MAXIM MAX1703 User Manual

________________General Description

The MAX1703 is a high-efficiency, low-noise, step-up
DC-DC converter intended for use in battery-powered
wireless applications. It uses a synchronous-rectified
pulse-width-modulation (PWM) boost topology to gen­erate a 2.5V to 5.5V output from battery inputs, such as
one to three NiCd/NiMH cells or one Li-Ion cell. The
device includes a 2A, 75mΩ, N-channel MOSFET
switch and a 140mΩ, P-channel synchronous rectifier.

With its internal synchronous rectifier, the MAX1703
delivers up to 5% better efficiency than similar nonsyn­chronous converters. It also features a pulse-frequency­modulation (PFM) low-power mode to improve efficiency
at light loads, and a 1µA shutdown mode.

The MAX1703 comes in a 16-pin narrow SO package
and includes an uncommitted comparator that generates
a power-good or low-battery-warning output. It also
contains a linear gain block that can be used to build a
linear regulator.

For lower-power outputs and a smaller package, refer
to the MAX1700/MAX1701. For dual outputs (step-up
plus linear regulator), refer to the MAX1705/MAX1706.
For an on-board analog-to-digital converter, refer to the
MAX848/MAX849.

The MAX1703 evaluation kit is available to speed designs.

____________________________Features

♦ Up to 95% Efficiency
♦ Up to 1.5A Output
♦ Fixed 5V or Adjustable Step-Up Output

(2.5V to 5.5V)

♦ 0.7V to 5.5V Input Range
♦ Low-Power Mode (300µW)
♦ Low-Noise, Constant-Frequency Mode (300kHz)
♦ Synchronizable Switching Frequency

(200kHz to 400kHz)

♦ 1µA Logic-Controlled Shutdown
♦ Power-Good Comparator
♦ Uncommitted Gain Block

________________________Applications

Digital Cordless Phones Personal Communicators
PCS Phones Palmtop Computers
Wireless Handsets Hand-Held Instruments
Two-Way Pagers

MAX1703

1-Cell to 3-Cell, High-Power (1.5A),

Low-Noise, Step-Up DC-DC Converter

________________________________________________________________

Maxim Integrated Products

1

19-1336; Rev 2; 11/98

EVALUATION KIT MANUAL

FOLLOWS DATA SHEET

Ordering Information

Typical Operating Circuit

PART TEMP. RANGE

PIN-PACKAGE

MAX1703ESE -40°C to +85°C 16 Narrow SO

PGNDGNDFB

POUT

OUT

LXP, LXN

OFF

INPUT

0.7V TO 5.5V

OR

ON

SYNC

PWM

PFM

OUTPUT

5V OR ADJ

UP TO 1.5A

CLK/
SEL

ON

POKIN

POK

AO

AIN

REF

POWER-GOOD

INPUT

POWER-GOOD
OUTPUT

GAIN-BLOCK INPUT

GAIN-BLOCK
OUTPUT

MAX1703

Pin Configuration

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

REF ON

POUT

LXP

POUT

PGND

LXN

PGND

CLK/SEL

TOP VIEW

MAX1703

Narrow SO

FB

POKIN

AIN

OUT

GND

AO

POK

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone].

Switch On-Resistance

MAX1703

1-Cell to 3-Cell, High-Power (1.5A),
Low-Noise, Step-Up DC-DC Converter

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(CLK/SEL = AIN = ON = POKIN = FB = PGND = GND, OUT = POUT, LXP = LXN, V

OUT

= 5.3V (Note 1), TA= 0°C to +85°C, unless

otherwise noted. Typical values are at T

A

= +25°C.)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

OUT, ON, AO, POK to GND .....................................-0.3V to +6V

PGND to GND.....................................................................±0.3V

LXP, LXN to PGND .................................-0.3V to (V

POUT

+ 0.3V)

POUT, CLK/SEL, AIN, REF, FB,

POKIN to GND.......................................-0.3V to (V

OUT

+ 0.3V)

Continuous Power Dissipation (T

A

= +70°C)

Narrow SO (derate 8.70mW/°C above +70°C) .............696mW

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +160°C

Lead Temperature (soldering, 10sec) .............................+300°C

I

LOAD

< 1mA, TA= +25°C (Note 3)

CLK/SEL = GND

CLK/SEL = GND

(Note 2)

CLK/SEL = OUT

N-channel

VON= V

LXN

= V

OUT

= 5.5V

ON = OUT

CLK/SEL = OUT, no load to full load

V

LXP

= 0V, V

OUT

= VON= 5.5V

(Note 5)

V

OUT

= 1.5V

VFB< 0.1V, CLK/SEL = OUT,
0 ≤ I

LX

≤ 1.1A, V

BATT

= 3.7V

Adjustable output, CLK/SEL = OUT,
0 ≤ I

LX

≤ 1.1A, V

BATT

= 2.2V, V

OUT

= 3.3V

CLK/SEL = OUT (Note 1)

VFB= 1.25V

CLK/SEL = GND (Note 1)

