits apply to modules soldered directly to a 100-mm x 100-mm, double-sided PCB with 2 oz. copper. Applies to Figure 21 through Figure 26. 9 PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 APPLICATION INFORMATION Adjusting the Output Voltage of the PTN78000 Wide-Output Adjust Power Modules General A resistor must be connected between the VO Adjust control (pin 4) and GND (pin 1) to set the output voltage. The adjustment range is from 2.5 V to 12.6 V for PTN78000W. The adjustment range is from 11.85 V to 22 V for PTN78000H. If pin 4 is left open, the output voltage defaults to the lowest value. Table 2 gives the preferred value of the external resistor for several standard voltages, with the actual output voltage that the value provides. For other output voltages, the value of the required resistor can be calculated using Equation 1, and the constants for the applicable product in Table 1. Alternatilvey, RSET can be simply selected from the range of values given in Table 3. Figure 27 shows the placement of the required resistor. 1.25 V VO - Vmin RSET = 54.9 kW - RP (1) Table 1. RSET Formula Constants PRODUCT VMIN RP PTN780x0W 2.5 V 6.49 k PTN780x0H 11.824 V 6.65 k Input Voltage Considerations The PTN78000 is a step-down switching regulator. In order that the output remains in regulation, the input voltage must exceed the output by a minimum differential voltage. (Please refer to the input voltage range requirements in the electrical characteristics table.) Another consideration is the pulse width modulation (PWM) range of the regulator's internal control circuit. For stable operation, its operating duty cycle should not be lower than some minimum percentage. This defines the maximum advisable ratio between the regulator input and output voltage magnitudes. As an example, for satisfactory performance, the operating input voltage range of the PTN78000x must adhere to the following requirements. 1. For PTN78000W output voltages lower than 10 V, the minimum input voltage is (VO + 2 V ) or 7 V, whichever is higher. 2. For PTN78000W output voltages equal to 10 V and higher, the minimum input voltage is (VO + 2.5 V ) . 3. For PTN78000W, the maximum input voltage is (10 x VO ) or 36 V, whichever is less. 4. For PTN78000H output voltages lower than 19 V, the minimum input voltage is (VO + 3 V ) or 15 V, whichever is higher. 5. For PTN78000H output voltages equal to 19 V and higher, the minimum input voltage is (VO + 4 V ) . As an example, Table 2 gives the operating input voltage range for the common output bus voltages. In addition, the Electrical Characteristics define the available output voltage adjust range for various input voltages. Table 2. Standard Values of Rset for Common Output Voltages PRODUCT PTN780x0W PTN780x0H 10 VO (Required) RSET (Standard Value) VO (Actual) Operating VI Range 2.5 V Open 2.5 V 7 V to 25 V 3.3 V 78.7 k 3.306 V 7 V to 33 V 5V 21 k 4.996 V 7 V to 36 V 12 V 732 12.002 V 14.5 V to 36 V 12 V 383 k 12.000 V 15 V to 36 V 15 V 15 k 14.994 V 18 V to 36 V 18 V 4.42 k 18.023 V 21 V to 36 V 22 V 95.3 21.998 V 26 V to 36 V PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 VI 2 PTN78000W VO VI Inh Adj GND 3 VO 5 4 1 CI 2.2 mF RSET 0.05 W 1% (Ceramic) Inhibit GND CO 100 mF (Required) GND (1) A 0.05-W rated resistor may be used. The tolerance should be 1%, with a temperature stability of 100 ppm/C (or better). Place the resistor as close to the regulator as possible. Connect the resistor directly between pins 4 and 1 using dedicated PCB traces. (2) Never connect capacitors from VO