19-1336; Rev 2; 11/98
NUAL
KIT MA
ATION
ET
EVALU
TA SHE
WS DA
FOLLO
1-Cell to 3-Cell, High-Power (1.5A),
Low-Noise, Step-Up DC-DC Converter
____________________________Features
o
Up to 95% Efficiency
o
Up to 1.5A Output
o
Fixed 5V or Adjustable Step-Up Output
(2.5V to 5.5V)
o
0.7V to 5.5V Input Range
o
Low-Power Mode (300µW)
o
Low-Noise, Constant-Frequency Mode (300kHz)
o
Synchronizable Switching Frequency
(200kHz to 400kHz)
o
1µA Logic-Controlled Shutdown
o
Power-Good Comparator
o
Uncommitted Gain Block
________________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 gen-
erate 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 nonsyn-
chronous converters. It also features a pulse-frequency-
modulation (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.
MAX1703
Ordering Information
PART
MAX1703ESE
TEMP. RANGE
-40°C to +85°C
PIN-PACKAGE
16 Narrow SO
________________________Applications
Digital Cordless Phones
PCS Phones
Wireless Handsets
Two-Way Pagers
Personal Communicators
Palmtop Computers
Hand-Held Instruments
Typical Operating Circuit
INPUT
0.7V TO 5.5V
Pin Configuration
TOP VIEW
MAX1703
OFF
ON
PWM
OR
PFM
POWER-GOOD
INPUT
GAIN-BLOCK INPUT
POKIN
AIN
REF
FB
POK
AO
GND PGND
SYNC
ON
CLK/
SEL
OUT
LXP, LXN
POUT
OUTPUT
5V OR ADJ
UP TO 1.5A
REF 1
FB 2
POKIN 3
OUT 4
GND 5
16 ON
15 POUT
14 LXP
MAX1703
13 POUT
12 PGND
11 LXN
10 PGND
9
CLK/SEL
POWER-GOOD
OUTPUT
GAIN-BLOCK
OUTPUT
AIN 6
AO 7
POK 8
Narrow SO
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
1-Cell to 3-Cell, High-Power (1.5A),
Low-Noise, Step-Up DC-DC Converter
MAX1703
ABSOLUTE MAXIMUM RATINGS
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
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.
ELECTRICAL CHARACTERISTICS
(CLK/SEL = AIN =
ON
= POKIN = FB = PGND = GND, OUT = POUT, LXP = LXN, V
OUT
= 5.3V (Note 1),
T
A
= 0°C to +85°C,
unless
otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC-DC CONVERTER
Input Supply Range
Minimum Start-Up Voltage
Frequency in Start-Up Mode
Output Voltage
(Note 4)
FB Regulation Voltage
FB Input Current
Output Voltage Adjust Range
Output Voltage Lockout Threshold
Load Regulation (Note 6)
Supply Current in Shutdown
Supply Current in Low-Power Mode
Supply Current in Low-Noise Mode
DC-DC SWITCHES
POUT, LXP Leakage Current
LXN Leakage Current
Switch On-Resistance
Switch On-Resistance
V
LXP
= 0V, V
OUT
= V
ON
= 5.5V
V
ON
= V
LXN
= V
OUT
= 5.5V
N-channel
P-channel
N-Channel Current Limit
P-Channel Turn-Off Current
POWER-GOOD COMPARATOR
POKIN Trip Level
POKIN Input Current
POK Low Voltage
POK High Leakage Current
2
Rising V
POKIN
V
POKIN
= 0.7V
I
SINK
(POK) = 1mA, V
OUT
= 3.6V or
I
SINK
(POK) = 20µA, V
OUT
= 1V
V
OUT
= V
POK
= 5.5V
1.225
-20
0.03
0.01
1.250
1.275
20
0.4
1
V
nA
V
µA
CLK/SEL = OUT
CLK/SEL = GND
CLK/SEL = GND
2200
500
20
CLK/SEL = GND
CLK/SEL = OUT
0.1
0.1
0.14
0.075
0.13
2700
800
160
20
20
0.25
0.13
0.25
3200
1100
260
mA
mA
mA
Ω
µA
µA
(Note 5)
CLK/SEL = OUT, no load to full load
ON
= OUT
CLK/SEL = GND (Note 1)
CLK/SEL = OUT (Note 1)
(Note 2)
I
LOAD
< 1mA, T
A
= +25°C (Note 3)
V
OUT
= 1.5V
V
FB
< 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
V
FB
= 1.25V
2.5
2.0
2.15
-1.6
