PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 6-A, WIDE-INPUT ADJUSTABLE SWITCHING REGULATOR FEATURES APPLICATIONS • • • 1 • • • • • • • • 6-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 96%) On/Off Inhibit Undervoltage Lockout Output Current Limit Overtemperature Shutdown Operating Temperature: -40°C to 85°C Surface Mount Package Available General-Purpose, Industrial Controls, HVAC Systems, Test and Measurement, Medical Instrumentation, AC/DC Adaptors, Vehicles, Marine, and Avionics DESCRIPTION The PTN78020 is a series of high-efficiency, step-down integrated switching regulators (ISRs), that represent the third generation in the evolution of high-performance power modules designed for industrial use. The wide-input voltage range makes these modules suitable for a variety of applications that operate off 12–V, 24–V, and 28–V dc power. In new designs they should be considered in place of the PT6620, PT6650, PT6680, and PT6880 series of single in-line pin (SIP) products. The PTN78020 is smaller and lighter than its predecessors, and has either similar or improved electrical performance characteristics. The caseless, double-sided package has excellent thermal characteristics, and is compatible with TI's roadmap for RoHS and lead-free compliance. Operating from a wide-input voltage range, the PTN78020 provides high-efficiency, step-down voltage conversion for loads of up to 6 A. The output voltage is set using a single, external resistor. The PTN78020W may be set to any value within the range, 2.5 V to 12.6 V, and the PTN78020H from 11.85 V to 22 V. The output voltage of the PTN78020W 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 PTN78020H can be as little as 3 V lower than the input, allowing operation down to 15 V, with an output voltage of 12 V. The PTN78020 has undervoltage lockout, an integral on/off inhibit, and includes an output current limit and overtemperature protection. STANDARD APPLICATION VI 7 1 PTN78020 (Top View) 2 6 Inhibit 3 CI* Ceramic (Required) GND 4 VO VO Sense 5 RSET# 1%, 0.05 W (Required) CO* 330 mF (Required) L O A D GND *See the Application Information section for capacitor recommendations. The minimum input capacitance for is 2.2 mF for PTN78020W, and 18.8 mF (4 x 4.7 mF) for PTN78020H #RSET is required to adjust the output voltage. See the Application Information section for values. 1 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 © 2004–2008, Texas Instruments Incorporated PTN78020W PTN78020H SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 .................................................................................................................................................. www.ti.com 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 For the most current package and ordering information, see the Package Option Addendum at the end of this datasheet, or see the TI website at www.ti.com. ABSOLUTE MAXIMUM RATINGS (1) over operating free-air temperature range unless otherwise noted all voltages with respect to GND UNIT TA Operating free-air temperature Over VI range Wave solder temperature Surface temperature of module body or pins (5 seconds) Solder reflow temperature Surface temperature of module body or pins TS Storage temperature VI Input surge voltage, 10 ms maximum VINH Inhibit (pin 3) input voltage PO Output power (1) –40°C to 85°C Horizontal TH (suffix AH & AD) 260°C Horizontal SMD (suffix AS) 235°C Horizontal SMD (suffix AZ) 260°C –55°C to 125°C 38 V –0.3 V to 5 V VI ≤ 24 V or VO ≥ 15 V 90 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 PTN78020W 7 36 PTN78020H 15 36 –40 85 UNIT V °C PACKAGE SPECIFICATIONS PTN78020x (Suffix AH, AS, & AZ) Weight 7.3 grams Flammability Meets UL 94 V-O Mechanical shock Per Mil-STD-883D, Method 2002.3, 1 ms, 1/2 sine, mounted Mechanical vibration (1) 2 Mil-STD-883D, Method 2007.2, 20-2000 Hz Horizontal T/H (suffix AH and AD) 250 G Horizontal SMD (suffix AS and AZ) 125 G (1) (1) Horizontal T/H (suffix AH and AD) 20 G (1) Horizontal SMD (suffix AS and AZ) 10 G (1) Qualification limit. Submit Documentation Feedback Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 ELECTRICAL CHARACTERISTICS operating at 25°C free-air temperature, VI = 20 V, VO = 5 V, IO = IO (max), CI = 2.2 µF, CO = 330 µF (unless otherwise noted) PARAMETER IO Output current VI Input voltage range VO VO (adj) η PTN78020W TEST CONDITIONS MIN TA = 25°C, natural convection airflow MAX 0.1 6 (1) VI = 32 V 0.1 5 (1) VI = 36 V 0.1 4.5 (1) (2) 36 (3) ±2% (4) Over IO range 7 UNIT A V Set-point voltage tolerance TA = 25°C Temperature variation –40°C to +85°C Line regulation