CONDITIONS

mA20 160 260P-Channel Turn-Off Current

mA500 800 1100

N-Channel Current Limit

mA2200 2700 3200

0.075 0.13 Ω

0.14 0.25

µA0.1 20LXN Leakage Current

µA0.1 20POUT, LXP Leakage Current

µA150 300Supply Current in Low-Noise Mode

µA65 120Supply Current in Low-Power Mode

V0.9 1.1Minimum Start-Up Voltage

V0.7 5.5Input Supply Range

µA0.1 20Supply Current in Shutdown

%-1.6Load Regulation (Note 6)

V2.0 2.15 2.3Output Voltage Lockout Threshold

V2.5 5.5Output Voltage Adjust Range

kHz40 140 300Frequency in Start-Up Mode

V4.87 5.05 5.20

Output Voltage
(Note 4)

V1.21 1.24 1.255FB Regulation Voltage

nA0.1 20FB Input Current

UNITSMIN TYP MAXPARAMETER

P-channel 0.13 0.25

Switch On-Resistance

CLK/SEL = GND
CLK/SEL = OUT

Rising V

POKIN

V1.225 1.250 1.275POKIN Trip Level

V

POKIN

= 0.7V nA-20 20POKIN Input Current

I

SINK

(POK) = 1mA, V

OUT

= 3.6V or

I

SINK

(POK) = 20µA, V

OUT

= 1V

V0.03 0.4POK Low Voltage

V

OUT

= V

POK

= 5.5V µA0.01 1POK High Leakage Current

DC-DC CONVERTER

DC-DC SWITCHES

POWER-GOOD COMPARATOR

V

MAX1703

1-Cell to 3-Cell, High-Power (1.5A),

Low-Noise, Step-Up DC-DC Converter

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(CLK/SEL = AIN = ON = POKIN = FB = PGND = GND, OUT = POUT, LXP = LXN, V

OUT

= 5.3V (Note 1), TA= 0°C to +85°C, unless

otherwise noted. Typical values are at T

A

= +25°C.)

CLK/SEL = OUT, VFB= 0.5V

CLK/SEL = OUT, VFB= 0.5V

ON, CLK/SEL

CLK/SEL, V

OUT

= 5.5V

CLK/SEL, V

OUT

= 2.5V

ON, 1.2V < V

OUT

< 5.5V (Note 7)

V

AIN

= 1.5V, VAO= 5.5V

V

AIN

= 0.5V, IAO= 100µA

2.5V < V

OUT

< 5.5V

-1µA < I

REF

< 50µA

10µA < IAO< 100µA

V

AIN

= 1.5V

I

REF

= 0µA

IAO= 20µA

CONDITIONS

kHz200 400External Clock Frequency Range

%80 86 90Oscillator Maximum Duty Cycle

kHz260 300 340Internal Oscillator Frequency

µA-1 0.01 1Logic Input Current

V

0.8V

OUT

Input High Voltage

V

0.2V

OUT

Input Low Voltage

0.2V

OUT

mV0.2 5REF Supply Rejection

mV515REF Load Regulation

V1.237 1.250 1.263Reference Output Voltage

µA0.01 1AO Output High Leakage

V0.1 0.4AO Output Low Voltage

mmho51016Transconductance

nA-30 30AIN Input Current

V1.237 1.25 1.263AIN Reference Voltage

UNITSMIN TYP MAXPARAMETER

ns100Maximum CLK/SEL Rise/Fall Time

ns200Minimum CLK/SEL Pulse Width

ELECTRICAL CHARACTERISTICS

(CLK/SEL = AIN = ON = POKIN = FB = PGND = GND, OUT = POUT, LXP = LXN, V

OUT

= 5.3V (Note 1), TA= -40°C to +85°C, unless

otherwise noted. Typical values are at T

A

= +25°C.) (Note 8)

ON = OUT

(Note 5)

VFB< 0.1V, CLK/SEL = OUT,
0 ≤ I

LX

≤ 1.1A, V

BATT

= 3.7V

Adjustable output, CLK/SEL = OUT,
0 ≤ I

LX

≤ 1.1A, V

OUT

= 3.3V, V

BATT

= 2.2V

CLK/SEL = OUT (Note 1)

CLK/SEL = GND (Note 1)

CONDITIONS

µA300Supply Current in Low-Noise Mode

µA120Supply Current in Low-Power Mode

µA20Supply Current in Shutdown

V2.0 2.3Output Voltage Lockout Threshold

V4.87 5.20Output Voltage (Note 4)

V1.20 1.27FB Regulation Voltage

UNITSMIN TYP MAXPARAMETER

DC-DC CONVERTER

ON, 1.2V < V

OUT

< 5.5V

0.8V

OUT

GAIN BLOCK

REFERENCE

LOGIC INPUTS

MAX1703

1-Cell to 3-Cell, High-Power (1.5A),
Low-Noise, Step-Up DC-DC Converter

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(CLK/SEL = AIN = ON = POKIN = FB = PGND = GND, OUT = POUT, LXP = LXN, V

OUT

= 5.3V (Note 1), TA= -40°C to +85°C, unless

otherwise noted. Typical values are at T

A

= +25°C.) (Note 8)

CLK/SEL = GND
CLK/SEL = OUT

CLK/SEL = GND

CLK/SEL = OUT

N-channel

CONDITIONS

P-channel

Rising V

POKIN

V1.225 1.275POKIN Trip Level

0.25

Switch On-Resistance

mA500 1100

N-Channel Current Limit

mA2200 3600

0.13

IAO= 20µA

Ω

0.25

V1.23 1.27AIN Reference Voltage

UNITSMIN TYP MAXPARAMETER

Note 1: Supply current from the 5.05V output is measured between the 5.05V output and the OUT pin. This current correlates

directly to the actual battery supply current, but is reduced in value according to the step-up ratio and efficiency. Set
V

OUT

= 5.3V to keep the internal switch open when measuring the device operating current.

