Freescale Semiconductor Application Note AN3820 Rev. 1.0, 3/2009 i.MX25 Power Management Using the MC34704 1 Overview This document presents an analysis of using the MC34704 power management IC to supply a system based on the i.MX25. The focus was done on the i.MX25 itself, considering its needs in terms of voltage, current, and the power-up sequence. The DDR and Flash memory requirements were also taken into account. However, the MC34704 voltage capabilities are not limited to the scenarios presented within this document. © Freescale Semiconductor, Inc., 2009. All rights reserved. Contents 1 Overview 2 i.MX25 Requirements 2.1 Voltage Requirements 2.2 Power-up Sequencing 3 MC34704 PMIC 4 MC34704 and i.MX25 Compatibility 4.1 Power Breakdown 4.2 Power Sequencing 4.3 i.MX25 System Power Block Diagram 5 Software Considerations 5.1 I2C Communication Protocol 5.2 Power-up Command Sequence 5.3 Dynamic Voltage Scaling (DVS) 6 MC34704 Power Supply Design 6.1 Components Selection and Consideration 6.2 i.MX25 Power Management Schematic 6.3 Layout Example 6.4 Layout Consideration 7 Bill of Material 8 References i.MX25 Requirements 2 i.MX25 Requirements 2.1 Voltage Requirements Table 1 summarizes the approximate voltage requirements on i.MX25: Table 1. i.MX25 Voltage Requirements Parameter Min. Typ. Max. Units 1.15 1.34 1.52 V 1.38 1.45 1.52 V VDD_BAT 1.15 - 1.55 V I/O supply voltage GPIO1 (NFC, CSI, SDIO) NVDD_GPIO1 1.75 - 3.6 V I/O supply voltage GPIO2 (CRM, LCDC, JTAG, MISC) NVDD_GPIO2 3.0 3.3 3.6 V I/O supply voltage DDR (Mobile DDR mode) (EMI1, EMI2) NVDD_MDDR 1.75 - 1.95 V I/O supply voltage DDR (DDR2 mode) (EMI1, EMI2) NVDD_DDR2 1.75 - 1.9 V I/O supply voltage DDR (SDRAM mode) (EMI1, EMI2) NVDD_SDRAM 1.75 - 3.6 V USBPHY1 supply (HS) (USBPHY1_VDDA_BIAS, USBPHY1_UPLL_VDD. USBPHY1_VDDA) VDD_USBPHY1 3.17 3.3 3.43 V USBPHY2 supply (FS) (USBPHY2_VDD) VDD_USBPHY2 3.0 3.3 3.6 V OSC24M supply (OSC24M_VDD) VDD_OSC24M 3.0 3.3 3.6 V PLL supply (MPLL_VDD, UPLL_VDD) VDD_PLL 1.4 - 1.65 V Supply of touch screen ADC (NVCC_ADC) VDD_TSC 3.0 3.3 3.6 V VREF 2.5 VDD_tsc VDD_tsc FUSEVDD - 3.6 - Core supply voltage (at 266 MHz) Symbol QVDD Core supply voltage (at 400 MHz) Coin Battery External reference of touch screen ADC Fusebox program supply voltage (FUSE_VDD) V The i.MX25 processor consists of four major sets for the power supply voltage: digital logic domains (VDDn), I/O power supplies (NVDDx), analog power supplies, and the fuse voltage supply (FUSEVDD). These voltage domains can be grouped together, depending on the operating mode and needs of the I.MX processor, and the specific application. 2.2 Power-up Sequencing The external voltage regulators and power-on devices must provide the application’s processor with a specific sequence of power and resets to ensure proper operation. The recommended power-up sequences is as follows: 1. 2. 3. 4. Assert the power on reset signal (POR = Low) Turn on the Digital logic domain and I/O power supplies (VDDn and NVCCx) Turn on all Analog power supplies and FUSEVDD Negate the POR signal (POR = High) i.MX25 Power Management Using the MC34704 , Rev. 1.0 2 Freescale Semiconductor i.MX25 Requirements POR = Low I/O supplies Digital Logic 1.8 V 3.3 V NVDD_DDR NVDD_GPIO2 NVDD_GPIO1 1.34 V-1.45 V QVDD Analog Power Supplies 1.5 V 3.3 V VDD_USBPHY1 VDD_PLL VDD_USBPHY2 VDD_OSC24M VDD_TSC FUSEVDD 3.3 V POR = High Figure 1. i.MX25 Recommended