MAX8775 Evaluation Kit. Evaluates: MAX8775

Transcription

1 9-09; Rev 0; /0 General Description The MAX evaluation kit (EV kit) demonstrates the MAX s standard A application circuit. This dual PWM synchronous DC-DC converter steps down highvoltage batteries and/or AC adapters, generating precision low-voltage GPU core and I/O power supplies for notebook computers. The MAX EV kit provides a dynamically adjustable.v/.v output voltage (V OUT ) and a dynamically adjustable.v/.v output voltage (V OUT ) from V to V battery input range. It delivers up to A output current for each output voltage with greater than 90% efficiency. Both converters operate 0 out-of-phase to reduce input ripple current. The EV kit operates at a 0kHz fixed switching frequency and has superior line- and load-transient response. This EV kit is a fully assembled and tested circuit board. It also allows the evaluation of other dynamically adjustable output voltages in the 0.V to.v range by changing R R resistors. This EV kit can be configured for a single 0A output regulator by combining the outputs of both phases together. Features V to V Input Voltage Range Dynamically Selectable Output Voltages.V/.V (V OUT, Adjustable from 0.V to.v) Dynamically Selectable Output Voltages.V/.V (V OUT, Adjustable from 0.V to.v) A Load-Current Capability for Each Output 0A Load-Current Capability in Combined Mode 0kHz Switching Frequency True 0 Out-Of-Phase Operation Independent Selectable PWM and Skip Mode Operation Independent Power-Good Outputs Low-Profile Components Fully Assembled and Tested Ordering Information PART TEMP RANGE IC PACKAGE MAXEVKIT+ 0 C to +0 C Thi n QFN ( m m x m m ) +Indicates lead-free and RoHS-compliant EV kit. DESIGNATI QTY DESCRIPTI Component List DESIGNATI QTY DESCRIPTI C C C C C9, C0, C9 C C C 0µF ±0%, V XR ceramic capacitors (0) TDK CXRE0M AVX 0D0M Taiyo Yuden TMKBJ0MM 0µF,.V, mω, low-esr polymer capacitors (D-case) Panasonic EEFSX0DR or Sanyo RTPE0M or NEC/Tokin PSGD0EM µf,.v, XR ceramic capacitors (00) TDK C0XR0JMT.µF ±0%, 0V XR ceramic capacitor (00) TDK C0XRAM or Murata GRMRAM or AVX 00ZDMAT µf ±0%, 0V XR ceramic capacitor (00) TDK C0XRA0M or Murata GRMRA0M or AVX 00ZD0MAT C, C, C C, C C, C9 C0, C 0.µF ±0%, V XR ceramic capacitors (00) TDK C0XRE0K Murata GRMRE0K 0pF ±0%, 0V XR ceramic capacitors (00) TDK C0XRHK or Murata GRMRHK 00pF ±0%, 0V XR ceramic capacitors (00) TDK C0XRHK or Murata GRMRHK 00pF ±0%, 0V XR ceramic capacitors (00) TDK C0XRHK Murata GRMRHK C pf ±%, 0V C0G ceramic capacitor (00) TDK C0C0GH0J or Murata GRMCH0J or Taiyo Yuden UMK0CG0JZ C C 0 Not installed, capacitors (00) Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at --9-, or visit Maxim s website at

2 DESIGNATI QTY DESCRIPTI D, D A, 0V Schottky diodes Nihon ECQS0L Central Semiconductor CMSH-0M D, D LEDs, green clear SMD (00) LITE- Electronics LTST-C0GKT JU, JU -pin headers, 0.in centers JU, JU, JU -pin headers, 0.in centers L, L N, N N, N 0 N, N,, PGOOD, PGOOD 0.µH, 0A,.mΩ power inductor NEC-Tokin MPC00LR or Sumida CDEP0S-0RMC n- channel M OS FE Ts ( P ow er P AK S O- ) Siliconix (Vishay) SIDP or Renesas RJK00DPB Not installed n-channel MOSFETs (LFPAK) n- channel M OS FE Ts ( P ow er P AK S O- ) Siliconix (Vishay) SIADP or Renesas RJK00DPB Test points Keystone 000 Component List (continued) DESIGNATI QTY DESCRIPTI R, R 0.00Ω ±%, W resistors () Panasonic ERJMWTJMU R, R 0Ω ±% resistors (00) R, R, R 0Ω ±% resistors (00) R, R 0Ω resistors (00) R9 kω ±% resistor (00) R0, R kω ±% resistors (00) R, R ±% resistors (00) R, R 0kΩ ±% resistors (00) R, R 9kΩ ±% resistors (00) R, R9 0 Not installed, resistors (00) R0 R ±% resistors (00) SW -position, low-profile DIP switch ITT SD0HSB or equivalent U MAXETJ+ (-pin TQFN, mm x mm) Shunts, 0.in centers MAXEVKIT+ PCB Component Suppliers SUPPLIER PHE WEBSITE AVX Central Semiconductor Murata NEC/Tokin Nihon Panasonic -- Renesas Sanyo Sumida Taiyo Yuden TDK Vishay/Siliconix Note: Indicate you are using the MAX when contacting these manufacturers. Quick Start Recommended Equipment V to V, > 00W power supply, battery, or notebook AC adapter DC bias power supply, V at A Dummy loads capable of sinking A each Digital multimeter (DMM) 00MHz dual-trace oscilloscope Procedure ) Ensure that the circuit is connected correctly to the supplies and dummy loads prior to applying any power. ) Verify that all positions of switch SW are. Verify that there are shunts across JU and JU pins and,

