ATH15

ATH06T033 ASTEC | Alldatasheet

Document overview

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Technical content

Features

• Up to 6-A Output Current
• 3.3-V Input Voltage
• Wide-Output Voltage Adjust (0.8 V to 2.5 V)
• Efficiencies up to 94 %
• 103 W/in³ Power Density
• On/Off Inhibit
• Pre-Bias Startup
• Under-Voltage Lockout
• Operating T emp: –40 to +85 °C
• Auto-T rack™ Sequencing
• Output Over-Current Protection (Non-Latching, Auto-Reset)
• IPC Lead Free 2
• Safety Agency Approvals (Pending) UL 1950, CSA 22.2 950, & EN60950
• Point-of-Load Alliance (POLA) Compatible Auto-Track™ Sequencing Pin Configuration Pin Function

1 GND

2 T rack

4 Inhibit *

• Denotes negative logic: Open = Normal operation Ground = Function active NOMINAL SIZE = 0.87 in x 0.5 in (22,1 mm x 12,57 mm) ATH06T033 Series —3.3-V Input REVISION 00 (01DEC2003) Standard Application

Description

The ATH06T033 series is one of the smallest non-isolated power modules that features Auto-T rack™. Auto-T rack™ simplifies supply voltage sequencing in power systems by enabling modules to track each other, or any other external voltage, during power up and power down. Although small in size (0.87 in × 0.5 in), these modules are rated for up to 6 A of output current, and are an ideal choice in applications where space, performance, and a power-up sequencing capability are important attributes. The product provides high-performance step-down conversion from a 3.3-V input bus voltage. The output voltage of the ATH06T033 can be set to any voltage over the range, 0.8 V to 2.5 V , using a Rset = Required to set the output voltage to a value higher than 0.8 V. (See spec. table for values) Cin = Required 100 µF Co1 = Optional 100 µF capacitor Co2 = Optional 10 µF ceramic capacitor for reduced output ripple. single resistor. Other operating features include an on/off inhibit, output voltage adjust (trim), and output over-current protection. For high efficiency these parts employ a synchronous rectifier output stage, but a pre-bias hold-off capability ensures that the output will not sink current during startup. T arget applications include telecom, industrial, and general purpose circuits, including low-power dual-voltage systems that use a DSP , microprocessor, ASIC, or FPGA. Package options include both through- hole and surface mount configurations. VIN Inhibit GND GND VOUT Track R SET 1 %, 0.1 W (Required) Co 1 100 µF Electrolytic (Optional) C IN 100 µF (Required) Co 2 10 µF Ceramic (Optional) PTH03050W (Top View) ATH06T033-9S

North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Pin Descriptions Vin: The positive input voltage power node to the mod- ule, 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 V out power connections. It is also the 0 VDC reference for the control inputs. Vo Adjust: A 0.1 W 1 % resistor must be directly connected between this pin and 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 this pin is left open circuit, the output voltage will default to its lowest value. For further information on output volt- age adjustment consult the related application note. Rset = 10 kΩ · 0.8 V – 2.49 kΩ Vout – 0.8 V The specification table gives the preferred resistor values for a number of standard output voltages. Inhibit: The Inhibit pin is an open-collector/drain negative logic input that is referenced to GND. Applying a low- level ground signal to this input disables the module’s output and turns off the output voltage. When the Inhibit control is active, the input current drawn by the regula- tor is significantly reduced. If the Inhibit pin is left open-circuit, the module will produce an output when- ever a valid input source is applied. Track: This is an analog control input that allows the output voltage to follow another voltage during power- up and power-down sequences. The pin is active from 0 V up to the nominal set-point voltage. Within this range the module’s output will follow the voltage at the Track pin on a volt-for-volt basis. When the control volt- age is raised above this range, the module regulates at its nominal output voltage. If unused, this input may be left unconnected. For further information consult the related application note.

