Technical Specification Quarter Quarter 24V 1.8V 25A out in Brick Brick 25 Amp, No Heatsink, Isolated DC/DC Converter The PQ24018QGA25 PowerQor™ Giga quarter- brick converter is a next-generation, board-mount- able, isolated, fixed switching frequency dc/dc converter that uses synchronous rectification to achieve extremely high conversion efficiency. The power dissipated by the converter is so low that a heatsink is not required, which saves cost, weight, height, and application effort. All of the power and control components are mounted to the multi-layer PCB substrate with high-yield surface mount technolo- gy. Since the PowerQor converter has no explicit thermal connections, it is extremely reliable. PQ24018QGA25 Module Operational Features Protection Features  High efficiency, >84% at full rated load current  Input under-voltage lockout disables converter at low input voltage conditions  Delivers up to 25 amps of output current with mini- mal derating - no heatsink required  Output current limit and short circuit protection protects converter from excessive load current or  Wide input voltage range: 18V – 36V meets or short circuits exceeds all 24V bus standards  Output over-voltage protection protects load from  Fixed frequency switching provides predictable EMI damaging voltages performance  Thermal shutdown protects converter from abnor-  No minimum load requirement means no preload mal environmental conditions resistors required Mechanical Features Safety Features • Industry standard quarter-brick pin-out configuration  2000V, 10 MΩ input-to-output isolation provides  Industry standard size: 1.45” x 2.3” input/output ground separation  Total height less than 0.40”, permits better airflow  UL 1950 recognized (US & Canada), basic insula- and smaller card pitch tion rating (pending)  Total weight: 34 grams (1.2 oz.), lower mass great-  TUV certification to EN60950 (pending) ly reduces vibration and shock problems  Meets 72/23/EEC and 93/68/EEC directives which facilitates CE Marking in user’s end product Control Features  Board and plastic components meet 94V-0 flamma-  On/Off control referenced to input side (positive bility requirements and negative logic options are available)  NEBS and ETSI compliant  Remote sense for the output voltage compensates for output distribution drops  Output voltage trim permits custom voltages and voltage margining Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 1 Technical Specification Quarter Quarter 24V 1.8V 25A out in Brick Brick 2.30 (58.4) 0.14 (3.6) 2.00 (50.8) 0.300 (7.62) 0.150 (3.81) 0.43 (10.9) 1.45 0.450 0.600 0.600 (36.8) Top View (11.43) (15.24) (15.24) 0.300 (7.62) 0.145 (3.68) See Note 3 0.40 (10.2) Shown Actual Size Side View 1) Pins 1-3, 5-7 are 0.040” (1.02mm) dia. with 0.080” (2.03mm) dia. standoff shoulders. Pin No. Name Function 2) Pins 4 and 8 are 0.062” (1.57 mm) dia. with 0.100” 1 Vin(+) Positive input voltage (18 - 36V) (2.54mm) dia. standoff shoulders. 3) Other pin extension lengths available. 2 ON/OFF TTL input to turn converter on and off, referenced to 4) Undimensioned components are for visual reference only. Vin(-), with internal pull up. 5) Weight: 1.2 oz. (34g) typical 3 Vin(-) Negative input voltage 6) All dimensions in inches (mm) Tolerances: x.xx +/-0.02 in. (x.x +/-0.5mm) 4 Vout(-) Negative output voltage x.xxx +/-0.010 in. (x.xx +/-0.25mm) 1 5 SENSE(-) Negative remote sense 7) Workmanship: Meets or exceeds IPC-A-610B Class II 2 6 TRIM Output voltage trim 3 7 SENSE(+) Positive remote sense ABSOLUTE MAXIMUM RATINGS 8 Vout(+) Positive output voltage Input Voltage: Non-Operating: 72V continuous Notes: Operating: 60V continuous Input/Output Isolation Voltage: 2000V 1. Pin 5 should be connected to Vout(-) at load. Storage Temperature: -55°C to +125°C 2. Leave Pin 6 open for nominal output voltage. Operating Temperature: -40°C to +115°C 3. Pin 7 should be connected to Vout(+) at load. Voltage at ON/OFF input pin: +18V / -2V OPTIONS SAFETY  Logic sense - Negative (N); converter is on when the  UL 1950 - All modules are UL 1950 recognized (US & ON/OFF signal is low. Positive (P); converter is on Canada) with basic insulation rating. when the ON/OFF signal is high. Logic input is TTL  EN60950 - All modules are TUV certified to EN60950 compatible with an internal pull up. Use N or P as requirements. 