Power-up Sequencing Some of the voltage domain may be powered-up out of the recommended sequence if necessary. However, it is important to power QVDD before the FUSEVDD, to avoid an unintentional fuse blown. Figure 1 shows the recommended power-up sequence and power terminal grouping to achieve successful a power-up. Noticed that since the maximum operating voltage for the core voltage group is 1.52 V, caution must be taken in order to have a very tight regulation, and avoid overstressing or blowing the microprocessor terminals. i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 3 MC34704 PMIC 3 MC34704 PMIC The MC34704 family features both a 5-channel (MC34704B) and an 8-channel (MC34704A) power management IC (PMIC), housed in a 56 pin QFN package with pin-to-pin compatibility between both ICs. It is meant to address power management needs for various components and loads, with a target overall efficiency of > 89% at typical loads. The MC34704 accepts an input voltage from 2.7 V to 5.5 V, from various sources: • 1-cell Li-Ion/Polymer (2.7 V to 4.2 V) • 5.0 V USB supply or AC wall adapter The total voltage supply range the IC accommodates is 2.7 V to 5.5 V. Taking advantage of its buck/boost blocks, the MC34704 is a highly flexible power management unit. Output voltages can be ranged between 0.6 V to 3.6 V, even if low voltage is supplied by the battery. Additionally, the Dynamic Voltage Scaling (DVS) feature allows programming the output voltages (±20% of the nominal voltage), with the I2C bus on the fly. Hence, the dynamic power consumption of the i.MX can be dramatically reduced. Features: • • • • • • • • • • 8 DC/DC switching regulators with up to ±2% output voltage accuracy Programable Switching Frequency from 250 KHz - 1.0 MHz and 750 KHz to 2.0 MHz Effective Efficiency from 85% to 95% on REG1 - REG5 and 65% to 78% on REG6 - REG8 DVS (Dynamic voltage scaling) on all regulators. I2C programmability OV/UV detection for each regulator Over-current limit detection and short-circuit protection. Thermal limit detection (except REG7) Internal compensation for REG1, REG3, REG6, and REG8 True cutoff on all of the boost and buck-boost regulators. i.MX25 Power Management Using the MC34704 , Rev. 1.0 4 Freescale Semiconductor MC34704 and i.MX25 Compatibility 4 4.1 MC34704 and i.MX25 Compatibility Power Breakdown QVDD 1.45 V / ~140 mA REG3 Buck 5.0 V supply REG2 Buck.Boost VDDn, NVDD_GPIO, FUSEVDD 3.3 V Inverter Boost REG7 REG4 Buck.Boost VDD_DDR2 1.8 V REG8 Boost REG5 Buck.Boost Other I/O 3.3 V REG6 Boost I 2C interface Available only on the MC34704A REG1 Boost Reset Driver Soft start, UVLO Thermal protection RST (POR) SS FREQ Figure 2. MC34704 block diagram Figure 2 shows the block diagram for the MC34704 and the simplified voltage distribution compatible with the i.MX25 processor. Complementary LDO regulators may be needed in specific applications. A 1.5 V LDO is at least required to supply the PLL voltage. Figure 3 provides the detailed Power Map for a complete solution utilizing the MC34704A as the core PMIC, complemented with various LDOs to provide some application oriented voltages. i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 5 MC34704 and i.MX25 Compatibility 5.0 V_USB_OTG SWITCH REG1 - 5.0 V REG2 - 3.3 V REG3 - 1.45 V VMAIN CAN_5VDD NVCC_CRM NVCC_CSI NVCC_SDIO NVCC_NFC NVCC_JTAG NVCC_MISC NVCC_ADC VDD_I2C VDD_EMI_DATA