ATH30T033 Series --3.3-V Input 30-A, 3.3-V Input Non-Isolated Wide-Output Adjust Power Module REVISION 00 (30APR2004) Features NOMINAL SIZE = * Up to 30-A Output Current * 3.3-V Input Voltage * Wide-Output Voltage Adjust (0.8 V to 2.5 V) * 135 W/in Power Density * Efficiencies up to 93 % * On/Off Inhibit * Pre-Bias Startup * Margin Up/Down Controls * Under-Voltage Lockout 1.37 in x 1.12 in (34,8 mm x 28,5 mm) * Auto-TrackTM Sequencing * Output Over-Current Protection (Non-Latching, Auto-Reset) * Operating Temp: -40 to +85 C * Over-Temperature Shutdown * Safety Agency Approvals: UL 1950, CSA 22.2 950, EN60950 VDE (Pending) * Point-of-Load Alliance (POLA) Compatible Description Pin Configuration set to any value over the range 0.8 V to 2.5 V, using a single resistor. This series includes Auto-TrackTM. Auto-Track simplifies power-up and power-down supply voltage sequencing in a system by enabling modules to track each other, or any other external voltage. Each model also includes an on/off inhibit, output voltage adjust (trim), and margin up/down controls. An output voltage sense ensures tight load regulation, and an output over-current and thermal shutdown feature provide for protection against external load faults. Package options inlude both throughhole and surface mount configurations. The ATH30T033 is a series of highcurrent non-isolated power modules. The product is characterized by high efficiencies, and up to 30 A of output current, while occupying a mere 1.64 in of PCB area. In terms of cost, size, and performance, the series provides OEM's with a flexible module that meets the requirements of the most complex and demanding mixed-signal applications. These include the most densly populated, multi-processor systems that incorporate high-speed DSP's, microprocessors, and ASICs. The series uses double-sided surface mount construction and provides highperformance step-down power conversion from a 3.3-V input bus voltage. The output voltage of the ATH30T033 can be Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 Function GND Vin GND Inhibit * Vo Adjust Vo Sense GND Vout Vout GND Track Margin Down * Margin Up * * Denotes negative logic: Open = Normal operation Ground = Function active rackTM T o t Au ncing e u q Se Standard Application Track Rset = Required to set the desired output voltage higher than 0.8 V (see spec. table for values). Cin = Required 1,500 F capacitor. Cout = Optional 330 F capacitor. Margin Down Margin Up 13 12 11 1 VIN 2 10 9 PTH03030W ATH30T033-9S (Top View) VOUT 8 3 7 4 5 6 Inhibit Vo Sense + RSET 0.5 %, 0.1 W (Required) COUT 330 F (Optional) GND North America (USA): 1-888-41-ASTEC L O A D + CIN 1,500 F (Required) GND Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 ATH30T033 Series --3.3-V Input 30-A, 3.3-V Input Non-Isolated Wide-Output Adjust Power Module REVISION 00 (30APR2004) Ordering Information Input Voltage Output Voltage 2.95V to 3.65V 0.8V1 to 2.5V Options: "-J" "-SJ" - Output Current Model Number 30A ATH30T033-9(S)(J) Through-hole Termination, Tray Packaging SMT Termination, Tray Packaging Notes: 1 Preset output voltage is 0.8V; externally adjustable to 2.5V through the Vo,Adjust pin Pin Descriptions Vin: The positive input voltage power node to the module, which is referenced to common GND. Vout: The regulated positive power output with respect to the GND node. GND: This is the common ground connection for the Vin and Vout power connections. It is also the 0 VDC reference for the control inputs. Inhibit: The Inhibit pin is an open-collector/drain negative logic input that is referenced to GND. Applying a lowlevel ground signal to this input disables the module's output and turns off the output voltage. When the Inhibit control is active, the input current drawn by the regulator is significantly reduced. If the Inhibit pin is left open-circuit, the module will produce an output whenever a valid input source is applied. Vo Adjust: A 0.1 W 1 % resistor must be directly connected between this pin and pin 7 (GND) to set the output voltage to a value higher than 0.8 V. The temperature stability of the resistor should be 100 ppm/C (or better). The set point range for the output voltage is from 0.8 V to 2.5 V. The resistor value required for a