Octavo Systems LLC 的 OSD335x-SM Power Application Note 规格书

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OSD335x-SM Power Application Note

Rev.1 10/24/2017

Octavo Systems LLC

1 Introduction

This application note is intended for engineers to understand the power management system of

OSD335x-SM. It is also intended to aid in power budgeting for systems using the OSD335x-SM. It

provides an overview of the power management system inside the OSD335x-SM and runs through an

example application power budgeting procedure.

The OSD335x-SM contains the TPS65217C Power Management Integrated Circuit(PMIC) and the TL5209

Low Drop-Out(LDO) regulator as well as all associated passives for power management. The PMIC is

responsible for powering the AM335x processor and the DDR3 as well as provide output power for other

system needs. It provides configurable power-up and power-down sequencing required by the

processor and monitors the processor input voltage levels. The PMIC contains 3 DC-DC power

converters, 2 LDOs and 2 load switches that can be configured as LDOs that can be used as power

supplies. It can be powered by any combination of a 5V AC adapter, USB port, or Single Cell Li-Ion

battery. Figure 1 shows the power system of OSD335x-SM including connections between the PMIC and

various power domains of the processor.

Figure 1: Power connections inside OSD335x-SM

The OSD335x-SM allows the I/O voltage domains (VDDSHVx) of the AM335x to be set to either 1.8V or 3.3V.

The VDDSHVx pins of the OSD335x-SM (ie VDDSHV1 thru VDDSHV6), which can be found in Table 5.5, must be

connected to either a 1.8V or 3.3V power source in order to provide power to the I/Os. Recommendations on

how to connect the I/O voltage domain pins is in the OSD335x-SM Layout Guide in the Reference Documents

section. See the AM335x datasheet in the Reference Documents section for more information on the pins

associated with each I/O voltage domain.

1 P. .w T

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Table 1 shows the voltage output levels of each of the voltage sources. Each of the output voltages can

be changed dynamically using I2C commands when the PMIC is in active mode.

Table 1 PMIC voltage outputs

TPS65217C Voltage Source

OSD335x Voltage rail

Voltage (V)

DCDC1

VDDS_DDR

1.5

DCDC2

VDD_MPU

1.1

DCDC3

VDD_CORE

1.1

LDO1

SYS_RTC_1P8V

1.8

LDO2

SYS_VDD2_3P3V

3.3

LDO3

SYS_VDD_1P8V

1.8

LDO4

SYS_VDD3_3P3V

3.3

on

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Table of Contents

1 Introduction ............................................................................................................................................ 1

2 Revision History ...................................................................................................................................... 4

3 Power Up Sequence ............................................................................................................................... 5

3.1 Additional functions of the PMIC ............................................................................................................ 6

4 Power Budgeting: How to Approach it? ................................................................................................. 6

4.1 Step 1: Creating a Power Diagram .................................................................................................. 6

4.2 Step 2: Creating a Power Budget ..................................................................................................... 8

4.2.1 Maximum Power ...................................................................................................................... 8

4.2.2 Refining the Power Budget ..................................................................................................... 14

4.3 Step 3: Tally Up .............................................................................................................................. 16

5 Conclusion ............................................................................................................................................ 17

6 Reference Documents .......................................................................................................................... 17

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2 Revision History

Revision Number

Revision Date

Changes

Author

1

10/24/2017

Initial Release

Neeraj Dantu

Notice: The information provided within this document is for informational use only. Octavo Systems

provides no guarantees or warranty to the information contained.

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3 Power Up Sequence

The power-up sequence of the processor is shown below in Figure 2, with the numbers in red

representing the order in which they come up, and the main power up events are described below:

Figure 2: AM335x + PMIC power up sequence for OSD335x-SM

1. SYS_RTC_1P8V is activated.

2. PMIC_OUT_LDO_PGOOD rail which is connected externally to the processor’s RTC_PWRONRSTN

(Power on reset of RTC domain) is pulled high to indicate presence of right voltages for the RTC

domain of the processor to power-up.

3. RTC circuitry in the processor comes up and pulls the PMIC_IN_PWR_EN signal high instructing

the PMIC to start power-up sequence. The output of DCDC1 (VDDS_DDR) which powers the DDR

memory is also activated.