Adjust to GND or VO. Any capacitance added to the VO Adjust pin affects the stability of the regulator. Figure 27. PTN78000W VO Adjust Resistor Placement Table 3. PTN78000W Output Voltage Set-Point Resistor Values VO RSET VO RSET VO RSET VO RSET 2.50 V Open 3.7 V 50.7 k 6.1 V 12.6 k 9.0 V 4.07 k 2.55 V 1.37 M 3.8 V 46.3 k 6.2 V 12.1 k 9.2 V 3.75 k 2.60 V 680 k 3.9 V 42.5 k 6.3 V 11.6 k 9.4 V 3.46 k 2.65 V 451 k 4.0 V 39.3 k 6.4 V 11.1 k 9.6 V 3.18 k 2.70 V 337 k 4.1 V 36.4 k 6.5 V 10.7 k 9.8 V 2.91 k 2.75 V 268 k 4.2 V 33.9 k 6.6 V 10.2 k 10.0 V 2.66 k 2.80 V 222 k 4.3 V 31.6 k 6.7 V 9.85 k 10.2 V 2.42 k 2.85 V 190 k 4.4 V 29.6 k 6.8 V 9.47 k 10.4 V 2.20 k 2.90 V 165 k 4.5 V 27.8 k 6.9 V 9.11 k 10.6 V 1.98 k 2.95 V 146 k 4.6 V 26.2 k 7.0 V 8.76 k 10.8 V 1.78 k 3.00 V 131 k 4.7 V 24.7 k 7.1 V 8.43 k 11.0 V 1.58 k 3.05 V 118 k 4.8 V 23.3 k 7.2 V 8.11 k 11.2 V 1.40 k 3.10 V 108 k 4.9 V 22.1 k 7.3 V 7.81 k 11.4 V 1.22 k 3.15 V 99.1 k 5.0 V 21.0 k 7.4 V 7.52 k 11.6 V 1.05 k 3.20 V 91.5 k 5.1 V 19.9 k 7.5 V 7.24 k 11.8 V 889 3.25 V 85.0 k 5.2 V 18.9 k 7.6 V 6.97 k 12.0 V 734 3.30 V 79.3 k 5.3 V 18.0 k 7.7 V 6.71 k 12.2 V 585 3.35 V 74.2 k 5.4 V 17.2 k 7.8 V 6.46 k 12.4 V 442 3.40 V 69.8 k 5.5 V 16.4 k 7.9 V 6.22 k 12.6 V 305 3.45 V 65.7 k 5.6 V 15.6 k 8.0 V 5.99 k 3.50 V 62.1 k 5.7 V 15.0 k 8.2 V 5.55 k 3.55 V 58.9 k 5.8 V 14.3 k 8.4 V 5.14 k 3.60 V 55.9 k 5.9 V 13.7 k 8.6 V 4.76 k 3.65 V 53.2 k 6.0 V 13.1 k 8.8 V 4.40 k 11 PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 VI 2 PTN78000H VO VI Inh C1 4.7 mF C2 4.7 mF (Ceramic) (Ceramic) Adj GND 3 VO 5 1 4 C3 100 mF RSET 0.05 W 1% (Required) Inhibit GND GND (1) A 0.05-W rated resistor may be used. The tolerance should be 1%, with a temperature stability of 100 ppm/C (or better). Place the resistor as close to the regulator as possible. Connect the resistor directly between pins 4 and 1 using dedicated PCB traces. (2) Never connect capacitors from VO Adjust to either GND or VO. Any capacitance added to the VO Adjust pin affects the stability of the regulator. Figure 28. PTN78000H VO Adjust Resistor Placement Table 4. PTN78000H Output Voltage Set-Point Resistor Values 12 VO RSET VO RSET VO RSET 11.85 V 2633 k 13.50 V 34.3 k 17.20 V 6.12 k 11.90 V 896 k 13.65 V 30.9 k 17.40 V 5.66 k 11.95 V 538 k 13.80 V 28.1 k 17.60 V 5.23 k 12.00 V 383 k 13.95 V 25.6 k 17.80 V 4.83 k 12.10 V 242 k 14.10 V 23.5 k 18.00 V 4.46 k 12.15 V 204 k 14.25 V 21.6 k 18.20 V 4.11 k 12.20 V 176 k 14.40 V 19.9 k 18.40 V 3.79 k 12.25 V 154 k 14.55 V 18.5 k 18.60 V 3.48 k 12.30 V 138 k 14.70 V 17.2 k 18.80 V 3.19 k 12.35 V 124 k 14.85 V 16.0 k 19.00 V 2.91 k 12.40 V 113 k 15.00 V 14.9 k 19.20 V 2.65 k 12.45 V 103 k 15.15 V 13.9 k 19.40 V 2.41 k 12.50 V 94.9 k 15.30 V 13.1 k 19.60 V 2.18 k 12.55 V 87.9 k 15.45 V 12.3 k 19.80 V 1.95 k 12.60 V 81.8 k 15.60 V 11.5 k 20.00 V 1.74 k 12.65 V 76.4 k 15.75 V 10.8 k 20.20 V 1.54 k 12.70 V 71.7 k 15.90 V 10.2 k 20.40 V 1.35 k 12.75 V 67.5 k 16.05 V 9.59 k 20.60 V 1.17 k 12.80 V 63.7 k 16.20 V 9.03 k 20.80 V 995 12.85 V 60.2 k 16.35 V 8.51 k 21.00 V 829 k 12.90 V 57.1 k 16.50 V 8.03 k 21.20 V 669 12.95 V 54.3 k 16.65 V 7.57 k 21.40 V 516 13.00 V 51.7 k 16.80 V 7.14 k 21.80 V 229 13.05 V 49.3 k 17.10 V 6.36 k 22.00 V 94 PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 CAPACITOR RECOMMENDATIONS FOR PTN78000 WIDE-OUTPUT ADJUST POWER MODULES PTN78000W Input Capacitor The minimum requirement for the input of PTN78000W is 2.2 F of ceramic capacitance. The dielectric may be either an X5R or X7R temperature characteristic. Ceramic capacitors should