19-1735; Rev 0; 7/01
1.5µA I
Q
, Step-Up DC-DC Converters
in Thin SOT23-5
General Description
The MAX1722/MAX1723/MAX1724 compact, high-effi-
ciency, step-up DC-DC converters are available in tiny, 5-
pin thin SOT23 packages. They feature an extremely low
1.5µA quiescent supply current to ensure the highest pos-
sible light-load efficiency. Optimized for operation from
one to two alkaline or nickel-metal-hydride (NiMH) cells, or
a single Li+ cell, these devices are ideal for applications
where extremely low quiescent current and ultra-small size
are critical.
Built-in synchronous rectification significantly improves
efficiency and reduces size and cost by eliminating the
need for an external Schottky diode. All three devices fea-
ture a 0.5Ω N-channel power switch. The MAX1722/
MAX1724 also feature proprietary noise-reduction circuitry,
which suppresses electromagnetic interference (EMI)
caused by the inductor in many step-up applications. The
family offers different combinations of fixed or adjustable
outputs, shutdown, and EMI reduction (see
Selector
Guide).
o
o
o
o
o
o
o
o
o
o
o
Features
Up to 90% Efficiency
No External Diode or FETs Needed
1.5µA Quiescent Supply Current
0.1µA Logic-Controlled Shutdown
±1% Output Voltage Accuracy
Fixed Output Voltage (MAX1724) or Adjustable
Output Voltage (MAX1722/MAX1723)
Up to 150mA Output Current
0.8V to 5.5V Input Voltage Range
0.91V Guaranteed Startup (MAX1722/MAX1724)
Internal EMI Suppression (MAX1722/MAX1724)
Thin SOT23-5 Package (1.1mm max Height)
MAX1722/MAX1723/MAX1724
Ordering Information
PART
MAX1722EZK-T
MAX1723EZK-T
MAX1724EZK27-T
MAX1724EZK30-T
MAX1724EZK33-T
MAX1724EZK50-T
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
5 SOT23
5 SOT23
5 SOT23
5 SOT23
5 SOT23
5 SOT23
TOP
MARK
ADQF
ADQG
ADQH
ADQI
ADQJ
ADQK
Applications
Pagers
Remote Controls
Remote Wireless
Transmitters
Personal
Medical Devices
Digital Still Cameras
Single-Cell Battery-
Powered Devices
Low-Power Hand-Held
Instruments
MP3 Players
Personal Digital
Assistants (PDA)
Selector Guide
PART
MAX1722EZK
MAX1723EZK
MAX1724EZK27
MAX1724EZK30
OUTPUT (V)
Adjustable
Adjustable
Fixed 2.7
Fixed 3.0
Fixed 3.3
Fixed 5.0
SHDN
No
Yes
Yes
Yes
Yes
Yes
LX
DAMPING
Yes
No
Yes
Yes
Yes
Yes
Typical Operating Circuit
10µH
IN
0.8V TO 5.5V
MAX1724EZK33
MAX1724EZK50
Pin Configurations
TOP VIEW
LX
BATT
BATT
1
5
LX
MAX1724
OUT
ON
OFF
OUT
SHDN
GND
3.3V AT
UP TO 150mA
GND
2
MAX1722
FB
3
4
OUT
THIN SOT23-5
Pin Configurations are continued at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
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.
1.5µA I
Q
, Step-Up DC-DC Converters
in Thin SOT23-5
MAX1722/MAX1723/MAX1724
ABSOLUTE MAXIMUM RATINGS
OUT,
SHDN,
BATT, LX to GND ................................-0.3V to +6V
FB to GND ................................................-0.3V to (V
OUT
+ 0.3V)
OUT, LX Current.......................................................................1A
Continuous Power Dissipation (T
A
= +70°C)
5-Pin Thin SOT23 (derate 7.1mW/°C above +70°C) ...571mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................ +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
(V
BATT
= 1.2V, V
OUT
= 3.3V (MAX1722/MAX1723), V
OUT
= V
OUT(NOM)
(MAX1724),
SHDN
= OUT, R
L
=
∞,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Minimum Input Voltage
Operating Input Voltage
Minimum Startup Input Voltage
V
IN
SYMBOL
CONDITIONS
MAX1722/MAX1724
T
A
= +25°C
T
A
= +25°C,
R
L