VDD_EMI_ADDR OSC24M_VDD USBPHY1_VDD USBPHY2_VDD QVDD REG4 - 1.8 V DDR_VDDx NVCC_EMI1 NVCC_EMI2 REG5 - 3.3 V VDD_LCD_IO VDD_SD2_IO VDD_ESAI_IO GPS_3V3 VDD_CSI_IO AUDIO CODEC VDD_SIM_IO MC34704 LDO - 1.5 V MPLL_VDD UPLL_VDD WL_1V5ANA Figure 3. i.MX25 Power Detailed Power Map i.MX25 Power Management Using the MC34704 , Rev. 1.0 6 Freescale Semiconductor MC34704 and i.MX25 Compatibility 4.2 Power Sequencing RST=Low REG3 VDDQ REG2 VDDn, NVCCx, USBPHYx REG4 1.5 V LDO DDR_VDD, NVCC_EMIx UPLL_VDD, MPLL_VDD RST=High REG1 5 V_I/OS REG5 3.3 V I/OS Figure 4. MC34704 power sequencing The MC34704 provides standalone voltage on REG 2, 3, and 4, right after battery insertion or ON/OFF asserting. The LDO providing the 1.5 V is supplied from the main voltage supply (DC_5.0 V or USB). However, the output voltage is enabled with the REG2 output in order to assure proper sequencing. REG1 and REG5 are controlled via I2C, and can be turned ON/OFF once the RST signal (POR) on the MC34704 is set high. Note that even though this structure does not perfectly, follow the power-up sequence, it has been proven to work correctly, and may be counted as one of the recommended power-up sequences for the i.MX25 processor. REG2, 3, and 4 can only be powered off in two ways: 1. By a hardware power-off, holding down the ON/OFF terminal for a specific amount of time (programmable). 2. By a soft power-off, by setting high the ALLOFF bit via I2C. Note that these two processes will shut down the device completely, including REG1, REG5, 1.5 V_LDO, and I2C communication. To bring the device back up, generate a falling edge on the ON/OFF terminal (commonly using a push button.) i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 7 MC34704 and i.MX25 Compatibility t = SS t = SS t = SS REG1 REG5 REG2 REG4 1.5V LD O REG3 RST t = 10ms Figure 5. System Power-up Waveform Figure 5 shows the power sequence waveforms during a Power-up cycle. Note that REG1 through REG5 on the MC34704 ramp-up in a pre-defined soft start. The soft start is hardware configured and its value is selectable among 0.5, 2.0, 8.0, and 32 ms. The 1.5 V LDO waveform may reach its regulation point before or after REG4, depending on the selected soft start. 4.3 i.MX25 System Power Block Diagram I.MX25 Peripherals 5.0V_I/O VMAIN VOUT1 3.3V_I/O VOUT5 VIN PVIN2 PVIN3 PVIN4 PVIN5 VOUT3 VDDQ VOUT2 VDDn NVCCx USBPHYx VOUT4 NVCC_EMIx PLL_VDD I2C AGND RST I2C POR i.MX25 MC34704 VOUT_LDO xGND DDR_VDD 1.5 V LDO DDR2 MEM Figure 6. i.MX25 Power Pins i.MX25 Power Management Using the MC34704 , Rev. 1.0 8 Freescale Semiconductor Software Considerations 5 Software Considerations The MC34704 is programmed through a plain I2C protocol. The I.MX processor should include a firmware driver to translate the controlling instructions into I2C commands, to allow register writing and flag reading for communication acknowledgement. Such driver structure is not defined in this document. It discusses only the software portion that concerns the MC34704, as well as the I2C commands needed to interact with the MC34704. 5.1 I2C Communication Protocol The MC34704 is able to operate in two I2C modes: • • Non-accurate mode: which uses a single repetition of register address and data to be read or written during one cycle. This mode is used as the default by the MC34704. Accurate mode: where each Address and Data word is sent twice to make sure the information written or read is valid. To simplify the I2C protocol, only non-accurate mode will be discussed in this document. Figure 7 and Figure 8 show an example of a bits stream for an I2C writing and reading command respectively. 