given output voltage may be calculated from the following formula. If left open circuit, the output voltage will default to its lowest value. For further information on output voltage adjustment consult the related application note. Rset = 10 k * 0.8 V Vout - 0.8 V - 2.49 k The specification table gives the preferred resistor values for a number of standard output voltages. North America (USA): 1-888-41-ASTEC Vo Sense: The sense input allows the regulation circuit to compensate for voltage drop between the module and the load. For optimal voltage accuracy Vo Sense should be connected to Vout. It can also be left disconnected. Track: This is an analog control input that enables the output voltage to follow an external voltage. This pin becomes active typically 20 ms after the input voltage has been applied, and allows direct control of the output voltage from 0 V up to the nominal set-point voltage. Within this range the output will follow the voltage at the Track pin on a volt-for-volt basis. When the control voltage is raised above this range, the module regulates at its set-point voltage. The feature allows the output voltage to rise simultaneously with other modules powered from the same input bus. If unused, this input should be connected to Vin. Note: Due to the under-voltage lockout feature, the output of the module cannot follow its own input voltage during power up. For more information, consult the related application note. Margin Down: When this input is asserted to GND, the output voltage is decreased by 5% from the nominal. The input requires an open-collector (open-drain) interface. It is not TTL compatible. A lower percent change can be accomodated with a series resistor. For further information, consult the related application note. Margin Up: When this input is asserted to GND, the output voltage is increased by 5%. The input requires an open-collector (open-drain) interface. It is not TTL compatible. The percent change can be reduced with a series resistor. For further information, consult the related application note. Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 ATH30T033 Series --3.3-V Input 30-A, 3.3-V Input Non-Isolated Wide-Output Adjust Power Module REVISION 00 (30APR2004) Environmental & Absolute Maximum Ratings Characteristics Symbols Track Input Voltage Operating Temperature Range Solder Reflow Temperature Storage Temperature Mechanical Shock Vtrack Ta Treflow Ts Mechanical Vibration Weight Flammability -- -- (Voltages are with respect to GND) Conditions Over Vin Range Surface temperature of module body or pins -- Per Mil-STD-883D, Method 2002.3 1 msec, 1/2 Sine, mounted Mil-STD-883D, Method 2007.2 Suffix S 20-2000 Hz Suffix H Min Typ -0.3 -40 -- -- Max Units Vin + 0.3 85 235 (i) 125 V C C C -40 -- -- 500 -- G's -- -- -- 10 20 10 -- -- -- G's grams Meets UL 94V-O Notes: (i) During reflow of SMD package version do not elevate peak temperature of the module, pins or internal components above the stated maximum. Specifications (Unless otherwise stated, Ta =25 C, V in =3.3 V, Vout =2 V, Cin =1,500 F, C out =0 F, and Io =Iomax) Characteristics Typ Output Current Symbols Max Io Input Voltage Range Set-Point Voltage Tolerance Temperature Variation Line Regulation Load Regulation Total Output Variation Vin Vo tol Regtemp Regline Regload Regtot Efficiency Vo Ripple (pk-pk) Over-Current Threshold Transient Response Vr Io trip Margin Up/Down Adjust Margin Input Current (pins 12 /13) Track Input Current (pin 8) Track Slew Rate Capability Under-Voltage Lockout ttr Vtr Vo adj IIL margin IIL track dVtrack/dt UVLO Inhibit Control (pin4) Input High Voltage Input Low Voltage Input Low Current VIH VIL IIL inhibit Input Standby Current Switching Frequency External Input Capacitance External Output Capacitance Iin inh s Cin Cout Reliability MTBF 60 C, 200 LFM airflow 25 C, natural convection Over Io range -40 C 900 mA 1690 mA 1100 mA 1100 mA 10x12.5 16x15 12.5x13.5 12.5x13.5 3 1 1 1 1 1 1 1 6.3 V 6.3 V 10 V 10 V 1000 820 680 1000 0.013 0.010 0.090 0.068 4935 mA 5500 mA >900 mA 1050 mA 10x10.5 10x12.2 10x12.5 10x16 2 2 3 2 2 2 1 1 Nichicon, Aluminum: HD (Radial) PM (Radial) 6.3 V 10 V 1000 1500 0.053 0.050 1030 mA 1060 mA 10x12.5 16x15 2 1 1 1 Sanyo, Os-con: SP (Radial) SVP (SMD) 10 V 6.3 V 470 820 0.015 0.012 >4500 mA >5440 mA 10x10.5 10x12.7 3 [1] 2 Panasonic, Poly-Aluminum: WA (SMD) S/SE (SMD) 6.3 V 6.3 V 560 180 0.020 0.005 5100 mA 4000 mA 10x10.2 7.3x4.3x4.2 10 V 10 V 470 470 0.045 0.060 1723 mA 1826 mA 7.3L x5.7Wx4.1H 6.3 V 10 V 6.3 V 470 330 470 0.018 0.015 0.012 >1200 mA >3800 mA 4200 mA 10 V 16 V 470 2200 0.100 0.015 1440 mA 9740 mA Kemet, Ceramic X5R (SMD) 16 V 6.3 V 10 47 0.002 0.002 Murata, Ceramic X5R (SMD) 6.3 V 6.3 V 16 V 16 V 100 47 22 10 TDK, Ceramic X5R (SMD) 6.3 V 6.3 V 16 V 16 V 100 47 22 10 Panasonic: FC (Radial) FK (SMD) United Chemi-con FX, Oscon (Radial) PXA, (Poly-Aluminum (SMD.) LXZ, Aluminum (Radial) AVX, Tantalum: TPS (SMD) Kemet (SMD): T520, Poly-Tant T530, Poly-Tant/Organic Vishay-Sprague 595D, Tantalum (SMD) 94SA, Os-con (Radial) Vendor Part Number EEUFC1A561 EEUFC1C152S EEVFK1C152Q EEVFK1A222Q 6FX1000M PXA6.3VC820MJ12TP LXZ10VB681M10X12LL LXZ10VB102M10X16LL UHD0J102MPR UPM1A152MHH6 3 2 10SP470M 6SVP820M 4 1 EEFWA0J561P EEFSE0J181R 3 [ 1] 3 [ 1] 5 5 TPSE477M010R0045 TPSV477M010R0060 4.3W x7.3L x4.0H 3 [ 1] 5 3 [ 1] 5 3 2 T520X477M006SE018 T530X337M010AS T530X477M006AS 7.2Lx6W x4.1H 16x25 3 [ 1] 1 5 3 595D477X0010R2T 94SA108X0016HBP -- 1210 case 3225 mm 1 [ 2] 1 [ 2] 5 5 C1210C106M4PAC C1210C476K9PAC 0.002 -- 1210 case 3225 mm 1 [ 2] 1 [ 2] 1 [ 2] 3 5 5 5 GRM32ER60J107M GRM32ER60J476M GRM32ER61C226K GRM32DR61C106K 0.002 -- 1210 case 3225 mm 1 [ 2] 1 [ 2] 1 [ 2] 3 5 5 5 C3225X5R0J107MT C3225X5R0J476MT C3225X5R1C226MT C3225X5R1C106MT 3 N/ R [1] The total capacitance is slightly lower than 1,500 F, but is acceptable based on the combined ripple current rating. [2] A ceramic capacitor may be used to complement electrolytic types at the input to further reduce high-frequency ripple current North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH30T033 & ATH30T05 Series Adjusting the Output Voltage of the ATH30T033 & ATH30T05 Wide-Output Adjust Power Modules The Vo Adjust control (pin 4) sets the output voltage of the ATH30T033 and ATH30T05 products to a value higher than 0.8 V. The adjustment range of the ATH30T033 (3.3-V input) is from 0.8 V to 2.5 V 1, and the ATH30T05 (5-V input) from 0.8 V to 3.6 V. For an output voltage other than 0.8 V a single external resistor, Rset, must be connected directly between the Vo Adjust and GND pins 2. Table 2-1 gives the preferred value of the external resistor for a number of standard voltages, along with the actual output voltage that this resistance value provides. For other output voltages the value of the required resistor can either be calculated using the following formula, or simply selected from the range of values given in Table 2-2. Figure 2-1 shows the placement of the required resistor. Rset = 10 k * 0.8 V Vout - 0.8 V - 2.49 k Table 2-1; Preferred Values of Rset for Standard Output Voltages Vout (Standard) Rset (Pref'd Value) 3.3 V 1 2.5 V 2V 1.8 V 1.5 V 1.2 V 1V 0.8 V 698 2.21 k 4.12 k 5.49 k 8.87 k 17.4 k 36.5 k Open Vout (Actual) 3.309V 2.502 V 2.010 V 1.803 V 1.504 V 1.202 V 1.005 V 0.8 V Figure 2-1; Vo Adjust Resistor Placement Vo Sense 13 12 11 Table 2-2; Output Voltage Set-Point Resistor Values Va Req'd 0.800 0.825 0.850 0.875 0.900 0.925 0.950 0.975 1.000 1.025 1.050 1.075 1.100 1.125 1.150 1.175 1.200 1.225 1.250 1.275 1.300 1.325 1.350 1.375 1.400 1.425 1.450 1.475 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 Rset Va Req'd Open 318 k 158 k 104 k 77.5 k 61.5 k 50.8 k 43.2 k 37.5 k 33.1 k 29.5 k 26.6 k 24.2 k 22.1 k 20.4 k 18.8 k 17.5 k 16.3 k 15.3 k 14.4 k 13.5 k 12.7 k 12.1 k 11.4 k 10.8 k 10.3 k 9.82 k 9.36 k 8.94 k 8.18 k 7.51 k 6.92 k 6.4 k 5.93 k 5.51 k 5.13 k 4.78 k 4.47 k 2.00 2.05 2.10 2.15 2.20 2.25 2.30 2.35 2.40 2.45 2.50 2.55 2.60 2.65 2.70 2.75 2.80 2.85 2.90 2.95 3.00 3.05 3.10 3.15 3.20 3.25 3.30 3.35 3.40 3.45 3.50 3.55 3.60 Rset 4.18 k 3.91 k 3.66 k 3.44 k 3.22 k 3.03 k 2.84 k 2.67 k 2.51 k 2.36 k 2.22 k 2.08 k 1.95 k 1.83 k 1.72 k 1.61 k 1.51 k 1.41 k 1.32 k 1.23 k 1.15 k 1.07 k 988 914 843 775 710 647 587 529 473 419 367 6 Sense ATH30T05-9S PTH05030W GND 1, 3, 7 VO 8, 9 VOUT GND Adjust 10 5 R SET 1 %, 0.1 W COUT 330 F (Optional) Notes: 1. Modules that operate from a 3.3-V input bus should not be adjusted higher than 2.5 V. 2. Use a 0.1 W resistor. The tolerance should be 1 %, with temperature stability of 100 ppm/C (or better). Place the resistor as close to the regulator as possible. Connect the resistor directly between pins 5 and 10 using dedicated PCB traces. 