DEMO MANUAL DC065A NO DESIGN SWITCHER Power Validator Test Fixture Demo Board U DESCRIPTIO Providing power for the Pentium® microprocessor family is not a trivial task by any means. There are currently several different voltage specifications for different versions of the µP. Future upgrades will further challenge the power supply. In an effort to promote flexible, upgradable power supplies for their current and future microprocessors, Intel has defined a specification for a modularized power system for the CPU. This demo board is designed to accept modules built to the Intel specification and also accept an Intel Power Validator module. The Power Validator generates the fast load transients characteristic of the current generation of Pentium processors. In addition, there is a 5V to 3.3V at 7A, LT ®1584 based regulator (DC065A-A) included onboard which meets the needs of a 75MHz, 3.3V ±5% Pentium processor. An LT1585 version (DC065A-B) is available which is capable of only 4.6A* but in all other respects is identical to the LT1584 design. Either regulator may be disabled if desired, permitting installation of a plug-in module on the 30-pin header provided. , LTC and LT are registered trademarks of Linear Technology Corporation. Pentium is a registered trademark of Intel Corporation. *There is also a 5A version, the LT1585A available. Contact a Linear Technology Corporation sales representative for details. D BOARD PHOTOS Component Side 1 DEMO MANUAL DC065A NO DESIGN SWITCHER W W U PACKAGE A D SCHE ATIC DIAGRA S 3.3V LT1584CT LT1585CT VCORE 12V JMP1 FRONT VIEW J1 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 3 IN 2 OUT 1 ADJ T PACKAGE 3-LEAD TO-220 DISABLE E11 1 NOTES: UNLESS OTHERWISE SPECIFIED. 1. ALL RESISTOR VALUES OHMS, 5%, CHIP-1206. 2. ALL CERAMIC CAPACITORS 20%, 50V, CHIP-1206. 3. ALL POLARIZED CAPACITORS TANTALUM, 20%, SMT. 4. ALL 330 µF POLARIZED CAPACITORS SANYO 0S-CON. 5. REMOVE JMP2-7 BEFORE USING POWER MODULE SOCKET J1. 6. VERSION DC065A-A HAS LT1584. VERSION DCO65A-B HAS LT1585. 7. C7-C10 OPTIONAL. VCORE_GOOD E10 1 HEADER_15X2 POWER MODULE 5V SEE NOTE 5 AT-CONNECTORS 12V 5V J9 1 1 2 3 4 5 6 5V + E4 –5V 1 J8 3.3V + C24 330µF 6.3V PENTIUM VALIDATOR SOCKET PROTOTYPE AREA VSS 1 J3 BNC R1 51 E1 VCORE VCORE E8 –12V 1 + C22 330µF 6.3V VCORE TEST POINT E2 GND E9 GND INSIDE POWER VALIDATOR SOCKET CAVITY (SEE NOTE 7) VCORE + + + + + + + + + + C1-C10 100µF 10V C11-C20 1µF 25V 5V 1 1 1 JP2 JP3 JP4 VCORE LT1584/LT1585 POWER SUPPLY (SEE NOTE 6) 2 3 2 IN 2 + C26 220µF 10V + C27 220µF 10V + C28 220µF 10V U1 2 LT1584/LT1585 OUT ADJ 1 R3 189 0.5% 1 1 R2 110 0.5% 1 + C32 0.33 16V Figure 1. Power Validator Motherboard 2 C21 330µF 6.3V VCORE 1 E7 12V 1 + C23 330µF 6.3V VCORE E6 PWR_GOOD 1 5V J7 5V + C25 47µF 16V VCORE 1 E12 3.3V J4 GND E5 5V 12V 1 2 3 4 5 6 J6 3.3V J5 12V E3 GND 1 1 C29 220µF 10V + C30 220µF 10V + JP5 JP6 JP7 2 2 2 C31 220µF 10V DC065A • TA01 DEMO MANUAL DC065A NO DESIGN SWITCHER PARTS LIST REFERENCE DESIGNATOR C1-C6 QUANTITY 6 PART NUMBER DESCRIPTION VENDOR TELEPHONE TPSD107M010R0100 Cap., Tantalum, 100µF, 10V, 20% AVX (803) 946-0690 C7-C10 4 C11-C20 10 12063G105ZAT2A Optional Cap., Y5V, 1µF, 25V AVX (803) 946-0362 C21-C24 4 6SA330M Cap., OS-CON, 330µF, 6.3V, 20% SANYO (619) 661-6835 C25 1 TPSD476M016R0150 Cap., Tantalum, 47µF, 16V, 20% AVX (803) 946-0690 C26-C28 3 TPSE227M010R0100 Cap., Tantalum, 220µF, 10V, 20% AVX (803) 946-0690 C29-C31 3 Optional C32 1 1206YC334KAT2A Cap., X7R, 0.33, 16V, 10% AVX (803) 946-0362 E1-E12 12 1502-2 Terminal, 2-Turret, 0.092" KEYSTONE (718) 956-8900 JMP1-JMP7 7 TSW-102-07-G-S Jumper, 0.100", 2-Pin SAMTEC (800) 726-8329 J1 1 1-102567-3 Header, Shrouded, 15 x 2, 30-Pin AMP (717) 564-0100 J2 1 916560-2 Socket, PGA, ZIF, 320-Pin AMP (717) 