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19-3513; Rev 0; 11/04
MAX5069A Evaluation Kit
General Description
The MAX5069A evaluation kit (EV kit) is a fully assembled and tested circuit board that contains a high-efficiency, 120W isolated push-pull DC-DC converter. The circuit is configured for a +12V output voltage and provides up to 10A of output current. The circuit can be powered from either a +36V to +72V or -36V to -72V DC source, as used in the telecom/datacom markets, industrial environments, or in automotive 42V power systems. High efficiency up to 91% is achieved at 10A while using two n-channel primary-side MOSFETs switching at up to 90% combined duty cycle. On the secondary-side, reduced output-voltage ripple and high efficiency is achieved through full-wave rectification from a centertapped planar transformer. Galvanic isolation up to 500V is achieved by an optocoupler and the planar surfacemount transformer. The optocoupler helps in providing isolated secondary-side regulation. Operation at 500kHz allows the use of small magnetics and output capacitors. A SYNC input is featured to ease synchronization to an external clock. The EV kit provides cycle-by-cycle current-limit protection. Additional steadystate fault protection is provided by the integrating fault protection that reduces average dissipated power during continuous overload conditions. The MAX5069A also has a programmable input undervoltage lockout (UVLO) for protection during brownout conditions. The EV kit may be used to evaluate other versions of the MAX5069. Warning: The MAX5069A EV kit is designed to operate with high voltages. Dangerous voltages are present on this EV kit and on equipment connected to it. Users who power up this EV kit or power the sources connected to it must be careful to follow safety procedures appropriate to working with high-voltage electrical equipment. Under severe fault or failure conditions, this EV kit may dissipate large amounts of power, which could result in the mechanical ejection of a component or of component debris at high velocity. Operate this kit with care to avoid possible personal injury.
Features
120W High-Efficiency, Isolated, Push-Pull DC-DC Converter 36V to 72V Input Range +12V Output at 10A VOUT Regulation Better than 0.1% Over Line and Load 91% Efficiency at 48V and 10A Programmable Input UVLO Cycle-by-Cycle Current-Limit Protection Programmable Integrating Fault Protection 500kHz Oscillator Frequency External Clock SYNC Input Fully Assembled and Tested
Evaluates: MAX5069A
Ordering Information
PART MAX5069AEVKIT TEMP RANGE 0C to +50C* IC PACKAGE 16 TSSOP
*With 200LFM airflow.
Component List
DESIGNATION C1 QTY 1 DESCRIPTION 0.1F 10%, 16V X7R ceramic capacitor (0603) Murata GRM39X7R104K016AD 1F 10%, 100V X7R ceramic capacitors (1210) AVX 1210C105KAT9A 47F 10%, 16V X5R ceramic capacitors (1210) Murata GRM32ER61C476K 0.1F 10%, 50V X7R ceramic capacitor (0603) Murata GRM188R71H104K 10F 20%, 35V, low-impedance electrolytic capacitor (5mm x 6mm) Sanyo 35CV10KX 12pF 5%, 50V C0G ceramic capacitor (0603) Murata GRM1885C1H120J
C2, C3, C4
3
C5, C6, C7, C18, C19, C20
6
C8
1
C9
1
C10
1
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
MAX5069A Evaluation Kit Evaluates: MAX5069A
Component List (continued)
