Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - voltage regulator - special purpose TQFN 16 (4x4)

General Description

The MAX8506/MAX8507/MAX8508 integrate a PWM step-

down DC-DC regulator and a 75mΩ (typ) bypass FET to

power the PA in WCDMA and cdmaOne™ cell phones.

The supply voltage range is from 2.6V to 5.5V, and the

guaranteed output current is 600mA. One megahertz

PWM switching allows for small external components.

The MAX8506 and MAX8507 are dynamically controlled

to provide varying output voltages from 0.4V to 3.4V. The

MAX8508 is externally programmed for fixed 0.75V to

3.4V output. Digital logic enables a high-power (HP)

bypass mode that connects the output directly to the bat-

tery for all versions. The MAX8506/MAX8507/MAX8508

are designed so the output settles in less than 30µs for a

full-scale change in output voltage and load current.

The MAX8506/MAX8507/MAX8508 are offered in 16-pin

4mm x 4mm thin QFN packages (0.8mm max height).

Applications

WCDMA/NCDMA Cell Phones

Wireless PDAs, Palmtops, and Notebook

Computers

Wireless Modems

Features

♦ Integrated 75mΩ (typ) Bypass FET

♦ 38mV Dropout at 600mA Load

♦ Up to 94% Efficiency

♦ Dynamically Adjustable Output from 0.4V to 3.4V

(MAX8506, MAX8507)

♦ Externally Fixed Output from 0.75V to 3.4V

(MAX8508)

♦ 1MHz Fixed-Frequency PWM Switching

♦ 600mA Guaranteed Output Current

♦ Shutdown Mode 0.1µA (typ)

♦ 16-Pin Thin QFN (4mm x 4mm, 0.8mm max Height)

MAX8506/MAX8507/MAX8508

PWM Step-Down DC-DC Converters with 75m

ΩΩ

Bypass FET for WCDMA and cdmaOne Handsets

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-2918; Rev 1; 1/04

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

PART TEMP RANGE PIN-PACKAGE

MAX8506ETE -40°C to +85°C 16 Thin QFN

MAX8507ETE -40°C to +85°C 16 Thin QFN

MAX8508ETE -40°C to +85°C 16 Thin QFN

cdmaOne is a trademark of CDMA Development Group.

Pin Configurations appear at end of data sheet.

Typical Application Circuits continued at end of data sheet.

CURRENT-

LIMIT

CONTROL

PWM

DAC

BATTP

OUT

COMP

PGND

GND

REFIN

1MHz

OSC

REF

INPUT

2.6V TO 5.5V

4.7µH

OUTPUT

0.4V TO 3.4V OR V

BATT

4.7µF

0.3Ω

0.4Ω

0.075Ω

BATT

REF

2.2µF

0.22µF

SKIP

SHDN

MAX8506

MAX8507

(kΩ)

1500

1000

(pF)

100

(pF)

MAX8506

MAX8507

Typical Application Circuits (MAX8506/MAX8507)

Summary of content (11 pages)

