PT3660 Series 30-A Dual Output Isolated DC/DC Converter SLTS181 OCTOBER 2002 Features • Dual Outputs (Independantly Regulated) • Power-up/Down Sequencing • Input Voltage Range: 36V to 75V • 1500 VDC Isolation • Temp Range: –40° to 100°C • High Efficiency: 88% • Fixed Frequency Operation • Over-Current Protection (Both Outputs) • Dual Logic On/Off Control • Over-Temperature Shutdown • Over-Voltage Protection (Coordinated Shutdown) • Under-Voltage Lockout • Input Differential EMI Filter • Solderable Copper Case • Safety Approvals: UL1950 CSA 22.2 950 ADVANCE INFORMATION Description Ordering Information The PT3660 Excalibur™ Series is a 30-A rated, dual-output isolated DC/DC converter that combines state-of-the-art power conversion technology with unparalleled flexibility. These modules operate from a standard telecom (–48V) central office (CO) supply to produce two independantly regulated outputs. The PT3660 series is characterized with high efficiencies and ultra-fast transient response, and incorporates many features to facilitate system integration. These include a flexible “On/Off” enable control, output current limit, over-temperature protection, and an input undervoltage lockout. In addition, both output voltages are designed to meet the power-up/power-down sequencing requirements of popular DSP ICs. The PT3660 series is housed in space-saving solderable copper case. The package does not require a heatsink and is available in both vertical and horizontal configurations, including surface mount. The ‘N’ configuration occupies less than 2 in² of PCB area. This product is pin-compatible with the PT4660 series. Pt. No. PT3661o PT3662o PT3663o PT3665o PT3666o PT3667o PT3668o Case/Pin Configuration Vertical Horizontal SMD V 2 Adjust 1 13 Vo 1 adj Vo 1 +Vin Vo 2 9–12 Vo 1 21–24 Vo 2 PT3660 3 4 – V IN 2 L O A D EN 1* EN 2 –Vin * Inverted logic For technical support and more information, see inside back cover or visit www.ti.com COM 14–19 COM Order Suffix N A C Package Code (EKD) (EKA) (EKC) (Reference the applicable package code drawing for the dimensions and PC board layout) V 1 Adjust + V IN Vo1/Vo2 5.0/3.3 Volts 3.3/2.5 Volts 3.3/1.8 Volts 3.3/1.5 Volts 2.5/1.8 Volts 5.0/1.8 Volts 3.3/1.2 Volts PT Series Suffix (PT1234 x ) Typical Application 20 Vo 2 adj = = = = = = = L O A D PT3660 Series 30-A Dual Output Isolated DC/DC Converter SLTS181 OCTOBER 2002 Pin-Out Information Pin Function On/Off Logic Pin Function Pin Function Pin 3 Pin 4 Output Status 1 +Vin 10 +Vo1 19 COM 1 × Off 2 -Vin 11 +Vo1 20 Vo2 Adjust 0 1 On 3 EN 1 12 +Vo1 21 +Vo2 4 EN 2 13 Vo1 Adjust 22 +Vo2 × 0 Off 5 TEMP 14 COM 23 +Vo2 6 AUX 15 COM 24 +Vo2 7 Do Not Connect 16 COM 25 Do Not Connect 8 Do Not Connect 17 COM 26 Do Not Connect 9 +Vo1 18 COM Note: Shaded functions indicate signals that are referenced to the input (-Vin) potential. Notes: Logic 1 =Open collector Logic 0 = –Vin (pin 2) potential For positive Enable function, connect pin 3 to pin 2 and use pin 4. For negative Enable function, leave pin 4 open and use pin 3. +Vin: The positive input supply for the module with respect to –Vin. When powering the module from a –48V telecom central office supply, this input is connected to the primary system ground. –Vin: The negative input supply for the module, and the 0VDC reference for the EN 1, EN 2, TEMP, and AUX signals. When the module is powered from a +48V supply, this input is connected to the 48V–Return. EN 1: The negative logic input that enables the module output. This pin is TTL compatible and referenced to –Vin. A logic ‘0’ at this pin enables the module’s outputs. A logic ‘1’ or high impedance disables the module’s outputs. If not used, the pin must be connected to –Vin. EN 2: The positive logic input that enables the module output. This