Over VI range ±10 mV Load regulation Over IO range ±10 mV Total output voltage variation Includes set point, line, load –40 < TA < 85°C ±0.5% ±3% (4) 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 × VI Output voltage adjust range V Efficiency Output voltage ripple 20-MHz bandwith Current limit threshold ΔVO = –50 mV 12.6 VI = 24 V, RSET = 732 Ω, VO = 12 V 94% VI = 15 V, RSET = 21 kΩ, VO = 5 V 88% VI = 15 V, RSET = 78.7 kΩ, VO = 3.3 V IO (LIM) TYP VI ≤24 V 85% 1% VO V(PP) 8.5 A 1 A/µs load step from 50% to 100% IOmax Transient response Recovery time 200 VO over/undershoot 5 Input high voltage (VIH) Inhibit control (pin 3) Input low voltage (VIL) 1 Input standby current mA mA VI increasing 5.5 VI decreasing 5.2 Switching frequency Over VI and IO ranges CI External input capacitance Ceramic and nonceramic 440 2.2 Nonceramic Equiv. series resistance (nonceramic) (1) (2) (3) (4) (5) (6) (7) (8) Per Telcordia SR-332, 50% stress, TA = 40°C, ground benign 550 V 660 (6) Ceramic Calculated reliability V 17 FS MTBF 0.3 0.25 Undervoltage lockout External output capacitance (5) Pin 3 connected to GND UVLO CO Open –0.1 Input low current (IIL) II(stby) µs %VO µF 300 330 (7) 10 (8) kHz 2,000 5.6 µF mΩ 106 Hr Above an input voltage of 24 V, the maximum output current must be derated by 125 mA per volt above 24 V. 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 × 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 small, low-leakage (< 100 nA) MOSFET is recommended for control. See the Application Information section for further guidance. An external 2.2-µF ceramic capacitor is required across the input (VI and GND) for proper operation. Locate the capacitor close to the module. 330 µF 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 mΩ as the minimum when using max-ESR values to calculate. Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H Submit Documentation Feedback 3 PTN78020W PTN78020H SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 .................................................................................................................................................. www.ti.com ELECTRICAL CHARACTERISTICS operating at 25°C free-air temperature, VI = 24 V, VO = 12 V, IO = IO (max), CI = 4× 4.7 µF, CO = 330 µF (unless otherwise noted) PARAMETER IO Output current PTN78020H TEST CONDITIONS TA = 25°C, natural convection airflow MIN Vo =12 V 0.1 Vo =15 V 0.1 Vo = 22 V VI VO VO (adj) η 6 0.1 15 4.09 Set-point voltage tolerance TA = 25°C Temperature variation –40°C to +85°C Line regulation Over VI range ±10 Load regulation Over IO range ±10 Total output voltage variation Includes set point, line, load –40 < TA < 85°C 20-MHz bandwith ΔVO = –50 mV A (2) 36 V ±2% (4) ±0.5% mV mV ±3% Output voltage adjust range Current limit threshold UNIT (1) (1) (2) (3) Over IO range Output voltage ripple MAX 6 Input voltage range Efficiency IO (LIM) TYP (4) VI < 19 V 11.85 VI – 3 19 V ≤ VI ≤ 25 V 11.85 VI – 4 VI > 25 V 11.85 22 VI = 24 V, RSET = 383 k Ω, VO = 12 V 94% VI = 24 V, RSET = 15 kΩ, VO = 15 V 95% VI = 32 V, RSET = 95.3 Ω, VO = 22 V 96% 1% VO V V(PP) 8.0 A 1 A/µs load step from 50% to 100% IOmax Transient response Recovery time 200 µs VO over/undershoot 200 mV Input high voltage (VIH) Inhibit control (pin 3) 1 Input low voltage (VIL) –0.1 Input low current (IIL) II(stby) Input standby current Pin 3 connected to GND VI increasing UVLO Undervoltage lockout FS Switching frequency Over VI and IO ranges CI External input capacitance Ceramic and nonceramic External output capacitance VI decreasing (1) (2) (3) (4) (5) (6) (7) (8) 4 Calculated reliability 0.3 440 18.8 Nonceramic Per Telcordia SR-332, 50% stress, TA = 40°C, ground benign mA 17 mA V 550 660 (6) kHz µF 0 300 330 (7) 2,000 10 (8) 5.6 V 0.25 12 Equiv. series resistance (nonceramic) MTBF (5) 12.2 Ceramic CO Open µF mΩ 106 Hr The maximum output current is 6 A or a maximum output power of 90 W, whichever is less. Above an input voltage of 24 V, the maximum output current must be derated by 125 mA per volt above 24 V. See the Typica lCharacteristics section for further guidance. Above an output voltage of 15 V, the maximum output current must be derated by 285 mA per volt. The maximum output power is 90 W. See the application information for further guidance. 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. Four external 4.7-µF ceramic capacitors are required across the input (VI and GND) for proper operation. Locate the capacitors close to the module. 