0.1
65
150
20
120
300
40
4.87
1.21
0.7
0.9
140
5.05
1.24
0.1
5.5
1.1
300
5.20
1.255
20
5.5
2.3
V
V
kHz
V
V
nA
V
V
%
µA
µA
µA
CONDITIONS
MIN
TYP
MAX
UNITS
_______________________________________________________________________________________
1-Cell to 3-Cell, High-Power (1.5A),
Low-Noise, Step-Up DC-DC Converter
ELECTRICAL CHARACTERISTICS (continued)
(CLK/SEL = AIN =
ON
= POKIN = FB = PGND = GND, OUT = POUT, LXP = LXN, V
OUT
= 5.3V (Note 1),
T
A
= 0°C to +85°C,
unless
otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
GAIN BLOCK
AIN Reference Voltage
AIN Input Current
Transconductance
AO Output Low Voltage
AO Output High Leakage
REFERENCE
Reference Output Voltage
REF Load Regulation
REF Supply Rejection
LOGIC INPUTS
Input Low Voltage
Input High Voltage
Logic Input Current
Internal Oscillator Frequency
Oscillator Maximum Duty Cycle
External Clock Frequency Range
Minimum CLK/SEL Pulse Width
Maximum CLK/SEL Rise/Fall Time
ON,
1.2V < V
OUT
< 5.5V (Note 7)
CLK/SEL, V
OUT
= 2.5V
ON,
1.2V < V
OUT
< 5.5V
CLK/SEL, V
OUT
= 5.5V
ON,
CLK/SEL
CLK/SEL = OUT, V
FB
= 0.5V
CLK/SEL = OUT, V
FB
= 0.5V
0.8V
OUT
0.8V
OUT
-1
260
80
200
200
100
0.01
300
86
1
340
90
400
0.2V
OUT
0.2V
OUT
V
V
V
µA
kHz
%
kHz
ns
ns
I
REF
= 0µA
-1µA < I
REF
< 50µA
2.5V < V
OUT
< 5.5V
1.237
1.250
5
0.2
1.263
15
5
V
mV
mV
I
AO
= 20µA
V
AIN
= 1.5V
10µA < I
AO
< 100µA
V
AIN
= 0.5V, I
AO
= 100µA
V
AIN
= 1.5V, V
AO
= 5.5V
1.237
-30
5
10
0.1
0.01
1.25
1.263
30
16
0.4
1
V
nA
mmho
V
µA
CONDITIONS
MIN
TYP
MAX
UNITS
MAX1703
ELECTRICAL CHARACTERISTICS
(CLK/SEL = AIN =
ON
= POKIN = FB = PGND = GND, OUT = POUT, LXP = LXN, V
OUT
= 5.3V (Note 1),
T
A
= -40°C to +85°C,
unless
otherwise noted. Typical values are at T
A
= +25°C.) (Note 8)
PARAMETER
DC-DC CONVERTER
Output Voltage (Note 4)
FB Regulation Voltage
Output Voltage Lockout Threshold
Supply Current in Shutdown
Supply Current in Low-Power Mode
Supply Current in Low-Noise Mode
V
FB
< 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
(Note 5)
ON
= OUT
CLK/SEL = GND (Note 1)
CLK/SEL = OUT (Note 1)
4.87
1.20
2.0
5.20
1.27
2.3
20
120
300
V
V
V
µA
µA
µA
CONDITIONS
MIN
TYP
MAX
UNITS
_______________________________________________________________________________________
3
1-Cell to 3-Cell, High-Power (1.5A),
Low-Noise, Step-Up DC-DC Converter
MAX1703
ELECTRICAL CHARACTERISTICS (continued)
(CLK/SEL = AIN =
ON
= POKIN = FB = PGND = GND, OUT = POUT, LXP = LXN, V
OUT
= 5.3V (Note 1),
T
A
= -40°C to +85°C,
unless
otherwise noted. Typical values are at T
A
= +25°C.) (Note 8)
PARAMETER
DC-DC SWITCHES
Switch On-Resistance
N-channel
P-channel
N-Channel Current Limit
POWER-GOOD COMPARATOR
POKIN Trip Level
GAIN BLOCK
AIN Reference Voltage
Transconductance
REFERENCE
Reference Output Voltage
LOGIC INPUTS
Internal Oscillator Frequency
Oscillator Maximum Duty Cycle
CLK/SEL = OUT, V
FB
= 0.5V
CLK/SEL = OUT, V
FB
= 0.5V
260
80
340
92
kHz
%
I
REF
= 0µA
1.23
1.27
V
I
AO
= 20µA
10µA < I
AO
< 100µA
1.23
5
1.27
16
V
mmho
Rising V
POKIN
1.225
1.275
V
CLK/SEL = OUT
CLK/SEL = GND
2200
500
CLK/SEL = GND
CLK/SEL = OUT
0.25
0.13
0.25
3600
1100
mA
mA
Ω
CONDITIONS
MIN
TYP
MAX
UNITS
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.