3. Never connect capacitors from Vo Adjust to either GND or Vout. Any capacitance added to the Vo Adjust pin will affect the stability of the regulator. GND GND North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Point-of-Load Alliance The ATH family of non-isolated, wide-output adjust power modules are optimized for applications that require a flexible, high performance module that is small in size. These products are part of the "Point-of-Load Alliance" (POLA), which ensures compatible footprint, interoperability and true second sourcing for customer design flexibility. The POLA is a collaboration between Texas Instruments, Artesyn Technologies, and Astec Power to offer customers advanced non-isolated modules that provide the same functionality and form factor. Product series covered by the alliance includes the ATH06 (6 A), ATH10 (10 A), ATH12/15 (12/15 A), ATH18/22 (18/22 A), and the ATH26/30 (26/30 A). From the basic, "Just Plug it In" functionality of the 6-A modules, to the 30-A rated feature-rich ATH30, these products were designed to be very flexible, yet simple to use. The features vary with each product. Table 3-1 provides a quick reference to the available features by product and input bus voltage. ATH18/22 and ATH26/30 products incorporate over-temperature shutdown protection. All of the products referenced in Table 3-1 include Auto-TrackTM. This is a feature unique to the ATH family, and was specifically designed to simplify the task of sequencing the supply voltage in a power system. These and other features are described in the following sections. Soft-Start Power Up The Auto-TrackTM feature allows the power-up of multiple ATH modules to be directly controlled from the Track pin. However in a stand-alone configuration, or when the Auto-TrackTM feature is not being used, the Track pin should be directly connected to the input voltage, Vin (see Figure 3-1). Figure 3-1 10 5V 2 Table 3-1; Operating Features by Series and Input Bus Voltage VIN Inhibit 3.3 V / 5 V 15 A 12 V 12 A 3.3 V / 5 V 22 A 12 V 18 A 3.3 V / 5 V 30 A 12 V 26 A Pre-Bias Startup * * * * * * Thermal Shutdown 12 V 10 8 AA * * * * * * * * * * Output Sense 10 A * * * * * * * * * * Margin Up/Down PTHxx030 ATH26/30 6A 3.3 V / 5 V * * * * * * * * * * Auto-TrackTM PTHxx020 ATH18/22 12 V Over-Current PTHxx010 ATH12/15 6A On/Off Inhibit PTHxx060 ATH10 I OUT 3.3 V / 5 V Adjust (Trim) + PTHxx050 ATH06 Input Bus * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 8 5 Track Sense PTH05020W ATH22T05-9S 3 Series 9 Up Dn 3.3 V 6 Adjust GND 1 VO 7 CIN 1,000 F 4 + Features of the ATH Family of Non-Isolated Wide Output Adjust Power Modules RSET, 698 0.1 W, 1 % COUT 330 F GND GND When the Track pin is connected to the input voltage the Auto-TrackTM function is permanently disengaged. This allows the module to power up entirely under the control of its internal soft-start circuitry. When power up is under soft-start control, the output voltage rises to the set-point at a quicker and more linear rate. Figure 3-2 Vin (1 V/Div) Vout (1 V/Div) For simple point-of-use applications, the ATH06 provides operating features such as an on/off inhibit, output voltage trim, pre-bias startup (3.3/5-V input only), and over-current protection. The ATH10 (10 A), and ATH12/ 15 (12/15 A) include an output voltage sense, and margin up/down controls. Then the higher output current, Iin (5 A/Div) HORIZ SCALE: 5 ms/Div North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) From the moment a valid input voltage is applied, the soft-start control introduces a short time delay (typically 5 ms-10 ms) before allowing the output voltage to rise. The output then progressively rises to the module's setpoint voltage. Figure 3-2 shows the soft-start power-up characteristic of the 22-A output product (ATH22T05-9S), operating from a 5-V input bus and configured for a 3.3-V output. The waveforms were measured with a 5-A resistive load, with Auto-TrackTM disabled. The initial rise in input current when the input voltage