Ordering Information

6-A, 3.3-V I nput Non-Isolated Wide-Output Adjust Power Module ATH06T033 Series —3.3-V Input Input Voltage Output Voltage Output Current Model Number 2.95V to 3.65V 0.8 1 to 2.5V 6A ATH06T033-9(S)(J) Options: “-J” - Through-hole T ermination, T ray Packaging “-SJ” - SMT T ermination, T ray Packaging “-S” - SMT T ermination, T&R Packaging Notes: 1Preset output voltage is 0.8V; externally adjustable to 2.5V through the Vo,Adjust pin REVISION 00 (01DEC2003)

North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Environmental & Absolute Maximum Ratings (Voltages are with respect to GND) Characteristics Symbols Conditions Min Typ Max Units T rack Input Voltage V track –0.3 — V in + 0.3 V Operating T emperature Range T a Over Vin Range –40 (i) — 85 °C Solder Reflow T emperature T reflow Surface temperature of module body or pins 235 (ii) °C Storage T emperature T s — –40 — 125 °C Mechanical Shock Per Mil-STD-883D, Method 2002.3 — TBD — G’s1 msec, ½ Sine, mounted Mechanical Vibration Mil-STD-883D, Method 2007.2 Suffix H — TBD — G’s20-2000 Hz Suffix S — TBD — Weight — — 2.9 — grams Flammability — Meets UL 94V-O Notes: (i) For operation below 0 °C the external capacitors m ust bave stable characteristics. use either a low ESR tantalum, Os-Con®, or ceramic capacitor. (ii) During reflow of SMD package version do not elevate peak temperature of the module, pins or internal components above the s tated maximum. 6-A, 3.3-V I nput Non-Isolated Wide-Output Adjust Power Module ATH06T033 Series —3.3-V Input Specifications (Unless otherwise stated, Ta =25 °C, Vin =3.3 V , Vo =2.5 V , Coin =100 µF , Co1 =0 µF, Co2 =0 µF, and Io =Iomax) ATH06T033 Characteristics Symbols Conditions Min Typ Max Units Output Current I o 0.8 V ≤ Vo ≤ 2.5 V , 85 °C, natural convection 0 — 6 (1) A Input Voltage Range V in Over Io range 2.95 — 3.65 V Set-Point Voltage T olerance V o tol — — ±2 (2) %Vo T emperature Variation ∆Regtemp –40 °C <Ta < +85 °C — ±0.5 — %V o Line Regulation ∆Regline Over Vin range — ±10 — mV Load Regulation ∆Regload Over Io range — ±12 — mV T otal Output Variation ∆Regtot Includes set-point, line, load, ——± 3 (2) %Vo–40 °C ≤ Ta ≤ +85 °C Efficiency η Io =4 A R SET = 2.21 kΩ Vo = 2.5 V — 94 — RSET = 4.12 kΩ Vo = 2.0 V — 92 — RSET = 5.49 kΩ Vo = 1.8 V — 91 — %RSET = 8.87 kΩ Vo = 1.5 V — 90 — RSET = 17.4 kΩ Vo = 1.2 V — 88 — RSET = 36.5 kΩ Vo = 1.0 V — 87 — Vo Ripple (pk-pk) V r 20 MHz bandwidth, Co2 =10 µF ceramic — 20 (3) — mVpp Over-Current Threshold I o trip Reset, followed by auto-recovery — 12 — A T ransient Response 1 A/µs load step, 50 to 100 % I omax, Co1 =100 µF ttr Recovery Time — 70 — µSec ∆Vtr Vo over/undershoot — 100 — mV T rack Input Current (pin 2) I IL track Pin to GND — — –130 (4) µA T rack Slew Rate Capability dV track/dt Vtrack – Vo ≤ 50 mV and Vtrack < Vo(nom) 5 — — V/ms Under-Voltage Lockout UVLO V in increasing — 4.3 4.45 VVin decreasing 3.4 3.7 — Inhibit Control (pin4) R eferenced to GND Input High Voltage V IH Vin –0.5 — Open (4) V Input Low Voltage VIL –0.2 — 0.6 Input Low Current IIL inhibit Pin to GND — –130 — µA Input Standby Current I in inh Inhibit (pin 4) to GND, T rack (pin 2) open — 10 — mA Switching Frequency ƒ s Over Vin and Io ranges 550 600 650 kHz External Input Capacitance C in 100 (5) ——µ F External Output Capacitance C out 0 100 (6) TBD µF Reliability MTBF Per Bellcore TR-332 TBD — — 10 6 Hrs50 % stress, Ta =40 °C, ground benign Notes: (1) No derating is required when the module is soldered directly to a 4-layer PCB with 1 oz. copper. (2) The set-point voltage tolerance is affected by the tolerance and stability ofR SET. The stated limit is unconditionally met if R SET has a tolerance of 1 % with 100 ppm/°C or better temperature stability. (3) The pk-pk output ripple voltage is measured with an external 10 µF ceramic capacitor. See the standard application schematic . (4) This control pin has an internal pull-up to the input voltage Vin. If it is left open-circuit the module will operate when i nput power is applied. A small low-leakage (<100 nA) MOSFET is recommended for control. For further information, consult the related application note. (5) A 100 µF input capacitor is required for proper operation. The capacitor must be rated for a minimum of 300 mA rms of ripple current. (6) An external output capacitor is not required for basic operation. Adding 100 µF of distributed capacitance at the load will improve the transient response.