7 bit Physical Address + (w) bit ACK Sub-Address (MSB=0) ACK Data ACK 1010100 + 0 0 0XXXXXXX 0 XXXXXXXX 0 ACK Start Bit ACK ACK End Bit SDA 1 0 1 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 1 1 1 SCL Figure 7. Writing Sequence I2C Bit Stream. 7 bit Physical Add + (w) bit ACK Sub-Address (MSB=1) ACK RS Physical Add + (r) bit Data Read ACK 1010100 + 0 0 1XXXXXXX 0 1 1010100+1 XXXXXXXX 0 Start Bit ACK ACK ACK SDA 1 0 1 0 1 0 0 0 0 0 0 0 0 0 1 0 RS 1 0 1 0 1 0 0 1 0 0 0 0 1 1 1 1 SCL Figure 8. Reading Sequence I2C Bit Stream. By default, the MC34704’s physical address is set to 0x54 in a 7-bit format. The extra bit to complete the 8-bit indicates the reading or writing mode as shown in Figure 7 and Figure 8. After each byte read or sent, the MC34704 answers with an acknowledge bit, indicating the bite was transferred successfully. i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 9 Software Considerations Figure 9 shows the basic I2C register table, including both configuration and fault notification registers for each regulator on the MC34704. Figure 9. Basic I2C Register Table 5.2 Power-up Command Sequence The Power on process is straight forward: • • If there is a battery insertion, REG3, 2, and 4 will turn on in that order, enabling I2C communication protocol as well as the i.MX processor power on sequence. The MC34704 will set the COLDF flag to acknowledge that power on was a result of a battery insertion. During the power on process, the MPU should acknowledge that power-up was a result of a battery insertion, and then send an ALLOFF I2C command to disable the power supply and shut down until a desired hardware power on is present. If the ON/OFF terminal detects a falling edge, then the MC34704 starts a power on cycle ramping up of regulator 3, 2, and 4. The COLDF bit is not set high, and so when the i.MX processor reads this register, it acknowledges it is an actual power up, and starts a full power on sequence. By now, the PMIC is providing i.MX25 Power Management Using the MC34704 , Rev. 1.0 10 Freescale Semiconductor Software Considerations 1.45 V, 1.8 V, 3.3 V, and 1.5 V, which is dispensed by the extra LDO, and the processor can administer the following configuration commands: — REG2, REG3, and REG4 OV/UV response — REG1 and REG5 OV/UV response — REG5 Soft start timing (if desired) Now the processor can send a REG5 ON/OFF instruction via I2C, when the 3.3 V peripherals rail is required, and also enable REG1 if the 5.0 V voltage rail is needed. Subsequently, all voltage rails can be dynamically scaled (DVS) up or down using the 4 bits (4:1) from the REGxSET register. The i.MX processor can send an I2C power-off command for REG1 or REG5 independently or a complete shutdown by setting the ALLOFF bit on the GENERAL2 register when required. • • 5.3 Dynamic Voltage Scaling (DVS) All regulators on the MC34704 allow voltage scaling, programmable through I2C, Table 2 defines the DVS capability for each output as well as the I2C register corresponding to each. Table 2. MC34704 DVS Definition REGULATOR SCALING WINDOW SCALING STEP I2C REGISTER ADDRESS REGISTER BITS REG1 -10% to 10% 2.5% VGSET1 0x04 [4:1] REG2 -17.5% to 17.5% 2.5% REG2SET1 0x06 [4:1] REG3 -17.5% to 17.5% 2.5% REG3SET1 0x08 [4:1] REG4 -10% to 10% 1.0% REG4SET1 0x0A [4:1] REG5 -17.5% to 17.5% 2.5% REG5SET1 0x0C [4:1] For REG3, the MC34704 provides fine DVS adjustment on 0.5% steps, to achieve voltage scaling below the -17.5% windows allowed with the default DVS. The following sequence should be followed to assure proper scaling without activating OV/UV fault flags. 