DESIGNATION C11 QTY 1 DESCRIPTION 0.22F 10%, 10V X7R ceramic capacitor (0603) TDK C1608X7R1C224K 560pF 5%, 50V C0G ceramic capacitor (0603) Murata GRM1885C1H561J 1F 10%, 16V X5R ceramic capacitor (0603) TDK C1608X5R1C105K 0.033F 10%, 16V X7R ceramic capacitor (0603) Murata GRM188R71E333K 4700pF 10%, 250VAC X7R ceramic capacitor (2220) Murata GA355DR7GC472K Not installed, ceramic capacitor (0603) 0.015F 10%, 50V X7R ceramic capacitor (0603) Murata GRM188R71H153K Not installed, ceramic capacitors (1210) 47F 10%, 16V X5R ceramic capacitors (1210) Murata GRM32ER61C476K recommended 0.047F 10%, 25V X7R ceramic capacitor (0603) Murata GRM188R71E473K 470pF 10%, 100V C0G ceramic capacitor (0805) Murata GRM2165C2A471K 60V, 30A Schottky diode (TO220AB) International Rectifier 30CTQ060 or Vishay MBR30H60CT 200mA, 75V, ultra-high-speed diode (SOT323) Central Semiconductor CMSD2836 DESIGNATION D3 QTY 1 DESCRIPTION 200mA, 75V ultra-high-speed diode (SOT323) Central Semiconductor CMSD2838 100mA, 80V switching diodes (SOD-323) Diodes Inc. 1N4148WS 4.7H, 17A inductor Cooper HC2LP-4R7 or Coilcraft D05010P-472HCB 1000H, 0.045A inductor Coilcraft DS1608C-105 200V, 3.2A n-channel MOSFETs (SO-8) Vishay Si7450DP or International Rectifier IRF7492 20.0k 1% resistor (0603) 1.05k 1% resistor (0603) 200k 1% resistor (0603) 24.3k 1% resistor (0603) 499k 1% resistor (0805) 20.0k 1% resistor (0805) 10k 5% resistor (0805) 10k 1% resistor (0603) 1M 5% resistor (0603) 27k 5% resistor (1206) 3 5% resistors (1206) 220 5% resistor (0603) Not installed, resistor (2010) 0.060 1% resistor (2010) IRC LRC-LR2010-01-R060-F Not installed, resistor (0603) 15k 5% resistor (0603) 1k 1% resistor (0603) 2.2k 5% resistor (0603) 5.1k 5% resistor (0603) 10 5% resistor (1206)
C12
1
D4, D5
2
C13
1
L1
1
C14
1
L2
1
C15
1
N1, N2
2
C16
0
R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11, R12 R13 R14 R15 R16 R17 R18 R19 R20 R21
1 1 1 1 1 1 1 2 1 1 2 1 0 1 0 1 1 0 1 1
C17
1
C21, C22
0
C23
1
C24
1
D1
1
D2
1
2
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MAX5069A Evaluation Kit
Component List (continued)
DESIGNATION R22 TB1 T1 U1 U2 QTY 0 1 1 1 1 DESCRIPTION Not installed, resistor (1206) 2 points terminal block (0.2in center) 180W planar transformer Coilcraft B0860-C MAX5069AAUE (16-pin TSSOP-EP) High CTR optocoupler (ultra-small flat-lead) NEC PS2911-1-M 0.6V 0.5% shunt regulator (SOT23-5) Maxim MAX8515AEZK-T DESIGNATION VOUT, SGND None None None None None None None QTY 2 4 2 1 1 1 1 1 DESCRIPTION Uninsulated banana jacks Rubber bumpers Zinc-plated metal screws, 4-40 x 1/4 Nylon hex nut 4-40 Nylon screw 4-40 x 3/8 TO-220 thermally conductive insulating pad TO-220AB aluminum heatsink (10.4C/W) MAX5069 PC board
Evaluates: MAX5069A
U3
1
Component Suppliers
SUPPLIER AVX CEL/NEC; California Eastern Laboratories Central Semiconductor Coilcraft Cooper-Coiltronics International Rectifier IRC Murata Sanyo Electronic Device TDK Vishay PHONE 843-946-0238 408-588-2247 631-435-1110 847-639-6400 561-752-5000 310-322-3331 361-992-7900 770-436-1300 619-661-6835 847-803-6100 -- FAX 843-626-3123 408-588-2213 631-435-1824 847-639-1469 561-742-1178 310-726-8721 361-992-3377 770-436-3030 619-661-1055 847-390-4405 -- www.cel.com www.centralsemi.com www.coilcraft.com www.cooperet.com www.irf.com www.irctt.com www.murata.com www.sanyodevice.com www.component.tdk.com www.vishay.com WEBSITE www.avxcorp.com
Note: Indicate that you are using the MAX5069A when contacting these component suppliers.
Quick Start
Required Equipment * * * * 36V to 72V power supply capable of providing up to 6A 20A electronic load e.g., HP 6060B
DC-DC Converter Output
1) Connect the electronic load (+) terminal to the VOUT banana jack. Connect the electronic load (-) terminal to the SGND banana jack. 2) Connect a voltmeter to the VOUT and SGND terminals to measure the output voltage. 3) Connect the positive terminal of a 36V to 72V power supply to the +VIN terminal (TB1-1). Connect the power supply's ground to the -VIN terminal (TB1-2). 4) Turn on the electronic load and set it for "current mode" and up to 5A of current. 5) Turn on the power supply above 36V and verify that the voltmeter reads +12V normally. 6) Verify that the electronic load is drawing the appropriate current.