first starts to rise is the charge current drawn by the input capacitors. Power-up is complete within 15 ms. The power modules function normally when the Inhibit pin is left open-circuit, providing a regulated output whenever a valid source voltage is connected to Vin with respect to GND. Figure 3-3 shows the typical application of the inhibit function. Note the discrete transistor (Q1). The Inhibit control has its own internal pull-up to Vin potential. The input is not compatible with TTL logic devices. An opencollector (or open-drain) discrete transistor is recommended for control. Figure 3-3 Vo Sense Over-Current Protection The ATH18/22 and ATH26/30 series of products have over-temperature protection. These products have an on-board temperature sensor that protects the module's internal circuitry against excessively high temperatures. A rise in the internal temperature may be the result of a drop in airflow, or a high ambient temperature. If the internal temperature exceeds the OTP threshold, the module's Inhibit control is automatically pulled low. This turns the output off. The output voltage will drop as the external output capacitors are discharged by the load circuit. The recovery is automatic, and begins with a soft-start power up. It occurs when the the sensed temperature decreases by about 10 C below the trip point. VIN 2 9 5 8 1 7 4 RSET Q1 BSS138 VOUT 6 PTH05020W ATH22T05-9S 3 CIN 1,000 F + Over-Temperature Protection 10 COUT 330 F + For protection against load faults, all modules incorporate output over-current protection. Applying a load that exceeds the regulator's over-current threshold will cause the regulated output to shut down. Following shutdown a module will periodically attempt to recover by initiating a soft-start power-up. This is described as a "hiccup" mode of operation, whereby the module continues in a cycle of successive shutdown and power up until the load fault is removed. During this period, the average current flowing into the fault is significantly reduced. Once the fault is removed, the module automatically recovers and returns to normal operation. L O A D 1 =Inhibit GND GND Turning Q1 on applies a low voltage to the Inhibit control and disables the output of the module. If Q1 is then turned off, the module will execute a soft-start power-up. A regulated output voltage is produced within 20 msec. Figure 3-4 shows the typical rise in both the output voltage and input current, following the turn-off of Q1. The turn off of Q1 corresponds to the rise in the waveform, Q1 Vds. The waveforms were measured with a 5-A load. Figure 3-4 Note: The over-temperature protection is a last resort mechanism to prevent thermal stress to the regulator. Operation at or close to the thermal shutdown temperature is not recommended and will reduce the long-term reliability of the module. Always operate the regulator within the specified Safe Operating Area (SOA) limits for the worst-case conditions of ambient temperature and airflow. Vo (2V/Div) Iin (2A/Div) Output On/Off Inhibit Q1Vds (5V/Div) For applications requiring output voltage on/off control, each series of the ATH family incorporates an output Inhibit control pin. The inhibit feature can be used wherever there is a requirement for the output voltage from the regulator to be turned off. North America (USA): 1-888-41-ASTEC HORIZ SCALE: 10ms/Div Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Auto-TrackTM Function The Auto-TrackTM function is unique to the ATH family, and is available with the all "Point-of-Load Alliance" (POLA) products. Auto-TrackTM was designed to simplify the amount of circuitry required to make the output voltage from each module power up and power down in sequence. The sequencing of two or more supply voltages during power up is a common requirement for complex mixed-signal applications, that use dual-voltage VLSI ICs such as DSPs, micro-processors, and ASICs. How Auto-TrackTM Works Auto-TrackTM works by forcing the module's output voltage to follow a voltage presented at the Track control pin. This control range is limited to between 0 V and the module's set-point voltage. Once the track-pin voltage is raised above the set-point voltage, the module's output remains at its set-point 