be located within 0.5 inch (1,27 cm) of the regulator input pins. Electrolytic capacitors can be used at the input, but only in addition to the required ceramic capacitance. The minimum ripple current rating for any nonceramic capacitance must be at least 650 mArms. The ripple current rating of electrolytic capacitors is a major consideration when they are used at the input. This ripple current requirement can be reduced by placing more ceramic capacitors at the input, in addition to the minimum required capacitance. Tantalum capacitors are not recommended for use at the input bus, as none were found to meet the minimum voltage rating of 2 x (maximum dc voltage + ac ripple). The 2x rating is standard practice for regular tantalum capacitors to ensure reliability. Polymer-tantalum capacitors are more reliable and are available with a maximum rating of typically 20 V. These can be used with input voltages up to 16 V. PTN78000H Input Capacitor The minimum requirement for the input of PTN78000H is 2 x 4.7 F of ceramic capacitance. The dielectric may be either an X5R or X7R temperature characteristic. Ceramic capacitors should be located within 0.5 inch (1,27 cm) of the regulator input pins. Electrolytic capacitors can be used at the input, but only in addition to the required ceramic capacitance. The minimum ripple current rating for any nonceramic capacitance must be at least 350 mArms. The ripple current rating of electrolytic capacitors is a major consideration when they are used at the input. This ripple current requirement can be reduced by placing more ceramic capacitors at the input, in addition to the minimum required capacitance. Tantalum capacitors are not recommended for use at the input bus, as none were found to meet the minimum voltage rating of 2 x (maximum dc voltage + ac ripple). The 2x rating is standard practice for regular tantalum capacitors to ensure reliability. Polymer-tantalum capacitors are more reliable and are available with a maximum rating of typically 20 V. These can be used with input voltages up to 16 V. PTN78000W and PTN78000H Output Capacitors The minimum capacitance required to insure stability is a 100 F. Either ceramic or electrolytic-type capacitors can be used. The minimum ripple current rating for the nonceramic capacitance must be at least 150 mA rms. The stability of the module and voltage tolerances will be compromised if the capacitor is not placed near the output bus pins. A high-quality, computer-grade electrolytic capacitor should be adequate. A ceramic capacitor can be also be located within 0.5 inch (1,27 cm) of the output pin. For applications with load transients (sudden changes in load current), the regulator response improves with additional capacitance. Additional electrolytic capacitors should be located close to the load circuit. These capacitors provide decoupling over the frequency range, 2 kHz to 150 kHz. Aluminum electrolytic capacitors are suitable for ambient temperatures above 0C. For operation below 0C, tantalum or Os-Con type capacitors are recommended. When using one or more nonceramic capacitors, the calculated equivalent ESR should be no lower than 10 m (17 m using the manufacturer's maximum ESR for a single capacitor). A list of capacitors and vendors are identified in Table 5 and Table 6, the recommended capacitor tables. Ceramic Capacitors Above 150 kHz the performance of aluminum electrolytic capacitors becomes less effective. To further reduce the reflected input ripple current, or the output transient response, multilayer ceramic