Datasheet

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General Description

The MAX1763 is a high-efficiency, low-noise, step-up

DC-DC converter intended for use in battery-powered

wireless applications. This device maintains exception-

ally low quiescent supply current (110µA) despite its

high 1MHz operating frequency. Small external compo-

nents and a tiny package make this device an excellent

choice for small hand-held applications that require the

longest possible battery life.

The MAX1763 uses a synchronous-rectified pulse-

width-modulation (PWM) boost topology to generate

2.5V to 5.5V outputs from a wide range of input

sources, such as one to three alkaline or NiCd/NiMH

cells or a single Lithium-ion (Li+) cell. Maxim's propri-

etary Idle Mode™ circuitry significantly improves effi-

ciency at light load currents while smoothly transitioning

to fixed-frequency PWM operation at higher load cur-

rents to maintain excellent full-load efficiency. Low-

noise, forced-PWM mode is available for applications

that require constant-frequency operation at all load

currents. The MAX1763 may also be synchronized to

an external clock to protect sensitive frequency bands

in communications equipment.

The MAX1763 includes an on-chip linear gain block

that can be used to build a high-power external linear

regulator or as a low-battery comparator. Soft-start and

current limit functions permit optimization of efficiency,

external component size, and output voltage ripple.

The MAX1763 is available in a space-saving 16-pin

QSOP package or a high-power (1.5W) 16-pin TSSOP-

EP package.

Features

♦ Up to 94% Efficiency

♦ +0.7V to +5.5V Input Voltage Range

♦ 1.1V Guaranteed Startup Input Voltage

♦ Up to 1.5A Output

♦ Fixed 3.3V Output or Adjustable (2.5V to 5.5V)

♦ 1MHz PWM Synchronous-Rectified Topology

♦ 1µA Logic-Controlled Shutdown

♦ Analog Gain Block for Linear-Regulator or Low-

Battery Comparator

♦ Adjustable Current Limit and Soft-Start

♦ 1.5W TSSOP Package Available

MAX1763

1.5A, Low-Noise, 1MHz, Step-Up

DC-DC Converter

________________________________________________________________ Maxim Integrated Products 1

Pin Configuration

19-1698; Rev 2; 4/11

Ordering Information

+Denotes a lead(Pb)-free/RoHS-compliant package.

*EP = Exposed pad

Idle Mode is a trademark of Maxim Integrated Products.

PART TEMP RANGE PIN-PACKAGE

MAX1763EEE+ -40°C to +85°C 16 QSOP

MAX1763EUE+ -40°C to +85°C 16 TSSOP-EP*

Digital Cordless

Phones

PCS Phones

Wireless Handsets

Hand-Held

Instruments

Palmtop Computers

Personal

Communicators

Typical Operating Circuit

OFF

PWM

OFF

ONB

ONA

POUT

OUT

CLK/SEL

GND PGNDFB

ISET

REF

MAX1763

OR NORMAL

AIN

LBI OR GAIN

BLOCK INPUT

1.5μH

0.7V TO 5.5V

LBO OR

GAIN BLOCK OUTPUT

OUT

3.3V AT 1.5A

________________________Applications

ONA ONB

POUT

PGND

CLK/SEL

TOP VIEW

MAX1763

QSOP

TSSOP-EP

ISET

REF

OUT

GND

AIN

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

EVALUATION KIT

AVAILABLE

Summary of content (18 pages)