1. As an example, if the Track pin of a 2.5-V regulator is at 1 V, the regulated output will be 1 V. But if the voltage at the Track pin rises to 3 V, the regulated output will not go higher than 2.5 V. When under track control, the regulated output from the module follows the voltage at its Track pin on a voltfor-volt basis. By connecting the Track pin of a number of these modules together, the output voltages will follow a common signal during power-up and power-down. The control signal can be an externally generated master ramp waveform, or the output voltage from another power supply circuit 3. For convenience the Track control incorporates an internal RC charge circuit. This operates off the module's input voltage to provide a suitable rising voltage ramp waveform. Typical Application The basic implementation of Auto-TrackTM allows for simultaneous voltage sequencing of a number of AutoTrackTM compliant modules. Connecting the Track control pins of two or more modules forces the Track control of all modules to follow the same collective RC ramp waveform, and allows them to be controlled through a single transistor or switch; Q1 in Figure 3-5. To initiate a power-up sequence the Track control must first pulled to ground potential. This should be done at or before input power is applied to the modules, and then held for at least 10 ms thereafter. This brief period gives the modules time to complete their internal soft-start initialization, which enables them to produce an output voltage. Applying a logic-level high signal to the circuit's On/Off Control turns Q1 on and applies a ground signal to the Track control. After completing their internal soft-start intialization, the output of all modules will remain at zero volts while Q1 is on. 10 ms after a valid input voltage has been applied to all modules, Q1 can be turned off. This allows the track control voltage to automatically rise toward to the modules' input voltage. During this period the output voltage of each module will rise in unison with other modules, to its respective set-point voltage. North America (USA): 1-888-41-ASTEC Figure 3-6 shows the output voltage waveforms from the circuit of Figure 3-5 after the On/Off Control is set from a high to a low-level voltage. The waveforms, Vo1 and Vo2 represent the output voltages from the two power modules, U1 (3.3 V) and U2 (1.8 V) respectively. Vo1 and Vo2 are shown rising together to produce the desired simultaneous power-up characteristic. The same circuit also provides a power-down sequence. Power down is the reverse of power up, and is accomplished by lowering the track control voltage back to zero volts. The important constraint is that a valid input voltage must be maintained until the power down is complete. It also requires that Q1 be turned off relatively slowly. This is so that the Track control voltage does not fall faster than Auto-Track's slew rate capability, which is 1 V/ms. The components R1 and C1 in Figure 3-5 limit the rate at which Q1 can pull down the Track control voltage. The values of 100 k-ohm and 0.1 F correlate to a decay rate of about 0.17 V/ms. The power-down sequence is initiated with a low-to-high transition at the On/Off Control input to the circuit. Figure 3-7 shows the power-down waveforms. As the Track control voltage falls below the nominal set-point voltage of each power module, then its output voltage decays with all the other modules under Auto-TrackTM control. Notes on Use of Auto-TrackTM 1. The Track pin voltage must be allowed to rise above the module's set-point voltage before the module can regulate at its adjusted set-point voltage. 2. The Auto-TrackTM function will track almost any voltage ramp during power up, and is compatible with ramp speeds of up to 1 V/ms. 3. The absolute maximum voltage that may be applied to the Track pin is Vin. 4. The module will not follow a voltage at its Track control input until it has completed its soft-start initialization. This takes about 10 ms from the time that the module has sensed that a valid voltage has been applied its input. During this period, it is recommended that the Track pin be held at ground potential. 