Note 2: Minimum operating voltage. Since the regulator is bootstrapped to the output, once started it will operate down to a 0.7V

input.

Note 3: Start-up is tested with the circuit of Figure 2.
Note 4: In low-power mode (CLK/SEL = GND) the output voltage regulates 1% higher than low-noise mode (CLK/SEL = OUT or

synchronized).

Note 5: The regulator is in start-up mode until this voltage is reached. Do not apply full-load current below this voltage.
Note 6: Load regulation is measured from no-load to full load, where full load is determined by the N-channel switch current limit.
Note 7: The ON input has a total hysteresis of approximately 0.15 x V

OUT

.

Note 8: Specifications to -40°C are guaranteed by design and not production tested.

10µA < IAO< 100µA mmho516Transconductance

I

REF

= 0µA V1.23 1.27Reference Output Voltage

CLK/SEL = OUT, VFB= 0.5V kHz260 340Internal Oscillator Frequency
CLK/SEL = OUT, VFB= 0.5V %80 92Oscillator Maximum Duty Cycle

DC-DC SWITCHES

POWER-GOOD COMPARATOR

GAIN BLOCK

REFERENCE

LOGIC INPUTS

MAX1703

1-Cell to 3-Cell, High-Power (1.5A),

Low-Noise, Step-Up DC-DC Converter

_______________________________________________________________________________________

5

100

40

0.1 1 10 100 1000 10,000

EFFICIENCY vs. LOAD CURRENT

(V

OUT

= 5V)

50

MAX1703-01

LOAD CURRENT (mA)

EFFICIENCY (%)

60

80

70

90

VIN = 3.6V

VIN = 2.4V

VIN = 1.2V

PFM
PWM

100

40

0.1 1 10 100 1000 10,000

EFFICIENCY vs. LOAD CURRENT

(V

OUT

= 3.3V)

50

MAX1703-02

LOAD CURRENT (mA)

EFFICIENCY (%)

60

80

70

90

VIN = 2.4V

VIN = 1.2V

VIN = 0.9V

PFM
PWM

0

1

2

3

4

03412 56

NO-LOAD BATTERY CURRENT

vs. INPUT VOLTAGE

MAX1703-03

INPUT VOLTAGE (V)

BATTERY CURRENT (mA)

TA = +85°C

LOW-POWER MODE

TA = +25°C

TA = -40°C

0

0.5

1.0

2.0

1.5

2.5

0.5 3.0 3.5 4.01.0 1.5 2.0 2.5 4.5 5.0 5.5

SHUTDOWN SUPPLY CURRENT

vs. INPUT VOLTAGE

MAX1703-04

INPUT VOLTAGE (V)

SHUTDOWN CURRENT (µA)

TA = +85°C

INCLUDES ALL EXTERNAL
COMPONENT LEAKAGES.
CAPACITOR LEAKAGE
DOMINATES AT T

A

= +85°C

TA = +25°C,
T

A

= -40°C

1.2460

1.2470

1.2490

1.2480

1.2500

1.2510

1.2520

0 4050 607010 20 30 80 90

REFERENCE VOLTAGE

vs. REFERENCE CURRENT

MAX1703-07

REFERENCE CURRENT (µA)

REFERENCE VOLTAGE (V)

VIN = 3.6V
V

OUT

= 5V

LOW-POWER MODE

2.0

0.6

0.01 0.1 1 10 100 1000

START-UP VOLTAGE vs. LOAD CURRENT

0.8

MAX1703-05

LOAD CURRENT (mA)

START-UP VOLTAGE (V)

1.0

1.2

1.6

1.4

1.8

V

OUT

= 5V

PWM MODE

1.2450

1.2490

1.2470

1.2510

1.2530

1.2550

-40 20 40 60-20 0 80 100

REFERENCE VOLTAGE

vs. TEMPERATURE

MAX1703-06

TEMPERATURE (°C)

REFERENCE VOLTAGE (V)

9

100 1k 10k 100k 1M 10M

NOISE SPECTRUM

1

0

-1

MAX1703-14

FREQUENCY (Hz)

NOISE (mV

RMS

)

2

6

7

5

4

3

8

V

OUT

= 5V

V

IN

= 3.6V

I

LOAD

= 500mA

__________________________________________Typical Operating Characteristics

(VIN= +3.6V, V

OUT

= 5V, TA = +25°C, unless otherwise noted.)