PAGE 1
9-1698; Rev 2; 4/11 KIT ATION EVALU E L B AVAILA 1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter The MAX1763 is a high-efficiency, low-noise, step-up DC-DC converter intended for use in battery-powered wireless applications. This device maintains exceptionally low quiescent supply current (110µA) despite its high 1MHz operating frequency. Small external components and a tiny package make this device an excellent choice for small hand-held applications that require the longest possible battery life.
PAGE 2
MAX1763 1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter ABSOLUTE MAXIMUM RATINGS ONA, ONB, AO, OUT to GND.......................................0.3V, +6V PGND to GND.....................................................................±0.3V LX to PGND ............................................-0.3V to (VPOUT + 0.3V) CLK/SEL, REF, FB, ISET, POUT, AIN to GND.........................................-0.3V to (VOUT + 0.3V) POUT to OUT ......................................................................±0.
PAGE 3
1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter (CLK/SEL = ONB = FB = PGND = GND, ISET = REF, OUT = POUT, VONA = VAIN = VOUT = 3.6V, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS MIN TYP MAX UNITS DC-DC SWITCHES POUT Leakage Current VLX = 0V, VOUT = 5.5V 0.1 10 µA LX Leakage Current VLX = V ONB = VOUT = 5.5V, VONA = 0V 0.1 10 µA N channel 0.075 0.13 P channel 0.13 0.
PAGE 4
MAX1763 1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter ELECTRICAL CHARACTERISTICS (CLK/SEL = ONB = FB = PGND = GND, ISET = REF, OUT = POUT, VONA = VAIN = VOUT = 3.6V, TA = -40°C to +85°C, unless otherwise noted.) (Note 8) PARAMETER CONDITIONS MIN MAX UNITS 5.5 V DC-DC CONVERTER Input Voltage Range (Note 1) Minimum Startup Voltage (Note 2) ILOAD < 1mA, TA = +25°C Frequency in Startup Mode VOUT = 1.5V 125 1.1 V kHz 0.75 1000 1.
PAGE 5
1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter (CLK/SEL = ONB = FB = PGND = GND, ISET = REF, OUT = POUT, VONA = VAIN = VOUT = 3.6V, TA = -40°C to +85°C, unless otherwise noted.) (Note 8) PARAMETER CONDITIONS MIN MAX UNITS 1.4 V LOGIC INPUTS Gain-Block Enable Threshold (VOUT - VAIN) (Note 6) Gain-Block Disable Threshold (VOUT - VAIN) (Note 6) 0.2 V (0.2) VOUT CLK/SEL Input Low Level 2.5 V ≤ VOUT ≤ 5.5V CLK/SEL Input High Level 2.5 V ≤ VOUT ≤ 5.5V ONA and ONB Input Low Level (Note 7) 1.
PAGE 6
Typical Operating Characteristics (Circuit of Figure 2, VIN = +3.6V, VOUT = +5V, TA = +25°C, unless otherwise noted.) EFFICIENCY vs. OUTPUT CURRENT (VOUT = 5V) 70 80 A B EFFICIENCY (%) C 60 50 40 A: VIN = 2.4V B: VIN = 1.2V C: VIN = 0.9V = NORMAL MODE = FPWM MODE 30 20 10 B 70 C 60 50 40 A: VIN = 3.6V B: VIN = 2.4V C: VIN = 1.2V = NORMAL MODE = FPWM MODE 30 20 10 0 3.0 2.5 0.01 0.1 1 10 VOUT = 3.3V 2.0 1.5 VOUT = 5V 1.0 0.5 0 0 0.001 0.01 0.1 1 10 0.8 1.6 2.4 3.
PAGE 7
1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter LIGHT-LOAD SWITCHING WAVEFORMS LINE-TRANSIENT RESPONSE MAX1763 toc12 MAX1763 toc11 MAX1763 toc10 LOAD-TRANSIENT RESPONSE A A A B B C B 200ns/div VIN = 1.1V, VOUT = 3.3V, IOUT = 20mA A: LX NODE, 5V/div B: INDUCTOR CURRENT, 0.1A/div, AC COUPLED C: OUTPUT RIPPLE, 0.1V/div, AC COUPLED 40μs/div VIN = 2.4V TO 1.4V, IOUT = 70mA A: VIN, 1V/div B: VOUT, 5mV/div, AC-COUPLED 100μs/div VIN = 2.4V, VOUT = 3.3V, IOUT = 0.2A TO 1.35A A: IOUT, 0.
PAGE 8
1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter MAX1763 Pin Description PIN NAME FUNCTION ONA On Control Input. When ONA = high or ONB = low, the IC turns on. Connect ONA to OUT for normal operation (Table 3). 2 ISET N-Channel Current Limit Control. For maximum current limit, connect to REF. To reduce current, supply a voltage between REF and GND by means of a resistive voltage-divider. If soft-start is desired, connect a capacitor from ISET to GND.
PAGE 9
