ST STw4141 User Manual

查询STW4141供应商

for Digital Base Band and Multimedia Processor Supply

STw4141

Single Coil Dual Output Step Down DC/DC Converter

PRELIMINARY DATA

Features

■ Single coil dual output switc hi ng co nve r ter for

digital core supply & digital I/Os supply – Digital I/O supply:V – CPU CORE supply:V

■ Wide range of fixed output voltage

configurations availabl e

■ High efficiency synchronous step down

converter with up to 92 % for the entire device

■ Size and cost optimized application board

(7x8 mm, height 1.2mm) three capacitors and only one inductor necessary for both outputs

■ 2.7 V to 5.5 V battery input range

■ ±100mV output voltage accuracy full range in

PWM (Including Line and Load Transients)

■ 900 kHz fixed frequency PWM oper ation

■ PFM mode operation at light load current

■ PWM/PFM switch can be done automatically or

forced by setting external pin s (AUTO and MODE/SYNC)

■ MODE/SYNC input pin for external clock

synchronization from 600 kHz to 1.5 MHz

■ VSEL input pin for V

■ Ultra low shutdown current (Iq<1 µA)

■ Short circuit and thermal shutdown protections

OUT2/VOUT2(red.)

OUT1

OUT2

@ 200 mA

@ 400 mA

selection

Solution size

7 x 8 mm

TFBGA 3x3mm

16 bumps 0.5 mm pitch

Applications

■ Mobile phones

■ PDAs and hand held terminals

■ Portable media players

■ Digital still camera

■ WLAN and Bluetooth applications

Description

The STw4141 is a single coil dual output synchronous step down DC/DC converter that requires only four standard external components. It operates at a fixed 900 kHz switching frequency in PWM mode. The device can operate in PFM mode to maintain high efficiency over the full range of output currents. The STw4141 application requires a very small PCB area and offers a very efficient, accurate, space and cost saving solution to fulfill the requirements of digital baseband or multimedia processor supply (CORE & I/O).

Application Test Circuit

L 4.7 µH

VLX1 VLX2

=2.7V to 5.5V

10 µF

6.3 V

MODE/SYNC

PVDD

VDD

EN AUTO

AUTO

VSEL

A2 A3

STw4141

A1B3C4

PGND

GND

T_MODE

VOUT1

FB1

VOUT2

FB2

STATE

OUT1

22 µF

6.3 V

OUT2

22 µF

6.3 V

December 2005 1/27

This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.

OUT1

OUT2

=1.8V

=1.0V/1.2V

Rev 1

www.st.com

STw4141

Order Codes

Table 1. STw4141 ordering information

(1)

OUT2reduced

(CORE)

Supplied as

Part number Package type

Package marking

Output voltage options

(2)

OUT1

(I/O)

(CORE)

OUT2

STw41411

STA1 1.8 V 1.2 V 1.0 V Tray STw41411/T STA1 1.8 V 1.2 V 1.0 V Tapes/Reels STw41412 STA2 1.8 V 1.3 V 1.0 V Tray STw41412/T STA2 1.8 V 1.3 V 1.0 V Tapes/Reels STw41413 STA3 1.5 V 1.3 V 1.0 V Tray STw41413/T STA3 1.5 V 1.3 V 1.0 V Tapes/Reels

TFBGA 3x3x1.2

STw41414 STA4 1.8 V 1.5 V 1.3 V Tray

16 balls

STw41414/T STA4 1.8 V 1.5 V 1.3 V Tapes/Reels STw41415 STA5 1.8 V 1.35 V 1.0 V Tray STw41415/T STA5 1.8 V 1.35 V 1.0 V Tapes/Reels STw41416 STA6 1.8 V 1.25 V 1.0 V Tray STw41416/T STA6 1.8 V 1.25 V 1.0 V Tapes/Reels

1. The output configuration which will be introduced in production will be only those related to customer design-in.

2. THIS CONDITION MUST BE ALWAYS VALID.

VOUT1 VOUT2≥

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STw4141

Contents

1 STw4141 Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.3 DC electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.4 Dynamic electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.5 Soft start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.6 Settling time of VOUT2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.7 Line transients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.8 Load transients in AUTO mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.9 Load transients in PWM mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.10 Switching between PFM and PWM in FORCED MODE . . . . . . . . . . . . . . . . 13

2.11 Efficiency in PWM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.12 Efficiency in AUTO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2.13 Output voltages versus output currents in PWM and PFM . . . . . . . . . . . . . . 16