pin is TTL compatible and referenced to –Vin. A logic ‘1’ or high impedance enables the module’s outputs. If not used, the pin should be left open circuit. TEMP: This is the output voltage produced by the module’s internal temperature sensor. The voltage at this pin is referenced to –Vin and rises approximately 10mV/°C from an intital value of 0.1VDC at –40°C (Vtemp =0.5 + 0.01·Tsense). The signal is available whenever the module is supplied with a valid input voltage, and is independant of the enable logic status. (Note: A load impedance of less than 1MΩ will adversly affect the module’s over-temperature shutdown threshold. Use a high-impedance input when monitoring this signal.) AUX: Produces a regulated output voltage of 11.6V ±5%, which is referenced to –Vin. The current drawn from the pin must be limited to 10mA. The voltage may be used to indicate the output status of the module to a primary referenced circuit, or power a low-current amplifer. Vo1: The higher regulated output voltage, which is referenced to the COM node. Vo2: The lower regulated output voltage, which is referenced to the COM node. COM: The secondary return reference for the module’s two regulated output voltages. It is DC isolated from the input supply pins. Vo1 Adjust: Using a single resistor, this pin allows Vo1 to be adjusted higher or lower than the preset value. If not used, this pin should be left open circuit. Vo2 Adjust: Using a single resistor, this pin allows Vo2 to be adjusted higher or lower than the preset value. If not used, this pin should be left open circuit. For technical support and more information, see inside back cover or visit www.ti.com ADVANCE INFORMATION Pin Descriptions PT3660 Series 30-A Dual Output Isolated DC/DC Converter ADVANCE INFORMATION Specifications SLTS181 OCTOBER 2002 (Unless otherwise stated, Ta =25°C, Vin =48V, & Io 1=Io 2=10A) Characteristics Symbols Conditions Output Current Io1, Io2 Vo1 Io1+Io2 Vo2 Total (both outputs) Input Voltage Range Set Point Voltage Tolerance Temperature Variation Line Regulation Load Regulation Vin Votol ∆Regtemp ∆Regline ∆Regload Cross Regulation ∆Regcross Total Output Variation ∆Votol Efficiency η Vo Ripple (pk-pk) Vr Transient Response ttr Current Limit Output Rise Time Output Over-Voltage Protection Switching Frequency Under-Voltage-Lockout ILIM ton OVP fs UVLO Internal Input Capacitance Cin Min Vo1 ≤3.3V Vo1 =5.0V All voltages Vo1 ≤3.3V Vo1 =5.0V –40 to +100°C Case, Io1 =Io2 =0A Over Vin range with Io1=Io2=5A 1A ≤Io1 ≤Io1max, Io2 =1A 1A ≤Io2 ≤Io1max, Io1 =1A 1A ≤Io2 ≤Io1max, Io1 =1A 1A ≤Io1 ≤Io1max, Io2 =1A Includes set-point, line load, –40°C to +100°C case ∆Vo1 ∆Vo2 ∆Vo1 ∆Vo2 ∆Vo1 ∆Vo2 PT3661 PT3662 PT3663 PT3665 PT3666 PT3667 PT3668 Io1=Io2=5A, 20MHz bandwidth Vo =5V Vo <5V 1A/µs load step from 50% to 100% Iomax (either output) Each output with other unloaded At turn-on to within 90% of Vo Either output; shutdown and latch off Rising Falling PT3660 SERIES Typ Max 0 0 0 0 0 36 — — — — — — — — — — — — — — — — — — — — 15.5 — — 280 — 30 — — — — — 48 ±1 ±0.5 ±5 ±2 ±2 ±2 ±2 ±2 ±2 88 87 86 86 85 88 86 — — 25 6.0 18 5 125 (1) — 34 32 15 10 15 30 25 75 ±2 — ±10 ±10 ±10 ±10 ±5 ±3 ±3 — — — — — — — 75 50 100 — — 10 — 320 36 — — 2 — 3.5 0 — — — 0.8 Units A A A V %Vo %Vo mV mV mV %Vo % mVpp µSec %Vo A mSec %Vo kHz V µF On/Off Control Input High Voltage Input Low Voltage Input Low Current Referenced to –Vin VIH VIL IIL — 0.5 — mA Standby Current Iin standby Pins 2, 3, & 4 connected — 3 5 mA External Output Capacitance Primary/Secondary Isolation Per each output Operating Temperature Range Over-Temperature Protection Solder Reflow Temperature Storage Temperature Mechanical Shock Mechanical Vibration Ta OTP Treflow Ts — — Weight Flammability — — Over Vin range Case temperature (auto restart) Surface temperature of module pins or case — Per Mil-STD-883D, Method 2002.3 Per Mil-STD-883D, Method 2007.2, Suffix N 20–2,000Hz Suffixes A, C — Materials meet UL 94V-0 0 1500 — 10 — — –40 100 — –40 — — — — — — 1500 — 0.1 (3) 1.5 (3) — — — — 500 10 (6) 20 (6) 90 5,000 — — — — — 85 (4) — 215 (5) 125 — — — — µF V pF MΩ Temperature Sense Cout V iso C iso R iso Vtemp Output voltage at temperatures:- –40°C 100°C (2) V V °C °C °C °C G’s G’s grams Notes: (1) This is a fixed parameter. Adjusting Vo1 or Vo2 higher will increase the module’s sensitivity to over-voltage detection. For more information, see the application note on output voltage adjustment. (2) The EN 1 and EN2 control inputs (pins 3 & 4) have internal pull-ups and may be controlled with an open-collector (or open-drain) transistor. Both inputs are diode protected and can be connected to +Vin . The maximum open-circuit voltage is 5.4V. (3) Voltage output at “TEMP” pin is defined by the equation:- VTEMP = 0.5 + 0.01·T, where T is in °C. See pin descriptions for more information. (4) See SOA curves or consult the factory for the appropriate derating. (5) During solder reflow of SMD package version do not elevate the module case, pins, or internal component temperatures above a peak of 215°C. For further guidance refer to the application note, “Reflow Soldering Requirements for Plug-in Power Surface Mount Products,” (SLTA051). (6) The case pins on the through-holed package types (suffixes N & A) must be soldered. For more information see the applicable package outline drawing. For technical support and more information, see inside back cover or visit www.ti.com Typical Characteristics PT3661 30-A Dual Output Isolated DC/DC Converter SLTS181 OCTOBER 2002 PT3661 (V1/V2 =5.0V/3.3V); Vin =48V (See Notes A & B) Efficiency vs I1out; I2out @1A, 3A, and 6A Power Dissipation vs (Io1 + Io2) 20 100 16 90 80 6 3 1 70 Pd - Watts Efficiency - % I2 out 12 8 4 60 0 50 0 3 6 9 12 0 15 6 12 18 24 30 Io 1 + Io2 (A) I1 out (A) Safe Operating Area: (Io1 + Io2) Efficiency vs I1out; I2out @9A, 12A, and 15A 90 100 9 12 15 70 60 Ambient Temperature (°C) Efficiency - % I2 out 80 Airflow 70 300LFM 200LFM 100LFM Nat conv 60 50 40 30 20 50 0 3 6 9 12 0 15 5 10 15 20 25 30 Io1 + Io2 (A) I1 out (A) Cross Regulation: V1out vs I 2out @I1out =1A 5.05 V1 out (V) 5.025 5 4.975 4.95 0 3 6 9 12 15 I2 out (A) Cross Regulation: V2out vs I 1out @I2out =1A 3.32 V2 out (V) 3.31 3.3 3.29 3.28 0 3 6 9 12 15 I1 out (A) Note A: All Characteristic data in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the converter. Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperatures. For technical support and more information, see inside back cover or visit www.ti.com ADVANCE INFORMATION 80 90 Typical Characteristics PT3662—48V 30-A Dual Output Isolated DC/DC Converter SLTS181 OCTOBER 2002 PT3662 (V1/V2 =3.3V/2.5V); Vin =48V (See Notes A & B) Efficiency vs I1out; I2out @1A, 3A, and 6A Power Dissipation vs (Io 1 + Io2) 90 20 16 I2 out 6 3 1 80 Pd - Watts Efficiency - % 85 12 8 75 4 70 0 0 3 6 9 12 15 0 6 12 I1 out (A) 24 30 Safe Operating Area: (Io1 + Io 2) Efficiency vs I1out; I2out @9A, 12A, and 15A 90 90 Efficiency - % I2 out 9 12 15 80 75 Ambient Temperature (°C) 80 85 Airflow 70 300LFM 200LFM 100LFM Nat conv 60 50 40 30 70 20 0 3 6 9 12 15 0 I1 out (A) 5 10 15 20 25 30 Io1 + Io2 (A) Cross Regulation: V1out vs I 2out @I1out =1A 3.36 V1 out (V) 3.33 3.30 3.27 3.24 0 3 6 9 12 15 I2 out (A) Cross Regulation: V2out vs I 1out @I2out =1A 2.530 2.515 V2 out (V) ADVANCE INFORMATION 18 Io1 + Io2 (A) 2.500 2.485 2.470 0 3 6 9 12 15 I1 out (A) Note A: All Characteristic data in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the converter. Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperatures. For technical support and more information, see inside back cover or visit www.ti.com Typical Characteristics PT3663—48V 30-A Dual Output Isolated DC/DC Converter SLTS181 OCTOBER 2002 PT3663 (V1/V2 =3.3V/1.8V); Vin =48V (See Notes A & B) Efficiency vs I1out; I2out @1A, 3A, and 6A Power Dissipation vs (Io1 + Io2) 20 90 16 I2 out 6 3 1 80 Pd - Watts Efficiency - % 85 12 8 75 4 70 0 0 3 6 9 12 0 15 6 12 I1 out (A) 18 24 30 Io1 + Io2 (A) Safe Operating Area: (Io1 + Io2) Efficiency vs I 1out; I2out @9A, 12A, and 15A 90 90 9 12 15 80 75 Ambient Temperature (°C) Efficiency - % I2 out Airflow 70 300LFM 200LFM 100LFM Nat Conv 60 50 40 30 20 70 0 3 6 9 12 0 15 5 10 15 20 25 30 Io1 + Io2 (A) Iout (A) Cross Regulation: V1out vs I 2out @I1out =1A 3.36 3.34 V1 out (V) 3.32 3.3 3.28 3.26 3.24 0 3 6 9 12 15 I2 out (A) Cross Regulation: V2out vs I 1out @I2out =1A 1.82 V1 out (V) 1.81 1.8 1.79 1.78 0 3 6 9 12 15 I2 out (A) Note A: All Characteristic data in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the converter. Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperatures. For technical support and more information, see inside back cover or visit www.ti.com ADVANCE INFORMATION 80 85 Typical Characteristics PT3665—48V 30-A Dual Output Isolated DC/DC Converter SLTS181 OCTOBER 2002 PT3665 (V1/V2 =3.3V/1.5V); Vin =48V (See Notes A & B) Efficiency vs I 1out; I2out @1A, 3A, and 6A Power Dissipation vs (Io1 + Io2) 100 20 16 I2 out 80 6 3 1 70 Pd - Watts Efficiency - % 90 60 12 8 4 50 0 0 3 6 9 12 15 0 6 12 I1 out (A) 24 30 Safe Operating Area: (Io1 + Io 2) Efficiency vs I 1out; I2out @9A, 12A, and 15A 100 90 Efficiency - % I2 out 80 9 12 15 70 60 Ambient Temperature (°C) 80 90 Airflow 70 300LFM 200LFM 100LFM Nat Conv 60 50 40 30 50 20 0 3 6 9 12 15 0 I2 out (A) 5 10 15 20 25 30 Io1 + Io2 (A) Cross Regulation: V1out vs I 2out @I1out =1A 3.32 V1 out (V) 3.31 3.3 3.29 3.28 0 3 6 9 12 15 I2 out (A) Cross Regulation: V2out vs I 1out @I2out =1A 1.51 1.505 V2 out (V) ADVANCE INFORMATION 18 Io1 + Io2 (A) 1.5 1.495 1.49 0 3 6 9 12 15 I1 out (A) Note A: All Characteristic data in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the converter. Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperatures. For technical support and more information, see inside back cover or visit www.ti.com Typical Characteristics PT3666—48V 30-A Dual Output Isolated DC/DC Converter SLTS181 OCTOBER 2002 PT3666 (V1/V2 =2.5V/1.8V); Vin =48V (See Notes A & B) Efficiency vs I1out; I2out @1A, 3A, and 6A Power Dissipation vs I1out and I2out 100 10 90 8 80 6 3 1 70 Pd - Watts Efficiency - % I2 out 60 6 4 2 50 0 0 3 6 9 12 15 0 3 6 I1 out (A) 9 12 15 Io1 + Io2 (A) Efficiency vs I1out; I2out @9A, 12A, and 15A Safe Operating Area: (Io1 + Io2) 100 90 80 9 12 15 70 60 Ambient Temperature (°C) Efficiency - % I2 out Airflow 70 300LFM 200LFM 100LFM Nat Conv 60 50 40 30 50 20 0 3 6 9 12 15 0 I1 out (A) 5 10 15 20 25 30 Io1 + Io2 (A) Cross Regulation: V1out vs I2out @I1out =1A 2.52 V1 out (V) 2.51 2.5 2.49 2.48 0 3 6 9 12 15 I2 out (A) Cross Regulation: V2out vs I1out @I2out =1A 1.81 V2 out (V) 1.805 1.8 1.795 1.79 0 3 6 9 12 15 I1 out (A) Note A: All Characteristic data in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the converter. Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperatures. For technical support and more information, see inside back cover or visit www.ti.com ADVANCE INFORMATION 80 90 Typical Characteristics PT3667—48V 30-A Dual Output Isolated DC/DC Converter SLTS181 OCTOBER 2002 PT3667 (V1/V2 =5V/1.8V); Vin =48V (See Notes A & B) Efficiency vs I 1out; I2out @1A, 3A, and 6A Power Dissipation vs (Io1 + Io2) 100 20 16 I2 out 80 6 3 1 70 Pd - Watts Efficiency - % 90 60 12 8 4 50 0 0 3 6 9 12 15 0 6 12 I1 out (A) 24 30 Safe Operating Area: (Io1 + Io 2) Efficiency vs I 1out; I2out @9A, 12A, and 15A 90 100 Efficiency - % I2 out 80 9 12 15 70 60 Ambient Temperature (°C) 80 90 Airflow 70 300LFM 200LFM 100LFM Nat conv 60 50 40 30 50 20 0 3 6 9 12 15 0 I1 out (A) 5 10 15 20 25 30 Io1 + Io2 (A) Cross Regulation: V1out vs I 2out @I1out =1A 5.02 V1 out (V) 5.01 5 4.99 4.98 0 3 6 9 12 15 I2 out (A) Cross Regulation: V2out vs I 1out @I2out =1A 1.81 1.805 V2 out (V) ADVANCE INFORMATION 18 Io1 + Io2 (A) 1.8 1.795 1.79 0 3 6 9 12 15 I1 out (A) Note A: All Characteristic data in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the converter. Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperatures. For technical support and more information, see inside back cover or visit www.ti.com Typical Characteristics PT3668—48V 30-A Dual Output Isolated DC/DC Converter SLTS181 OCTOBER 2002 PT3668 (V1/V2 =3.3V/1.2V); Vin =48V (See Notes A & B) Efficiency vs I1out; I2out @1A, 3A, and 6A Power Dissipation vs (Io 1 + Io2) 100 20 16 I2 out 80 6 3 1 70 Pd - Watts Efficiency - % 90 60 12 8 4 50 0 0 3 6 9 12 0 15 6 12 18 24 30 Io1 + Io2 (A) I1 out (A) Efficiency vs I1out; I2out @9A, 12A, and 15A Safe Operating Area: (Io1 + Io 2) 90 100 80 9 12 15 70 60 Ambient Temperature (°C) Efficiency - % I2 out Airflow 70 300LFM 200LFM 100LFM Nat Conv 60 50 40 30 20 50 0 3 6 9 12 0 15 5 10 15 20 25 30 Io1 + Io2 (A) I1 out (A) Cross Regulation: V1out vs I 2out @I1out =1A 3.32 V1 out (V) 3.31 3.3 3.29 3.28 0 3 6 9 12 15 I2 out (A) Cross Regulation: V2out vs I 1out @I2out =1A 1.21 V2 out (V) 1.205 1.2 1.195 1.19 0 3 6 9 12 15 I1 out (A) Note A: All Characteristic data in the above graphs has been developed from actual products tested at 25°C. This data is considered typical data for the converter. Note B: SOA curves represent operating conditions at which internal components are at or below manufacturer’s maximum rated operating temperatures. For technical support and more information, see inside back cover or visit www.ti.com ADVANCE INFORMATION 80 90 Application Notes PT3660, PT4660 & PT4680 Series Operating Features & System Considerations for the PT3660/4660/4680 Dual-Output Converters Over-Current Protection Under-Voltage Lock-Out The dual-outputs of the PT3660, PT4660, and PT4680 series of DC/DC converters have independent output voltage regulation and current limit control. Applying a load current in excess of the current limit threshold at either output will cause the respective output voltage to drop. However, the voltage at Vo2 is derived from Vo1. Therefore a current limit fault on Vo1 will also cause Vo2 to drop. Conversely, a current limit fault applied to Vo2 will only cause Vo2 voltage to drop, and Vo1 will remain in regulation. The Under-Voltage Lock-Out (UVLO) circuit prevents operation of the converter whenever the input voltage to the module is insufficient to maintain output regulation. The UVLO has approximately 2V of hysterisis. This is to prevent oscillation with a slowly changing input voltage. Below the UVLO threshold the module is off and the enable control inputs, EN1 and EN2 are inoperative. The current limit circuitry incorporates a limited amount of foldback. The fault current flowing into an absolute short circuit is therefore slightly less than the current limit threshold. Recovery from a current limit fault is automatic and the converter will not be damaged by a continuous short circuit at either output. Output Over-Voltage Protection Each output is monitored for over voltage (OV). For fail safe operation and redundancy, the OV fault detection circuitry uses a separate reference to the voltage regulation circuits. The OV threshold is fixed, and set nominally 25% higher than the set-point output voltage. If either output exceeds the threshold, the