330 µF 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 mΩ as the minimum when using max-ESR values to calculate. Submit Documentation Feedback Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 PIN ASSIGNMENT 1 7 PTN78020 (Top View) 2 6 3 4 5 TERMINAL FUNCTIONS TERMINAL NAME NO. GND 1, 7 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. VI 2 I The positive input voltage power node to the module, which is referenced to common GND. Inhibit 3 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 produces an output whenever a valid input source is applied. VO Adjust 4 I A 1% resistor must be connected between this pin and GND (pin 7) to set the output voltage of the module. If left open-circuit, the output voltage is set to its default value. The temperature stability of the resistor should be 100 ppm/°C (or better). The standard resistor value for a number of common output voltages is provided in the application information. VO Sense 5 I The sense input allows the regulation circuit to compensate for voltage drop between the module and the load. For optimum voltage accuracy, VO Sense should be connected to VO. If the sense feature is not used, this pin may be left disconnected. VO 6 O The regulated positive power output with respect to the GND node. Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H Submit Documentation Feedback 5 PTN78020W PTN78020H SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 .................................................................................................................................................. www.ti.com TYPICAL CHARACTERISTICS (7-V INPUT) (1) (2) EFFICIENCY vs OUTPUT CURRENT OUTPUT VOLTAGE RIPPLE vs OUTPUT CURRENT 50 Efficiency - % 90 VO = 5 V 80 VO = 3.3 V 70 60 40 30 VO = 3.3 V VO = 5 V 20 0 1 2 3 4 5 6 0 1 1 2 3 4 5 6 0 1 IO - Output Current - A 2 3 4 5 6 IO - Output Current - A Figure 2. Figure 3. TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT 90 90 80 80 Airflow Temperature Derating - oC Temperature Derating - oC VO = 3.3 V VO = 5 V Figure 1. 200 LFM 70 100 LFM 60 Nat conv 50 40 VO = 3.3 V 30 Airflow 200 LFM 70 100 LFM 60 Nat conv 50 40 VO = 5 V 30 20 20 0 1 2 3 4 IO - Output Current - A Figure 4. 6 2 0 IO - Output Current - A (2) 3 10 0 50 4 PD- Power Dissipation - W VO- Output Voltage Ripple - mVPP 100 (1) POWER DISSIPATION vs OUTPUT CURRENT 5 6 0 1 2 3 4 IO - Output Current - A 5 6 Figure 5. 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. For surface mount packages (AS and AZ suffix), multiple vias (plated through holes) are required to add thermal paths around the power pins. Please refer to the mechanical specification for more information. Applies to Figure 4 and Figure 5. Submit Documentation Feedback Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 TYPICAL CHARACTERISTICS (15-V INPUT) (1) (2) EFFICIENCY vs OUTPUT CURRENT OUTPUT VOLTAGE RIPPLE vs OUTPUT CURRENT 50 VO- Output Voltage Ripple - mVPP VO = 12 V 90 Efficiency - % VO = 5 V 80 VO = 3.3 V 70 60 40 VO = 5 V 0 1 2 3 4 5 VO = 12 V 30 20 VO = 3.3 V 10 6 0 1 2 VO = 5 V 1 2 3 4 5 0 6 1 2 3 4 IO - Output Current - A IO - Output Current - A Figure 7. Figure 8. Figure 6. TEMPERATURE DERATING vs OUTPUT CURRENT 5 6 TEMPERATURE DERATING vs OUTPUT CURRENT 90 90 200 LFM 80 Temperature Derating - oC 80 Temperature Derating - oC VO = 3.3 V 3 0 IO - Output Current - A Airflow 70 100 LFM 60 50 Nat conv 40 VO = 5 V 30 200 LFM Airflow 70 100 LFM 60 Nat conv 50 40 VO = 12 V 30 20 20 0 1 2 3 4 IO - Output Current - A Figure 9. (2) 4 VO = 12 V 0 50 5 PD - Power Dissipation - W 100 (1) POWER DISSIPATION vs OUTPUT CURRENT 5 6 0 1 2 3 4 IO - Output Current - A 5 6 Figure 10. 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 6, Figure 7, and Figure 8. 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. For surface mount packages (AS and AZ suffix), multiple vias (plated through holes) are required to add thermal paths around the power pins. Please refer to the mechanical specification for more information. Applies to Figure 9 and Figure 10. Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H Submit Documentation Feedback 7 PTN78020W PTN78020H SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 .................................................................................................................................................. www.ti.com TYPICAL CHARACTERISTICS (24-V INPUT) (1) (2) EFFICIENCY vs OUTPUT CURRENT VO - Output Voltage Ripple - mVPP 90 Efficiency - % 6 70 VO = 18 V VO = 15 V 80 VO = 12 V 70 VO = 5 V 60 POWER DISSIPATION vs OUTPUT CURRENT 50 VO = 3.3 V 40 VO = 12 V 60 VO = 15 V 50 40 VO = 18 V 30 20 VO = 5 V 10 5 PD - Power Dissipation - W 100 OUTPUT VOLTAGE RIPPLE vs OUTPUT CURRENT VO = 5 V 4 VO = 3.3 V 3 VO = 12 V 2 VO = 15 V 1 0 1 2 3 4 5 VO = 18 V VO = 3.3 V 0 6 0 1 IO - Output Current - A 2 3 5 4 0 6 0 1 IO - Output Current - A 2 3 4 5 Figure 11. Figure 12. Figure 13. TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT 90 6 IO - Output Current - A 90 90 200 LFM 80 70 Airflow 60 100 LFM 50 Nat conv 40 30 70 Airflow 50 Nat conv 40 30 1 2 3 4 IO - Output Current - A 5 6 Figure 14. 