13th letter in part number to indicate logic.  72/23/EEC - All modules meet 72/23/EEC directives.  Pin Length - a variety of pin lengths are available for  93/68/EEC - All modules meet 93/68/EEC directives. all modules (see last page). The14th letter in the part  94V-0 - All modules meet 94V-0 flammability require- number indicates pin length. ments for board and plastic components.  Feature Set - Quarter-bricks are available with  NEBS - All modules meet NEBS compatibility. Standard (S) feature options only. Use S as 15th letter in part number to indicate feature set.  An external input fuse must always be used to meet these safety requirements. Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 2 Technical Specification Quarter Quarter 24V 1.8V 25A out in Brick Brick PQ24018QGA25 ELECTRICAL CHARACTERISTICS T =25°C, airflow rate=300 LFM, V =24Vdc, nominal Vout unless otherwise noted; full operating temperature range is -40°C to A in +115°C ambient temperature with appropriate power derating. Specifications subject to change without notice. PARAMETER NOTES and CONDITIONS PQ24018QGA25 Min. Typ. Max. Units INPUT CHARACTERISTICS Operating Input Voltage Range 18 24 36 V Input Under-Voltage Lockout Turn-On Voltage Threshold 15.5 16.0 16.5 V Turn-Off Voltage Threshold 14.0 14.5 15.0 V Lockout Hysteresis Voltage 1.0 1.5 2.0 V Maximum Input Current 100% Load, 18Vin 3.0 A No-Load Input Current 60 100 mA Off Converter Input Current 1.6 3 mA Input Reflected-Ripple Current P-P thru 3.3µH inductor; Figures 13 & 15 6 mA OUTPUT CHARACTERISTICS Output Voltage Set Point 1.782 1.800 1.816 V Output Voltage Regulation + + Over Line 0.1 (2) 0.3 (5) % (mV) + + Over Load 0.1 (2) 0.3 (5) % (mV) + + Over Temperature 9 27 mV Total Output Voltage Range over sample line, load and temperature 1.75 1.85 V Output Voltage Ripple and Noise 20MHz bandwidth; Figures 13 & 16 Peak-to-Peak Full Load, 1µF ceramic, 10µF tantalum 25 50 mV RMS Full Load, 1µF ceramic, 10µF tantalum 612 mV Operating Output Current Range 025A Output DC Current-Limit Inception Output Voltage 10% Low; Fig. 17 & 18 26 30 34 A Short-Circuit Protection (redundant shutdown) 52 56 60 A DYNAMIC CHARACTERISTICS Input Voltage Ripple Rejection 120 Hz; Figure 20 TBD dB Output Voltage Current Transient 470µF load cap, 5A/µs; Figure 12 Positive Step Change in Output Current 50% Io to 75% Io 190 mV Negative Step Change in Output Current 75% Io to 50% Io 190 mV Settling Time to within 1% Vout nominal 700 µs Turn-On Transient Turn-On Time Full load, Vout=90% nom.; Figs 9 & 10 1 4 8 ms Start-Up Inhibit Period -40°C to +125°C; Figure F 180 200 215 ms Maximum Output Capacitance Full load; 5% overshoot of Vout at startup 35,000 µF EFFICIENCY 100% Load Figure 1 84 % 50% Load 87 % TEMPERATURE LIMITS FOR POWER DERATING CURVES Semiconductor Junction Temperature Plastic Package rated to 150°C 125 °C Board Temperature Board rated to 165°C 125 °C Transformer Temperature Figures 5 - 8 125 °C ISOLATION CHARACTERISTICS Isolation Voltage 2000 V Isolation Resistance 10 MΩ Isolation Capacitance 470 pF FEATURE CHARACTERISTICS Switching Frequency 220 240 260 kHz ON/OFF Control (Option P) Off-State Voltage -2 0.8 V On-State Voltage 2.4 18 V ON/OFF Control (Option N) Off-State Voltage 2.4 18 V On-State Voltage -2 0.8 V ON/OFF Control (Either Option) Pull-Up Voltage See circuit diagram; Figure B Vin/3 9.6 V Pull-Up Resistance Pull up to Vin/3 33 kΩ Output Voltage Trim Range Across Pins 8 & 4; Figures C & D -20 +10 % Output Over-Voltage Protection Over full temp range; % of nominal Vout 117 122 127 % Over-Temperature Shutdown Average PCB Temperature 125 °C Patents: SynQor is protected under various patents, including but not limited to U.S. Patent # 5,999,417. Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 3 Performance Curves Quarter Quarter 24V 1.8V 25A out in Brick Brick 95 88 90 87 86 85 85 80 84 75 83 70 82 18Vin 25 C 65 24Vin 40 C 81 36Vin 55 C 80 60 0 3 5 8 10 13 15 18 20 23 25 0 100 200 300 400 500 Air Flow (LFM) Load Current (A) Figure 1: Efficiency at nominal output voltage vs. load current for min- Figure 2: Efficiency at nominal output voltage and 60% rated power vs. imum, nominal, and maximum input voltage at 25°C. airflow rate for ambient air temperatures of 25°C, 40°C, and 55°C (nominal input voltage). 