4
_______________________________________________________________________________________
1-Cell to 3-Cell, High-Power (1.5A),
Low-Noise, Step-Up DC-DC Converter
__________________________________________Typical Operating Characteristics
(V
IN
= +3.6V, V
OUT
= 5V, T
A
= +25°C, unless otherwise noted.)
MAX1703
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 5V)
MAX1703-01
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 3.3V)
MAX1703-02
NO-LOAD BATTERY CURRENT
vs. INPUT VOLTAGE
LOW-POWER MODE
BATTERY CURRENT (mA)
3
MAX1703-03
100
90
EFFICIENCY (%)
80
70
60
50
40
0.1
1
10
100
V
IN
= 3.6V
100
V
IN
= 2.4V
90
EFFICIENCY (%)
80
70
60
50
40
PFM
PWM
V
IN
= 1.2V
V
IN
= 0.9V
4
V
IN
= 2.4V
V
IN
= 1.2V
2
T
A
= +85°C
1
T
A
= +25°C
T
A
= -40°C
0
1
2
3
4
5
6
INPUT VOLTAGE (V)
PFM
PWM
1000
10,000
0
0.1
1
10
100
1000
10,000
LOAD CURRENT (mA)
LOAD CURRENT (mA)
SHUTDOWN SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX1703-04
START-UP VOLTAGE vs. LOAD CURRENT
MAX1703-05
REFERENCE VOLTAGE
vs. TEMPERATURE
MAX1703-06
2.5
SHUTDOWN CURRENT (µA)
2.0
1.6
1.4
1.2
1.0
0.8
0.6
1.5
T
A
= +85°C
REFERENCE VOLTAGE (V)
0.01
0.1
1
10
100
1000
START-UP VOLTAGE (V)
INCLUDES ALL EXTERNAL
COMPONENT LEAKAGES.
CAPACITOR LEAKAGE
DOMINATES AT T
A
= +85°C
2.0
1.8
V
OUT
= 5V
PWM MODE
1.2550
1.2530
1.2510
1.0
T
A
= +25°C,
T
A
= -40°C
1.2490
0.5
1.2470
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE (V)
1.2450
-40
-20
0
20
40
60
80
100
LOAD CURRENT (mA)
TEMPERATURE (°C)
REFERENCE VOLTAGE
vs. REFERENCE CURRENT
MAX1703-07
NOISE SPECTRUM
8
7
NOISE (mV
RMS
)
6
5
4
3
2
1
0
V
OUT
= 5V
V
IN
= 3.6V
I
LOAD
= 500mA
MAX1703-14
1.2520
1.2510
REFERENCE VOLTAGE (V)
1.2500
1.2490
1.2480
1.2470
1.2460
0
10
20
30
40
50
60
70
80
V
IN
= 3.6V
V
OUT
= 5V
LOW-POWER MODE
9
-1
90
100
1k
10k
100k
1M
10M
REFERENCE CURRENT (µA)
FREQUENCY (Hz)
_______________________________________________________________________________________
5
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