converter is shutdown and must be actively reset. The OV protection circuit can be reset by momentarily turning the converter off. This is accomplished by either cycling one of the output enable control pins (EN1 or EN2), or by removing the input power to the converter. Note: If Vo1 or Vo2 is adjusted to a higher voltage, the margin between the respective steadystate output voltage and its OV threshold is reduced. This can make the module sensitive to OV fault detection, that may result from random noise and load transients. Over-Temperature Protection The converter has an internal temperature sensor. At a case temperature of approximately 115°C the converter will shut down, and will automatically restart when the temperature returns to about 100°C. The analog voltage generated by the sensor is also made available at the ‘TEMP’ output (pin 5), and can be monitored by the host system for diagnostic purposes. Consult the ‘Pin Descriptions’ section of the data sheet for further information on this feature. Primary-Secondary Isolation The PT4460/80 and PT3660 series of DC/DC converters incorporate electrical isolation between the input terminals (primary) and the output terminals (secondary). All converters are production tested to a withstand voltage of 1500VDC. The isolation complies with UL60950 and EN60950, and the requirements for operational isolation. This allows the converter to be configured for either a positive or negative input voltage source. The regulation control circuitry for these modules is located on the secondary (output) side of the isolation barrier. Control signals are passed between the primary and secondary sides of the converter via a proprietory magnetic coupling scheme. This eliminates the use of opto-couplers. The data sheet ‘Pin Descriptions’ and ‘Pin-Out Information’ provides guidance as to which reference (primary or secondary) that must be used for each of the external control signals. Fuse Requirements To comply with safety agency requirements, these converters must be operated with an external input fuse. A fast-acting 250-V fuse is required. Table 1-1 gives the recommended current rating for the product series being used. Table 1-1; Recommended Fuse Rating Product Input Total Series Bus Iout Fuse Rating PT4660 PT4680 PT3660 7A 10A 7A For technical support and more information, see inside back cover or visit www.ti.com 48V 24V 48V 20A 20A 30A Application Notes PT3660, PT4660 & PT4680 Series Using the On/Off Enable Controls on the PT3660/ 4660/4680 Series of Dual-Output Converters The PT3660/4660 (48V input) and PT4680 (24V input) series of dual-output DC/DC converters incorporate both positive and negative logic Output Enable controls. EN1 (pin 3) is the positive enable input, and EN2 (pin 4) is the negative enable input. Both inputs are TTL logic compatible, and are electrically referenced to -Vin (pin 2) on the primary (input) side of the converter. A pull-up resistor is not required, but may be added if desired. Adding a pull-up resistor from either input, up to +Vin, will not damage the converter. the outputs of the converter. An example of this configuration is detailed in Figure 2-2. Note: The converter will only produce and output voltage if a valid input voltage is applied to ±Vin. Figure 2-2; Negative Enable Configuration 3 4 EN 1* EN 2 PT4660 1 =Outputs On BSS138 – V IN Automatic (UVLO) Power-Up Connecting EN1 (pin 3) to -Vin (pin 2) and leaving EN2 (pin 4) open-circuit configures the converter for automatic power up. (See data sheet “Typical Application”). The converter control circuitry incorporates an “Under Voltage Lockout” (UVLO) function, which disables the output until the minimum specified input voltage is present at ±Vin. (See data sheet Specifications). The