The products listed hereunder are prototype or pre-production devices which have not been fully qualified to Astec’s specifications. Product specifications are subject to change without notice. Astec makes no warranty, either expressed, implied, or statutory, including implied warranty of merchantab ility or fitness for a specific purpose, of these products. North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Note A: Characteristic data has been developed from actual products tested at 25°C. This data is considered typical data for the Converter. Typical Characteristics Characteristic Data; Vin =3.3 V (See Note A) Efficiency vs Load Current Power Dissipation vs Load Current Output Ripple vs Load Current (See Note 3 to T able) 6-A, 3.3-V I nput Non-Isolated Wide-Output Adjust Power Module ATH06T033 Series —3.3-V Input 0.2 0.4 0.6 0.8 1.2 0123456 Iout - Amps Pd - Watts 100 0123456 Iout - Amps Efficiency - % 2.5 V 1.8 V 1.5 V 1.2 V 1.0 V VOUT 0123456 Iout - Amps Ripple - mV 1.8 V 1.5 V 1.2 V 1.0 V 2.5 V VOUT

North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Adjusting the Output Voltage of the ATH06T033 & ATH06T05 Wide-Output Adjust Power Modules The Vo Adjust control (pin 5) sets the output voltage to a value higher than 0.8 V . The adjustment range of the ATH06T033 (3.3-V input) is from 0.8 V to 2.5 V 1, and the ATH06T05-9xx (5-V input) from 0.8 V to 3.6 V . The adjustment method requires the addition of a single external resistor, R set, that must be connected directly between the Vo Adjust and GND pins 2. T able 1-1 gives the preferred value of the external resistor for a number of standard voltages, along with the actual output volt- age 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 T able 1-2. Figure 1-1 shows the placement of the required resistor. Rset = 10 kΩ · 0.8 V – 2.49 kΩVout – 0.8 V Figure 1-1; Vo Adjust Resistor Placement 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 1 using dedicated PCB traces. 3. Never connect capacitors from V o Adjust to either GND or Vout. Any capacitance added to the Vo Adjust pin will affect the stability of the regulator.