capacitors must be added. Ceramic capacitors have low ESR and their resonant frequency is higher than the bandwidth of the regulator. When placed at the output, their combined ESR is not critical as long as the total value of ceramic capacitance does not exceed 200 F. 13 PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 Tantalum Capacitors Tantalum type capacitors may be used at the output, and are recommended for applications where the ambient operating temperature can be less than 0C. The AVX TPS, Sprague 593D/594/595, and Kemet T495/T510/T520 capacitors series are suggested over many other tantalum types due to their rated surge, power dissipation, and ripple current capability. As a caution, many general-purpose tantalum capacitors have considerably higher ESR, reduced power dissipation, and lower ripple current capability. These capacitors are also less reliable as they have lower power dissipation and surge current ratings. Tantalum capacitors that do not have a stated ESR or surge current rating are not recommended for power applications. When specifying Os-Con and polymer tantalum capacitors for the output, the minimum ESR limit is encountered well before the maximum capacitance value is reached. Capacitor Table The capacitor table, Table 5 and Table 6, identifies the characteristics of capacitors from various vendors with acceptable ESR and ripple current (rms) ratings. The recommended number of capacitors required at both the input and output buses is identified for each capacitor type. This is not an extensive capacitor list. Capacitors from other vendors are available with comparable specifications. Those listed are for guidance. The rms rating and ESR (at 100 kHz) are critical parameters necessary to insure both optimum regulator performance and long capacitor life. Designing for Load Transients The transient response of the dc/dc converter has been characterized using a load transient with a di/dt of 1 A/s. The typical voltage deviation for this load transient is given in the data sheet specification table using the required value of output capacitance. As the di/dt of a transient is increased, the response of a converter's regulation circuit ultimately depends on its output capacitor decoupling network. This is an inherent limitation of any dc/dc converter once the speed of the transient exceeds its bandwidth capability. If the target application specifies a higher di/dt or lower voltage deviation, the requirement can only be met with additional output capacitor decoupling. In these cases, special attention must be paid to the type, value, and ESR of the capacitors selected. If the transient performance requirements exceed those specified in the data sheet, the selection of output capacitors becomes more important. Review the minimum ESR in the characteristic data sheet for details on the capacitance maximum. Table 5. Recommended Input/Output Capacitors (PTN78000W) CAPACITOR CHARACTERISTICS QUANTITY WORKING VOLTAGE (V) VALUE (F) EQUIVALENT SERIES RESISTANCE (ESR) () 85C MAXIMUM RIPPLE CURRENT (Irms) (mA) FC( Radial) 50 180 0.119 850 10 x 16 FC (SMD) 3 100 0.15 670 10 x 10,2 1 (1) United Chemi-Con PXA (SMD) 16 180 0.016 4360 8 x 12 1 (1) 1 LXZ 50 120 0.160 620 x 2 10 x 12,5 MVY(SMD) 50 100 0.300 500 10 x 10 1 Nichicon UWG (SMD) 50 100 0.300 500 10 x 10 1 F559 (Tantalum) 10 100 0.055 2000 7.7 x 4,3 N/R HD 50 100 0.074 724 8 x 11,5 1 Sanyo Os-Con SVP (SMD) 20 100 0.024 2500 8 x 12 1 (1) 2 20SVP100M (VI and VO 16 V) SP 16 100 0.032 2890 10 x 5 1 (1) 2 16SP100M (VI and VO 14 