12 6.0 10 5.5 8 5.0 6 4.5 4 4.0 18Vin 2 25 C 24Vin 3.5 40 C 36Vin 0 55 C 3.0 0 3 5 8 10 13 15 18 20 23 25 0 100 200 300 400 500 Load Current (A) Air Flow (LFM) Figure 3: Power dissipation at nominal output voltage vs. load current Figure 4: Power dissipation at nominal output voltage and 60% rated for minimum, nominal, and maximum input voltage at 25°C. power vs. airflow rate for ambient air temperatures of 25°C, 40°C, and 55°C (nominal input voltage). 25 20 15 10 400 LFM (2.0 m/s) 300 LFM (1.5 m/s) 200 LFM (1.0 m/s) 5 100 LFM (0.5 m/s) 0 LFM (0 m/s) 0 Semiconductor junction temperature is 0 2540 5570 85 within 1°C of surface temperature o Vin = 24V Ambient Air Temperature ( C) Figure 5: Maximum output power derating curves vs. ambient air tem- Figure 6: Thermal plot of converter at 25 amp load current with 55°C perature for airflow rates of 0 LFM through 400 LFM with air flowing air flowing at the rate of 200 LFM. Air is flowing across the converter across the converter from pin 1 to pin 3 (nominal input voltage). sideways from pin 1 to pin 3 (nominal input voltage). Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 4 Efficiency (%) Iout (A) Power Dissipation (W) Efficiency (%) Power Dissipation (W) Performance Curves Quarter Quarter 24V 1.8V 25A out in Brick Brick 25 20 15 10 400 LFM (2.0 m/s) 300 LFM (1.5 m/s) 200 LFM (1.0 m/s) 5 100 LFM (0.5 m/s) 0 LFM (0 m/s) 0 0 2540 5570 85 Semiconductor junction temperature is o within 1°C of surface temperature Vin = 24V Ambient Air Temperature ( C) Figure 7: Maximum output power derating curves vs. ambient air tem- Figure 8: Thermal plot of converter at 25 amp load current with 55°C perature for airflow rates of 0 LFM through 400 LFM with air flowing air flowing at the rate of 200 LFM. Air is flowing across the converter lengthwise from output to input (nominal input voltage). from output to input (nominal input voltage). Figure 9: Turn-on transient at full load (resistive load) (2 ms/div). Figure 10: Turn-on transient at zero load (2 ms/div). Ch1: Vout (500mV/div) Ch1: Vout (500mV/div) Ch2: ON/OFF input (5V/div) Ch2: ON/OFF input (5V/div) Figure 11: Output voltage response to step-change in load current (50%-75%-50% Figure 12: Output voltage response to step-change in load current (50%-75%-50% of Iout(max); dI/dt = 0.1A/µs). Load cap: 10µF, 100 mΩ ESR tantalum capacitor and of Iout(max): dI/dt = 5A/µs). Load cap: 470µF, 30 mΩ ESR tantalum capacitor and 1µF ceramic capacitor. Ch1: Vout (100mV/div), Ch2: Iout (10A/div). 1µF ceramic capacitor. Ch1: Vout (100mV/div), Ch2: Iout (10A/div). Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 5 Iout (A) Performance Curves Quarter Quarter 24V 1.8V 25A out in Brick Brick Figure 15 3.3 µH Figure 14 source impedance Figure 16 i i S C DC/DC V OUT Converter V SOURCE 10 µF, 1 µF 100 µF, ceramic 100mΩ ESR ≅0.33Ω ESR capacitor tantalum electrolytic capacitor capacitor Figure 14: Input Terminal Ripple Current, i , at full rated output cur- Figure 13: Test set-up diagram showing measurement points for Input c rent and nominal input voltage with 3.3µH source impedance and Terminal Ripple Current (Figure 14), Input Reflected Ripple Current 100µF electrolytic capacitor (500 mA/div). See Figure 13. (Figure 15) and Output Voltage Ripple (Figure 16). Figure 15: Input reflected ripple current, i , through a 3.3 µH source Figure 16: Output voltage ripple at nominal input voltage and rated s inductor at nominal input voltage and rated load current (10 mA/div). load current (20 mV/div). Load capacitance: 1µF ceramic capacitor See Figure 13. and 10µF tantalum capacitor. Bandwidth: 20 MHz. See Figure 13. 2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 18V 1.1 24 V 1.0 0.9 36 V 0.8 0 5 10 15 20 25 30 35 Load Current (A) Figure 17: Output voltage vs. load current showing typical current limit Figure 18: Load current (20A/div) as a function of time when the con- curves. Below 0.9V (typical), the converter will shut off, and restart verter attempts to turn on into a 10 mΩ short circuit. Top trace after a start-up inhibit period has elapsed. (see Figure F) (2.5ms/div) is an expansion of the on-time portion of the bottom trace. Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 6 Output Voltage (V) Performance Curves Quarter Quarter 24V 1.8V 25A out in Brick Brick 1 0 -10 -20 0.1 18 Vin -30 18 Vin 24 Vin 24 Vin 36 Vin -40 36 Vin 0.01 -50 -60 -70 0.001 10 100 1,000 10,000 100,000 10 100 1,000 10,000 100,000 Hz Hz Figure 19: Magnitude of incremental output impedance (Z = Figure 20: Magnitude of incremental forward transmission (FT = out v /i ) for minimum, nominal, and maximum input voltage at full v /v ) for minimum, nominal, and maximum input voltage at full out out out in rated power. rated power. 0 100 -10 -20 10 18 Vin 18 Vin -30 24 Vin 24 Vin 36 Vin 36 Vin -40 1 -50 -60 0.1 10 100 1,000 10,000 100,000 10 100 1,000 10,000 100,000 Hz Hz Figure 21: Magnitude of incremental reverse transmission (RT = Figure 22: Magnitude of incremental input impedance (Z = v /i ) in in in i /i ) for minimum, nominal, and maximum input voltage at full rated for minimum, nominal, and maximum input voltage at full rated power. in out power. Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 7 Reverse Transmission (dB) Output Impedance ( ) Ω Ω Input Impedance ( ) Forward Transmission (dB) Ω Ω Technical Specification Quarter Quarter 24V 1.8V 25A out in Brick Brick the converter. Because the PowerQor converter is much BASIC OPERATION AND lighter, vibration and shock-induced problems are greatly FEATURES reduced. Moreover, due to the lack of failure-prone explicit The PowerQor series converter uses a two-stage power cir- thermal connections and the lack of potting material the cuit topology. The first stage is a buck-converter that keeps PowerQor converter is more reliable than conventional the output voltage constant over variations in line, load, and dc/dc converters. temperature. The second stage uses a transformer to provide The PowerQor series converter uses the industry standard the functions of input/output isolation and voltage step- pin-out configuration used by other vendors of comparably down to achieve the low output voltage required. sized and rated dc/dc converters. The unit is pin for pin Both the first stage and the second stage switch at a fixed compatible with the Lucent QW series. frequency for predictable EMI performance. Rectification of The PowerQor converter has many standard control and the transformer’s output is accomplished with synchronous protection features. All shutdown features are non-latching, rectifiers. These devices, which are MOSFETs with a very meaning that the converter shuts off for 200ms before low on-state resistance, dissipate far less energy than restarting. (see Figure F) Schottky diodes used in conventional dc/dc converters. This is the primary reason that the PowerQor converter has such  An ON/OFF input permits the user to control when the high efficiency—even at very low output voltages and very converter is on and off in order to properly sequence dif- high output currents. ferent power supplies and to reduce power consumption during a standby condition. Dissipation throughout the converter is so low that the PowerQor converter requires no heatsink to deliver  Remote sense inputs permit the user to maintain an a greater level of power than can be delivered by a con- accurate voltage at the load despite distribution voltage ventional, Schottky-diode-based dc/dc converter with a drops between the converter’s output and the load. 0.5” high heatsink. At equivalent ambient air temperature, airflow rate, and output power level, the hottest semicon-  An output voltage trim input permits the user to trim ductor junction temperature and the hottest PCB temperature the output voltage up or down to achieve a custom volt- within the PowerQor converter are cooler than those found age level or to do voltage margining. in conventional dc/dc converters with a 0.5” high heatsink  An input under-voltage lockout avoids input system attached. instability problems while the input voltage is rising. Since a heatsink is not required, the PowerQor converter  The output current limit protects both the converter does not need a metal baseplate or potting material to help and the board on which it is mounted against a short cir- conduct the dissipated energy to the heatsink. The cuit condition. (see Figure 18) PowerQor converter can thus be built more simply using high yield surface mount techniques on a PCB substrate.  