0.800 Open

0.825 318 k Ω 0.850 158 k Ω 0.875 104 k Ω 0.900 77.5 k Ω 0.925 61.5 k Ω 0.950 50.8 k Ω 0.975 43.2 k Ω 1.000 37.5 k Ω 1.025 33.1 k Ω 1.050 29.5 k Ω 1.075 26.6 k Ω 1.100 24.2 k Ω 1.125 22.1 k Ω 1.150 20.4 k Ω 1.175 18.8 k Ω 1.200 17.5 k Ω 1.225 16.3 k Ω 1.250 15.3 k Ω 1.275 14.4 k Ω 1.300 13.5 k Ω 1.325 12.7 k Ω 1.350 12.1 k Ω 1.375 11.4 k Ω 1.400 10.8 k Ω 1.425 10.3 k Ω 1.450 9.82 k Ω 1.475 9.36 k Ω 1.50 8.94 k Ω 1.55 8.18 k Ω 1.60 7.51 k Ω 1.65 6.92 k Ω 1.70 6.4 k Ω 1.75 5.93 k Ω 1.80 5.51 k Ω 1.85 5.13 k Ω 1.90 4.78 k Ω 1.95 4.47 k Ω Vout (Standard) R set (Pref’d Value) V out (Actual) 3.3 V 1 698 Ω 3.309V 2.5 V 2.21 k Ω 2.502 V 2 V 4.12 k Ω 2.010 V 1.8 V 5.49 k Ω 1.803 V 1.5 V 8.87 k Ω 1.504 V 1.2 V 17.4 k Ω 1.202 V 1 V 36.5 k Ω 1.005 V 0.8 V Open 0.8 V Table 1-1; Preferred Values of R set for Standard Output Voltages ATH06T033 & ATH06T05 Series Table 1-2; Output Voltage Set-Point Resistor Values Va Req’d R set Va Req’d R set 2.00 4.18 k Ω 2.05 3.91 k Ω 2.10 3.66 k Ω 2.15 3.44 k Ω 2.20 3.22 k Ω 2.25 3.03 k Ω 2.30 2.84 k Ω 2.35 2.67 k Ω 2.40 2.51 k Ω 2.45 2.36 k Ω 2.50 2.22 k Ω 2.55 2.08 k Ω 2.60 1.95 k Ω 2.65 1.83 k Ω 2.70 1.72 k Ω 2.75 1.61 k Ω 2.80 1.51 k Ω 2.85 1.41 k Ω 2.90 1.32 k Ω 2.95 1.23 k Ω 3.00 1.15 k Ω 3.05 1.07 k Ω 3.10 988 Ω 3.15 914 Ω 3.20 843 Ω 3.25 775 Ω 3.30 710 Ω 3.35 647 Ω 3.40 587 Ω 3.45 529 Ω 3.50 473 Ω 3.55 419 Ω 3.60 367 Ω VIN C IN 100 µF (Required) + C OUT 100 µF (Optional) GND VOUT R SET 1 % 0.1 W PTH05050W Track VIN VO GNDInhibit ATH06T05-9J