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Voltmeter 330F, 100V bulk storage capacitor to be connected to the input terminals of the EV kit * A fan to provide at least 200LFM airflow for extended operation at 10A The MAX5069A EV kit is fully assembled and tested. Follow these steps to verify board operation. Do not turn on the power supply until all connections are completed.
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MAX5069A Evaluation Kit Evaluates: MAX5069A
Detailed Description
The MAX5069A EV kit is a 120W, isolated, push-pull DC-DC converter that provides +12V at up to 10A output. The circuit can be powered from a 36V to 72V DC source. The user should supply an additional 330F bulk storage capacitor between the input terminals (+VIN, -VIN). This capacitor should be rated for 100V and be able to carry approximately 2A of ripple current. Lower ripple-current-rated capacitors should be acceptable for short-term operation The push-pull converter achieves high efficiency by using two external n-channel MOSFETs on the primary side that can switch up to 90% combined duty cycle that results in lower primary RMS currents through the MOSFET switches resulting in improved efficiency. Cycle-by-cycle current limiting prevents the primary current from reaching destructive levels, whereas the fault integration feature provides hiccup fault protection. For a continuous short circuit at the output, the MAX5069's fault integration feature provides hiccup fault protection. This greatly minimizes destructive temperature rise during persistent overload conditions. Pin 8 of the MAX5069A, capacitor C11, and resistor R9 form the fault integration circuit. Current-sense resistors R14 and R15 sense the current through the primary of transformer T1 and turn off the respective MOSFET (N1 or N2) that is switching when the trip level of 314mV (typ) is reached. The planar surface-mount transformer features a bias winding that, along with diode-pair D2, D3, and inductor L2, provide full-wave rectification for the bias voltage powering the MAX5069A once the input voltage is stable. Upon initial input-voltage application, bootstrap resistor R10 and reservoir capacitor C9 enable the MAX5069A to startup within approximately 200ms. The transformer uses a secondary-side center tap and dual Schottky diode D1 to provide full-wave rectification for reduced output-voltage ripple. When either MOSFET is turned off and the alternate turned on, both D1 diodes are conducting. The transformer provides galvanic isolation up to 500V. Resistor R21 and capacitor C24 form a snubber network that suppresses transient overvoltage ringing at diode D1 caused by transformer T1 leakage inductance and diode D1 junction capacitance. On the transformer's secondary side, a 0.6V shunt regulator (MAX8515, U3) along with feedback resistors R1 and R2 provide secondary-side voltage feedback through optocoupler U2 to the primary side. The MAX5069A receives the voltage feedback signal on the primary side from biasing resistors R16, R17, R18, and optocoupler U2.
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The MAX5069A controller's internal oscillator clock switches at 500kHz and the frequency is programmed by resistor R3. The duty cycle of both MOSFETs is varied to control energy transfer to the output. The MAX5069A EV kit's maximum duty cycle is 90% as configured. Resistor R4 sets the dead time for both switches and has an impact on the maximum duty cycle. The MAX5069A brownout and input-supply startup UVLO threshold voltage is set by resistors R5 and R6. This prevents the power supply from starting up or operating below the programmed input supply voltage. Test point TP1 is provided to connect an external clock to the SYNC pin on the MAX5069A. The EV kit's PC board layout is a 4-layer 2oz copper PC board.