UVLO circuitry ensures a clean transition during power-up and powerdown, allowing the converter to tolerate a slow-rising input voltage. For most applications EN1 and EN2, can be configured for automatic power-up. Positive Output Enable (Negative Inhibit) To configure the converter for a positive enable function, connect EN1 (pin 3) to -Vin (pin 2), and apply the system On/Off control signal to EN2 (pin 4). In this configuration, a logic ‘0’ (-Vin potential) applied to pin 4 disables the converter outputs. An example of this configuration is detailed in Figure 2-1. Figure 2-1; Positive Enable Configuration 3 2 –Vin On/Off Output Voltage Sequencing The output voltages from these dual-output DC/DC converters are independantly regulated, and are internally sequenced to meet the power-up requirements of popular microprocessor and DSP chipsets. Figure 2-3 shows the waveforms from a PT4661 after the converter is enabled at t=0s. During power-up, the Vo1 and Vo 2 voltage waveforms typically track within 0.4V prior to Vo2 reaching regulation. The waveforms were measured with a 5-Adc resistive load at each output, and with a 48-VDC input source applied. The converter typically produces a fully regulated output within 25ms. The actual turn-on time will vary slightly with input voltage, but the power-up sequence is independent of the load at either output. Figure 2-3; Vo1, Vo2 Power-Up Sequence Vo1 (2V/Div) EN 1* Vo2 (2V/Div) 4 EN 2 PT4660 IIN (0.5A/Div) 1 =Outputs Off BSS138 – V IN 2 –Vin 0 5 10 15 20 25 30 35 t (milliseconds) Negative Output Enable (Positive Inhibit) To configure the converter for a negative enable function, EN2 (pin 4) is left open circuit, and the system On/Off control signal is applied to EN1 (pin 3). A logic ‘0’ (-Vin potential) must then be applied to pin 3 in order to enable During turn-off, both outputs drop rapidly due to the discharging effect of actively switched rectifiers. The voltage at Vo 1 remains higher than Vo2 during this period. The discharge time is typically 100µs, but will vary with the amount of external load capacitance. For technical support and more information, see inside back cover or visit www.ti.com Application Notes PT3660, PT4660 & PT4680 Series Adjusting the Output Voltage of the PT3660, PT4660, and PT4680 Dual-Output Converters 3. Vo2 must always be at least 0.3V lower than Vo1. 4. The over-voltage protection threshold is fixed, and is set nominally 25% above the set-point output voltage. Adjusting Vo1 or Vo2 higher will reduce the voltage margin between the respective steady-state output voltage and its over-voltage (OV) protection threshold. This could make the module sensitive to OV fault detection, as a result of random noise and load transients. Note: An OV fault is a latched condition that shuts down both outputs of the converter. The fault can only be cleared by cycling one of the Enable control pins (EN1* / EN2), or by momentarily removing the input power to the module. The dual output voltages from the PT3660/PT4660 (48V Bus), and PT4680 (24V Bus) series of DC/DC converters can be independently adjusted by up to 10%, higher or lower than the factory trimmed pre-set voltage. The adjustment requires the addition of a single external resistor 1. Table 3-1 gives the adjustment range of Vo1 and Vo2 for each model in the series as V a(min) and V a(max). Vo1 Adjust Down: Add a resistor (R1), between pin 13 (V1 Adj) and pin 12 (Vo1) 2. 