An output over-voltage limit circuit shuts the unit down if the output voltage at the output pins gets too Unlike conventional dc/dc converters, which have critical high. thermal connections between the power components and the baseplate, and between the baseplate and the heatsink, the  A sensor located in a central spot of the PCB provides a PowerQor converter has no explicit, failure-prone thermal PCB temperature limit. If, due to an abnormal con- connections. dition, this spot gets too hot, the converter will turn off. Once the converter has cooled, it will automatically turn Compared to a conventional Schottky-diode-based dc/dc on again without the need to recycle the input power. converter with a 0.5” high heatsink, the PowerQor convert- er is more efficient and therefore it dissipates less than half the energy. Additionally, because the PowerQor converter is CONTROL PIN DESCRIPTIONS thinner (0.4” vs. 1.0”), the board-to-board pitch in a rack Pin 2 (ON/OFF): The ON/OFF input, Pin 2, permits the can be much smaller, and cooling airflow is less impeded by user to control when the converter is on or off. This input is Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 8 Technical Specification Quarter Quarter 24V 1.8V 25A out in Brick Brick referenced to the return terminal of the 24V input bus. There voltage across the output (pins 8 and 4) to determine when are two versions of the PowerQor series converter that differ it should trigger, not the voltage across the converter’s sense by the sense of the logic used for the ON/OFF input. In the pins (pins 7 and 5). Therefore, the resistive drop on the PQxxyyyQGAzzPxx version, the ON/OFF input is active board should be small enough so that output OVP does not high (meaning that a high turns the converter on). In the trigger, even during load transients. PQxxyyyQGAzzNxx version, the ON/OFF signal is active Pin 6 (TRIM): The TRIM input permits the user to adjust the low (meaning that a low turns the converter on). Figure A output voltage across the sense leads up or down. To lower details five possible circuits for driving the ON/OFF pin. the output voltage, the user should connect a resistor Figure B shows detail of the internal ON/OFF circuitry. between Pin 6 and Pin 5, which is the SENSE(-) input. To raise the output voltage, the user should connect a resistor Pins 7 and 5 (SENSE(+)): The SENSE(+) inputs correct between Pin 6 and Pin 7, which is the SENSE(+) input. for voltage drops along the conductors that connect the con- verter’s output pins to the load. A resistor connected between Pin 6 and Pin 5 will decrease the output voltage. For a desired decrease of ∆ percent of Pin 7 should be connected to Vout(+) and Pin 5 should be the nominal output voltage, the value of this resistor should connected to Vout(-) at the point on the board where regu- be lation is desired. That is, 511 R (kΩ) = - 10.22 trim-down [Vout(+) - Vout(-)] – [SENSE(+) - SENSE (-)] < 10%Vout ( ) ∆% Pins 7 and 5 must be connected for proper regulation of the where output voltage. However, if these connections are not made, V – V NOM DES nothing catastrophic will happen to the converter under nor- ∆ = x 100% ( ) V mal operating conditions—the converter will simply deliver NOM an output voltage that is slightly higher than its specified and value. V = Nominal Voltage NOM V = Desired Voltage DES Note: the output over-voltage protection circuit senses the ON/OFF ON/OFF ON/OFF _ _ _ Vin( ) 5V Vin( ) Vin( ) Vin(+) Negative Logic Positive Logic Remote Enable Circuit (Permanently Enabled) 100k (Permanently Enabled) ON/OFF 5V 50k ON/OFF TTL TTL/ ON/OFF CMOS 100pF 50k _ _ Vin( ) Vin( ) _ Vin( ) Open Collector Enable Circuit Direct Logic Drive Figure A: Various circuits for driving the ON/OFF pin. Figure B: Internal ON/OFF pin circuitry (detail) Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 