8 Airflow 100 LFM 60 50 Nat conv 40 30 VO = 15 V 20 0 70 VO = 12 V 20 (2) 100 LFM 60 VO = 5 V (1) 80 200 LFM Temperature Derating - °C 200 LFM Temperature Derating - °C Temperature Derating - °C 80 20 0 1 2 3 4 IO - Output Current - A 5 6 0 Figure 15. 1 2 3 4 IO - Output Current - A 5 6 Figure 16. 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 11, Figure 12, and Figure 13. 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. For surface mount packages (AS and AZ suffix), multiple vias (plated through holes) are required to add thermal paths around the power pins. Please refer to the mechanical specification for more information. Applies to Figure 14 through Figure 16. Submit Documentation Feedback Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 TYPICAL CHARACTERISTICS (32-V INPUT) (1) (2) VO = 12 V VO = 15 V VO = 5 V VO = 3.3 V 0 1 2 3 4 80 7 70 6 60 VO = 22 V 50 40 VO = 12 V 30 20 0 5 VO = 5 V VO = 3.3 V 10 0 1 2 3 4 VO = 3.3 V 4 3 VO = 22 V 2 VO = 15 V 1 0 1 2 3 4 Figure 18. Figure 19. TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT TEMPERATURE DERATING vs OUTPUT CURRENT 90 90 200 LFM Temperature Derating - °C 200 LFM 80 70 Airflow 60 100 LFM 50 Nat conv 40 30 80 70 Airflow 60 100 LFM 50 Nat conv 40 30 VO = 5 V 20 20 1 2 3 4 IO - Output Current - A 5 Airflow 70 60 100 LFM 50 Nat conv 40 30 20 1 2 3 4 5 0 1 2 3 4 5 IO - Output Current - A IO - Output Current - A Figure 20. 200 LFM 80 VO = 15 V VO = 12 V 0 5 IO - Output Current - A Figure 17. 90 0 VO = 5 V 5 0 5 VO = 12 V IO - Output Current - A IO - Output Current - A Temperature Derating - °C VO = 15 V Temperature Derating - °C 75 70 65 60 55 50 45 40 VO = 22 V POWER DISSIPATION vs OUTPUT CURRENT PD - Power Dissipation - W 100 95 90 85 80 OUTPUT VOLTAGE RIPPLE vs OUTPUT CURRENT VO - Output Voltage Ripple - mVPP Efficiency - % EFFICIENCY vs OUTPUT CURRENT Figure 21. Figure 22. TEMPERATURE DERATING vs OUTPUT CURRENT Temperature Derating - °C 90 80 200 LFM 70 100 LFM 60 Nat conv Airflow 50 40 30 VO = 22 V 20 0 1 2 3 IO - Output Current - A 4 Figure 23. (1) (2) 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 17, Figure 18, and Figure 19. 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. For surface mount packages (AS and AZ suffix), multiple vias (plated through holes) are required to add thermal paths around the power pins. Please refer to the mechanical specification for more information. Applies to Figure 20 through Figure 23. Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H Submit Documentation Feedback 9 PTN78020W PTN78020H SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 .................................................................................................................................................. www.ti.com APPLICATION INFORMATION Adjusting the Output Voltage of the PTN78020x Series of Wide-Output Adjust Power Modules General A resistor must be connected between the VO Adjust control (pin 4) and GND (pin 7) to set the output voltage. The adjustment range is from 2.5 V to 12.6 V for PTN78020W. The adjustment range is from 11.85 V to 22 V for PTN78020H. 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 a number of standard voltages, with the actual output voltage that the value provides. For other output voltages, the value of the required resistor can either be calculated using Equation 1 and the constants for the applicable product in Table 1. Figure 24 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 kΩ PTN780x0H 11.824 V 6.65 kΩ Input Voltage Considerations The PTN78020 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. 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 PTN78020x must adhere to the following requirements. 1. For PTN78020W output voltages lower than 10 V, the minimum input voltage is (VO + 2 V ) or 7 V, whichever is higher. 2. For PTN78020W output voltages equal to 10 V and higher, the minimum input voltage is (VO + 2.5 V ) . 3. For PTN78020W, the maximum input voltage is (10 × VO ) or 36 V, whichever is less. 4. For PTN78020H output voltages lower than 19 V, the minimum input voltage is (VO + 3 V ) or 15 V, whichever is higher. 