5. The module is capable of both sinking and sourcing current when following a voltage at its Track pin. Therefore startup into an output prebias is not supported during Auto-TrackTM control. Note: A pre-bias holdoff is not necessary when all supply voltages rise simultaneously under the control of Auto-TrackTM. 6. The Auto-TrackTM function can be disabled by connecting the Track pin to the input voltage (Vin). With Auto-TrackTM disabled, the output voltage will rise at a quicker and more linear rate after **Auto-Track is a trademark of Texas Intruments, Inc. Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Figure 3-5; Sequenced Power Up & Power Down Using Auto-Track U1 10 9 8 5 Track Inhibit + CIN PTH05020W ATH22T05-9S VIN VO Vo1 =3.3 V 6 GND 3 7 1 COUT 4 R2 698 + 2 +5 V C1 0.1 F U2 9 8 5 Track 2 CIN 0V Figure 3-6; Simultaneous Power Up with Auto-TrackTM Control + R1 100 k 10 Q1 BSS138 ATH15T05-9S PTH05010W VIN Inhibit 3 VO Vo2 =1.8 V 6 GND 1 7 4 R3 5k49 COUT + On/Off Control 1 = Power Down 0 = Power Up Figure 3-7; Simultaneous Power Down with Auto-TrackTM Control Vo1 (1 V/Div) Vo1 (1 V/Div) Vo2 (1 V/Div) Vo2 (1 V/Div) On/Off Input (5 V/Div) On/Off Input (5 V/Div) HORIZ SCALE: 10 ms/Div HORIZ SCALE: 10 ms/Div North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Margin Up/Down Controls Notes: The ATH10 (10A), ATH12/15 (12/15A), ATH18/22 (18/ 22A) and ATH26/30 (26/30A) products incorporate Margin Up and Margin Down control inputs. These controls allow the output voltage to be momentarily adjusted 1, either up or down, by a nominal 5 %. This provides a convenient method for dynamically testing the operation of the load circuit over its supply margin or range. It can also be used to verify the function of supply voltage supervisors. The 5 % change is applied to the adjusted output voltage, as set by the external resistor, Rset at the Vo Adjust pin. The 5 % adjustment is made by pulling the appropriate margin control input directly to the GND terminal 2. A low-leakage open-drain device, such as an n-channel MOSFET or p-channel JFET is recommended for this purpose 3. Adjustments of less than 5 % can also be accommodated by adding series resistors to the control inputs. The value of the resistor can be selected from Table 3-2, or calculated using the following formula. Up/Down Adjust Resistance Calculation 1. The Margin Up* and Margin Dn* controls were not intended to be activated simultaneously. If they are their affects on the output voltage may not completely cancel, resulting in the possibility of a slightly higher error in the output voltage set point. 2. The ground reference should be a direct connection to the module GND at pin 7 (pin 1 for the ATH06). This will produce a more accurate adjustment at the load circuit terminals. The transistors Q1 and Q2 should be located close to the regulator. 3. The Margin Up and Margin Dn control inputs are not compatible with devices that source voltage. This includes TTL logic. These are analog inputs and should only be controlled with a true open-drain device (preferably a discrete MOSFET transistor). The device selected should have low off-state leakage current. Each input sources 8 A when grounded, and has an open-circuit voltage of 0.8 V. To reduce the margin adjustment to something less than 5 %, series resistors are required (See RD and RU in Figure 3-8). For the same amount of adjustment, the resistor value calculated for RU and RD will be the same. The formulas is as follows. RU or RD = 499 % - 99.8 Table 3-2; Margin Up/Down Resistor Values % Adjust 5 4 3 2 1 k Where % = The desired amount of margin adjust in percent. RU / RD 0.0 k 24.9 k 66.5 k 150.0 k 397.0 k Figure 3-8; Margin Up/Down Application Schematic 10 9 8 1 7 PTH05010W ATH15T05-9S (Top View) VIN 0V 2 RD 4 MargUp 5 RU RSET 0.1 W, 1 % Cin MargDn +VOUT 6 3 + +Vo + Cout Q2 GND North America (USA): 1-888-41-ASTEC L O A D Q1 GND Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Pre-Bias Startup Capability Notes Only selected products in the ATH family incorporate this capability. Consult Table 3-1 to identify which products are compliant. 1. Startup includes the short delay (approx. 