1. 2. 3. 4. 5. Set the REG3SET1 register (ADD 0x08) to 0x10. Mask the fault response by writing 0x80 to ADD 0x22. Write a 0xAD to REG3DAC (ADD 0x49). Decrease REG3DAC by one until reaching the desired value on REG3. Clear the fault response masking by writing 0x00 to ADD 0x22. i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 11 MC34704 Power Supply Design 6 6.1 6.1.1 MC34704 Power Supply Design Components Selection and Consideration Inductor Selection VG serves as the internal supply for all gate drivers within the MC34704. L1 dimensions depend directly on the inductance value and the saturation current ISAT. Chose an inductor with inductance value between 2.2 to 4.7 μH, and an ISAT around 150 mA. To select Inductors L2 - L5, choose inductance values between 3.0 to 4.7 μH, with an ISAT of approximately twice the maximum current to be demanded from each regulator. Note: make sure to use power inductors and not choke inductors for these components. Shielded “Drum Core” inductors with low DCR are recommended to improve the performance of the MC34704. 6.1.2 Capacitor and Resistor selection Choose capacitors with at least twice the voltage rating as the maximum voltage that the capacitor will be exposed to. For output capacitors, use capacitance values from 10 to 22 μF. Resistors are straightforward to choose. The important thing to consider, while calculating the output voltage of each regulator, is to take into consideration the resistor accuracy , especially on those voltage rails where the output voltage is close to the maximum voltage rating of the I.MX terminal. A miscalculation of the resistor accuracy may cause the output voltage to go slightly above the maximum allowed, overstressing or damaging the processor terminal in the application. Use 1% or smaller tolerance resistors to have good control of output voltage values. Note: for more details on external component calculation, please refer to the MC34704 data sheet that can be found at www.freescale.com. i.MX25 Power Management Using the MC34704 , Rev. 1.0 12 Freescale Semiconductor MC34704 Power Supply Design 6.2 i.MX25 Power Management Schematic U12 VOUT8 VOUT1/NC0 23 VG 22 0 OHM REG8 30mA Boost SW8 2 D5 MBR120VLSFT1G 2 20 REG1/VG 500mA Boost SW1 21 1 C176 47UF 2 1 1 1 19 REG1_5V for LCD backlight R286 C167 47UF BKLT_5V_60MA_A VIN 2 3.0UH L21 BT8 17 FB8 53 PVIN5 PVIN2 46 54 BT5D BT2D 45 52 SW5D SW2D 47 VOUT2 48 24 VIN C170 10.0uF C173 68PF 49 BT2U 42 FB2 44 R265 2.7K 1% C155 1uF 55 BT5U FB5 R322 33.0K C172 68PF R333 33.0K 1% C130 10PF C164 10PF 1% GND R334 68K 1% 5 SW2U C138 1uF 1 R310 15K 1% SW5U RS- 50 L19 4.7UH 1 R309 68K 1% REG2 500mA Buck-Boost 0.02 OHM RC0805 C171 22UF GND REG5 500mA Buck-Boost 2 R253 2.7K CPU_3.3V R291 1 L16 4.7UH 4 VOUT5 1 C165 22UF for Digital and Analog 3.3V to CPU REG2_3V3 RS+ 51 R318 for IO and Peripherial on CPU board C124 1uF 2 for IO and Peripherial on Per board REG5_3V3 U25 MAX4372FEUK+ VCC C186 1uF OUT BT1 VMAIN 3 C175 10.0uF 