National Semiconductor LP3972 User Manual
AN-1621 LP3972 USB Evaluation Board Rev B
1 General Description
The LP3972 Flex PMU is a complete power management IC designed for advanced processors. It
contains 5 low noise low dropout regulators, 3 DC/DC buck converters, a backup battery charger, real
time clock supply regulator [RTC], 2 GPO’s and high speed I2C serial interface to program individual
regulator output voltages as well as offer on/off control. This USB evaluation board features independent
USB powering, virtual voltmeter bank all in a compact demonstration platform.
2 Key Features
• 2.7V to 5.5V input voltage range
• Programmable V
• Up to 95% efficiency
• ±3% output voltage accuracy
• 1.5A output current [bucks]
OUT
User's Guide
SNVA235A–May 2007–Revised April 2013
0.8 to 3.3 volts
3 Applications
• Personal Media Players
• Smart Phones
• PDA Phones
• Digital Cameras
4 Evaluation Board/Kit Overview
The LP3972 Evaluation Board supports complete functional evaluation of the power management IC. The
functions of the chip are controlled by the I2C interface. The I2C interface on the rev B and later USB
boards are driven via a COP8 microprocessor which supports a connection via the USB port and offers
chip powering and virtual software voltage measurement of all regulators. In addition, the LP3972 can be
powered directly through the USB port for full function. If high current Buck testing is desired, an external
LI ION cell or PS capable of supplying 2 amps or more will need to be connected to the appropriate
connector.
The evaluation board/kit consists of:
• LP3972 Flex_PMU device soldered down in RSB-40 pin 5X5 WQFN package
• Full USB interface
• LED LDO monitoring with current limit resistors [selectable]
• External power LDO, Buck output and main battery/supply connectors offered in heavy duty turret pins
and solder pads
• Socket for back-up battery
• Users guide
• Codeloader Software version 1.2.0.2 or greater [may be sent via email]
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SNVA235A–May 2007–Revised April 2013 AN-1621 LP3972 USB Evaluation Board Rev B
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USB B connector
COP8CBDE9
8 Bit CMOS microcontroller with
8K memory, 10 Bit AD converter
LP3972
FlexPMU
USB 9604
Full speed node controller
Enhanced DMA support
SDA/SCL
communications
Analog to Digital conversion
voltmeter lines
LDO outputs and LED
monitoring
Buck switcher ouputs
and LED monitoring
Power selection
USB/External
External VCC Pads
/Turret pins
Evaluation Board/Kit Overview
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Figure 1. LP3972 Evaluation Board Version B
Figure 2. LP3972 Flex_PMU USB Evaluation Board Block Operational Diagram
2
AN-1621 LP3972 USB Evaluation Board Rev B SNVA235A–May 2007–Revised April 2013
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5 Pin Description 5 × 5 Package
Pin Description 5 × 5 Package
Pin # Name I/O
(1)
Type
(1)
Description
1 PKEY I D CPU Wakeup Input
2 nTJ I D CPU Wakeup Input
3 SP I D CPU Wakeup Input
4 EXT_WAKEUP O D CPU Wakeup Input
5 FB1, Feedback Buck1 I A Buck 1 Feedback
6 VIN1 = V
7 LDO_V
8 LDO_V
BATT
_1 O P LDO1 Output
OUT
_2 O P LDO2 Output
OUT
I P Battery Input for Powering Internal
Circuits and LDO1-3
9 nRST In I D Chip Reset Input
10 LDO GND 1 G G Ground
11 LDO V
12 LDO_V
13 LDO_V
Bypass O A Bypass Capacitor for Reference
REF
_3 O P LDO3 Output
OUT
_4 O P LDO4 Output
OUT
14 VINLDO_4 I P Input Power for LDO4
15 Back-Up Battery V
16 LDO_V
_0 (RTC) O P LDO_RTC Output
OUT
IN
I P Back Up Battery Input
17 nBatt_FLT O D Main Battery Fault Output
18 PGND Buck2 G G Ground
19 V
Buck2 O P Buck Switcher2 Output
OUT
20 VINBuck2 I P Buck Switcher 2 Battery Input
21 SDA I/O D I2C Data Line
22 SCL I D I2C Clock Input
23 FB2, Feedback Buck2 I A Buck Switcher 2 Feedback
24 nRST Out O D Reset Output
25 LDO_V
_5 O P LDO5 Output
OUT
26 VIN2 (LDO 5 Only) I P Battery Input Power for LDO5
27 VDDA I P Analog Power Input
28 FB3, Feedback Buck3 I A Buck Switcher 3 Feedback
29 GPIO1/nCHG_EN I/O D General Purpose I/O #1/BUBATT
Charger EN
30 GPIO2 I/O D General Purpose I/O #2
31 VINBuck3 I P Buck Switcher 3 Battery Input
32 V
Buck3 I P Buck Switcher 2 Output
OUT
33 PGND Buck3 G G Buck3 NMOS Power Ground
34 Buck 1 2 & 3 AVSS/NCHBLK G G Buck1, 2, 3 Analog Ground
35 SYNC (Buck Clock input) I D Buck Switcher External Clock Input
36 Sys_En I D Power Domain Enable
37 Pwr_En I D Power Domain Enable
38 PGND Buck1 G G Buck1 NMOS Power Ground
39 V
Buck1 O P Buck Switcher 1 Output
OUT
40 VINBuck1 I P Buck Switcher 1 Battery Input
(1)
A: Analog Pin; D: Digital Pin; G: Ground Pin; I: Input Pin; I/O: Input/Output; O: Output Pin; P: Power Pin
SNVA235A–May 2007–Revised April 2013 AN-1621 LP3972 USB Evaluation Board Rev B
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Operating Instructions
6 Operating Instructions
The following instructions give general instructions for use of LP3972 with the evaluation board. Practice
standard ESD protection (ground cable) to prevent any unwanted damaging ESD events.