3 and JU pins and. Verify that there is no shunt across JU. ) Turn on VIN, input/battery power supply before turning on the +V bias power. ) Verify that the output voltages are V OUT =.V, V OUT =.V. Detailed Description Jumper Settings Table. Jumper JU Functions (Output Voltage, V OUT ) JU Installed (default) Not installed REFIN PIN Connected to a voltage-divider formed by R, R, and R Connected to a voltage-divider formed by R and R Table. Jumper JU Functions (Output Voltage, V OUT ) JU Installed Not installed (default) REFIN PIN Connected to a voltage-divider formed by R, R, and R through JU pins and Connected to a voltage-divider formed by R and R through JU pins and V OUT OUTPUT VOLTAGE V OUT =.V V OUT =.V V OUT OUTPUT VOLTAGE V OUT =.V V OUT =.V Table. Jumper JU Functions (Overvoltage Protection Selection, OVP) JU OVP PIN OVP MODE and C onnected to V D D OVP is disabled and ( d efaul t) Connected to REFIN OV P i s enab l ed ; over vol tag e thr eshol d for V OU T i s 00m V ab ove the vol tag e at the OV P p i n Table. Jumper JU Functions (Overvoltage Protection Selection, OVP) JU OVP PIN OVP MODE and C onnected to V D D OVP is disabled and ( d efaul t) Connected to REFIN OV P i s enab l ed ; over vol tag e thr eshol d for V OU T i s 00m V ab ove the vol tag e at the OV P p i n Evaluating Other Dynamic Output Voltages (VOUT and V OUT ) The EV kit output is preset to.v/.v (VOUT) and.v/.v (VOUT). However, the output voltage at V OUT can also be adjusted between 0.V and.v by selecting R, R, and R values. The MAX regulates V OUT to the voltage set at REFIN by sensing the CSL pin. By changing the voltage at REFIN, the MAX can be used in applications that require dynamic output-voltage changes between two set points. Using jumper JU, a resistor can be switched in and out of the REFIN resistor-divider, dynamically changing the voltage at REFIN. The two output voltages are determined by the following equations: V OUT(LOW) = V REF (R//R) / (R + R//R) when JU is installed. V OUT(HIGH) = V REF (R) / (R + R) when JU is not installed. Where V REF =.V. Similarly, the output voltage at V OUT can also be adjusted between 0.V and.v by selecting R, R, and R values. Using jumper JU, a resistor can be switched in and out of the REFIN resistor-divider, dynamically changing the voltage at REFIN. The two output voltages are determined by the following equations: V OUT(LOW) = V REF (R//R) / (R + R//R) when JU is installed. V OUT(HIGH) = V REF (R) / (R + R) when JU is not installed. Where V REF =.V. Continuously Adjustable Output Voltages The MAX can support continuously adjustable output voltages when the respective REFIN pin is driven by a voltage source or a function generator. Such a configuration allows for tracking applications to be supported. Changing the Switching Frequency The switching frequency of the MAX can be adjusted by changing the OSC resistor R9. As configured, the MAX EV kit operates at 0kHz. When changing the switching frequency, refer to the MAX data sheet for the proper component selection and calculations for the MOSFETs, inductors, and output capacitors.