9 Technical Specification Quarter Quarter 24V 1.8V 25A out in Brick Brick Figure C graphs this relationship between R and ∆. Note: The TRIM feature does not affect the voltage at which trim-down The output voltage can be trimmed down as much as 20%. the output over-voltage protection circuit is triggered. Trimming the output voltage too high may cause the over- 10,000 voltage protection circuit to trip, particularly during tran- sients. TOTAL DC VARIATION OF Vout: For the converter to 1,000 meet its full specifications, the maximum variation of the dc value of Vout, due to both trimming and remote load voltage drops, should not be greater than +10%/-20% 100 PROTECTION FEATURES 10 0 2 4 6 8 10 12 14 16 18 20 Input Under-Voltage Lockout: The converter is % Decrease in Output Voltage designed to turn off when the input voltage is too low, help- ing avoid an input system instability problem, described in Figure C: Trim Down Graph for 1.8Vout more detail below. The lockout circuitry is a comparator with dc hysteresis. When the input voltage is rising, it must A resistor connected between Pin 6 and Pin 7 will increase exceed a typical value of 16V before the converter will turn the output voltage. For a desired increase of ∆ percent of the on. Once the converter is on, the input voltage must fall nominal output voltage, the value of this resistor should be below a typical value of 14.5V before the converter will turn off. Output Current Limit: The current limit does not change 5.11V (100+∆%) OUT 511 _ _ R trim-up = (kΩ) 10.22 appreciably as the output voltage drops. However, once the ) ( 1.225∆% ∆% impedance of the short across the output is small enough to make the output voltage drop below approximately 60% of where its nominal value, the converter turns off. V = Nominal Output Voltage OUT The converter then enters a mode where it repeatedly turns on and off at a 5 Hz (nominal) frequency with a 5% duty cycle until the short circuit condition is removed. This pre- Figure D graphs this relationship between Rtrim-up and ∆. vents excessive heating of the converter or the load board. The output voltage can be trimmed up as much as 10%. Output Over-Voltage Limit: If the voltage across the 10,000 output pins exceeds the O.V. threshold, the converter will immediately stop switching. This prevents damage to the load circuit due to 1) a sudden unloading of the converter, 1,000 2) a release of a short-circuit condition, or 3) a release of a current limit condition. Load capacitance determines exactly how high the output voltage will rise in response to these 100 conditions. After 200 ms the converter will automatically restart. Thermal Shutdown: The PowerQor series has a temper- 10 01 23 456 78 9 10 ature sensor located such that it senses the average temper- % Increase in Output Voltage ature of the converter. The thermal shutdown circuit is designed to turn the converter off when the temperature at Figure D: Trim Up Graph for 1.8Vout the sensed location reaches 125°C. It will allow the con- Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 10 Trim Resistance (kOhms) Trim Resistance (kOhms) Technical Specification Quarter Quarter 24V 1.8V 25A out in Brick Brick verter to turn on again when the temperature of the sensed location falls below 115°C. APPLICATION CONSIDERATIONS Input System Instability: This condition can occur because a dc/dc converter appears incrementally as a negative resistance load. A detailed application note titled “Input System Instability” is available on the SynQor web site (www.synqor.com) which provides an understanding of why this instability arises, and shows the preferred solu- tion for correcting it. Application Circuits: Figure E below provides a typical circuit diagram which is useful when using input filtering and voltage trimming. Input Filtering Vin(+) Vout(+) Electrolytic 3.3µH Vsense(+) Capacitor 100µF R trim-up ESR ≅0.33Ω Trim or ON/OFF R C trim-down load I load _ 18V < Vin < 36V Vsense( ) _ _ Vin( ) Vout( ) Figure E: Typical application circuit (negative logic unit, permanently enabled). Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 11 Technical Specification Quarter Quarter 24V 1.8V 25A out in Brick Brick STARTUP INHIBIT PERIOD Figure F shows three turn-on scenarios, where a Startup Inhibit Period is initiated at t , t , and t : 0 1 2 The Startup Inhibit Period ensures that the converter will remain off for at least 200ms when it is shut down for any Before time t , when the input voltage is below 16V (typ.), 0 reason. When an output short is present, this generates a the unit is disabled by the Input Under-Voltage Lockout fea- 5Hz "hiccup mode," which prevents the converter from over- ture. When the input voltage rises above 16V, the Input heating. In all, there are seven ways that the converter can Under-Voltage Lockout is released, and a Startup Inhibit be shut down, initiating a Startup Inhibit Period: Period is initiated. At the end of this delay, the ON/OFF pin is evaluated, and since it is active, the unit turns on.  Input Under-Voltage Lockout  Input Over-Voltage Shutdown (not present in Quarter- At time t , the unit is disabled by the ON/OFF pin, and it 1 brick) cannot be enabled again until the Startup Inhibit Period has  Output Over-Voltage Protection elapsed.  Over Temperature Shutdown When the ON/OFF pin goes high after t , the Startup Inhibit 2  Current Limit Period has elapsed, and the output turns on within the 4ms  Short Circuit Protection (typ.) "Turn On Time."  Turned off by the ON/OFF input V in Under-Voltage Lockout Turn-On Threshold ON/OFF (pos logic) ON OFF ON OFF ON V 4ms (typical out turn on time) 200ms (typical start-up 200ms 200ms inhibit period) t t t t 0 1 2 Figure F: Startup Inhibit Period (turn-on time not to scale) Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 12 Technical Specification Quarter Quarter 24V 1.8V 25A out in Brick Brick ORDERING INFORMATION PART NUMBERING SYSTEM The tables below show the valid model numbers and order- The part numbering system for SynQor’s PowerQor DC/DC ing options for converters in this product family. When converters follows the format shown in the example below. ordering SynQor converters, please ensure that you use the PQ 48 033 H T A 50 N K S complete 15 character part number consisting of the 12 character base part number and the additional 3 characters Options (see Ordering Information) for options. Output Current Output Max Output Full Load Model Number Input Voltage Thermal Design Voltage Current Efficiency Performance Level PQ24018QGA25xyz 18 - 36 V 1.8 V 25 A 84% PQ24033QGA25xyz 18 - 36 V 3.3 V 25 A 87% Package Size PQ24050QGA20xyz 18 - 36 V 5.0 V 20 A 87% Output Voltage PQ24120QGA08xyz 18 - 36 V 12 V 8.3 A 88% Input Voltage PQ24150QGA07xyz 18 - 36 V 15 V 6.7 A 87% Product Family The following option choices must be included in place of the x y z spaces in the model numbers listed above. The first 12 characters comprise the base part number and the last 3 characters indicate available options. Although Options Description: x y z there are no default values for enable logic and pin length, Enable Pin Feature Logic Length Set the most common options are negative logic and 0.145” K - 0.110" pins. These part numbers are more likely to be readily avail- P - Positive N - 0.145" S - Standard able in stock for evaluation and prototype quantities. N - Negative R - 0.180" Y - 0.250" Application Notes Available  Current Sharing for Full Feature Modules  EMI Characteristics  Thermal Relief Vias  Input System Instability All application notes and technical white papers can be downloaded in pdf format at www.synqor.com. Contact SynQor for further information: Warranty SynQor offers a three (3) year limited warranty. Complete warranty Phone: 978-567-9596 information is listed on our web site or is available upon request from Toll Free: 888-567-9596 SynQor. Fax: 978-567-9599 E-mail: sales@synqor.com Information furnished by SynQor is believed to be accurate and reliable. Web: www.synqor.com However, no responsibility is assumed by SynQor for its use, nor for any infringements of patents or other rights of third parties which may result Address: 188 Central Street from its use. No license is granted by implication or otherwise under any Hudson, MA 01749 patent or patent rights of SynQor. Product # PQ24018QGA25 Phone 1-888-567-9596 Doc.# 005-2QG218D_A 3/1/02 Page 13