5. For PTN78020H output voltages equal to 19 V and higher, the minimum input voltage is (VO + 4 V ) . Table 2 gives the operating input voltage range for the common output bus voltages. In addition, the Electrical Characteristics table defines the available output voltage adjust range for various input voltages. Table 2. Standard Values of Rset for Common Output Voltages PRODUCT VO (Required) PTN780x0W PTN780x0H 10 Submit Documentation Feedback 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 kΩ 3.306 V 7 V to 33 V 5V 21 kΩ 4.996 V 7 V to 36 V 12 V 732 Ω 12.002 V 14.5 V to 36 V 12 V 383 kΩ 12.000 V 15 V to 36 V 15 V 15 kΩ 14.994 V 18 V to 36 V 18 V 4.42 kΩ 18.023 V 21 V to 36 V 22 V 95.3 21.998 V 26 V to 36 V Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 5 Sense VI 2 PTN78020W VI Inhibit 3 VO VO 6 GND GND Adjust 1 7 4 CI 2.2 mF Ceramic RSET 0 .05 W CO 330 mF 1% 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 7 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 24. PTN78020W VO Adjust Resistor Placement Table 3. PTN78020W Output Voltage Set-Point Resistor Values VO (V) RSET (kΩ) VO (V) RSET (kΩ) VO (V) RSET (kΩ) VO (V) RSET (kΩ) 2.50 Open 3.7 V 50.7 6.1 12.6 9.0 4.07 2.55 1370 3.8 V 46 6.2 12.1 9.2 3.75 2.60 680 3.9 V 42.5 6.3 11.6 9.4 3.46 2.65 451 4.0 V 39.3 6.4 11.1 9.6 3.18 2.70 337 4.1 V 36.4 6.5 10.7 9.8 2.91 2.75 268 4.2 V 33.9 6.6 10.2 10.0 2.66 2.80 222 4.3 V 31.6 6.7 9.85 10.2 2.42 2.85 190 4.4 V 29.6 6.8 9.47 10.4 2.20 2.90 165 4.5 V 27.8 6.9 9.11 10.6 1.98 2.95 146 4.6 V 26.2 7.0 8.76 10.8 1.78 3.00 131 4.7 V 24.7 7.1 8.43 11.0 1.58 3.05 118 4.8 V 23.3 7.2 8.11 11.2 1.40 3.10 108 4.9 V 22.1 7.3 7.81 11.4 1.22 3.15 99.1 5.0 V 21.0 7.4 7.52 11.6 1.05 3.20 91.5 5.1 V 19.9 7.5 7.24 11.8 0.889 3.25 85.0 5.2 V 18.9 7.6 6.97 12.0 0.734 3.30 79.3 5.3 V 18.0 7.7 6.71 12.2 0.585 3.35 74.2 5.4 V 17.2 7.8 6.46 12.4 0.442 3.40 69.8 5.5 V 16.4 7.9 6.22 12.6 0.305 3.45 65.7 5.6 V 15.6 8.0 5.99 3.50 62.1 5.7 V 15.0 8.2 5.55 3.55 58.9 5.8 V 14.3 8.4 5.14 3.60 55.9 5.9 V 13.7 8.6 4.76 3.65 53.2 6.0 V 13.1 8.8 4.40 Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H Submit Documentation Feedback 11 PTN78020W PTN78020H SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 .................................................................................................................................................. www.ti.com 5 Sense VI 2 PTN78020H VI Inhibit 3 VO VO 6 GND GND Adjust 1 7 4 CI 4 x 4.7 mF Ceramic RSET CO 330 mF 0 .05 W 1% 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 7 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 25. PTN78020H VO Adjust Resistor Placement Table 4. PTN78020H Output Voltage Set-Point Resistor Values 12 VO RSET VO RSET VO RSET 11.85 V 2633 kΩ 13.50 V 34.3 kΩ 17.20 V 6.12 kΩ 11.90 V 896 kΩ 13.65 V 30.9 kΩ 17.40 V 5.66 kΩ 11.95 V 538 kΩ 13.80 V 28.1 kΩ 17.60 V 5.23 kΩ 12.00 V 383 kΩ 13.95 V 25.6 kΩ 17.80 V 4.83 kΩ 12.10 V 242 kΩ 14.10 V 23.5 kΩ 18.00 V 4.46 kΩ 12.15 V 204 kΩ 14.25 V 21.6 kΩ 18.20 V 4.11 kΩ 12.20 V 176 kΩ 14.40 V 19.9 kΩ 18.40 V 3.79 kΩ 12.25 V 154 kΩ 14.55 V 18.5 kΩ 18.60 V 3.48 kΩ 12.30 V 138 kΩ 14.70 V 17.2 kΩ 18.80 V 3.19 kΩ 12.35 V 124 kΩ 14.85 V 16.0 kΩ 19.00 V 2.91 kΩ 12.40 V 113 kΩ 15.00 V 14.9 kΩ 19.20 V 2.65 kΩ 12.45 V 103 kΩ 15.15 V 13.9 kΩ 19.40 V 2.41 kΩ 12.50 V 94.9 kΩ 15.30 V 13.1 kΩ 19.60 V 2.18 kΩ 12.55 V 87.9 kΩ 15.45 V 12.3 kΩ 19.80 V 1.95 kΩ 12.60 V 81.8 kΩ 15.60 V 11.5 kΩ 20.00 V 1.74 kΩ 12.65 V 76.4 kΩ 15.75 V 10.8 kΩ 20.20 V 1.54 kΩ 12.70 V 71.7 kΩ 15.90 V 10.2 kΩ 20.40 V 1.35 kΩ 12.75 V 67.5 kΩ 16.05 V 9.59 kΩ 20.60 V 1.17 kΩ 12.80 V 63.7 kΩ 16.20 V 9.03 kΩ 20.80 V 995 Ω 12.85 V 60.2 kΩ 16.35 V 8.51 kΩ 21.00 V 829 kΩ 12.90 V 57.1 kΩ 16.50 V 8.03 kΩ 21.20 V 669 Ω 12.95 V 54.3 kΩ 16.65 V 7.57 kΩ 21.40 V 516 Ω 13.00 V 51.7 kΩ 16.80 V 7.14 kΩ 21.80 V 229 Ω 13.05 V 49.3 kΩ 17.10 V 6.36 kΩ 22.00 V 94 Ω Submit Documentation Feedback Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 CAPACITOR RECOMMENDATIONS for the PTN78020 WIDE-OUTPUT ADJUST POWER MODULES PTN78020W Input Capacitor The minimum requirement for the input capacitance is a 2.2-µF ceramic capacitor for PTN78020W, in either a X5R or X7R temperature characteristic. Ceramic capacitors should be located within 0.5 inch (1,27 cm) of the regulator's 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 500 mA rms for VO ≤ 5.5. For VO > 5.5 V, the minimum ripple current rating is 750 mA rms. 