564-0100 J3 1 227699-3 Con., PC-MNT, BNC, 50Ω AMP (717) 564-0100 J4-J7 4 575-4 Jack, Banana, .175-ID, Low Profile KEYSTONE (718) 956-8900 J8, J9 2 15-48-0406 Header, 6-Pin, Std-AT MOLEX (408) 946-4700 R1 1 CR32-510J-T Res., Chip, 51, 1/8W, 5% AVX (803) 946-0524 R2 1 CR32-1100F-T Res., Chip, 110, 1/8W, 1% AVX (803) 946-0524 R3 1 CR32-1820F-T Res., Chip, 182, 1/8W, 1% AVX (803) 946-0524 U1* 1 LT1584CT IC, +VREG, LT1584 LTC (408) 432-1900 7 SNT-100-BK-T Shunt, 0.100cc SAMTEC (800) 726-8329 Standoff, #4-40 x 1/2", F/F, Plastic ANY Screw, #4-40, 3/8", Pan Hd, Phil ANY Heat Sink, for LT1584 THERMALLOY 8 8 ** 1 7021B-MT (214) 243-4321 * U1 may be substituted with an LT1585CT for 4.6A design, version DC065A-B. ** Heat sink may be substituted with a 7020B-MT for 4.6A design. 3 DEMO MANUAL DC065A NO DESIGN SWITCHER U OPERATIO PENTIUM POWER DEMANDS The supply voltage for these processors is clock frequency dependent. The standard Pentium processor has a supply requirement of 3.3V ±5%, while the Pentium VR processor has a supply spec of 3.3V +5%/–0%. The Pentium VRE processor requires 3.525V ±75mV. In all cases, the CPU can cycle from a standby condition which consumes approximately 200mA to a full load current of approximately 4.0A in 2 clocks or as little as 20ns. The supply must remain within the appropriate voltage limitations at all times, even during these large load transients. Disabling the stop clock modes will not relieve the designer of the need to handle the fast transients. Events such as an “L1 cache miss” will generate transients of similar magnitude during normal operation. As may be imagined, the decoupling network supplying power to the CPU is critical in maintaining a clean voltage supply. DECOUPLING CAPACITOR NETWORK REQUIREMENTS For the Pentium VR processor spec, the supply must be designed using a set point of 3.38V with a ±2.5% tolerance. The Pentium VRE processor spec is even tighter. With only ±2% total deviation from the ideal voltage allowed, the magnitude of the transients must be carefully controlled. Some of the error budget must remain for the static tolerances such as line and load regulation, temperature variation and initial set point. Realistically, approximately 45mV peak transient response is obtainable. To achieve this, a large number of low ESR tantalum capacitors must be installed as close to the processor as possible. The microprocessor socket cavity is the best place for these capacitors. As an absolute minimum, use 6 pieces of a 100µF, 10V AVX type TPS tantalum for a Pentium VR or VRE processor supply. If more height is available, such as with a ZIF socket, it is preferred to use 6 each, 220µF, 10V parts instead. When using the 100µF parts there is very little margin in the design. Do not reduce the quantity of the capacitors if larger values are used. The ESR specs are the same for the 100µF, 220µF and 330µF capacitors. The reason for paralleling 6 caps is to reduce the ESR as well as providing bulk capacitance. In standard 3.3V ±5% applications, a slightly larger transient can be tolerated, so 4 somewhat less capacitance may be used. It is recommended that you use at least 4 each of the 100µF AVX tantalums. Intel recommends 24 each, 1µF ceramic capacitors in addition to the tantalum bulk decoupling. These additional ceramics have little effect on the transient response but do effect the amount of high frequency clock noise reflected back onto the supply by the CPU. DEMO BOARD CHARACTERISTICS This demo board has provisions for a pair of standard “AT” style power entry connectors for 5V and 12V power input. Also, along the top of the board are provisions for banana plug inputs for 3.3V, 5V and 12V power. The 3.3V is provided in accordance with the Intel