5. Never connect capacitors to either the Vo1 Adjust or Vo2 Adjust pins. Any capacitance added to these control pins will affect the stability of the respective regulated output. Vo1 Adjust Up: To increase the output, add a resistor R2 between pin 13 (V1 Adj) and pin 14 (COM) 2, 4. Vo2 Adjust Down: Add a resistor (R3) between pin 20 (V2 Adj) and pin 21 (Vo2) 2. The adjust up and adjust down resistor values can also be calculated using the following formulas. Be sure to select the correct formula parameter from Table 3-1 for the output and model being adjusted. Vo2 Adjust Up: Add a resistor R4 between pin 20 (V2 Adj) and pins 19 (COM) 2, 4. Refer to Figure 3-1 and Table 3-2 for both the placement and value of the required resistor. (R1) or (R3) = Ko (Va – Vr ) Vr (Vo – Va) – Rs kΩ Notes: 1. Adjust resistors are not required if Vo1 and Vo2 are to remain at their respective nominal set-point voltage. In this case, V1 Adj (pin 13) and V2 Adj (pin 20) are left open-circuit R2 or R4 = Ko Va – Vo – Rs kΩ Where: Vo Va Vr Ko Rs = = = = = 2. Use only a single 1% resistor in either the (R1) or R2 location to adjust Vo1, and in the (R3) or R4 location to adjust Vo2. Place the resistor as close to the converter as possible. Original output voltage, (Vo1 or Vo2) Adjusted output voltage The reference voltage from Table 3-1 The multiplier constant in Table 3-1 The series resistance from Table 3-1 Figure 3-1; Placement of Output Adjust Resistors + V IN Vo 1 1 +Vin Vo 2 9–12 V o1 21–24 V o2 (R1) PT4660 V o 1 adj 3 4 – V IN 2 EN 1* EN 2 V o 2 adj 13 L O A D 20 R2 –Vin COM (R3) 14–19 * Inverted logic For technical support and more information, see inside back cover or visit www.ti.com R4 COM L O A D Application Notes continued PT3660, PT4660 & PT4680 Series Table 3-1; ADJUSTMENT RANGE AND FORMULA PARAMETERS Vo1 Bus 24V Bus Pt.# 48V Bus Pt.# Adj. Resistor Vo(nom) Va(min) Va(max) Vr Ω) Ko (V·kΩ Ω) Rs (kΩ PT4681/7 PT4661/7 (R1)/R2 PT4682/3/5 PT4662/3/5 (R1)/R2 PT4688 PT4668 (R1)/R2 PT4686 PT4666 (R1)/R2 Vo2 Bus (2) PT4681 PT4661 (R3)/R4 PT4682 PT4662 (R3)/R4 PT4683/6/7 PT4663/6/7 (R3)/R4 PT4685 PT4665 (R3)/R4 PT4688 PT4668 (R3)/R4 5.0V 4.5V 5.5V 2.5V 1.248 20.0 3.3V 2.97V 3.63V 1.65V 8.234 20.0 3.3V 2.97V 3.63V 2.5V 10.96 4.99 2.5V 2.25V 2.75V 1.25 6.24 20.0 3.3V 2.97V 3.63V 1.5V 1.8 4.99 2.5V 2.25V 2.75V 1.5V 2.0 3.32 1.8V 1.62V 1.98V 1.5V 1.9 3.32 1.5V 1.35 1.65 TBD TBD TBD 1.2V 1.08 1.32 0.6V 0.726 4.22 Table 3-2a; ADJUSTMENT RESISTOR VALUES, Vo1 24V Bus Pt.# PT4681/7 48V Bus Pt.# PT4661/7 Adj. Resistor (R1)/R2 Vo(nom) Va(req’d) 5.5 5.4 5.3 5.2 5.1 5.0 4.9 4.8 4.7 4.6 4.5 5.0V 5.0kΩ 11.2kΩ 21.6kΩ 42.4kΩ 105.0kΩ (99.8)kΩ (37.4)kΩ (16.6)kΩ (6.2)kΩ (0.0) Va(req’d) 3.6 3.54 3.48 3.42 3.36 3.3 3.24 3.18 3.12 3.06 3.0 PT4682/3/5 PT4662/3/5 (R1)/R2 PT4688 PT4668 (R1)/R2 3.3V 3.3V PT4686 PT4666 (R1)/R2 2.5V Va(req’d) 7.4kΩ 14.3kΩ 25.7kΩ 48.6kΩ 117.0kΩ 31.5kΩ 40.7kΩ 55.9kΩ 86.3kΩ 178.0kΩ (112.0kΩ) (43.6kΩ) (20.8kΩ) (9.3kΩ) (2.5kΩ) (49.1kΩ) (19.9kΩ) (10.1kΩ) (5.2kΩ) (2.3kΩ) 2.75 2.7 2.65 2.6 2.55 2.5 2.45 2.4 2.35 2.3 2.25 5.0kΩ 11.2kΩ 21.6kΩ 42.4kΩ 105.0kΩ (99.8kΩ) (37.4kΩ) (16.6kΩ) (6.2kΩ) (0.0kΩ) R1/R3 = (Blue), R2/R4 = Black Table 3-2b; ADJUSTMENT RESISTOR VALUES, Vo2 24V Bus Pt.# 48V Bus Pt.# Adj. Resistor Vo(nom) Va(req’d) 3.6 3.54 3.48 3.42 3.36 3.3 3.24 3.18 3.12 3.06 3.0 2.75 2.7 2.65 2.6 2.55 2.5 2.45 2.4 2.35 2.3 2.25 PT4681 PT4661 (R3)/R4 PT4682 PT4662 (R3)/R4 3.3V 2.5V 1.0kΩ 2.5kΩ 5.0kΩ 10.0kΩ 25.0kΩ (29.8)kΩ (11.8)kΩ (5.8)kΩ (2.8)kΩ (1.0)kΩ 4.7kΩ 6.7kΩ 10.0kΩ 16.7kΩ 36.7kΩ (22.0)kΩ (8.7)kΩ (4.2)kΩ (2.0)kΩ (0.7)kΩ Va(req’d) 1.95 1.9 1.85 1.8 1.75 1.7 1.65 1.6 1.55 1.5 1.45 1.4 1.35 1.3 1.275 1.25 1.225 1.2 1.175 1.15 1.125 1.1 PT4683/6/7 PT4663/6/7 (R3)/R4 PT4685 PT4665 (R3)/R4 PT4688 PT4668 (R3)/R4 1.8V 1.5V 1.2V 9.4kΩ 15.7kΩ 34.7kΩ (3.0)kΩ TBD TBD TBD (TBD) (TBD) (TBD) 3.0kΩ 5.5kΩ 10.3kΩ 24.8kΩ (23.6)kΩ (9.1)kΩ (4.3)kΩ (1.8)kΩ R1/R3 = (Blue), R2/R4 = Black For technical support and more information, see inside back cover or visit www.ti.com IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. 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