3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.2 PWM and PFM mode operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.3 Current limiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.4 Short circuit protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.5 Thermal shutdown protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.1 User mode details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.2 Aut omatic PWM/PFM mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.3 User selected PWM/PFM mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.4 External clock synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.5 Checking Transient response versus external components . . . . . . . . . . . . . 20

4.6 Bill of Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.6.1 Inductor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

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STw4141

4.6.2 Input capacitor (CIN selection) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.6.3 Output capacitors (COUT selection) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.6.4 Capacitors selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.7 PCB layout considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.7.1 PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.7.2 TFBGA16 internal bumps access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

5 Package Outline and Mechanical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4/27

STw4141 1 STw4141 Pinout

1 2 3

1 STw4141 Pinout

Figure 1. Pin assignment in TFBGA 3x3 mm - 16 bumps 0.5 mm pitch

12 34

4321

PGND

PVDD

MODE/

SYNC

FB1

VLX1

STATE

AUTO

FB2

VLX2

T_MODE

VSEL

VDD

VOUT1

VOUT2

GND

Top v i ew

Table 2. STw4141 pin description

Pin Symbol Description

A1 PGND Power ground B1 PVDD Power supply voltage

MODE/SYNC = High to forced PWM mode

C1 MODE/SYNC

D1 FB1 Feedback 1 A2 VLX1 External inductor connection pin 1

B2 STATE

MODE/SYNC = Low to forced PFM mode MODE/SYNC = 600 kHz - 1.5 MHz external clock synchronization in PWM

Output STATE pin allow the user to monitor operation mode of the product STATE = High - PFM mode STATE = Low - PWM mode If not used must be left unconnected.

VOUT1

VOUT2

GND

VLX2

T_MODE

VSEL

VDD

Bottom view

VLX1

STATE

AUTO

FB2

PGND

PVDD

MODE

SYNC

FB1

PWM/PFM automatic switch control pin

C2 AUTO

AUTO = High - PWM/PFM mode automatic switch ENABLED AUTO = Low - PWM/PFM mode automatic switch DISABLED

PWM/PFM mode controlled by MODE/SYNC pin) D2 FB2 Feedback 2 A3 VLX2 External inductor connection pin 2 B3 T_MODE Input signal for test mode selection. This pin must be connected to GND.

Voltage selection input C3 VSEL

VSEL = High - VOUT1 = 1.8V, VOUT2 = 1.2V (valid for STA1)

VSEL = Low - VOUT1 = 1.8V, VOUT2 = 1.0V (valid for STA1)

(For other voltage options see

Table 1: STw4141 ordering information

) D3 VDD Signal supply voltage A4 VOUT1 Output voltage 1

5/27

1 STw4141 Pinout STw4141

Table 2. STw4141 pin description

Pin Symbol Description

B4 VOUT2 Output voltage 2 C4 GND Signal ground

Enable Input:

D4 EN

EN = Low - Device in shutdown mode, EN = High - Enable device This pin must be connected either to VDD or GND.

PGND pin

This is the ground pin related to power sign al. This pin should be connected to the board ground plane by short and wide track or multiply vias to reduce impedance and EMI.

GND pins This is the ground pin related to analog signal.

PVDD pin

This pin is designed to provide power to the device. This path leads high currents. It should be wide and short to minimize track impedance to reduce losses and EMI.

VDD pin

This pin is designed to provide signal supply voltage to the device. There is no specific requirement for its related track design.

VLX1/VLX2 pins

External coil is connected on those pins. It should be placed as closed as possible to the device in order minimize resistances which cause looses. These paths lead high currents.

VOUT1 pin3

It is the first output voltage of this device. This path leads high currents. It should be wide and short to minimize track impedance to reduce losses and EMI.

VOUT2 pin

It is the second output v olta ge of t his d e vic e. This p ath le ads h igh c urrents . It shou ld be wide and short to minimize track impedance to reduce losses and EMI.

FB1 pin Intended to measure VOUT1 voltage in order to ensure the regulation of this output. FB2 pin Intended to measure VOUT2 voltage in order to ensure the regulation of this output.

ENABLE pin

This is the enable pin of the device. Pulling this pin to ground, forces the device into shutdown mode. Pulling this pin to VDD enables the device. This pin must be terminated.

MODE/SYNC pin

The MODE/SYNC pin is a multipurpose pin which provides mode selection and frequency synchronization. The devic e c an al so be s yn chr onized to an external cl ock signal from 600 kHz to 1.5 MHz by the MODE/SYNC pin. During synchronization, the mode is forced to PWM mode and the top switch turn-on is synchronized to the rising edge of the external clock.