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 2.2 µF. Tantalum capacitors are not recommended for use at the input bus, as none were found to meet the minimum voltage rating of 2 × (maximum dc voltage + ac ripple). This voltage derating 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. PTN78020H Input Capacitor The minimum requirement for PTN78020H the input capacitance is 18.8 µF (4x 4.7-µF) or equivalent . Ceramic capacitors should be located within 0.5 inch (1,27 cm) of the regulator's 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 500 mA rms for VO ≤ 5.5. For VO > 5.5 V, the minimum ripple current rating is 750 mA rms. The ripple current rating of electrolytic capacitors is a major consideration when they are used at the input. Tantalum capacitors are not recommended for use at the input bus, as none meet the minimum voltage rating of 2 × (maximum dc voltage + ac ripple). This voltage derating 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. PTN78020W/PTN78020H Output Capacitor The minimum capacitance required to ensure stability is a 330 µF. Either ceramic or electrolytic-type capacitors can be used. The minimum ripple current rating for the nonceramic capacitance must be at least 250 mA rms. The stability of the module and voltage tolerances are 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 0°C. For operation below 0°C, 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 mΩ (17 mΩ 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 300 µF. Also, to prevent the formation of local resonances, do not place more than three identical ceramic capacitors with values of 10 µF or greater in parallel. Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H Submit Documentation Feedback 13 PTN78020W PTN78020H SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 .................................................................................................................................................. www.ti.com 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 0°C. 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 tables, Table 5 and Table 6, identifies the characteristics of capacitors from a number of 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 ensure 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/µs. 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. Table 5. Recommended Input/Output Capacitors (PTN78020W) CAPACITOR CHARACTERISTICS QUANTITY WORKING VOLTAGE (V) VALUE (µF) EQUIVALENT SERIES RESISTANCE (ESR) (Ω) 85°C MAXIMUM RIPPLE CURRENT (mArms) Panasonic FC( Radial) 35 330 0.068 1050 10 × 16 FK (SMD) 50 330 0.12 900 12,5 × 13,5 United Chemi-Con PXA (SMD) 16 330 0.014 4360 10 × 12,2 PS 16 330 0.014 5500 LXZ 35 220 0.090 MVZ(SMD) 25 470 0.09 Nichicon UWG (SMD) 35 330 0.15 670 10 × 10 SP 20 180 0.032 4280 10 ×10.5 2 (1) ≤2 20SP180M (VI ~VO ≤ 16 V) Sanyo Os-Con SVP (SMD) 16 330 0.020 4700 10 × 12,7 1 (1) ≤1 16SVP330M (VI ≤ 14 V) SP 20 180 0.032 4280 10 ×10.5 2 (1) ≤2 20SP180M (VI ≤ 16 V) 20 100 0.085 1543 7,3 L × 4,3 W × 4,1 H N/R (2) ≤3 TPSV107M020R0085 (VO ≤ 10 V) 20 100 0.200 > 817 3225 N/R (2) ≤3 TPSE107M020R0200 (VO ≤ 10 V) CAPACITOR VENDOR/ COMPONENT SERIES AVX Tantalum TPS (SMD) (1) (2) 14 PHYSICAL SIZE (mm) INPUT BUS OUTPUT BUS 1 VENDOR NUMBER 1 EEUFC1V331 (VI < 30 V) (1) 1 EEVFK1H331Q 1 (1) ≤1 PXA16VC331MJ12TP (VI < 14 V) 10 × 12,5 1 (1) ≤1 16PS330M J12 (VI < 14 V) 760 10 × 12,5 1 (1) 2 LXZ35VB221M10X12LL (VI < 30 V) 670 10 × 10 1 1 MVZ25VC471MJ10TP (VI < 24 V) (VO ≤ 5.5 V) 1 UWG1V331MNR1GS 1 1 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. Not recommended (N/R). The voltage rating does not meet the minimum operating limits in most applications. Submit Documentation Feedback Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 Table 5. Recommended Input/Output Capacitors (PTN78020W) (continued) CAPACITOR CHARACTERISTICS QUANTITY WORKING VOLTAGE (V) VALUE (µF) EQUIVALENT SERIES RESISTANCE (ESR) (Ω) 85°C MAXIMUM RIPPLE CURRENT (mArms) Kemet X5R Ceramic 6.3 47 0.002 >1000 3225 N/R (3) ≤4 C1210C476K9PAC (VO ≤ 5.5 V) TDK X5R Ceramic 6.3 47 0.002 >1000 3225 N/R (3) ≤4 C3225X5R0J476MT (VO ≤ 5.5 V) Murata X5R Ceramic 6.3 47 0.002 >1000 3225 N/R (3) ≤4 GRM42-2X5R476M6.3 (VO ≤ 5.5 V) Murata X7R Ceramic 50 4.7 0.002 >1000 3225 TDK X7R Ceramic 50 2.2 0.002 >1000 3225 TDK X7R Ceramic 25 2.2 0.002 >1000 3225 ≥1 (4) Kemet X7R Ceramic 25 2.2 0.002 >1000 3225 ≥1 AVX X7R Ceramic 25 2.2 0.002 >1000 3225 ≥1 TDK X7R Ceramic 50 1.0 0.002 >1000 3225 CAPACITOR VENDOR/ COMPONENT SERIES PHYSICAL SIZE (mm) INPUT BUS 1 GRM32ER71H475KA88L ≥1 1 C3225X7R1H225KT 1 C3225X7R1E225KT/MT (VI~VO ≤ 20 V) (4) 1 C1210C225K3RAC (VO ≤ 20 V) (4) 1 C12103C225KAT2A (VO ≤ 20 V) ≥2 (5) 1 C3225X7R1H105KT 1 C1210C105K5RAC 1 C330C105K5R5CA 1 RPER71H2R2KK6F03 Kemet X7R Ceramic 50 1.0 0.002 >1000 3225 ≥2 Kemet Radial Through-hole 50 1.0 0.002 >1000 5,08 × 7,62 × 9,14 H ≥2 (5) Murata Radial Through-hole 50 2.2 