0 OHM C180 1uF 18 2 VIN C166 10.0uF C163 1uF R319 15K 1% GND C177 1000PF C181 1000PF 56 VIN COMP5 3 PVIN4 2 BT4D C125 10.0uF COMP2 43 PVIN3 11 BT3 10 CURRENT_MEAS_CPU3V3 VIN C135 10.0uF C182 0.01uF C132 0.01uF 12 L20 4.7UH for MX25 Core CORE_1.45V REG3_1V45 VOUT3 R262 13 R312 34.0K 1% C156 150PF 5 FB3 14 RS+ FB4 RS- BT4U 8 1% C134 22UF R320 12.7K C117 5PF OUT VMAIN C184 1uF R276 62.0K 1% 7 0.02 OHM RC0805 R313 18K 1% SW4U 4 6 REG3 550mA Buck U28 MAX4372FEUK+ VCC REG4 300mA Buck-Boost GND RS- VCC OUT GND SW3 C185 0.01uF C161 120PF 3 2 1 VOUT4 1 5 R331 680 OHM 1% RS+ U31 MAX4372FEUK+ SW4D 5 L22 4.7UH R325 68K 1% 4 GND 4 VMAIN 3 C151 22UF 2 RC0805 1 0.02 OHM1% 1 REG4_1V8 R264 2 for DDR2 DDR_1.8V AGND 2 AGND AGND 9 COMP4 C160 1uF CURRENT_MEAS_CORE VIN AGND CURRENT_MEAS_DDR R304 10K GND 32 VOUT7/PGND2 ONOFF 41 1 0 OHM GND 2 R328 ON_OFF REG2_3V3 R305 1.0K 1% DRV7/NC3 RST 27 C133 0.1UF CC0201 1.5V 1 VIN 3 EN REG2_3V3 C150 1uF 10K GND R314 2 VOUT 5 ADJ 4 GND R335 4.99K 1% 1.5V VDDI 39 output,2.5V GND R315 10K C153 2.2UF D6 GREEN DNP 1 REG7 60mA IVTER U23 VIN POR_B 2 31 R323 10K GND GND RT9179 GND R336 18K 1% Vout=(1+4.99K/18K)x1.175=1.5V GND C187 0.01uF 30 FB7/AGND1 29 VREF7/NC2 28 COMP7/NC1 36 FREQ 16 phase control,default 2MHz SS 15 soft start timng AGND 37 SCL 25 SDA 26 R327 10K DNP C144 1uF R330 10K DNP VOUT6/PGND5 AGND 35 34 33 SW6/PGND4 REG6 60mA Boost 1 0 OHM 1 0 OHM LION 40 VIN VIN 38 VIN PGND 57 BT6/NC4 FB6/AGND3 2 R306 2 R307 I2C1_CLOCK <8,9,12> I2C1_DATA <8,9,12> VMAIN 0 OHM R332 C183 1uF MC34704 AGND Figure 10. MC34704 + 1.5 V LDO Schematic i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 13 MC34704 Power Supply Design 6.3 Layout Example The following layout is an implementation of the MC34704 interacting with the i.MX25 in the PDK developed by Freescale. The layout stacking is defined based upon the i.MX requirements of a 10 layer PCB. Layer 2 and 8 correspond to GND planes, while layers 5 and 6 are power planes. For simplification, these layers will not be presented, since they do not provide significant information about the power management design. The remaining layers are dedicated to signal and voltage rail routing, and are shown in Figure 11 through Figure 17. This layout design has been cropped to show components placement and routing, relating to the power supply design with the MC34704 (U10). However, some extra components may be shown as part of the complete system design using the i.MX25 chip. 6.3.1 Top Layer Figure 11. MC34704 Top Layer PCB Layout Implementation. i.MX25 Power Management Using the MC34704 , Rev. 1.0 14 Freescale Semiconductor MC34704 Power Supply Design 6.3.2 Internal Layer 1 (Signal) Figure 12. MC34704 Implementation Internal Layer 1 i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 15 MC34704 Power Supply Design 6.3.3 Internal Layer 2 (Signal) Figure 13. MC34704 Implementation Internal Layer 2 i.MX25 Power Management Using the MC34704 , Rev. 1.0 16 Freescale Semiconductor MC34704 Power Supply Design 6.3.4 Internal Layer 3 (GND + Signals) Figure 14. MC34704 Implementation Internal Layer 3 i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 17 MC34704 Power Supply Design 6.3.5 Internal Layer 4 (Signal) Figure 15. MC34704 Implementation Internal Layer 4 i.MX25 Power Management Using the MC34704 , Rev. 1.0 18 Freescale Semiconductor MC34704 Power Supply Design 6.3.6 Bottom Layer Figure 16. MC34704 