module specification and will only be needed for future upgrade designs. It is not connected to the 3.3V output of the onboard regulator or any of the LTC plug-in modules currently available. All input supplies have onboard decoupling capacitors to reduce the effects of long distribution cables. There are also test points for all input and output voltages as well as access to optional “power good” monitor functions. A BNC type connector is provided for monitoring the CPU supply during testing. This line is terminated into 50Ω and it allows measurement of the “core voltage” at one of the socket pins. This point should be connected to an oscilloscope input with a 50Ω BNC cable. It is not necessary to terminate the oscilloscope end at 50Ω as the edge rates are slow enough not to cause any reflections or unusual perturbations. The onboard LT1584 with its associated heat sink is set up to provide 3.3V at up to 7.0A. The regulator used is an adjustable device with an external divider. The lower resistor of the divider is bypassed with a 0.33µF capacitor to speedup the regulator transient response time. Fixed 3.3V regulators are available from LTC. However, due to the inability to add a large value speedup capacitor to the internal feedback divider, there is a substantial increase in the transient response time (approximately 2X). A corresponding increase in the number of decoupling capacitors is required. The addition of the 2 divider resistors and the 0.33µF ceramic capacitor required by the adjustable regulator more than pay for themselves due to the reduction in bulk capacitance that results compared to the fixed voltage parts. DEMO MANUAL DC065A NO DESIGN SWITCHER U OPERATIO The board utilizes 6 each, 100µF tantalums and 10 each, 1µF ceramics on planes located in the processor socket cavity. Also, an area is provided to the right of the socket for additional capacitors, if it is desired to further reduce the transient magnitude. Jumpers JP-2 thru JP-7 permit disabling the onboard regulator if a plug-in module is to be used. The resistance of the jumpers causes a slight degradation of the load regulation as measured at the CPU. TEST SETUP Install the power validator in the socket and connect a 5V “silver box” supply to the input connectors. Be sure to observe the proper connector orientation. The connectors are not configured the same as on a normal motherboard. Test points adjacent to the connectors correspond to the supply voltages at those pins. The oscilloscope should be connected to the board with a BNC cable. Be careful of potential ground loop problems. In general it is best to use an isolation transformer for the oscilloscope or use isolated probes. This will eliminate several measurement errors that are likely to exist otherwise. For safety reasons, be sure to keep the off-line case grounded. Voltmeters should be connected to the input and output test points. The power validator should be powered up and set according to the instructions provided by Intel. If the demo board’s onboard regulator is to be used, be sure jumpers JMP2 through JMP7 are installed. If you plan to use a plug-in power supply module, remove these jumpers to isolate the LT1584. Also, a fan which provides approximately 100 linear feet per minute of air flow should be aimed at the LT1584 heat sink or the plug-in module. Jumper JMP1 connects the CPU core and I/O power pins on the power module header together. Leave this jumper installed if the CPU you intend to use only requires a single supply voltage. At this point it should be safe to power up the off-line supply. TEST RESULTS raised from 200mA to 3.2A and the load delta held constant at 3.8A, the waveform remains essentially unchanged. The transient droop