0.004 >1000 10 H × 10 W×4D (4) (5) VENDOR NUMBER ≥1 (5) (3) OUTPUT BUS ≥1 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 rating of the ceramic capacitor limits the regulator operating input voltage to 20 V. Select a alternative ceramic component to operate at a higher input voltage. A total capacitance of 2 µF is an acceptable replacement value for a single 2.2-µF ceramic capacitor Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H Submit Documentation Feedback 15 PTN78020W PTN78020H SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 .................................................................................................................................................. www.ti.com Table 6. Recommended Input/Output Capacitors (PTN78020H) CAPACITOR CHARACTERISTICS QUANTITY WORKING VOLTAGE (V) VALUE (µF) EQUIVALENT SERIES RESISTANCE (ESR) (Ω) 85°C MAXIMUM RIPPLE CURRENT (mArms) Panasonic FC( Radial) 35 330 0.068 1050 10 × 16 FK (SMD) 50 330 0.12 900 12,5 × 13,5 LXZ 35 220 0.09 760 10 × 12,5 MVY(SMD) 35 220 0.15 670 Nichicon UWG (SMD) 35 330 0.15 Sanyo Os-Con SP (SMD 20 180 TDK X7R Ceramic 25 2.2 Murata X7R Ceramic 25 Kemet X7R Ceramic CAPACITOR VENDOR/ COMPONENT SERIES PHYSICAL SIZE (mm) INPUT BUS OUTPUT BUS 1 VENDOR NUMBER 1 EEUFC1V331 (VI < 30 V) 1 (1) 1 EEVFK1H331Q 1 (1) 2 LXZ35VB2231M10X12LL (VI < 30 V) 10 × 10 1 2 MVY35VC221M10X10TP (VI < 30 V) 670 10 × 10 1 1 UWG1V331MNR1GS (VI < 30 V) 0.032 4280 10 ×10.5 2 0.002 >1000 3225 ≥8 (2) 1 C3225X7R1E225KT/MT (VO ≤ 20 V) 2.2 0.002 >1000 3225 ≥8 (2) 1 GRM32RR71E225K (VO ≤ 20 V) 25 2.2 0.002 >1000 3225 ≥8 (2) 1 C1210C225K3RAC (VO ≤ 20 V) AVX X7R Ceramic 25 2.2 0.002 >1000 32225 ≥8 (2) 1 C12103C225KAT2A (VO ≤ 20 V) Murata X7R Ceramic 50 4.7 0.002 >1000 3225 ≥4 1 GRM32ER71H475KA88L TDK X7R Ceramic 50 3.3 0.002 >1000 3225 ≥6 1 CKG45NX7R1H335M Murata Radial Through-hole 50 3.3 0.004 >1000 12,5 H x 12,5 W x 4D ≥6 1 RPER71H3R3KK6F03 Kemet Radial Through-hole 50 4.7 0.002 >1000 5,08 × 7,62 × 9,14 H 1 C350C475K5R5CA (1) (2) (3) (1) ≥4 (3) ≤2 20SP180M (VI~ VO ≤ 16 V) 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 rating of the ceramic capacitor limits the regulator operating input voltage to 20 V. Select a alternative ceramic component to operate at a higher input voltage. A total capacitance of 2 µF is an acceptable replacement value for a single 2.2-µF ceramic capacitor Power-Up Characteristics When configured per the standard application, the PTN78020 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 26 shows the power-up waveforms for a PTN78020W, 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. 16 Submit Documentation Feedback Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 VI (5 V/div) VO (2 V/div) II (2 A/div) t - Time = 5 ms/div Figure 26. 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 is to prevent 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 PTN78020 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 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 itself off, reducing the output voltage to zero. The module instantly restarts when the sensed temperature decreases by a few degrees. 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. Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H Submit Documentation Feedback 17 PTN78020W PTN78020H SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 .................................................................................................................................................. www.ti.com Output On/Off Inhibit For applications requiring output voltage on/off control, the PTN78020 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 27 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 28 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. 5 Sense VI = 12 V 2 VI PTN78020 Inhibit CI 2.2 mF (Ceramic) Q1 Inhibit 3 GND 1 VO = 5 V 6 VO Adjust 7 4 RSET 21 k 0.05 W 1% + CO 330 mF L O A D BSS 138 GND GND Figure 27. On/Off Inhibit Control Circuit VO (2 V/div) II (2 A/div) Q1 VGS (10 V/div) t - Time = 5 ms/div Figure 28. Power Up Response From Inhibit Control 18 Submit Documentation Feedback Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 Optional Input/Output Filters Power modules include internal input and output ceramic capacitors in all of their designs. However, some applications require much lower levels of either input reflected or output ripple/noise. This application 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-µF ceramic capacitors, such as C4 shown in Figure 29. Ceramic capacitors should be placed close to the output power terminals. A single 1-µF 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 required to improve the regulator 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 2.2-µF ceramic capacitor, near the input power pins, reduces reflected conducted ripple/noise by 30% to 50%. 