Implementation Bottom Layer i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 19 MC34704 Power Supply Design 6.3.7 All layers combination Figure 17. MC34708 All Layers Displayed 6.4 • • • • • • • Layout Consideration Create a ground plane layer and tie it to ground signals with vias. Place test vias as close to the IC as possible, to ensure a good measurement values. PVIN, VIN, and VOUT signals have to be tracked with a wide and straight copper area. Never trace the feedback signal in parallel to the SW signal. Ensure the SW inductor is placed as close to its pads as possible. The SW track must be as thin and short as possible. Make sure the I/O connectors are capable of managing the load current. i.MX25 Power Management Using the MC34704 , Rev. 1.0 20 Freescale Semiconductor Bill of Material 7 Bill of Material Table 3. Simplified Bill of Material Reference Description(1) Quantity Part C14 1 0.1 μF CAP CER 0.1 μF 6.3 V 10% X5R 0201 C29, C96, C97, C100 4 0.01 μF CAP CER 0.01 μF 25 V 10% X7R 0402 C74, C75 2 47 μF CAP CER 47 μF 16 V 10% X5R 1210 C76, C80, C81, C85, C86, C107, C108, C146 8 1.0 μF CAP CER 1.0 μF 25 V 10% X7R 0603 C77, C78, C79, C94, C95 5 10.0 μF CAP CER 10 μF 16 V 10% X7R 0805 C82, C83, C98, C99 4 22 μF CAP CER 22 μF 6.3 V 10% X5R 0805 C84, C87 2 68 PF CAP CER 68 PF 50 V 5% C0G 0603 C90, C91 2 10 PF CAP CER 10 PF 50 V 1% C0G 0603 C92, C93 2 1000 PF CAP CER 1000 PF 25 V 5% C0G CC0603 C101 1 120 PF CAP CER 120 PF 50 V 5% C0G 0603 C102 1 5.0 PF CAP CER 5.0 PF 50 V 0.25 PF C0G 0805 C104 1 150 PF CAP CER 150 PF 50 V 5% C0G 0603 C142 1 2.2 μF CAP CER 2.2 μF 6.3 V 20% X5R 0402 D2 1 MBR120VLSFT1G D3 1 GREEN LED GREEN GAP ON GAP SM 0603 L11 1 3.0 μH IND PWR 3.0 μ[email protected] KHZ 3.0 A 30% SMT L12, L13, L14, L15 4 4.7 μH IND PWR 4.7 μ[email protected] MHZ 1.2 A 20% SMT R234, R268, R271, R272, R273, R274 6 10 K RES MF 10 K 1/16 W 5% 0402 R247, R248 2 2.7 K RES MF 2.70 K 1/10 W 1% 0603 R249, R251, R261 3 68 K RES MF 68 K 1/10 W 1% 0603 R250 1 1.0 K RES MF 1.0 K 1/16 W 1% 0402 R254, R257 2 15 K RES MF 15.0 K 1/10 W 1% 0603 R255, R256 2 33.0 K R259 1 680 OHM R266 1 34.0 K RES MF 34.0 K 1/10 W 1% 0603 R267 1 62.0 K RES MF 62.0 K 1/10 W 1% 0603 R285 1 4.99 K RES MF 4.99 K 1/10 W 1% 0603 DIODE SCH RECT 1.0 A 20 V SMT RES MF 33 K 1/10 W 1% 0603 RES MF 680 OHM 1/10 W 1% 0603 i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 21 Bill of Material Table 3. Simplified Bill of Material Reference Description(1) Quantity Part R287, R298 2 18 K RES MF 18.0 K 1/10 W 1% 0603 R302 1 12.7 K RES MF 12.7 K 1/10 W 1% 0603 U10 1 MC34704 IC LIN DCDC PWR SWT 2.0 MHZ 2.7-5.5 V QFN56 U18 1 RT9179(1) IC VREG LDO ADJ 1.175-4.5 V 300 MA 3-5.5 V SOT-23-5 Notes: 1. Freescale does not assume liability, endorse, or warrant components from external manufacturers referenced in drawings or tables. While Freescale offers component recommendations, it is the customer’s responsibility to validate their application. i.MX25 Power Management Using the MC34704 , Rev. 1.0 22 Freescale Semiconductor References 8 References 1. MC34704 data sheet MC34704 2. i.MX25 data sheet 3. i.MX25 PDK i.MX25 Power Management Using the MC34704 , Rev. 1.0 Freescale Semiconductor 23 How to Reach Us: Home Page: www.freescale.com Web Support: http://www.freescale.com/support USA/Europe or Locations Not Listed: Freescale Semiconductor, Inc. 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