= 3kΩ
MAX1724EZK27
MAX1724EZK30
Output Voltage
V
OUT
MAX1724EZK33
MAX1724EZK50
Output Voltage Range
Feedback Voltage
Feedback Bias Current
N-Channel On-Resistance
P-Channel On-Resistance
N-Channel Switch Current Limit
Switch Maximum On-Time
Synchronous Rectifier Zero-
Crossing Current
Quiescent Current into OUT
Shutdown Current into OUT
Quiescent Current into BATT
V
OUT
V
FB
I
FB
R
DS(ON)
R
DS(ON)
I
LIM
t
ON
V
OUT
forced to 3.3V
(Notes 3, 4)
MAX1723/MAX1724
(Notes 3, 4)
MAX1722/MAX1724
(Note 4)
T
A
= +25°C
T
A
= +85°C
T
A
= +25°C
T
A
= +85°C
MAX1722/MAX1723
MAX1722/MAX1723
MAX1722/MAX1723
V
OUT
forced to 3.3V
V
OUT
forced to 3.3V
V
OUT
forced to 3.3V
400
3.5
5
T
A
= +25°C
T
A
= 0°C to +85°C
T
A
= +25°C
T
A
= +85°C
MAX1722/MAX1724
MAX1723 (Note 2)
MAX1722/MAX1724
MAX1723 (Note 2)
T
A
= +25°C
T
A
= 0°C to +85°C
T
A
= +25°C
T
A
= 0°C to +85°C
T
A
= +25°C
T
A
= 0°C to +85°C
T
A
= +25°C
T
A
= 0°C to +85°C
2.673
2.633
2.970
2.925
3.267
3.218
4.950
4.875
2
1.223
1.210
1.5
2.2
0.5
1.0
500
5
20
1.5
0.01
0.1
0.001
0.01
0.5
1.0
2.0
600
6.5
35
3.6
0.5
1.235
5.0
3.3
3.0
0.91
1.2
0.83
0.87
2.7
MIN
TYP
0.8
5.5
5.5
0.91
1.2
2.727
2.767
3.030
3.075
3.333
3.383
5.050
5.125
5.5
1.247
1.260
20
V
V
nA
Ω
Ω
mA
µs
mA
µA
µA
µA
V
MAX
UNITS
V
V
V
2
_______________________________________________________________________________________
1.5µA I
Q
, Step-Up DC-DC Converters
in Thin SOT23-5
ELECTRICAL CHARACTERISTICS (continued)
(V
BATT
= 1.2V, V
OUT
= 3.3V (MAX1722/MAX1723), V
OUT
= V
OUT(NOM)
(MAX1724),
SHDN
= OUT, R
L
=
∞,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Shutdown Current into BATT
SHDN
Voltage Threshold
SHDN
Input Bias Current
V
IL
V
IH
SYMBOL
CONDITIONS
MAX1724 (Note 4)
MAX1723/MAX1724
MAX1723/MAX1724
MAX1723/MAX1724,
V
SHDN
= 5.5V
T
A
= +25°C
T
A
= +85°C
T
A
= +25°C
T
A
= +85°C
75
MIN
TYP
0.001
0.01
400
500
2
7
800
100
MAX
0.5
UNITS
µA
mV
nA
MAX1722/MAX1723/MAX1724
ELECTRICAL CHARACTERISTICS
(V
BATT
= 1.2V, V
OUT
= 3.3V (MAX1722/MAX1723), V
OUT
= V
OUT(NOM)
(MAX1724),
SHDN
= OUT, R
L
=
∞,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MAX1724EZK27
Output Voltage
V
OUT
MAX1724EZK30
MAX1724EZK33
MAX1724EZK50
Output Voltage Range
Feedback Voltage
N-Channel On-Resistance
P-Channel On-Resistance
N-Channel Switch Current Limit
Switch Maximum On-Time
Synchronous Rectifier Zero-
Crossing Current
Quiescent Current into OUT
SHDN
Voltage Threshold
V
IL
V
IH
V
OUT
V
FB
R
DS(ON)
R
DS(ON)
I
LIM
t
ON
V
OUT
forced to 3.3V
(Notes 3,4)
MAX1723/MAX1724
MAX1723/MAX1724
75
800
MAX1722/MAX1723
MAX1722/MAX1723
V
OUT
forced to 3.3V
V
OUT
forced to 3.3V
V
OUT
forced to 3.3V
400
3.5
5
MIN
2.633
2.925
3.218
4.875
2
1.200
TYP
MAX
2.767
3.075
3.383
5.125
5.5
1.270
1.0
2.0
620
6.5
35
3.6
V
V
Ω
Ω
mA
µs
mA
µA
mV
V
UNITS
Note 1:
Limits are 100% production tested at T
A
= +25°C. Limits over the operating temperature range are guaranteed by design.
Note 2:
Guaranteed with the addition of a Schottky MBR0520L external diode between LX and OUT when using the MAX1723
with only one cell, and assumes a 0.3V voltage drop across the Schottky diode (see Figure 3).
Note 3:
Supply current is measured with an ammeter between the output and OUT pin. This current correlates directly with actual
battery supply current, but is reduced in value according to the step-up ratio and efficiency.
Note 4:
V
OUT
forced to the following conditions to inhibit switching: V
OUT
= 1.05
✕
V
OUT(NOM)
(MAX1724), V
OUT
= 3.465V
(MAX1722/MAX1723).