AUTO pin

This pin allows th e de vice to au tomatica lly s witch from PWM to PFM mo de f ollowi ng load on b oth 2 outputs.

STATE pin This output pin informs user in which state the device is working: PWM or PFM mode.

VSEL pin

This pin is used to reduce V

(CORE) output voltage in order to r edu ce the proc essor power

OUT2

consumption when entering into sleep mode.

6/27

STw4141 2 Electrical Characteristics

2 Electrical Characteristics

2.1 Absolute maximum ratings

Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied. All voltages are referenced to GND.

Table 3. Absolute maximum ratings

Symbol Parameter Value Unit

SEL

MODE/SYNC

AUTO

T_MODE

STATE

,FB

OUT1

OUT2, FB2

VLX

STG

Power Supply Voltage -0.3 to 6 V Signal Supply Voltage -0.3 to 6 V Enable Input V oltage Selection Operating Mode Selection/Synchronization Input PWM/PFM automatic switch selection Test mode select ion Operating mode information Output Voltage 1, Feedback 1 -0.3 to 3.3 V

-0.3 to V

OUT1

Output Voltage 2, Feedback 2 -0.3 to 3.3 V External Inductor Connection Pin 1

-0.3 to V

External Inductor Connection Pin 2 -0.3 to 3.3 V Operating Temperature Range -40 to 85 °C Maximum Operating Junction Temperature 150 °C Storage Temperature Range -65 to 150 °C

V V V V V V

2.2 Thermal data

Table 4. Thermal data

Symbol Parameter Value Unit

thJA

Thermal Resistance Junction-Ambient TFBGA 3x3 mm – 16 bumps - 0.5 mm pitch

150 °C/W

7/27

2 Electrical Characteristics STw4141

2.3 DC electrical characteristics

Characteristics measured over recommended operating conditions unless otherwise is noted. All typical values are referred to T

Table 5. DC electrical characteristics

Symbol Parameter Test Conditions Min. Typ Max. Unit

PVDD Power supply voltage 2.7 5.5 V I

LIM

OUT1

OUT2

Peak current limit 1.6 A

(1)

Output voltage 1

Output voltage 2

(2)

VSEL = VDD, MODE/SYNC = VDD

VSEL = GND, MODE/SYNC = VDD

= 25°C, PVDD = 3.6V, VDD = 3.6V.

-3 +3 %

OUT1

OUT2

Output current 1 200 mA Output current 2 400 mA

Quiescent Current (PWM)

Quiescent Current (PFM)

Shutdown Current

Enable functions

Enable Threshold High 0.9 V

Enable Threshold Low 0.4 V

Mode/sync functions

MODE/SYNC Threshold High

MODE/SYNC Threshold Low

M/S

OUT1

= 0 mA, I

OUT2

= 0 mA

EN = VDD, VSEL = VDD MODE/SYNC = VDD, AUTO = GND

OUT1

= 0 mA, I

OUT2

= 0 mA

EN = VDD, VSEL = VDD MODE/SYNC = GND, AUTO = GND

EN = GND, VSEL = GND MODE/SYNC = GND, AUTO = GND

600 µA

90 µA

15µA

0.9 V

0.4 V

VSEL functions

Voltage Selection

SEL

Threshold High Voltage Selection

Threshold Low

8/27

0.9 V

0.4 V

STw4141 2 Electrical Characteristics

Table 5. DC electrical characteristics

Symbol Parameter Test Conditions Min. Typ Max. Unit

Auto functions

Voltage Selection

AUTO

Threshold High Voltage Selection

Threshold Low

State functions

Voltage Selection

STATE

1. . This condition must always be valid.

VOUT1 VOUT2≥

2. Output voltage accuracy excludes line and load transients

Threshold High Voltage Selection

Threshold Low

Lmax

= 100k, C

Lmax

= 10pF 0.7V

= 10pF 0.3 V

0.9 V

0.4 V

OUT1

2.4 Dynamic electrical characteristics

Characteristics measured over recommended operating conditions unless otherwise is noted. All typical values are referred to T

= 25°C, PVDD = 3.6V, VDD = 3.6V.

Table 6. Dynamic electrical characteristics

Symbol Parameter Test Conditions Min. Typ Max. Unit

SYNC

Ts Settling time (soft start) 400 µs

TS2

Switching frequency 900 kHz Sync mode frequency 600 1500 kHz

Settling time V

(reduced)/V

OUT2

VSEL change from GND to VDD 80 µs

OUT2

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