PAGE 1
9-2918; Rev 1; 1/04 PWM Step-Down DC-DC Converters with 75mΩ Bypass FET for WCDMA and cdmaOne Handsets Features The MAX8506/MAX8507/MAX8508 integrate a PWM stepdown DC-DC regulator and a 75mΩ (typ) bypass FET to power the PA in WCDMA and cdmaOne™ cell phones. The supply voltage range is from 2.6V to 5.5V, and the guaranteed output current is 600mA. One megahertz PWM switching allows for small external components.
PAGE 2
MAX8506/MAX8507/MAX8508 PWM Step-Down DC-DC Converters with 75mΩ Bypass FET for WCDMA and cdmaOne Handsets ABSOLUTE MAXIMUM RATINGS BATTP, BATT, OUT, SHDN, SKIP, HP, REFIN, FB to GND ...........................................................-0.3V to +6V PGND to GND .......................................................-0.3V to +0.3V BATT to BATTP......................................................-0.3V to +0.3V OUT, COMP, REF to GND.......................-0.3V to (VBATT + 0.3V) LX Current (Note 1) ....
PAGE 3
PWM Step-Down DC-DC Converters with 75mΩ Bypass FET for WCDMA and cdmaOne Handsets (V BATT = V BATTP = 3.6V, SHDN = SKIP = BATT, HP = GND, V REFIN = 1.932V (MAX8506), V REFIN = 1.70V (MAX8507), CREF = 0.22µF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2) PARAMETER CONDITIONS P-Channel Current-Limit Threshold MIN TYP MAX UNITS 1.00 1.25 1.50 A N-Channel Current-Limit Threshold SKIP = BATT (PWM mode) -0.6 -0.45 -0.30 SKIP = GND (normal mode) 0.03 0.
PAGE 4
Typical Operating Characteristics (VBATT = VBATTP = 3.6V, SHDN = SKIP = BATT, HP = GND, TA = +25°C, unless otherwise noted.) (See the Typical Application Circuits.) RLOAD = 15Ω 90 EFFICIENCY vs. INPUT VOLTAGE 100 RLOAD = 15Ω 90 MAX8506 toc03 100 MAX8506 toc01 100 EFFICIENCY vs. OUTPUT VOLTAGE IN PWM MODE MAX8506 toc02 EFFICIENCY vs. OUTPUT VOLTAGE IN NORMAL MODE 90 RLOAD = 10Ω 80 RLOAD = 5Ω 70 EFFICIENCY (%) EFFICIENCY (%) RLOAD = 10Ω 80 RLOAD = 5Ω 70 60 0.5 1.0 1.5 2.0 2.5 3.
PAGE 5
PWM Step-Down DC-DC Converters with 75mΩ Bypass FET for WCDMA and cdmaOne Handsets (VBATT = VBATTP = 3.6V, SHDN = SKIP = BATT, HP = GND, TA = +25°C, unless otherwise noted.) (See the Typical Application Circuits.) LIGHT-LOAD SWITCHING WAVEFORM IN PWM MODE LIGHT-LOAD SWITCHING WAVEFORM IN NORMAL MODE MAX8506 toc09 MAX8506 toc10 VLX 2V/div VLX 2V/div VOUT AC-COUPLED 5mV/div VOUT AC-COUPLED 20mV/div VOUT = 0.4V LOAD = 10Ω, SKIP = GND VOUT = 0.
PAGE 6
PWM Step-Down DC-DC Converters with 75mΩ Bypass FET for WCDMA and cdmaOne Handsets MAX8506/MAX8507/MAX8508 Pin Description PIN NAME FUNCTION MAX8506 MAX8507 MAX8508 1 1 SHDN 2 2 GND Ground. Connect to PGND and directly to EP. 3 3 REF Reference Output. Output of the internal 1.25V reference. Bypass to GND with a 0.22µF capacitor. 4 — REFIN External Reference Input. Connect to the output of a digital-to-analog converter for dynamic adjustment of the output voltage.
PAGE 7
PWM Step-Down DC-DC Converters with 75mΩ Bypass FET for WCDMA and cdmaOne Handsets During PWM operation, the MAX8506/MAX8507/ MAX8508 regulate the output voltage by switching at a constant frequency and then modulating the duty cycle with PWM control. The error-amp output, the main switch current-sense signal, and the slope-compensation ramp are all summed using a PWM comparator.
PAGE 8
MAX8506/MAX8507/MAX8508 PWM Step-Down DC-DC Converters with 75mΩ Bypass FET for WCDMA and cdmaOne Handsets Synchronous Rectification An N-channel synchronous rectifier operates during the second half of each switching cycle (off-time). When the inductor current falls below the N-channel currentcomparator threshold or when the PWM reaches the end of the oscillator period, the synchronous rectifier turns off. This prevents reverse current from the output to the input in pulse-skipping mode.
PAGE 9
PWM Step-Down DC-DC Converters with 75mΩ Bypass FET for WCDMA and cdmaOne Handsets PART NUMBER INDUCTANCE (µH) ESR (mΩ) SATURATION CURRENT (A) DIMENSIONS (mm) Murata LQH32C-53 4.7 150 0.650 2.5 x 3.2 x 1.7 Sumida CDRH2D11 4.7 135 0.500 3.2 x 3.2 x 1.2 Taiyo Yuden LBLQ2016 4.7 250 0.210 1.6 x 2.0 x 1.6 D312C 4.7 200 0.790 3.6 x 3.6 x 1.2 SUPPLIER TOKO capacitor ripple.
PAGE 10
PWM Step-Down DC-DC Converters with 75mΩ Bypass FET for WCDMA and cdmaOne Handsets MAX8506/MAX8507/MAX8508 Typical Application Circuits (MAX8508) (continued) INPUT 2.6V TO 5.5V OUTPUT 0.75V TO 3.4V OR VBATT 4.7µH 4.7µF 2.2µF BATTP LX BATT OUT MAX8508 0.075Ω SKIP SHDN REF 0.4Ω REF CURRENTLIMIT CONTROL PWM 0.22µF R1 1MHz OSC 0.3Ω FB R2 HP 0.75V PGND COMP GND RC 5.
PAGE 11
PWM Step-Down DC-DC Converters with 75mΩ Bypass FET for WCDMA and cdmaOne Handsets 24L QFN THIN.EPS PACKAGE OUTLINE 12, 16, 20, 24L THIN QFN, 4x4x0.8mm 21-0139 C 1 2 PACKAGE OUTLINE 12, 16, 20, 24L THIN QFN, 4x4x0.8mm 21-0139 C 2 2 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.