5 Sense 2 VI PTN78020W VI Inhibit C1 1 µF 50 V Ceramic (1) C2 2.2 µF 50 V Ceramic (Required) 3 GND VO 6 VO Adjust + 1 7 4 (2) RSET (1) C3 330 µF (Required) GND C4 1 µF Ceramic GND UDG−06049 (1) See the specifications for required value and type. For the PTN78020H, C2 = 4 × 4.7 µF. (2) See the Application Information section for suggeted value and type. Figure 29. Adding High-Frequency Bypass Capacitors To The Input and Output π Filters If a further reduction in ripple/noise level is required for an application, higher order filters must be used. A π (pi) filter, employing a ferrite bead (Fair-Rite part number 2773021447 or equivalent) in series with the input or output terminals of the regulator reduces the ripple/noise by at least 20 db (see Figure 30 and Figure 31). In order for the inductor to be effective in reduction of ripple and noise, ceramic capacitors are required. (Note: see Capacitor Recommendations for the PTN78020W 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 × 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 6 A on the output bus. 1-µH to 5-µH inductors can be used in place of the ferrite inductor bead. Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H Submit Documentation Feedback 19 PTN78020W PTN78020H SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 .................................................................................................................................................. www.ti.com 5 Sense L1 1−5 µH 2 VI C1 2.2 µF 50 V Ceramic (1) C3 2.2 µF 50 V Ceramic (Required) C2 330 µF 50 V (Optional) Vo PTN78020W Inhibit GND GND + (4) VI 3 1 Adjust 7 L2 1−5 µH 6 Vo + 4 C4 330 µF (Required) (2) RSET GND + C5 1 µF Ceramic (3) C6 100 µF GND UDG−06050 (1) See the specifications for required value and type. For the PTN78020H, C3 = 4 × 4.7 µF. (2) See the Application Information section for suggeted value and type. (3) Recommended whenever IO > 2A. (4) For PTN78020H, C1 ≤ 4.7 µF. Figure 30. Adding π 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 31. π-Filter Attenuation vs. Load Current 20 Submit Documentation Feedback Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H PTN78020W PTN78020H www.ti.com .................................................................................................................................................. SLTS228B – DECEMBER 2004 – REVISED APRIL 2008 5 L2 1 µH to 5 µH Sense L1 1 µH to 5 µH VI 2 VI Inhibit GND GND C1 1 µF 50 V Ceramic C2 330 µF 50 V (Optional) (1) 3 1 Adjust 7 C3 2.2 µF 50 V Ceramic (Required) VO 6 VO PTN78020W L3 1 µH to 5 µH + + 4 (1) (2) RSET C4 330 µF (Required) GND C5 1 µF Ceramic C6 (3) 100 µF GND UDG−05089 (1) See the specifications for required value and type. For the PTN78020H, C2 = 4 × 4.7 µF. (2) See the Application Information section for suggeted value and type. (3) Recommended whenever IO > 2A. (4) For PTN78020H, C1 ≥ 4.7 µF. Figure 32. Adding π Filters (IO = 3 A to 6 A) Copyright © 2004–2008, Texas Instruments Incorporated Product Folder Link(s): PTN78020W PTN78020H Submit Documentation Feedback 21 PACKAGE OPTION ADDENDUM www.ti.com 8-Dec-2008 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty PTN78020HAH ACTIVE DIP MOD ULE EUK 7 20 Pb-Free (RoHS) Call TI N / A for Pkg Type PTN78020HAS ACTIVE DIP MOD ULE EUL 7 20 TBD Call TI Level-1-235C-UNLIM/ Level-3-260C-168HRS PTN78020HAST ACTIVE DIP MOD ULE EUL 7 200 TBD Call TI Level-1-235C-UNLIM/ Level-3-260C-168HRS PTN78020HAZ ACTIVE DIP MOD ULE EUL 7 20 Pb-Free (RoHS) Call TI Level-3-260C-168 HR PTN78020HAZT ACTIVE DIP MOD ULE EUL 7 200 Pb-Free (RoHS) Call TI Level-3-260C-168 HR PTN78020WAD ACTIVE DIP MOD ULE EUK 7 20 Pb-Free (RoHS) Call TI N / A for Pkg Type PTN78020WAH ACTIVE DIP MOD ULE EUK 7 20 Pb-Free (RoHS) Call TI N / A for Pkg Type PTN78020WAS ACTIVE DIP MOD ULE EUL 7 20 TBD Call TI Level-1-235C-UNLIM/ Level-3-260C-168HRS PTN78020WAST ACTIVE DIP MOD ULE EUL 7 200 TBD Call TI Level-1-235C-UNLIM/ Level-3-260C-168HRS PTN78020WAZ ACTIVE DIP MOD ULE EUL 7 20 Pb-Free (RoHS) Call TI Level-3-260C-168 HR PTN78020WAZT ACTIVE DIP MOD ULE EUL 7 200 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), Pb-Free (RoHS Exempt), 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. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. 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. 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