4. Output of LDO3 (SYS_VDD_1P8V) is activated

5. Output of LDO2 (SYS_VDD2_3P3V) is activated

6. Output of LDO4 (SYS_VDD3_3P3V) is activated

7. Outputs of DCDC2 (VDD_MPU) and DCDC3 (VDD_CORE) are activated

8. PMIC_OUT_PGOOD which is connected externally to the processor’s PWRONRSTN (Power on

reset of AM335x) of the processor is pulled high releasing the processor from reset.

datasheet

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This power up sequence and delays between each step of the sequence are already programmed

into the PMIC inside the OSD335x so you don’t need to worry about it. The power-down sequence

follows the reverse order of the power-up sequence.

3.1 Additional functions of the PMIC

The PMIC also performs some tertiary functions. A few of the key functions are listed below. For a

complete explanation of all the functions provided by the TPS65217C PMIC refer to the datasheet.

1. The PMIC retrieves the processor from OFF or SLEEP mode upon detecting a falling edge on

PMIC_IN_PB_IN. It also power cycles the processor if PMIC_IN_PB_IN is held low for more than

8 seconds.

2. It provides an active low wake up signal (PMIC_OUT_NWAKEUP) which is de-asserted when a

wakeup event is detected.

3. The PMIC has an interrupt pin (PMIC_OUT_NINT) to signal an event or fault condition to the

processor. The pin is released when the processor reads the INT register.

4. PMIC provides a linear charger for Single Cell Li-Ion batteries and allows charging of the battery

and powering of the system at the same More information can be obtained from the datasheet.

5. The TPS65217C provides protection to the AM335x and itself in the event of catastrophic

situations like an unexpected short or excessive current leakage.

6. It monitors the functioning of a battery if one is connected and charges the battery when

possible.

Now that the function and of the PMIC and its relationship with the processor is clear, the process of

power budgeting discussed below can be better understood.

4 Power Budgeting: How to Approach it?

It is a good practice to make a power budget for your product/design at the beginning of the project.

Good power budgeting contributes to circuit robustness, increased product life and reduced cost of the

product. A power budget should include the availability of power, operating temperature, amount of

data collected, communication, and operation modes of the processor.

4.1 Step 1: Creating a Power Diagram

The first step in making a power budget is to have a power diagram that shows all the power paths of

the system. Start with all the available power sources for the system. For OSD335x, this would include

power rails that are described in the datasheet as output power supplies. There are six output power

rails on the OSD335x including a 2.75V – 5.5 output (SYS_VOUT), three 3.3V outputs (SYS_VDD1_3P3V,

SYS_VDD2_3P3V and SYS_VDD3_3P3V) and three 1.8V outputs (SYS_RTC_1P8V, SYS_VDD_1P8V and

SYS_ADC_1P8V).

Perk:

Range of SYS_VOUT is determined by input power supply voltage. For example, if the SiP is being powered

through a battery (VIN_BAT), SYS_VOUT can be 2.75 V – 5.5 V depending on the battery voltage. Due to the

dropout behavior of the LDO TL5209, its output voltage rail SYS_VDD1_3P3V should not be used when the

OSD335x is being powered through VIN_BAT. Please refer to the TL5209 datasheet for details.

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Next, put in the power consuming components and connect them to the appropriate power rail. The

connection should be based on the voltage input level for the component. Current supply capacities of

the power rails and ease of use can also be factors for choosing the best power rail for the component.

In order to understand this process, let us use the OSD3358-SM-RED Platform. The board provides

access to many peripherals of OSD335x-SM and has a number of external components powered by the

OSD335x-SM. Figure 3 shows the completed power system diagram for the design. It shows most of the

components that draw at least a nominal amount of power.

The diagram not only shows the power rail for a particular component but also lists all the components

that are being powered by a power rail. In addition to helping with the power budgeting, this allows you

to identify power issues early in the design process and make necessary adjustments.

Figure 3: OSD3358-SM-RED power system diagram

Table 2 datasheet datasheet

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4.2 Step 2: Creating a Power Budget

The next step involves making a power budget to estimate power consumption of each component and

thus the total power consumption of the board.

4.2.1 Maximum Power

There are several challenges involved in accurately estimating the power consumption of each

component. For example, it is difficult to estimate how much current, the AM3358 processor and the

DDR Memory draw since that is highly application specific. Power consumption will also depend on the

presence of a USB device or a Micro SD card. To account for all situations, we can start out by assuming

maximum power consumption for all the components. Table 2 shows the power budget table for

OSD3358-SM-RED assuming maximum power consumption for each component.