V) CAPACITOR VENDOR/ COMPONENT SERIES (1) (2) 14 PHYSICAL SIZE (mm) VENDOR NUMBER INPUT BUS OUTPUT BUS 1 1 EEUFC1H181 1 EEVFC1V101P 2 PXA16VC180MF60 1 LXZ50VB121M10X12LL (1) 1 MVY50VC101M10X10TP (VO 5.5 V) (1) 1 UWG1H101MNR1GS (VO 5.5 V) (1) 3 (2) 1 F551A107MN (VO 5 V) UHD1H101MPR The voltage rating of the input capacitor must be selected for the desired operating input voltage range of the regulator. To operate the regulator at a higher input voltage, select a capacitor with the next higher voltage rating. The maximum voltage rating of the capacitor must be selected for the desired set-point voltage (VO ). To operate at a higher output voltage, select a capacitor with a higher voltage rating. PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 Table 5. Recommended Input/Output Capacitors (PTN78000W) (continued) CAPACITOR CHARACTERISTICS QUANTITY WORKING VOLTAGE (V) VALUE (F) EQUIVALENT SERIES RESISTANCE (ESR) () 85C MAXIMUM RIPPLE CURRENT (Irms) (mA) 20 100 0.085 1543 20 100 0.200 > 817 Murata X5R Ceramic 6.3 100 0.002 >1000 3225 N/R (1) 2 GRM32ER60J107M (VO 5.5 V) TDK X5R Ceramic 6.3 100 0.002 >1000 3225 N/R (1) 2 C3225X5R0J107MT (VO 5.5 V) Murata X5R Ceramic 16 47 0.002 >1000 3225 1 4 GRM32ER61C476M (VO ~ VI 13.5 V) Kemet X5R Ceramic 6.3 47 0.002 >1000 3225 N/R (1) 4 C1210C476K9PAC (VO 5.5 V) TDK X5R Ceramic 6.3 47 0.002 >1000 3225 N/R (1) 4 C3225X5R0J476MT (VO 5.5 V) Murata X5R Ceramic 6.3 47 0.002 >1000 3225 N/R (1) 4 GRM422X5R476M6.3 (VO 5.5 V) TDK X7R Ceramic 25 2.2 0.002 >1000 SMD 1 (4) 1 C3225X7R1E225KT/MT (VI and VO 20 V) Murata X7R Ceramic 25 2.2 0.002 >1000 3225 1 (4) 1 GRM32RR71E225K (VI and VO 20 V) Kermet X7R Ceramic 25 2.2 0.002 >1000 3225 1(4) 1 C1210C225K3RAC (VI and VO 20 V) AVX X7R Ceramic 25 2.2 0.002 >1000 1(4) 1 12103C225KAT2A (VI and VO 20 V) Kemet X7R Ceramic 50 1 0.002 >1000 2 1 C1210C105K5RAC Murata X7R Ceramic 50 4.7 0.002 >1000 1 1 GRM32ER71H475KA88L TDK X7R Ceramic 50 2.2 0.002 >1000 1 1 C3225X7R1H225KT Murata X7R Ceramic 50 1 0.002 >1000 3225 2 (5) 1 GRM32RR71H105KA01L TDK X7R Ceramic 50 1 0.002 >1000 3225 2 (5) 1 C3225X7R1H105KT 2 (5) 1 C330C105K5R5CA 1 1 RPER71H2R2KK6F03 CAPACITOR VENDOR/ COMPONENT SERIES AVX Tantalum TPS (SMD) INPUT BUS 7,3 L x 4,3 W x 4,1 H N/R (3) 3 TPSV107M020R0085 (VO 10 V) N/R (3) 3 TPSE107M020R0200 (VO 10 V) SMD Kemet Radial Through-hole 50 1 0.002 >1000 5,08 x 7,62 x 9,14 H Murata Radial Through-hole 50 2.2 0.004 >1000 10 H x 10 W x4D (3) (4) (5) VENDOR NUMBER PHYSICAL SIZE (mm) (1) (5) OUTPUT BUS Not reccomended (N/R). The voltage rating does not meet the minimum operating limits in most applications. The maximum rating of the ceramic capacitor limits the regulator's operating input voltage to 20 V. Select a alternative ceramic component to operate at a higher input voltage. A total capacitance of 2 F is an acceptable replacement value for a single 2.2-F ceramic capacitor. 15 PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 Table 6. Recommended Input/Output Capacitors (PTN78000H) CAPACITOR CHARACTERISTICS QUANTITY WORKING VOLTAGE (V) VALUE (F) EQUIVALENT SERIES RESISTANCE (ESR) () 85C MAXIMUM RIPPLE CURRENT (Irms) (mA) Panasonic FC( Radial) 50 100 0.162 615 10 x 12,5 1 1 EEUFC1H1081 FK (SMD) 50 150 0.18 670 10 x 10,2 1 1 EEVFK1H151P FC (SMD) 35 100 0.15 670 10 x 10,2 1 (1) 1 EEVFC1V101P (VI 32 V) United Chemi-Con PS (Radial ) 25 100 0.020 4320 8 x 12,5 1 (1) 1 LXZ 50 120 0.160 620 10 x 12,5 1 1 LXZ50VB121M10X12LL MVY(SMD) 50 100 0.300 500 10 x 10 1 1 MVY50VC101M10X10TP Nichicon UWG (SMD) 50 100 0.300 500 10 x 10 1 1 F559 (Tantalum) 10 100 