Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - DC/DC voltage regulator Boost uMAX 10

AVAILABLE

Functional Diagrams

Pin Configurations appear at end of data sheet.

Functional Diagrams continued at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

For pricing, delivery, and

ordering information, please contact Maxim Direct

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EVALUATION KIT AVAILABLE

General Description

The MAX1674/MAX1675/MAX1676 compact, high-effi-

ciency, step-up DC-DC converters fit in small µMAX

packages. They feature a built-in synchronous rectifier,

which improves efficiency and reduces size and cost

by eliminating the need for an external Schottky diode.

Quiescent supply current is only 16µA.

The input voltage ranges from 0.7V to V

OUT

, where

OUT

can be set from 2V to 5.5V. Start-up is guaran-

teed from 1.1V inputs. The MAX1674/MAX1675/

MAX1676 have a preset, pin-selectable output for 5V or

3.3V. The outputs can also be adjusted to other volt-

ages using two external resistors.

All three devices have a 0.3Ω N-channel MOSFET

power switch. The MAX1674 has a 1A current limit. The

MAX1675 has a 0.5A current limit, which permits the

use of a smaller inductor. The MAX1676 comes in a

10-pin µMAX package and features an adjustable cur-

rent limit and circuitry to reduce inductor ringing.

________________________Applications

Pagers

Wireless Phones

Medical Devices

Hand-Held Computers

PDAs

RF Tags

1 to 3-Cell Hand-Held Devices

____________________________Features

♦ 94% Efficient at 200mA Output Current

♦ 16µA Quiescent Supply Current

♦ Internal Synchronous Rectifier (no external diode)

♦ 0.1µA Logic-Controlled Shutdown

♦ LBI/LBO Low-Battery Detector

♦ Selectable Current Limit for Reduced Ripple

♦ Low-Noise, Anti-Ringing Feature (MAX1676)

♦ 8-Pin and 10-Pin µMAX Packages

♦ Preassembled Evaluation Kit (MAX1676EVKIT)

High-Efficiency, Low-Supply-Current,

Compact, Step-Up DC-DC Converters

GNDLBO

SHDN

REF

OUT

LXLBI

MAX1674

MAX1675

µMAX

TOP VIEW

OUT

GND

BATTCLSEL

LBO

LBI

MAX1676

µMAX

SHDNREF

MAX1674

MAX1675

INPUT

0.7V TO V

OUT

SHDN

LBO

OUT

LBI

0.1µF

LOW-BATTERY

DETECT OUT

OFF

REF

GND

OUTPUT

3.3V, 5V, OR

ADJ (2V TO 5.5V)