Table 2: Power budget table with maximum power consumption

Part Name

Part Number

Max Current (mA)

Supply voltage

rail Voltage

(V)

Max Power (mW)

AM3358

U1

307.8

Internal

5

1539

TPS65217C

U1

< 1

Internal

5

<5

TL5209

U1

25

Internal

5

125

DDR RAM

U1

339

Internal

1.5

508.5

TPS2051

U15

< 1

SYS_VOUT

5

< 5

USB Connectors

X4, X5

< 500

SYS_VOUT

5

< 2500

24LC32AT

U1

3

Internal

3.3

15

APX811

U4

20

SYS_VDD1_3P3V

3.3

66

USB2534-1080AEN

U8

80

SYS_VDD1_3P3V

3.3

264

ASDMB-12.000MHZ

Y3

15

SYS_VDD1_3P3V

3.3

49.5

ASDMB-24.576MHz

Y5

15

SYS_VDD1_3P3V

3.3

75

DM3BT-DSF-PEJS

X3

200

SYS_VDD1_3P3V

3.3

1000

SDIN8DE2-16G

U7

80

SYS_VDD1_3P3V

3.3

400

SN74LVC1G07DCK

U3

24

SYS_VDD1_3P3V

3.3

120

SN74LVC2G241DCUR

U6

24

SYS_VDD1_3P3V

3.3

120

AR8035-AL1A

U9

128

SYS_VDD1_3P3V

3.3

422.4

TDA19988BHN

U10

77

SYS_VDD_1P8V

1.8

385

MPU-9250

U23

3.7

SYS_VDD1_3P3V

3.3

12.21

TMP468

U17

10

SYS_VDD1_3P3V

3.3

33

BMP280

U22

1

SYS_VDD1_3P3V

3.3

S25FL127S

U21

50

SYS_VDD1_3P3V

3.3

165

AT97SC3205T

U16

25

SYS_VDD1_3p3V

3.3

82.5

Total

~7895

**SDIN8DE2-16G datasheet is not available on the internet. So, an equivalent datasheet was used to

determine current consumption

**AT97SC3205T datasheet does not specify current consumption. So, an equivalent datasheet was used

Maximum current consumption values can be found from the component datasheets for most devices.

However, there is no deterministic way of calculating the current consumed by the AM335x and the

DDR3 as they are highly application specific. The next two sections will explore how to use tools

provided by TI and Micron to estimate the max power used by the AM335x and DDR.

AM335x Power Estimation Tool htt : www.U.com too‘ owerest Device Revision P621 DDR Type DDRBL DDR Loading 1 Junction Temperature ('C) 40 Power Estimation Mode Max Sman Reﬂex 01f VDDSHV1 Voltage [V] 3.3 VDDSHV2 Voltage [V] 3.3 VDDSHV3 Voltage [V] 3.3 VDDSHV4 Voltage [V] 3.3 VDDSHV5 Voltage [V] 3.3 VDDSHV6 Voltage [V] 3.3

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4.2.1.1 Using Power Estimation Tool for estimating AM3358 power consumption

Texas Instruments provides access to a power estimation tool that can calculate the internal power

consumption of AM3358 including individual power domains of the processor. The process involves

filling out a spreadsheet and submitting it to a webpage. The detailed procedure is described in the wiki

page “AM335x Power Estimation Tool”. A short overview of the process with notes on usage with the

OSD335x is given below. The inputs shown in the screenshots were put in to calculate the maximum

power consumption of AM335x.

1. Download either the simplified or the advanced spreadsheet for AM335x from

http://www.ti.com/tool/powerest

2. In section A, among other inputs, set the device revision to PG2.1, DDR type to , DDR loading to

1, and all the VDDSHVx voltages to 3.3. The power modes of AM335x are discussed later in this

document.

Figure 4: System configuration in power estimation spreadsheet

OPP Slot 0 CORE OPP 0PP100 MPU OPP NI'I'RO MPU Frequency (Mill) 1000 Slot 0 ARM Sub—system Utilization % ConexAB 1M ConexAB NEON 1W SGX Sub—system (For SGX- Slot 0 enabled devices only) Utilization 56 SGX 1W

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3. Set the Operational Performance Point (OPP), MPU frequency and Utilization percentages in

Section B.