0.055 2000 7.7 x 4,3 N/R HD 50 100 0.074 724 8 x 11,5 1 Sanyo Os-Con SVP (SMD) 20 100 0.024 2500 8 x 12 1 (1) 2 20SVP100M (VI and VO 16 V) SP 20 120 0.024 3110 8 x 10,5 1 (1) 2 20SP120M (VI and VO 16 V) (1) 1 GRM32ER61C476M (VO 13.5 V) CAPACITOR VENDOR/ COMPONENT SERIES PHYSICAL SIZE (mm) INPUT BUS OUTPUT BUS (1) 3 VENDOR NUMBER 25PS100MJ12 (VI and VO 22 V) UWG1H101MNR1GS (2) 1 F551A107MN (VO 5 V) UHD1H101MPR Murata X5R Ceramic 16 47 0.002 >1000 3225 1 TDK X7R Ceramic 25 2.2 0.002 >1000 SMD 5 (3) 1 C3225X7R1E225KT/MT (VI and VO 20 V) Murata X7R Ceramic 25 2.2 0.002 >1000 3225 5 (3) 1 GRM32RR71E225K (VI and VO 20 V) Kemet X7R Ceramic 25 2.2 0.002 >1000 3225 5 (3) 1 C1210C225K3RAC (VI and VO 20 V) AVX X7R Ceramic 25 2.2 0.002 >1000 5 (3) 1 12103C225KAT2A (VI and VO 20 V) Kemet X7R Ceramic 50 1 0.002 >1000 9 (4) 1 C1210C105K5RAC Murata X7R Ceramic 50 4.7 0.002 >1000 2 1 GRM32ER71H475KA88L TDK X7R Ceramic 50 3.3 0.002 >1000 3 1 CKG45NX7R1H335M 2 1 C350C475K5R5CA 3 1 RPER71H3R3KK6F03 SMD Kemet Radial Through-hole 50 4.7 0.003 >1000 5,08 x 7,62 x 9,14 H Murata Radial Through-hole 50 3.3 0.003 >1000 12,5 H x 12,5 Wx4D (1) (2) (3) (4) 16 The voltage rating of the input capacitor must be selected for the desired operating input voltage range of the regulator. To operate the regulator at a higher input voltage, select a capacitor with the next higher voltage rating. The maximum voltage rating of the capacitor must be selected for the desired set-point voltage (VO ). To operate at a higher output voltage, select a capacitor with a higher voltage rating. The maximum rating of the ceramic capacitor limits the regulator's operating input voltage to 20 V. Select a alternative ceramic component to operate at a higher input voltage. A total capacitance of 2 F is an acceptable replacement value for a single 2.2-F ceramic capacitor PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 Power-Up Characteristics When configured per the standard application, the PTN78000 power module produces a regulated output voltage following the application of a valid input source voltage. During power up, internal soft-start circuitry slows the rate that the output voltage rises, thereby limiting the amount of in-rush current that can be drawn from the input source. The soft-start circuitry introduces a short time delay (typically 5 ms-10 ms) into the power-up characteristic. This is from the point that a valid input source is recognized. Figure 29 shows the power-up waveforms for a PTN78000W, operating from a 12-V input and with the output voltage adjusted to 5 V. The waveforms were measured with a 1.5-A resistive load. VI (5 V/div) VO (2 V/div) II (0.5 A/div) t - Time = 5 ms/div Figure 29. Power-Up Waveforms Undervoltage Lockout The undervoltage lockout (UVLO) circuit prevents the module from attempting to power up until the input voltage is above the UVLO threshold. This prevents the module from drawing excessive current from the input source at power up. Below the UVLO threshold, the module is held off. Current Limit Protection The PTN78000 modules protect against load faults with a continuous current limit characteristic. Under a load fault condition, the output current cannot exceed the current limit value. Attempting to draw current that exceeds the current limit value causes the module to progressively reduce its output voltage. Current is continuously supplied to the fault until it is removed. On removal of the fault, the output voltage promptly recovers. When limiting output current, the regulator experiences higher power