measures approximately 44mV pk. and is nearly symmetrical. Note the offset voltage between the high load and low load condition on the output waveform. This is the load regulation of the regulator including any distribution (I)(R) drops. When using the socketed modules the additional resistance of the connector pins makes the use of remote sense desirable to ensure that the (I)(R) drops are kept under control. The photo in Figure 3 shows the same transient at 2µs/div. There is a fast leading edge droop followed by one short ring. The output then begins to slowly recover toward its final value. The layout techniques utilized here keep VOUT = 50mV/DIV IOUT = 2A/DIV 200µs/DIV Figure 2. Transient Response VOUT = 50mV/DIV IOUT = 2A/DIV The results should look like Figure 2. The test conditions were as follows: VIN = 5.0V, VOUT = 3.30V. Load steps from 200mA to 4.0A. It should be noted that as the minimum load current is 2µs/DIV Figure 3. Transient Response 5 DEMO MANUAL DC065A NO DESIGN SWITCHER U OPERATIO ringing to a minimum. To appreciate the effects of parasitic inductance, try connecting a 100µF tantalum capacitor to the area on the right side of the socket and note the difference in transient amplitude, especially the leading edge spike. Now remove the capacitor and solder a couple of inches of 24AWG wire to the capacitor and reconnect it to the power planes. The difference in performance is quite noticeable. AVAILABLE PLUG-INS Several additional boards are available for use with the Power Validator demo board. Both linear and switching regulators have been designed and built to comply with the Intel module specification. We anticipate developing additional designs as technology improvements warrant. Contact Linear Technology for further details. W U PCB LAYOUT A D FIL 6 Component Side Copper Solder Side Copper Component Side Solder Mask Solder Side Solder Mask DEMO MANUAL DC065A NO DESIGN SWITCHER W U PCB LAYOUT A D FIL Component Side Silkscreen U PC FAB DRAWI G 7.000 H K K K NOTES: UNLESS OTHERWISE SPECIFIED. 1. FINISHED MATERIAL IS FR4, 0.062" THICK, 2-OZ COPPER. 2. PCB WILL BE DOUBLE-SIDED WITH PLATED THROUGH HOLES. 3. PTH SIZES AFTER PLATING, 0.001" MIN WALL THICKNESS. 4. USE PADMASTER PROCESS. 5. SOLDER MASK BOTH SIDES USING PC-401 OR EQUIVALENT. 6. SILKSCREEN COMPONENT SIDE USING WHITE NONCONDUCTIVE INK. 7. ALL DIMENSIONS IN INCHES, ±0.005". 8. ALL HOLE SIZES AFTER PLATING, ±0.003" MAX. H K D A B (8x) G H H C (30x) C E C G HOLE CHART A (64x) 5.500 A G A (5x) G G B (320x) G H C H C HH H D H H H NUMBER OF HOLES SYMBOL DIAMETER A 0.020 71 B 0.030 328 44 C 0.040 D 0.045 8 E 0.075 14 G 0.094 12 H 0.120 12 K 0.210 4 TOTAL HOLES 493 0.200 DC065A • PCB01 0.200 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 7 DEMO MANUAL DC065A NO DESIGN SWITCHER U.S. Area Sales Offices NORTHEAST REGION Linear Technology Corporation 3220 Tillman Drive, Suite 120 Bensalem, PA 19020 Phone: (215) 638-9667 FAX: (215) 638-9764 Linear Technology Corporation 266 Lowell St., Suite B-8 Wilmington, MA 01887 Phone: (508) 658-3881 FAX: (508) 658-2701 SOUTHEAST REGION Linear Technology Corporation 17000 Dallas Parkway Suite 219 Dallas, TX 75248 Phone: (214) 733-3071 FAX: (214) 380-5138 SOUTHWEST REGION Linear Technology Corporation 22141 Ventura Blvd. Suite 206 Woodland Hills, CA 91364 Phone: (818) 703-0835 FAX: (818) 703-0517 CENTRAL REGION Linear Technology Corporation Chesapeake Square 229 Mitchell Court, Suite A-25 Addison, IL 60101 Phone: (708) 620-6910 FAX: (708) 620-6977 NORTHWEST REGION Linear Technology Corporation 782 Sycamore Dr. Milpitas, CA 95035 Phone: (408) 428-2050 FAX: (408) 432-6331 International Sales Offices FRANCE Linear Technology S.A.R.L. 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