Figure 5: Processor options and utilization in power estimation spreadsheet

4. Input Utilization percentages for peripheral usage of AM335x in section C.

Slol 0 Module Name Utilization 56 EDMA 1M EMIF 1M GPMC 1W OCMC—RAM 1M LCDC 1“ USB 1“ Ethernet MAC 1” PRUSS 1W McASP1 1W McASPZ 1N MMC1 1M MMCZ 1N MMC3 1M Misc. Peripherals (UART, SPI, I26, CAN, GPIO, eHRPWM, eQEP, 1M RTC etc) Module Name Slot 0 ADC

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Figure 6: Peripheral utilization in power estimation spreadsheet

5. Enable/Disable analog modules in Section D

Figure 7: ADC module usage in power estimation spreadsheet

6. Click on the submit button in the spreadsheet. This will open a webpage to which the edited

spreadsheet can be uploaded to. This requires logging in to TI’s website.

7. A power analysis report will be emailed to the email address attached to the user account

logged into.

m T sstEus AM335x Power Estimation Report mm m. um. mmleﬂD‘lJmns ammo" rump-11mm): 40 mu. mm mm AM can in. mm] mmououm I I I VDIla 01V) Currant“) mm max Laalaga Acllva VDD MPU 1.33 1.30 0.020 0.010 VDD CORE 1.10 1.10 0.010 0.411 VDDS DPLL 1.00 1.00 0.000 0.010 V008 SMM 1.00 1 .00 0.000 0.000 0.00007 VDDS DDR 1.” 1 .00 0.000 0.000 0.000 0.00010 VDDS 1P5 1.00 1 .00 0.000 0.000 0.000 0.01 000 VDDS SF! 0.00 0.00 0.000 0.000 0.000 0.01770 V00“ PUV USN/1 VDDA ADC 1.00 1.00 0.000 0.000 0.000 0.00000 VDDA! PSV US$011 0.00 0.00 0.000 0.000 0.000 0.00000 ﬁnal 1 .00001 Nohl : VDDB_DPLL Incum- VDD$_PLL_MPU. VDDS_PLL_CDRE_LCD and VDD$_PLL_DDR pow" suppllon vuns_snm Includu vnos_sRAM_conE_aa and vuns_amu_mu_aa pawn luppﬂu vnos_1n lncludu vans, vnns_mc, vnns_osc ma 1,: v VDDSNVX pow-r Inwllu V008 0F: lncllld'l 0.0 V VDUSﬂVl pow" Iuppllol Processor SDK Linux kernel gerformance guide AM335x gower consumption summam sgreadsheet

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Figure 8: Power estimation result

The worst-case current consumption can be obtained by maximizing the inputs to the spreadsheet.

Other relevant resources that help estimation of AM335x power usage are given below:

1. Processor SDK Linux kernel performance guide

2. AM335x power consumption summary

4.2.1.2 Estimating Power for the DDR3

Like the AM335x spreadsheet, Micron provides a spreadsheet to estimate DDR3L power consumption.

Though the exact power consumption depends on the part number of the memory, the spreadsheet

serves as a ball park estimation tool. A brief use case of the spreadsheet is shown below.

1. Download the spreadsheet available for the DDR3L memory on Micron’s website.

. m DRAM Density Number 01 DO: per DRAM Speed Grade Mode Register bit 12: Precharge PD Exit Mode {{{4 quRD DORS SDQAM mm weer Der MNldual DO mmsmuwmwnuosnunmlsnw quwﬁ DDR3 SDRAM termination power per mammal DO uumg WRITEs m Ims new Pompom DDR3 seam Ierlnmahon power per numeual DO aumg READS 1mm mner DRAM POQWRMH DOES SDMM lemunahon power per mwual DO dumg WRITES to «he! DRAM The percentage mm Ina! an banks on me DRAM ﬁle In a precnarged SIM! The percemage at me all bank manage line for which cxz rs new Low The manage mm: at Ieasl one bank acllve nm: to: much CKE I: held LOW Page VIII late RDSCME The percentage o'clock cyclesmlch are mmtmg read data rmm me DRAM Wﬂscms mpememage onlock cyclesvmxn are unpunmg m dale lo the DRAM IennRDunx The manage onlockcyclesumxn are lemma} 3 read data In ”lame! DRAM Ingrmwnsum The managemuocuyclesmxn are \ terminal: . me data m anomer DRAM amps“. Tne average lune between ACT commands lo 5 u as [Ills OW (Includes ACT losame or dlﬂefeﬂl Dam In me same DRAM Genet

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2. Input SDRAM configuration inputs in the “DDR3 Config” The screenshot shows inputs specific to

DDR3 memory used in OSD335x.