dissipation, which increases its temperature. If the temperature increase is excessive, the module's overtemperature protection begins to periodically turn the output voltage completely off. Overtemperature Protection A thermal shutdown mechanism protects the module's internal circuitry against excessively high temperatures. A rise in temperature may be the result of a drop in airflow, a high ambient temperature, or a sustained current-limit condition. If the junction temperature of the internal control IC rises excessively, the module turns off, reducing the output voltage to zero. The module instantly restarts when the sensed temperature decreases by a few degrees. Note: Overtemperature protection is a last resort mechanism to prevent damage to the module. It should not be relied on as permanent protection against thermal stress. Always operate the module within its temperature derated limits, for the worst-case operating conditions of output current, ambient temperature, and airflow. Operating the module above these limits, albeit below the thermal shutdown temperature, reduces the long-term reliability of the module. 17 PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 Output On/Off Inhibit For applications requiring output voltage on/off control, the PTN78000 power module incorporates an output on/off Inhibit control (pin 3). The inhibit feature can be used wherever there is a requirement for the output voltage from the regulator to be turned off. The power module functions normally when the Inhibit pin is left open-circuit, providing a regulated output whenever a valid source voltage is connected to VI with respect to GND. Figure 30 shows the the circuit used to demonstrate the inhibit function. Note the discrete transistor (Q1). Turning Q1 on applies a low voltage to the Inhibit control pin and turns the module off. The output voltage decays as the load circuit discharges the capacitance. The current drawn at the input is reduced to typically 17 mA. If Q1 is then turned off, the module executes a soft-start power up. A regulated output voltage is produced within 20 ms Figure 31 shows the typical rise in the output voltage, following the turn off of Q1. The turn off of Q1 corresponds to the fall in the waveform, Q1 Vgs. The waveforms were measured with a 1.5-A resistive load. PTN78000W VI = 12 V 2 VI VO = 5 V 5 VO Inh GND Adj 3 1 4 CI 2.2 F Ceramic Inhibit RSET 21 k 0.05 W 1% CO 100 F Q1 BSS138 GND GND Figure 30. On/Off Inhibit Control Circuit VO (2 V/div) II (0.5 A/div) Q1 VGS (10 V/div) t - Time = 5 ms/div Figure 31. Power Up Response From Inhibit Control 18 L O A D PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 Optional Input/Output Filters Power modules include internal input and output ceramic capacitors in all their designs. However, some applications require much lower levels of either input reflected or output ripple/noise. This application note describes various filters and design techniques found to be successful in reducing both input and output ripple/noise. Input/Output Capacitors The easiest way to reduce output ripple and noise is to add one or more 1-F ceramic capacitors, such as C4 shown in Figure 32. Ceramic capacitors should be placed close to the output power terminals. A single 1-F capacitor reduces the output ripple/noise by 10% to 30% for modules with a rated output current of less than 3 A. (Note: C3 is recommended to improve the regulators transient response and does not reduce output ripple and noise.) Switching regulators draw current from the input