North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 ATH06T033 & ATH06T05 Series Table 2-1: Recommended Input/Output Capacitors ATH06T033/T05: Capacitor Recommendations Input Capacitor The recommended input capacitance is determined by 100 µF minimum capacitance, and 300 mA (rms) mini- mum ripple current rating. Ripple current and less than 300 m Ω equivalent series resistance (ESR) values are the major considerations, along with temperature, when designing with different types of capacitors. T antalum capacitors have a recommended minimum volt- age rating of twice 2× (the maximum DC voltage + AC ripple). This is standard practice for tantalum capacitors to insure reliability. Output Capacitors (Optional) The ESR of the recommended capacitors is equal to or less than 300 m Ω . Electrolytic capacitors have marginal ripple performance at frequencies greater than 400 kHz but excellent low frequency transient response. Above the ripple frequency, ceramic capacitors are necessary to improve the transient response and reduce any high frequency noise components apparent during higher current excursions. Tantalum/ Ceramic Capacitors T antalum capacitors are acceptable on the output bus. T antalum, Os-con, or ceramic capacitor types are recom- mended for applications where ambient temperatures fall below 0 °C. Ceramic capacitors may be used instead of electrolytic types on both the input and output bus. The input bus must have the minimum amount of capacitance. A single 10 µF ceramic capacitor may also be used on the output bus to reduce output ripple. Capacitor Table T able 2-1 identifies the characteristics of capacitors from a number of vendors with acceptable ESR and ripple current (rms) ratings. The number of capacitors required at both the input and output buses is identified for each capacitor type. This is not an extensive capacitor list. Capacitors from other vendors are available with comparable specifications. Those listed are for guidance. The RMS ripple current rating and ESR are the critical parameters necessary to insure both opti- mum regulator performance and long capacitor life. /rodneVroticapaC tnenopmoC seireS scitsiretcarahCroticapaCy titnauQ gnikroW egatloV) Fµ(eulaV tnelaviuqE)RSE( ecnatsiseRseireS elppiRxaM C°58ta )smrI(tnerruC eziSlacisyhP )mm( tupnI suB tuptuO suB rebmuNrodneV TMS(CFcinosanaP )TMS(AW V52 V01 Fµ001 Fµ021 003.0 Ω 530.0 Ω Am054 Am0082 8× 01 3.8 × 9.6 P101E1CFVEE P121A1AWFEE CFcinosanaP )TMS(KF V61 V61 022F µ 033F µ 051.0 Ω 061.0 Ω Am555 Am006 01 × 2.01 8× 2.01 122C1CFUEE P133C1KFVEE noC–imehCdetinU SF )TMS(AXP )TMS(ZVM SP V01 V01 V61 V01 Fµ001 021F µ 022F µ Fµ072 040.0 Ω 720.0 Ω 071.0 Ω 410.0 Ω Am0012 Am0342 Am054 Am0244 3.6 × 8.9 8× 7.6 8× 01 8× 5.11 M001SF01 PT08HM121CV01AXP PT01HM122CV52ZVM 11HM072SP01 nocihciN )TMS(GW 55F MP V53 V01 V52 001F µ 001F µ 051F µ 051.0 Ω 550.0 Ω 061.0 Ω Am076 Am0002 Am064 01 × 01 3,4x7,7 01 × 5.11 SG1RNM101V1GWU NM701A155F HPM151E1MPU ®noc-sOoynaS )TMS(PVS PS APT V01 V61 V01 021F µ Fµ001 µ001F 040.0 Ω 520.0 Ω 080.0 Ω Am0052> Am0082> Am0021> 7×8 3.6 × 8.9 3.7 × 8.4 M021PVS01 M001SPS61 M001APT01 SPTmulatnaTXVAV 01 V01 Fµ001 Fµ022 01.00 Ω 001.0 Ω Am0901> Am4141> L3.7 × W3.4 × H1.4 0010R010M701DSPT 0010R010M722VSPT temeK0 25T 594T V01 V01 Fµ001 Fµ001 080.0 Ω 001.0 Ω Am0021 Am0011> L3.7 × W7.5 × H0.4 SA010M701D025T SA010M701X594T D595/D495eugarpSV 01 V01 Fµ051 Fµ021 090.0 Ω 041.0 Ω Am0011 Am0001> L3.7 × W0.6 × H1.4 T2C0100X751D495 T2D0100X721D595 R5XcimareC-KDT R5XcimareCataruM esaC0121 V3.6 V3.6 Fµ74 Fµ74 200.0 Ω 200.0 Ω Am0041> Am0001> L6.3 × W8.2 × H8.2 TM/TK674J0R5X5223C 3.6/M674J06RE23MRG

ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Features of the ATH Family of Non-Isolated Wide Output Adjust Power Modules 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 cust omer design flexibility. The POLA is a collaboration between T exas Instruments, Artesyn T echnologies, and Astec Power to offer customers advanced non-isolated modules that provide the same functionality and form factor. Prod- uct 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 Series, these products were designed to be very flexible, yet simple to use. The features vary with each product. T able 3-1 provides a quick reference to the available features by product and input bus voltage. Table 3-1; Operating Features by Series and Input Bus Voltage For simple point-of-use applications, the ATH06 (6A) 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, ATH18/22 (18/22A) and ATH26/30 (26/30A) products incor- porate over-temperature shutdown protection. All of the products referenced in T able 3-1 include Auto-T rack™. Power-Up Characteristics When configured per their standard application all the ATH products will produce a regulated output voltage fol- lowing the application of a valid input source voltage. All the modules include soft-start circuitry. This slows the initial rate in which the output voltage can rise, thereby limiting the amount of in-rush current that can be drawn from the input source. The soft-start circuitry also introduces a short time delay (typically 5 ms-10 ms) into the power-up characteristic. This delay is from the point that a valid input source is recognized, to the initial rise of the output voltage. Figure 3-1 shows the power-up characteristic of the 22-A output product (ATH22T05-9xx), operating from a 5-V input bus and configured for a 3.3-V output. The wave- forms were measured with a 5-A resistive load. The initial rise in input current when the input voltage first starts to rise is the charge current drawn by the input capacitors. Figure 3-1 Vo (2V/Div) Iin (2A/Div) Vin (5V/Div) HORIZ SCALE: 10ms/Div Over-Current Protection 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. Series Input Bus I OUT