10 ms) prior to the output voltage rising, followed by the rise of the output voltage under the module's internal soft-start control. Startup is complete when the output voltage has risen to either the setpoint voltage or the voltage at the Track pin, whichever is lowest. A pre-bias startup condition occurs as a result of an external voltage being present at the output of a power module prior to its output becoming active. This often occurs in complex digital systems when current from another power source is backfed through a dual-supply logic component, such as an FPGA or ASIC. Another path might be via clamp diodes as part of a dual-supply power-up sequencing arrangement. A prebias can cause problems with power modules that incorporate synchronous rectifiers. This is because under most operating conditions, these types of modules can sink as well as source output current. 2. To ensure that the regulator does not sink current when power is first applied (even with a ground signal applied to the Inhibit control pin), the input voltage must always be greater than the output voltage throughout the power-up and power-down sequence. 3. The Auto-TrackTM function can be disabled at power up by immediately applying a voltage to the module's Track pin that is greater than its set-point voltage. This can be easily accomplished by connecting the Track pin to Vin. The ATH family of power modules incorporate synchronous rectifiers, but will not sink current during startup 1, or whenever the Inhibit pin is held low. However, to ensure satisfactory operation of this function, certain conditions must be maintained. 2 Figure 3-9 shows an application demonstrating the pre-bias startup capability. The startup waveforms are shown in Figure 3-10. Note that the output current from the ATH15T033 (Io) shows negligible current until its output voltage rises above that backfed through diodes D1 and D2. Figure 3-10; Pre-Bias Startup Waveforms Vin (1 V/Div) Note: The pre-bias start-up feature is not compatible with Auto-TrackTM. When the module is under Auto-TrackTM control, it will sink current if the output voltage is below that of a back-feeding source. To ensure a pre-bias hold-off one of two approaches must be followed when input power is applied to the module. The Auto-TrackTM function must either be disabled 3, or the module's output held off (for at least 50 ms) using the Inhibit pin. Either approach ensures that the Track pin voltage is above the set-point voltage at start up. Vo (1 V/Div) Io (5 A/Div) HORIZ SCALE: 5 ms/Div Figure 3-9; Application Circuit Demonstrating Pre-Bias Startup VIN = 3.3 V 10 9 5 8 Track 2 VIN Sense ATH15T033-9S PTH03010W Inhibit 3 GND 1 VO Vo = 2.5 V 6 + Vadj 7 Io 4 VCCIO VCORE + CIN 330 F North America (USA): 1-888-41-ASTEC R2 2k21 + COUT 330 F Europe (UK): 44(1384)842-211 ASIC Asia (HK): 852-2437-9662 Application Notes ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) Remote Sense The ATH10, ATH12/15, ATH18/22, and ATH26/30 products incorporate an output voltage sense pin, Vo Sense. The Vo Sense pin should be connected to Vout at the load circuit (see data sheet standard application). A remote sense improves the load regulation performance of the module by allowing it to compensate for any `IR' voltage drop between itself and the load. An IR drop is caused by the high output current flowing through the small amount of pin and trace resistance. Use of the remote sense is optional. If not used, the V o Sense pin can be left open-circuit. An internal low-value resistor (15- or less) is connected between the Vo Sense and Vout. This ensures the output voltage remains in regulation. With the sense pin connected, the difference between the voltage measured directly between the Vout and GND pins, and that measured from V o Sense to GND, is the amount of IR drop being compensated by the regulator. This should be limited to a maximum of 0.3 V. Note: The remote sense feature is not designed to compensate for the forward drop of non-linear or frequency dependent components that may be placed in series with the converter output. Examples include OR-ing diodes, filter inductors, ferrite beads, and fuses. When these components are enclosed by the remote sense connection they are effectively placed inside the regulation control loop, which can adversely affect the stability of the regulator. North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662