line in pulses at their operating frequency. The amount of reflected (input) ripple/noise generated is directly proportional to the equivalent source impedance of the power source including the impedance of any input lines. The addition of C1, minimum 1-F ceramic capacitor, near the input power pins, reduces reflected conducted ripple/noise by 30% to 50%. PTN78000W VI 2 VI VO VO 5 Inh GND Adj 3 1 4 C1 1 mF 50 V Ceramic GND C2* 2.2 mF 50 V Ceramic (Required) RSET C3# 100 mF (Optional) C4 1 mF Ceramic GND * See specifications for required value and type. For PTN78000H, C2 is equal to 2 x 4.7 mF. # See Application Information for suggested value and type. Figure 32. Adding High-Frequency Bypass Capacitors To The Input and Output Filters If a further reduction in ripple/noise level is required for an application, higher order filters must be used. A (pi) filter, employing a ferrite bead (Fair-Rite part number 2673000701 or equivalent) in series with the input or output terminals of the regulator reduces the ripple/noise by at least 20 db (see Figure 33 and Figure 34). In order for the inductor to be effective in reduction of ripple and noise ceramic capacitors are required. (Note: see Capacitor Recommendations for the PTN78000W for addtional information on vendors and component suggestions.) These inductors plus ceramic capacitors form an excellent filter because of the rejection at the switching frequency (650 kHz - 1 MHz). The placement of this filter is critical. It must be located as close as possible to the input or output pins to be efffective. The ferrite bead is small (12,5 mm x 3 mm), easy to use, low cost, and has low dc resistance. Fair-Rite also manufactures a surface-mount bead (part number 2773021447), through hole (part number 2673000701) rated to 5 A, but in this application, it is effective to 5 A on the output bus. Inductors in the range of 1 H to 5 H can be used in place of the ferrite inductor bead. 19 PTN78000W, PTN78000H www.ti.com SLTS230A - NOVEMBER 2004 - REVISED APRIL 2005 VI L1 1 - 5 mH 2 PTN78000W VI VO Inh 3 C1 1 mF 50 V Ceramic GND 1 5 L2 1 - 5 mH VO Adj 4 C2* 2.2 mF 50 V Ceramic (Required) RSET C3 # 100 mF (Required) C4 1 mF Ceramic GND C5 GND * See specifications for required value and type. For the PTN78000H, C2 is equal to 2x 4.7 mF. # See the Application Information for suggested value and type. Recommended when IO is greater than 2 A. Figure 33. Adding Filters (IO 3 A) 45 40 Attenuation - dB 35 1 MHz 30 25 20 600 kHz 15 10 0 0.5 1 1.5 2 Load Current - A 2.5 3 Figure 34. -Filter Attenuation vs. Load Current 20 PACKAGE OPTION ADDENDUM www.ti.com 24-Jun-2005 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty PTN78000HAH ACTIVE DIP MOD ULE EUS 5 56 TBD Call TI Call TI PTN78000HAS ACTIVE DIP MOD ULE EUT 5 49 TBD Call TI Call TI PTN78000HAST ACTIVE DIP MOD ULE EUT 5 250 TBD Call TI Call TI PTN78000HAZ ACTIVE DIP MOD ULE EUT 5 49 Pb-Free (RoHS) Call TI Level-3-260C-168 HR PTN78000HAZT ACTIVE DIP MOD ULE EUT 5 250 Pb-Free (RoHS) Call TI Level-3-260C-168 HR PTN78000WAH ACTIVE DIP MOD ULE EUS 5 56 TBD Call TI Level-1-235C-UNLIM PTN78000WAS ACTIVE DIP MOD ULE EUT 5 49 TBD Call TI Level-1-235C-UNLIM PTN78000WAST ACTIVE DIP MOD ULE EUT 5 250 TBD Call TI Level-1-235C-UNLIM PTN78000WAZ ACTIVE DIP MOD ULE EUT 5 49 Pb-Free (RoHS) Call TI Level-3-260C-168 HR PTN78000WAZT ACTIVE DIP MOD ULE EUT 5 250 Pb-Free (RoHS) Call TI Level-3-260C-168 HR Lead/Ball Finish MSL Peak Temp (3) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. 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