4 SW ST A T U S PIN CTROL SW-A SW-B SW-C SW-D SW-E SW Operating Mode Tables Separate Mode Operation O N p i n i s O N p i n i s O N p i n i s O N p i n i s DTRANS p i n i s DTRANS p i n i s SKIP p i n i s SKIP p i n i s SKIP p i n i s SKIP p i n i s SW ST A T U S PIN CTROL S W- A S W- B S W- C S W- D S W- E SKIP pin is connected to pin is connected to pin is connected to pin is connected to DTRANS pin is connected to DTRANS pin is connected to SKIP pin is connected to SKIP pin is connected to MAX OPERATI Enables SMPS output Disables SMPS output Enables SMPS output Disables SMPS output Enables forced downward transitions Disables forced downward transitions E nab l es p ul se- ski p p i ng op er ati on for S M P S D i sab l es p ul se- ski p p i ng op er ati on for S M P S E nab l es p ul se- ski p p i ng op er ati on for S M P S D i sab l es p ul se- ski p p i ng op er ati on for S M P S Combined Mode Operation MAX OPERATI Enables the combined SMPS output Disables the combined SMPS Enables Phase Disables Phase Enables forced downward transitions Disables forced downward transitions E nab l es p ul se- ski p p i ng op er ati on for b oth p hases D i sab l es p ul se- ski p p i ng op er ati on for b oth p hases Not used in combined mode Combined Mode Operation The MAX EV kit can be configured as a dualphase, single-output, high-current regulator by combining the outputs of both phases together. This works well for high-current applications with load currents above 0A, up to a maximum of approximately 0A. To configure the MAX in combined mode: ) Connect REFIN to (JU pins and ). This configures the MAX in combined mode. ) Connect OVP to (JU pins and ). ) Connect the two outputs together using a lowimpedance short right at the output side of currentsense resistors R and R. A copper strap or strip of solder wick works well. ) Connect SLEW and SLEW together using a short wire. Note that since SLEW and SLEW are connected together, the end application could use one slew capacitor with twice the value (e.g., 000pF instead of x 0pF). While in combined mode, some pins perform a different function. The following lists the changes in pin function: REFIN sets the combined output voltage. OVP sets the combined overvoltage threshold. PGOOD indicates the output voltage is in regulation. PGOOD indicates the currents in both phases are in balance. is the overall / control for the MAX. enables/disables Phase to allow for -phase or -phase operation. CCI sets the current balance integration time constant. CCI is not required in separate mode operation. Table. Jumper JU Functions (Combined Mode Selection, REFIN) JU REFIN PIN MAX OUTPUT and and (default) Connected to Connected to voltage-divider formed by R, R, and R Combined mode, the MAX operates as a -phase, highcurrent, single-output regulator Separate mode, the MAX operates as a two single-phase, dynamic output voltage regulator

5 R 9 JU JU C μf 0V C 0.μF C 0pF R R0 SW-C 0 SW-A SW-B R0 kω PGOOD D R kω PGOOD REF D R 9kΩ % R % C R 0kΩ % R 9kΩ % REF R % JU C R 0kΩ % JU JU R 0Ω R9 kω % C 0pF REF 9 VCC REF OSC SLEW SLEW DTRANS DH BST LX DL P 0 CSH U MAX CSL DH 0 PGOOD BST LX PGOOD DL 9 OVP REFIN CSH CSL OVP REFIN CCI 0 SKIP SKIP 9 R R SW-D SW-E C.μF 0V R 0Ω C R 0Ω C C pf C 0.μF N C 00pF C0 00pF C 0.μF N VOUT C9 00pF C 00pF C0 μf.v VBIAS V N N C μf.v VIN N C 0μF V C 0μF V VIN V TO V VOUT D R 0Ω R L 0.μH C R 0.00Ω C 0μF.V C 0μF.V VOUT.V R 0Ω VIN N C 0μF V C 0μF V VOUT D R 0Ω R9 L 0.μH C R 0.00Ω C 0μF.V C 0μF.V VOUT.V R 0Ω VOUT C μf.v C μf.v C μf.v C μf.v C9 μf.v C9 μf.v C0 μf.v C μf.v C μf.v C μf.v Figure. MAX EV Kit Schematic

6 Figure. MAX EV Kit Component Placement Guide Component Side Figure. MAX EV Kit PCB Layout Component Side

7 Figure. MAX EV Kit PCB Layout Internal Layer, P Plane Figure. MAX EV Kit PCB Layout Internal Layer, VBIAS/VOUT/P Layer

8 Figure. MAX EV Kit PCB Layout Internal Layer, VOUT//P Plane Figure. MAX EV Kit PCB Layout Internal Layer, P Plane

9 Figure. MAX EV Kit PCB Layout Solder Side Figure 9. MAX 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, 0 San Gabriel Drive, Sunnyvale, CA Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.