UP TO 300mA

LOW-BATTERY

DETECT IN

PART

MAX1674EUA

-40°C to +85°C

TEMP. RANGE PIN-PACKAGE

8 µMAX

_______________Ordering Information

MAX1675EUA

-40°C to +85°C 8 µMAX

MAX1676EUB

-40°C to +85°C 10 µMAX

Typical Operating Circuit

Pin Configurations

MAX1674/MAX1675/MAX1676

19-1360; Rev 3; 3/00

Summary of content (12 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters LE AVAILAB General Description The MAX1674/MAX1675/MAX1676 compact, high-efficiency, step-up DC-DC converters fit in small µMAX packages. They feature a built-in synchronous rectifier, which improves efficiency and reduces size and cost by eliminating the need for an external Schottky diode. Quiescent supply current is only 16µA. The input voltage ranges from 0.
PAGE 2
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters ABSOLUTE MAXIMUM RATINGS Supply Voltage (OUT to GND) ..............................-0.3V to +6.0V Switch Voltage (LX to GND) .....................-0.3V to (VOUT + 0.3V) Battery Voltage (BATT to GND).............................-0.3V to +6.0V SHDN, LBO to GND ..............................................-0.3V to +6.0V LBI, REF, FB, CLSEL to GND ...................-0.3V to (VOUT + 0.3V) Switch Current (LX) ........
PAGE 3
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters ELECTRICAL CHARACTERISTICS (continued) (VBATT = 2V, FB = OUT (VOUT = 3.3V), RL = ˙∞, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Operating Current into OUT (Note 3) Shutdown Current into OUT SYMBOL Efficiency CONDITIONS MIN TYP MAX UNITS VFB = 1.4V, VOUT = 3.3V 16 35 µA SHDN = GND 0.1 1 µA VOUT = 3.
PAGE 4
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters ELECTRICAL CHARACTERISTICS (continued) (VBATT = 2V, FB = OUT, RL = ∞, TA = -40°C to +85°C, unless otherwise noted.) (Note 4) MAX UNITS CLSEL Input Current PARAMETER SYMBOL ICLSEL MAX1676, CLSEL = OUT 3 µA SHDN Input Current I SHDN VSHDN = 0 or VOUT 75 nA V LBO = 5.5V, VLBI = 5.
PAGE 5
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters Typical Operating Characteristics (continued) (L = 22µH, CIN = 47µF, COUT = 47µF 0.1µF, CREF = 0.1µF, TA = +25°C, unless otherwise noted.) NO-LOAD BATTERY CURRENT vs. INPUT BATTERY VOLTAGE 100 80 ILIMIT = 0.5A, 5.0V 60 ILIMIT = 0.5A, 3.3V 20 ILIMIT = 1A, 3.3V 0 1.0 0.8 0.6 WITH 1N5817 -1.0 0.01 0.1 1 100 MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE (VOUT = 3.3V) 0.6 0.4 0.
PAGE 6
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters Typical Operating Characteristics (continued) (L = 22µH, CIN = 47µF, COUT = 47µF 0.1µF, CREF = 0.1µF, TA = +25°C, unless otherwise noted.) LOAD-TRANSIENT RESPONSE LINE-TRANSIENT RESPONSE MAX1674 TOC17 VIN = 2.4V VOUT = 3.
PAGE 7
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters Detailed Description The MAX1674/MAX1675/MAX1676 compact, step-up DC-DC converters start up with voltages as low as 0.9V and operate with an input voltage down to 0.7V.
PAGE 8
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters As a result, the synchronous rectifier significantly improves efficiency without the addition of an external component. Conversion efficiency can be as high as 94%, as shown in the Typical Operating Characteristics. For low-voltage inputs from single cells (Alkaline, NiCd, or NiMH), use an external Schottky diode such as the 1N5817 to ensure start-up. Voltage Reference The voltage at REF is nominally +1.30V.
PAGE 9
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters Selecting the Output Voltage VOUT can be set to 3.3V or 5.0V by connecting the FB pin to GND (5V) or OUT (3.3V) (Figures 5 and 6). To adjust the output voltage, connect a resistor-divider from VOUT to FB to GND (Figure 7). Choose a value less than 260kΩ for R6.
PAGE 10
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters VIN VTRIP (VH, VL) MAX1674 MAX1675 MAX1676 R3 47µF 22µH R1 200Ω VOUT OUT 47µF 0.1µF LBI BATT (MAX1676) LX VOUT OUT R3 CLSEL (MAX1676) LBI R2 100k R4 LBO 47µF 0.1µF FB GND R7 SHDN MAX1674 MAX1675 REF MAX1676 GND LBO R2 100k LOWBATTERY OUTPUT R4 0.1µF  VH = 1.3V 1 +   VL = 1.3V 1 +  ( ) R3 R3  +  R7 R4  ( ) (VOUT − 1.3V) R 3  R3 −  R4 (1.
PAGE 11
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters Table 1. Suggested Components PRODUCTION METHOD INDUCTORS RECTIFIERS (OPTIONAL) CAPACITORS Surface Mount Sumida CD43 series Sumida CD54 series Coilcraft DT1608C Coilcraft DO1608C Coiltronics Uni-PAC Murata LQH4 series Sprague 593D series Sprague 595D series AVX TPS series ceramic Miniature Through-Hole Sumida RCH654-220 Sanyo OS-CON series Table 2.
PAGE 12
MAX1674/MAX1675/MAX1676 High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters Optional External Rectifier VIN Although not required, a Schottky diode (such as the MBR0520) connected between LX and OUT allows lower start-up voltages (Figure 10) and is recommended when operating at input voltages below 1.3V. Note that adding this diode provides no significant efficiency improvement.