1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter MAX1763 UNDERVOLTAGE LOCKOUT OUT IC POWER POUT CONTROLLER 2.15V EN STARTUP OSCILLATOR D Q P Q LX ONA ON ONB REF 1.25V RDY EN REFERENCE OSC EN REF GND CLK/SEL N Q 1MHz OSCILLATOR MODE DUAL MODE/ FB FB FB PGND ISET ISET AIN AO MAX1763 GAIN BLOCK N 0.938V Figure 1. Functional Diagram Table 1. Typical Available Output Current NUMBER OF CELLS 1 NiCd/NiMH INPUT VOLTAGE (V) OUTPUT VOLTAGE (V) OUTPUT CURRENT (mA) 1.2 3.
PAGE 10
MAX1763 1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter Table 2. Selecting the Operating Mode CLK/SEL MODE FEATURES 0 Normal operation High efficiency at all loads. Fixed frequency at all but light loads. 1 Forced PWM Low noise, fixed frequency at all loads. External clock 500kHz to 1.2MHz Synchronized PWM Low noise, fixed frequency at all loads.
PAGE 11
1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter ONA 0 ONB 0 MAX1763 On 0 1 Off 1 0 On 1 1 On RG 20k VIN 2.5V 1.5μH AO CLK/SEL LX 3.3V MBRO520L TO VIN OR VOUT ONB POUT MAX1763 AIN POWER-OK OUTPUT AO POUT R3 165k ONA C4 220μF R5 4.7Ω MAX1763 R6 150k R3 COUT 47μF C1 47μF OUT C2 1μF AIN R4 R4 100k Figure 3. Using the Gain Block as a Power-OK Comparator ISET REF C3 0.22μF PGND FB GND VIN 1.8V TO 5.5V CLK/SEL ONA ONB 0.22μF R5 4.7Ω C4 220μF RG 20k OUT C2 1.
PAGE 12
MAX1763 1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter The output capacitance can be determined by the function: OUT COUT ≥ [ (VREF / VOUT) ✕ GM ✕ GFS ✕ CG ✕ (RG ✕ 2) ] and COUT ≥ 10 ✕ [ (VREF / [VOUT ✕ GBP]) ✕ GM ✕ GFS ✕ RG ] where VREF is the 0.983V reference voltage, GM is the 10mS internal amplifier transconductance, GFS is the external MOSFET transconductance, RG is the gatesource resistor, and GBP is the gain-bandwidth product of the internal gain block, 63Mrad/s.
PAGE 13
1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter INDUCTORS CAPACITORS Coilcraft LPT3305 Motorola MBR0520L Kemet T510 series Sanyo POSCAP series Sumida Panasonic SP/CB Table 5. Component Suppliers DIODES AVX TPS series Nihon EP10QY03 At an ambient temperature of +70°C, continuous power dissipation for the QSSOP package is 667mW, while the TSSOP-EP can dissipate 1.5W. A first-order estimate of power dissipation can be determined by calculating the output power delivered to the load (e.g., 3.
PAGE 14
MAX1763 1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter Bypass Components A few ceramic bypass capacitors are required for proper operation. Bypass REF to GND with 0.22µF. Also, bypass OUT to GND with a 1µF ceramic capacitor, and connect OUT to POUT with a 4.7Ω resistor. Each of these components should be placed as close to their respective IC pins as possible, within 0.2in (5mm). Table 5 lists suggested suppliers. The MAX1763 TSSOP-EP package features an exposed thermal pad on its underside.
PAGE 15
1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 16 QSOP E16+1 21-0055 90-0167 16 TSSOP-EP U16E+3 21-0108 90-0120 Note: The MAX1763EEE is a 16-pin QSOP and does not have a heat slug. Use the MAX1763EUE for higher power dissipation. ______________________________________________________________________________________ 15 MAX1763 Package Information For the latest package outline information and land patterns (footprints), go to www.
PAGE 16
MAX1763 1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter Package Information (continued) For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PAGE 17
1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter ______________________________________________________________________________________ 17 MAX1763 Package Information (continued) For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PAGE 18
MAX1763 1.5A, Low-Noise, 1MHz, Step-Up DC-DC Converter Revision History REVISION NUMBER REVISION DATE DESCRIPTION PAGES CHANGED 2 4/11 Added lead-free designation, added conditions for use when VIN > VOUT, updated Pin Description section 1, 5, 8, 13 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.