Figure 9: DDR3 configuration in power estimation spreadsheet

3. Input DRAM usage conditions in “System Config” These inputs may vary based on use case. The

inputs shown below are for estimating worst case power consumption of the RAM.

Figure 10: DDR3 system configuration in power estimation spreadsheet

m Psys Power Consumption Summary Total Background Power Total DDR3 SDRAM Power TERM 2nd rank ACT 182.1 mW Total Activate Power 182.1 mW RD 0.0 mW WR 70.3 mW READ IIO 0.0 mW Write ODT 207.6 mW — ACT STBY 40.9 mW PRE STBY 0 0 mW ACT PDN O 0 mW PRE PDN 0 0 mW REF 7 6 mW

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4. The “Summary” page will show the power consumption summary for previously entered inputs.

Figure 11: DDR3 power consumption summary

From the results, the worst case current consumption was calculated to be 339 mA with 1.5 V input

4.2.2 Refining the Power Budget

Some of the current consumption numbers are highly unrealistic. No system uses all the processor cores

and peripherals at a 100% utilization. The DDR current consumption is calculated assuming 100% of the

time is spent writing to the memory with lowest ACT command interval. So, while it is safe to use these

figures to assume worst case load, the system would be vastly over-designed. It is better to build a

second power budget table with typical current consumptions and a more application specific scenario

while keeping the previous version in mind.

Table 3 Tab|e4 Tab‘e 3.

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Table 3 Application specific power budget table

Part Name

Part Number

Max Current (mA)

Supply voltage

rail

Voltage

(V)

Max Power (mW)

AM3358

U1

186.4

Internal

5

932

TPS65217C

U1

< 1

Internal

5

<5

TL5209

U1

8

Internal

5

125

DDR RAM

U1

206

Internal

1.5

309

TPS2051

U8

< 1

SYS_VOUT

5

< 5

USB2534-1080AEN

U8

45

SYS_VDD1_3P3V

3.3

148.5

USB Connector

X4, X5

< 500

SYS_VOUT

5

< 2500

24LC32AT

U1

1

Intenal

3.3

5

DM3BT-DSF-PEJS

X3

100

SYS_VDD1_3P3V

3.3

500

SDIN8DE2-16G

U7

80

SYS_VDD1_3P3V

3.3

400

SN74LVC1G07DCK

U3

16

SYS_VDD1_3P3V

3.3

80

SN74LVC2G241DCUR

U6

16

SYS_VDD1_3P3V

3.3

80

AR8035-AL1A

U9

33.9

SYS_VDD1_3P3V

3.3

111.8

MPU-9250

U23

3.2

SYS_VDD1_3P3V

3.3

10.6

S25FL127S

U21

24

SYS_VDD1_3P3V

3.3

79.2

Total

5291

Table 3 shows an application specific power budget table in which the processor is operated in

conditions described in Table 4. All the other peripherals and features are assumed to be disabled in this

scenario and ‘typical’ current consumption values from component datasheets are used rather than

‘maximum’ current consumption values.

Table 4 AM335x application specific operating conditions

Feature/peripheral

Utilization (%)

Cortex A8

70

Cortex A8 NEON

70

CORE OPP

OPP100

MPU OPP

NITRO

MPU Frequency

1 GHz

EMIF

70

OCMC RAM

70

USB

70

Ethernet MAC

70

MMC1

70

Miscellaneous Peripherals

50

ADC

OFF

Note that the utilization percentages of each feature/peripheral of the AM335x processor are still high.

This is done to leave ourselves some head room if the board runs into an unexpected scenario. Similarly,

the RAM usage is also safely assumed to have a 20% page hit rate, a 10ns interval between ACT

commands, 30% of the time spent reading from RAM and 30% of the time writing to the RAM. Also,

observe that several components of the board are not in use and so are left out of Table 3.