_______________________________________________________________________________________
3
1.5µA I
Q
, Step-Up DC-DC Converters
in Thin SOT23-5
MAX1722/MAX1723/MAX1724
Typical Operating Characteristics
(Figure 3 (MAX1723), Figure 7 (MAX1722), Figure 8 (MAX1724), V
BATT
= V
IN
= 1.5V, L = 10µH, C
IN
= 10µF, C
OUT
= 10µF, T
A
= +25°C,
unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 5.0V)
MAX1722 toc01
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 3.3V)
MAX1722 toc02
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 2.5V)
MAX1722 toc03
100
V
IN
= 2.0V
V
IN
= 3.3V
V
IN
= 4.0V
100
V
IN
= 2.5V
100
90
EFFICIENCY (%)
90
EFFICIENCY (%)
80
V
IN
= 2.0V
90
EFFICIENCY (%)
V
IN
= 2.0V
80
V
IN
= 1.5V
80
70
V
IN
= 1.0V
V
IN
= 1.5V
L = DO1606
50
0.01
0.1
1
10
100
1000
LOAD CURRENT (mA)
70
70
60
60
V
IN
= 1.5V
0.01
0.1
1
V
IN
= 1.0V
L = DO1606
60
V
IN
= 1.0V
50
0.01
0.1
1
10
L = DO1606
100
1000
50
10
100
1000
LOAD CURRENT (mA)
LOAD CURRENT (mA)
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE
MAX1722 toc04
STARTUP VOLTAGE
vs. LOAD CURRENT
2.2
STARTUP VOLTAGE (V)
2.0
1.8
1.6
1.4
1.2
1.0
0.8
RESISTIVE LOAD
V
OUT
= 5.0V
MAX1722 toc05
QUIESCENT CURRENT INTO OUT
vs. OUTPUT VOLTAGE
1.8
1.6
QUIESCENT CURRENT (µA)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
NO LOAD
MAX1722 toc06
MAX1722 toc08
200
V
OUT
= 2.5V
160
I
OUT(MAX)
(mA)
2.4
2.0
120
V
OUT
= 5.0V
80
V
OUT
= 3.3V
40
0
0
1
2
3
4
5
INPUT VOLTAGE (V)
0.6
0.01
0.1
1
LOAD CURRENT (mA)
10
100
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
OUTPUT VOLTAGE (V)
STARTUP VOLTAGE vs.
TEMPERATURE
NO LOAD
1.0
STARTUP VOLTAGE (V)
0.8
0.6
0.4
0.2
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
MAX1722 toc07
SWITCHING WAVEFORMS
1.2
I
LX
500mA/div
V
OUT
50mV/div
V
LX
2V/div
1µs/div
I
OUT
= 50mA, V
OUT
= 5.0V, V
IN
= 3.3V
4
_______________________________________________________________________________________
1.5µA I
Q
, Step-Up DC-DC Converters
in Thin SOT23-5
MAX1722/MAX1723/MAX1724
Typical Operating Characteristics (continued)
(Figure 3 (MAX1723), Figure 7 (MAX1722), Figure 8 (MAX1724), V
BATT
= V
IN
= 1.5V, L = 10µH, C
IN
= 10µF, C
OUT
= 10µF, T
A
= +25°C,
unless otherwise noted.)
LOAD-TRANSIENT RESPONSE
MAX1722 toc09
SHUTDOWN RESPONSE
MAX1722 toc10
3.3V
5V
A
V
OUT
2V/div
0
50mA
B
0
0
2V
V
SHDN
1V/div
A: V
OUT
, 50mV/div
B: I
OUT
, 20mA/div
200µs/div
1ms/div
V
IN
= 3.3V, V
OUT
= 5.0V, R
OUT
= 100Ω
SHUTDOWN INPUT THRESHOLD
vs. TEMPERATURE
0.7
SHUTDOWN THRESHOLD (mV)
0.6
RISING EDGE
0.5
0.4
FALLING EDGE
0.3
0.2
0.1
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
MAX1722 toc11
0.8
Pin Description
PIN
NAME
MAX1722
1
—
2
3
4
5
MAX1723
—
1
2
3
4
5
MAX1724
1
3
2
—
4
5
BATT
SHDN
GND
FB
OUT
LX
Battery Input and Damping Switch Connection
Shutdown Input. Drive high for normal operation. Drive low for shutdown.
Ground
Feedback Input to Set Output Voltage. Use a resistor-divider network to
adjust the output voltage. See
Setting the Output Voltage
section.
Power Output. OUT also provides bootstrap power to the IC.
Internal N-channel MOSFET Switch Drain and P-Channel Synchronous
Rectifier Drain
5
FUNCTION
_______________________________________________________________________________________