12 V 6 A  

Adjust (Trim) Thermal Shutdown Pre-Bias Startup Margin Up/Down Auto-Track™ 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. ATH10 ATH06 ATH12/15 ATH18/22 ATH26/30 10 A

ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Figure 3-5; Simultaneous Power Up with Auto-Track Control PTH05010W Track VIN VO GNDInhibit PTH05020W Track VIN VO GNDInhibit

7 COUT

Vo2 =2V Vo1 =3.3V +5V On/Off Control 1 = Power Down 0 = Power Up BSS138 0.047µF 100k 698 4k12 Figure 3-4; Sequenced Power Up & Power Down Using Auto-Track Figure 3-6; Simultaneous Power Down with Auto-Track Control Vo1 (1V/Div) Vo2 (1V/Div) On/Off Input (5V/Div) HORIZ SCALE: 5ms/Div Vo1 (1V/Div) Vo2 (1V/Div) On/Off Control (5V/Div) HORIZ SCALE: 5ms/Div ATH22T05-9SJ ATH15T05-9SJ

ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Margin Up/Down Controls 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 accom- modated by adding series resistors to the control inputs (See Figure 3-4). The value of the resistor can be selected from T able 3-2, or calculated using the following formula. Up/Down Adjust Resistance Calculation T o reduce the margin adjustment to something less than 5 %, series resistors are required (See R D and R U in Figure 3-7). For the same amount of adjustment, the resistor value calculated for R U and R D will be the same. The formulas is as follows. RU or RD = 499 – 99.8 k Ω ∆% Where ∆ % = The desired amount of margin adjust in percent. Notes: 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 Q 1 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 µA when grounded, and has an open-circuit voltage of 0.8 V . Figure 3-7; Margin Up/Down Application Schematic Table 3-2; Margin Up/Down Resistor Values % Adjust R U / RD 5 0.0 k Ω 4 24.9 k Ω 3 66.5 k Ω 2 150.0 k Ω 1 397.0 k Ω Cout +Cin VIN GND MargDn L O A D +VOUT MargUp +Vo RD RU PTH05010W (Top View) 10 9 8 543 GND RSET

0.1 W, 1 %

ATH Series of Wide-Output Adjust Power Modules (3.3/5-V Input) North America (USA): 1-888-41-ASTEC Europe (UK): 44(1384)842-211 Asia (HK): 852-2437-9662 Pre-Bias Startup Capability Only selected products in the ATH family incorporate this capability. Consult T able 3-1 to identify which products are compliant. 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 com- plex 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. The ATH family of power modules incorporate synchro- nous rectifiers, but will not sink current during startup or whenever the Inhibit pin is held low. However, to ensure satisfactory operation of this function, certain conditions must be maintained.

2 Figure 3-7 shows an application

demonstrating the pre-bias startup capability. The start- up waveforms are shown in Figure 3-9. Note that the output current from the ATH15T033-9xx (I o) shows neg- ligible current until its output voltage rises above that backfed through diodes D 1 and D2. Note: The pre-bias start-up feature is not compatible with Auto-Track. When the module is under Auto-Track control, it is fully active and will sink current if the output voltage is below that of a back-feeding source. Therefore to ensure a pre- bias hold-off, one of two approaches must be followed when input power is applied to the module. The Auto-Track function must either be disabled 3, or the module’s output held off using the Inhibit pin. The latter allows Auto-Track’s internal (RC) voltage ramp to rise above the set-point voltage. Notes 1. Startup is the relatively short period (approx. 10 ms) prior to the output voltage rising. The startup period immediately follows either the application of a valid input source v oltage, or the release of a ground signal at the Inhibit pin. 2. T o 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-T rack 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 V in through a 1-k Ω resistor. Vo = 2.5 V VIN = 3.3 V 2k21 1k0 ASIC VCORE VCCIO Io PTH03010W Track VIN VO GNDInhibit Vadj Sense CIN 330 µF D1, D2 MBR3100 COUT 330 µF Figure 3.8; Application Circuit Demonstrating Pre-Bias Startup Vin (1 V/Div) Vo (1 V/Div) Io (5 A/Div) HORIZ SCALE: 5 ms/Div Figure 3.9; Pre-Bias Startup Waveforms ATH15T033-9S