LM3370SD-3021EV National Semiconductor, LM3370SD-3021EV Datasheet

LM3370SD-3021EV

Manufacturer Part Number

LM3370SD-3021EV

Description

BOARD EVALUATION LM3370SD-3021

Manufacturer

National Semiconductor

Series

PowerWise®r

Datasheets

1.LM3370SD-3021NOPB.pdf (26 pages)

2.LM3370SD-3021EV.pdf (14 pages)

Specifications of LM3370SD-3021EV

Main Purpose

DC/DC, Step Down

Outputs And Type

2, Non-Isolated

Voltage - Output

1.2V, 3.3V

Current - Output

600mA, 600mA

Voltage - Input

2.7 ~ 5.5V

Regulator Topology

Buck

Frequency - Switching

2MHz

Board Type

Fully Populated

Utilized Ic / Part

LM3370

Lead Free Status / RoHS Status

Not applicable / Not applicable

Power - Output

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LM3370 Evaluation Board

Introduction

The LM3370 evaluation board is a working demonstration of

a DUAL step down DC-DC converter. This application note

contains information about the evaluation board. For more

details and electrical characteristic on the dual buck converter

operation, please refer to the LM3370 datasheet.

General Description

The LM3370 is a dual step-down DC-DC converter optimized

for powering ultra-low voltage circuits from a single Li-Ion cell

or 3 cell NiMH/NiCd batteries. Automatic intelligent switching

between PWM low-noise and PFM low current mode offers

improved system efficiency. The I

namic controls of the output voltages, Auto PFM/PWM mode

Typical Application

Operating Information

The LM3370SD evaluation board is pre-programmed to 1.2V

at V

tional interface hardware is needed). If different default output

option is desired, the same evaluation board can be used by

demount the existing device and replace with new voltage

option ( voltage option can be order from National's website).

The device comes with the following default setting: Auto PFM

and PWM transition mode when the I

is not enabled. For other settings, I

must be used to enable all other functions. Registers infor-

mation are listed on page 4 for I

Powering Up The Evaluation Board

•

Apply a voltage at the "Vin_EXT" pin only (not Vin_IO).

OUT1

and 3.3V at V

OUT2

for evaluation purpose (no addi-

C compatible interface.

C compatible offers dy-

C compatible interface

201750

FIGURE 1. Typical Application Circuit

National Semiconductor

Application Note 1428

Anne Lu

January 9, 2008

selection and other enabling enchantment features such as

power-on-reset (nPOR) and spread spectrum.

Operating Conditions

•

Package

•

If interface capability is available via I

& SCL test pins of the evaluation board are brought out for

such function. The SDA & SCL pins of the evaluation board

are connected to 2 kΩ resistors and pulled up to V

C Compatible Interface

C Interface Ready

Recommended load current: 0 to 600mA

TLA20CWA micro SMD, (3.0mm x 2.0mm x 0.6mm)

LLP16 non-pullback, (4mm x 5mm x 0.8mm)

All logic pins are tied to "Vin” on the evaluation board

Do not power the “Vin_IO” pin unless powering the logic

pins via an external source. (Jumper at Vin_IO must be

removed.)

additional connection required. (For any reason if V

not directly tied to V

than the two inputs (V

OUT1

OUT2

range: 2.7V

pin is tied to V

(1.8V to 3.3V at 100mV steps increment).

(1V to 2V at 50mV step increment)

≤

IN1

, V

& V

IN1

≤

5.5V

or V

IN2

20175001

needs to be equal or greater

on the evaluation board, no

IN2

) for proper operation.)

C compatible, the SDA

www.national.com

pin.

Related parts for LM3370SD-3021EV

LM3370SD-3021EV Summary of contents

Page 1

... NiMH/NiCd batteries. Automatic intelligent switching between PWM low-noise and PFM low current mode offers improved system efficiency. The I namic controls of the output voltages, Auto PFM/PWM mode Typical Application Operating Information The LM3370SD evaluation board is pre-programmed to 1. and 3. for evaluation purpose (no addi- OUT1 OUT2 tional interface hardware is needed) ...

Page 2

Package Marking Information 16-Lead LLP Package FIGURE 1. Top Marking Pin Descriptions (LLP www.national.com 20175009 V Power supply voltage input to PFET and NFET ...

Page 3

Package Marking Information (micro SMD) Top View Pin Descriptions (micro SMD) Pin # Name A1 SW1 A2 V IN1 A3 SGND A4 FB1 B1 PGND1 B2 PGND1_S B3 SDA B4 SCL SGND C3 nPOR1 C4 nPOR2 ...

Page 4

TABLE 1. Output Selection Table via I Data Code 00000 00001 00010 00011 00100 00101 00110 00111 01000 01001 01010 01011 01100 01101 01110 01111 10000 10001 10010 10011 10100 10101 10110 10111 11000 11001 * Can be trimmed at ...

Page 5

... Order Number Voltage Option LM3370SD - 3013 LM3370SDX - 3013 LM3370SD - 3021 LM3370SDX - 3021 LM3370SD - 3416 LM3370SDX - 3416 LM3370SD-3621 LM3370SDX-3621 LM3370SD - 3806 LM3370SDX - 3806 LM3370SD - 4221 LM3370SDX - 4221 Device Ordering Information (micro SMD) Order Number Voltage Option LM3370TL-3607 NOPB LM3370TLX-3607 NOPB LM3370TL-3008 NOPB ...

Page 6

Registers Information www.national.com Device Address Register 00 Register 01 6 20175010 20175002 20175003 ...

Page 7

... Evaluation Board Layout (LLP) LM3370SD is a 4-layer board designed to maximize the performance fo the device. Register 02 Silk Screen 20175012 7 20175004 www.national.com ...

Page 8

Top Layer 20175006 Mid Layer 1 20175007 8 ...

Page 9

Mid Layer 2 20175008 Bottom Layer 20175011 9 www.national.com ...

Page 10

Evaluation Board Layout (micro SMD) The LM3370TL applications is of similar layout to the LLP board with the exception of the SCL, SDA pins. When using the USB interface cable the order of these pins is reversed. www.national.com Silk Screen ...

Page 11

Mid Layer 1 20175028 Bottom Layer 20175029 11 www.national.com ...

Page 12

Bill of Materials Component Manufacture Name LM3370 C & C TDK IN1 IN2 muRata C & C TDK OUT1 OUT2 muRata L1 & L2 Taiyo-Yuden R1-2(SDA+SCL) Vishay R3-4 (nPOR1-2) Vishay TEST Pins & Connectors GND, *Vin_EXT, Vin_IO ...

Page 13

Notes 13 www.national.com ...

Page 14

... For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock Conditioners www.national.com/timing Data Converters www.national.com/adc Displays www.national.com/displays Ethernet www.national.com/ethernet Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www ...

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