Tab‘e 5, Table 5,

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4.3 Step 3: Tally Up

Thus, we have an extreme scenario and an application specific application scenario for our power

budget. The usage scenarios should now be stacked up to the supply capacities of output power rails of

OSD335x that we outlined in step 1 to make sure everything checks out. Given below are the conditions

that need to be verified and corresponding usage on the OSD3358 SBC reference design from the

datasheet:

Table 5 Current limitations from OSD335x datasheet

Condition

Limitation

Extreme

Application

VIN_AC input current

2.0 A

1.58 A

1.05 A

VIN_USB input current* (See below)

1.3 A

1.58 A

1.05 A

VIN_BAT input current (5V battery)

2.0 A

1.58 A

1.05 A

SYS_VOUT output current

500 mA

500mA

SYS_VDD1_3P3V (VDD_3V3B) output current

500 mA

752.7mA

318.1mA

SYS_VDD2_3P3V (VDD_3V3AUX) output current

150 mA

–

SYS_RTC_1P8V (VDD_RTC) output current

100 mA

–

SYS_VDD_1P8V (VDD_1V8) output current

250 mA

77mA

–

SYS_ADC_1P8V (VDD_ADC) output current

25 mA

–

From Table 5, although SYS_VOUT current consumption looks like it touches the maximum

recommended output current, it is highly unlikely to have a USB device that would draw 500mA in the

application. The extreme condition input current exceeds the USB input current limit. But, there are

alternative input power paths(AC and BAT) that can mitigate this issue even though the scenario will

never occur. The load current for the SYS_VDD1_3P3V voltage rail also exceeds the output current limit

in the extreme scenario. So, that voltage rail may fail if components begin to draw maximum specified

currents. But, the application specific current draws taken into account while designing the board are

significantly lower than the limits. More weight was placed on the application scenario vs theoretical

maximum current consumptions during the design. As can be seen from Table 5, there is enough room

for the board to be able to deal with most unexpected situations of high current consumption in an

application scenario.

While this board presents no problems in power analysis for an application, there might be situations

where the current draws are close or exceed the power rail limits in a design. In this case, alternative

approaches to design can solve the problem. The OSD335x has multiple rails of 1.8V and 3.3V. So,

spreading out the total current consumption of all the parts among the available power rails can be a

Perk:

By default, VIN_USB is limited to 500mA. A current limiting register in the PMIC needs to be modified

to allow current greater than 500mA. Another important thing to keep in mind is the type of

components used for power supply. While the MPU domain, CORE domain and the DDR memory are

powered by efficient DC to DC converters, all the other power rails come from LDOs. So, current

consumption of the components powered by LDOs is a direct addition to the overall current

consumption irrespective of the level of the voltage rail.

Software Power Management with the OSD335X Family TP865217C datasheet TL5209 LDO datasheet AM335X datasheet Powering the AM335X with TP565217C Using Power Estimation Tool to estimate power consumption of AM335x Processor SDK Linux kernel gerformance guide AM335X power consumgtion summaﬂ Sgreadsheet for DDR3 power consumgtion estimation AM335X Power Management User Guide Linux Core Power Management User’s guide AM335X Power Management User Guide AM335X Power Management Standby User’s Guide

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first approach. If that does not resolve the issue, alternative power paths need to be designed. This

might involve using more regulators and/or using AC/BAT input instead of the current limiting USB

input.

5 Conclusion

This document discussed the power management system of OSD335x-SM and presented a power

budgeting procedure that helps in efficient product design. Most of the above discussion centers around

hardware. However, software also plays an important role in power management. Some aspects of

software power management and a case study on its advantages are presented in the application note:

Software Power Management with the OSD335x Family.

6 Reference Documents

1. TPS65217C datasheet

2. TL5209 LDO datasheet

3. AM335x datasheet

4. Powering the AM335x with TPS65217C

5. Using Power Estimation Tool to estimate power consumption of AM335x

6. Processor SDK Linux kernel performance guide

7. AM335x power consumption summary

8. Spreadsheet for DDR3 power consumption estimation

9. AM335x Power Management User Guide

10. Linux Core Power Management User’s guide

11. AM335x Power Management User Guide

12. AM335x Power Management Standby User’s Guide

Octavo Systems LLC 的 OSD335x-SM Power Application Note 规格书

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