1. Check that the jumpers are in default settings (jumpers are introduced later in this document).
2. Load version .202 or later of the codeloader program into PC.
3. Connect the USB cable [standard USB AB cable] from the USB connector to PC port.
4. Open the codeloader program up, verify that “USB” port has been selected.
5. Verify that successful communications link has been established by toggling “READ ALL”.
6. If there is no communication, key the USB RST [SW1] switch once on the board for reboot.
7. If the voltmeter monitoring function is desired, select “POLL STATUS”.
8. LDO/buck outputs may be monitored directly off the appropriate header output pins.
9. Note that for full load testing, an external PS must be connected to TP1/TP2 and jumper J1 must be
removed. This is because the USB port source spec is limited to 500 mA and removing the jumper will
disconnect the USB supply.
10. PWR EN/SYS En is selectable via codeloader software assignment.
11. Hardware reset can be accomplished by pressing the nREST_In momentary switch.
12. Battery backup is possible by inserting appropriate rechargeable cell into supplied holder.
13. Switches PKEY, nTJ, and SP, are provided for use in normal evaluation mode.
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7 List of Components
Item Qty Reference Value Pkg. Manuf. Part Number
1 5 C1,C21,CC,CD,CF1 10 µF 0805 Panasonic ECJ2FF1A106Z
2 2 C2,C3 100 µF 3528-21 Kemet T520B107M006ASE040
3 8 C4,C7,C13,C15,C16,C31,CA 1 µF 0805 Kemet C0805C105K4RACTU
4 6 C5,C6,C8,C9,C25,C29 10 µf 1206 Taiyo-Yuden JMK316BJ106M
5 6 C14,C19,C20,C23,C24,C26 0.47 µF 0805 TDK C2012X7R1E474K
6 2 C17,C18 47 pF 0805 Murata GRM2195C2A470JZ01D
7 4 C22,C30,C32,C33 0.1 µF 0805 Murata GRM21BR71E104KA01L
8 2 C27,C28 15 pF 0805 Yageo 0805CG150J9B200
9 1 BT2 Battery Holder SMT Seiko BH0414
10 1 NOT INSTALLED Backup Battery Micro4 Seiko MS412F
11 4 D6,D7,D10,D11 Schottky PM 457 On Semi MBRM120LT3
12 2 D8 (PWR EN), D9 (SYS EN) Green LED 1206 Lumex SML-LX1206GC-TR
13 9 LDO1(D13), LDO2(D14), Red LED 1206 Lumex SML-LX1206IC-TR
LDO3(D18), LDO4(D17),
LDO5(D19), LDORTC(D16)
D2,D3,D12
14 2 L1,L2 1 µH Inductor 0805 TDK MLF2012A1R0K
15 3 L3,L4,L5 2.2 µH Inductor SMT Toko FDSE0312
16 1 Q1 XTAL 24 MHz 18 PF SMD Citizen HCM49-24.000MABJT
17 7 R1,R2,R23,R31,R32,R33,R3 330Ω 0805 SEI 807065R330
18 1 R8 100Ω 0805 NIC NRC10J101TR
19 1 R9 49.9Ω 0805 Rohm MCR10EZHF49R9
20 11 R10,R11,R12,R17,R18,R22, 10K 0805 Yageo 9C08052A1002FKHFT
R24,R26,R27,R36,R37
21 1 R12 0Ω 0805 Yaego 9C08052A0R00JLHFT
,CB
4
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AN-1621 LP3972 USB Evaluation Board Rev B SNVA235A–May 2007–Revised April 2013
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