Evaluating Other Output Voltages, Current Limits, UVLOs
VOUT Output Voltage The MAX5069A EV kit's output (VOUT) is set to +12V by feedback resistors R1 and R2. To generate other output voltages in the vicinity of +12V (from +8V to +15V, limited by the output capacitor and diode D1 voltage rating), select different voltage-divider resistors (R1, R2). Resistor R2 is typically chosen to be less than 2k. Using the desired output voltage, resistor R1 is then found by the following equation: V R1 = R2 OUT - 1 VREF where VREF = 0.6V The maximum output current should be limited to less than 10A. The usable output voltage range for the EV kit is +8V to +15V. Additionally, ICs U3, U2, and resistor R19 limit the minimum output voltage (VOUT) to +2.6V. For voltages outside the above range, a different turns ratio transformer may be required. Current Limiting The EV kit features cycle-by-cycle current limiting of the transformer primary current. Current-sense resistors R14 and R15 sense the current through the primary of transformer T1 and turn off MOSFET N1 or N2 when the trip level of 314mV (typ) is reached. Current-sense resistors R14 and R15 limit the peak primary current to approximately 5.3A (314mV / 0.060 5.3A). This will limit short-circuit current on the secondary output (VOUT) to 20A typically. To evaluate lower current limits, current-sense resistors R14 and R15 must be replaced with different value surface-mount resistors (2010 size) as determined by the following equation:
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MAX5069A Evaluation Kit
RCS = VSENSE NS N x (1.2 x IOUTMAX ) P
N1 DRAIN VOLTAGE
Push-Pull DC-DC Converter
Evaluates: MAX5069A
where R CS = parallel combination of R14 and R15, VSENSE = 0.314V, NS = 2, NP = 5, and IOUTMAX = maximum DC output current (10A or less). Note that some fine-tuning may be required when selecting the currentlimit resistors. Errors are introduced as a result of the MAX5069A IC current-limit propagation delays. Input Undervoltage Lockout (UVLO) The MAX5069A EV kit features a brownout and inputsupply startup UVLO circuit that prevents operation below the programmed input-supply start voltage. Resistors R5 and R6 set the input undervoltage lockout threshold of the EV kit. To evaluate other input UVLO voltages, replace resistor R5 with another surface-mount resistor (0805 size). Using the desired startup voltage, resistor R5 is then found by the following equation: VINSTARTUP R5 = - 1 x R6 1.231V where VINSTARTUP is the desired startup voltage at which the EV kit starts and resistor R6 is typically in the 20k range. Refer to the MAX5069A/D UVLO Adjustment and Bootstrap Undervoltage Lockout sections of the MAX5069 data sheet for additional information on the UVLO/EN pin of the MAX5069A IC.
0V
N2 DRAIN VOLTAGE
0V 1s/div
Figure 1. MOSFETs N1 and N2 Drain-Source Voltage Waveforms (50V per Division, 1s per Division)
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Evaluates: MAX5069A
MAX5069A Evaluation Kit
Figure 2. MAX5069A EV Kit Schematic
D3 2 3 R22 OPEN L 1 VOUT C21 OPEN 2 R7 10k 3 L 1 1 3T 5 6 3 2 D1 L1 4.7H VOUT T1 VOUT R VOUT C22 OPEN D2 SYNC R L2 1000H IN C2 1F 100V C3 1F 100V TP1 1 RT REG5 15 VCC 14 5 3 R11 3 4 5T 4 1 6 3 2 C15 4700pF 250VAC C16 OPEN SGND N1 D4 NDRVB UVLO/EN PGND 6 FB 4 1 R13 220 C12 560pF N2 10 3 2 5 FB U3 GND PGND 2 1 D5 R12 3 11 5 7 8 12 10 6 5T 7 8 2T C13 1F NDRVA 13 C24 470pF 100V C8 0.1F C9 10F 35V 2 IN 1 2T R21 8 10 C5 47F 16V C6 47F 16V C7 47F 16V C18 47F 16V U1 C1 0.1F 16 R10 27k C4 1F 100V 2 SYNC VCC 3 SCOMP
6
MAX5069A IN
C19 47F 16V C20 47F 16V R1 20.0k 1% R2 1.05k 1% 4 DT 5 R19 2.2k SGND 7 COMP AGND 8 FLTINT CS 9
TB1
+VIN
TB1-1
-VIN
TB1-2
R3 200k 1% SYNC
R5 499k 1%
C10 12pF
R4 24.3k 1%
R6 20.0k 1%
R8 10k 1%
R20 5.1k
C14 0.033F R9 1M R14 OPEN VCC 4 R17 15k R15 0.060 1%
MAX8515
IN U2 1 C17 0.015F OUT 3 4 VOUT
C11 0.22F
3
2 C23 0.047F
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R16 OPEN R18 1k 1%
MAX5069A Evaluation Kit Evaluates: MAX5069A
Figure 3. MAX5069A EV Kit Component Placement Guide--Component Side
Figure 4. MAX5069A EV Kit PC Board Layout--Component Side
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MAX5069A Evaluation Kit Evaluates: MAX5069A
Figure 5. MAX5069A EV Kit PC Board Layout--Inner Layer, GND Plane Figure 6. MAX5069A EV Kit PC Board Layout--Inner Layer, VCC Plane 8 _______________________________________________________________________________________
MAX5069A Evaluation Kit Evaluates: MAX5069A
Figure 7. MAX5069A EV Kit PC Board Layout--Solder Side
Figure 8. MAX5069A EV Kit Component Placement Guide--Solder Side
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9 (c) 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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