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 0.5ΩN-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).
Applications
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
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
________________________________________________________________ Maxim Integrated Products 1
GND
OUTFB
15LXBATT
MAX1722
THIN SOT23-5
TOP VIEW
2
34
LX
OUT
IN
0.8V TO 5.5V
3.3V AT
UP TO 150mA
ON OFF
BATT
MAX1724
SHDN
GND
10µH
OUT
Typical Operating Circuit
19-1735; Rev 0; 7/01
Ordering Information
Selector Guide
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)
Pin Configurations are continued at end of data sheet.
PART
MAX1722EZK
MAX1723EZK
MAX1724EZK27 Fixed 2.7
Adjustable
Adjustable
OUTPUT (V) SHDN
No
Yes
Yes
MAX1724EZK30
MAX1724EZK33
MAX1724EZK50 Fixed 5.0
Fixed 3.3
Fixed 3.0 Yes
Yes
Yes
LX
DAMPING
Yes
No
Yes
Yes
Yes
Yes
ADQK
ADQJ
ADQI
ADQH
ADQG
ADQF
TOP
MARK
5 SOT23
5 SOT23
5 SOT23-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
MAX1724EZK50-T
MAX1724EZK33-T
MAX1724EZK30-T
5 SOT23
5 SOT23
5 SOT23
PIN-
PACKAGE
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
MAX1724EZK27-T
MAX1723EZK-T
MAX1722EZK-T
PART
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.
Pin Configurations
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VBATT = 1.2V, VOUT = 3.3V (MAX1722/MAX1723), VOUT = VOUT(NOM) (MAX1724), SHDN = OUT, RL= ∞, TA= 0°C to +85°C,
unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
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, SHDN, BATT, LX to GND ................................-0.3V to +6V
FB to GND ................................................-0.3V to (VOUT + 0.3V)
OUT, LX Current.......................................................................1A
Continuous Power Dissipation (TA= +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
TA= +85°C
TA= +25°C
TA= 0°C to +85°C
TA= +25°C
TA= 0°C to +85°C
TA= +25°C
TA= 0°C to +85°C
TA= +25°C
TA= 0°C to +85°C
TA= +25°C
TA= 0°C to +85°C
TA= +25°C
MAX1723 (Note 2)
MAX1722/MAX1724
Shutdown Current into OUT 0.1 µA
Quiescent Current into OUT 1.5 3.6 µA
Quiescent Current into BATT 0.01 µA
MAX1723/MAX1724
(Notes 3, 4)
(Notes 3, 4)
MAX1722/MAX1724
(Note 4)
PARAMETER SYMBOL MIN TYP MAX UNITS
2.633 2.767
Output Voltage VOUT
2.673 2.7 2.727
V
0.87 1.2
Minimum Startup Input Voltage 0.83 0.91 V
2.970 3.0 3.030
2.925 3.075
3.267 3.3 3.333
3.218 3.383
Operating Input Voltage
Minimum Input Voltage 0.8 V
VIN
0.91 5.5 V
1.2 5.5
4.950 5.0 5.050
4.875 5.125
Output Voltage Range VOUT 2 5.5 V
Feedback Voltage VFB
1.223 1.235 1.247 V
1.210 1.260
Feedback Bias Current IFB
1.5 20 nA
2.2
N-Channel On-Resistance RDS(ON) 0.5 1.0 Ω
P-Channel On-Resistance RDS(ON) 1.0 2.0 Ω
N-Channel Switch Current Limit ILIM 400 500 600 mA
Switch Maximum On-Time tON 3.5 5 6.5 µs
Synchronous Rectifier Zero-
Crossing Current 52035
mA
CONDITIONS
MAX1724EZK50
MAX1724EZK27
TA= +25°C,
RL= 3kΩ
MAX1724EZK30
MAX1722/MAX1723
MAX1722/MAX1723
MAX1724EZK33
MAX1722/MAX1723
MAX1722/MAX1724
VOUT forced to 3.3V
TA= +25°C
VOUT forced to 3.3V
VOUT forced to 3.3V
VOUT forced to 3.3V
MAX1722/MAX1724
MAX1723 (Note 2)
TA= +85°C
TA= +25°C 0.01 0.5
TA= +85°C
TA= +25°C 0.001 0.5
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VBATT = 1.2V, VOUT = 3.3V (MAX1722/MAX1723), VOUT = VOUT(NOM) (MAX1724), SHDN = OUT, RL= ∞, TA= 0°C to +85°C,
unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
Note 1: Limits are 100% production tested at TA= +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: VOUT forced to the following conditions to inhibit switching: VOUT = 1.05 ✕VOUT(NOM) (MAX1724), VOUT = 3.465V
(MAX1722/MAX1723).
VIL MAX1723/MAX1724
TA= +85°C
TA= +25°C
TA= +85°C
TA= +25°C 0.001 0.5
SHDN Voltage Threshold VIH 500 800 mV
Shutdown Current into BATT 0.01 µA
SHDN Input Bias Current 7nA
MAX1724 (Note 4)
MAX1723/MAX1724,
VSHDN = 5.5V
PARAMETER SYMBOL MIN TYP MAX UNITSCONDITIONS
MAX1723/MAX1724
75 400
2 100
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX1724EZK27 2.633 2.767
MAX1724EZK30 2.925 3.075
MAX1724EZK33 3.218 3.383
O utp ut V ol tag eV
OUT
MAX1724EZK50 4.875 5.125
V
O utp ut V ol tag e Rang eV
OUT MAX1722/MAX1723 2 5.5 V
Feedback Voltage VFB MAX1722/MAX1723 1.200 1.270 V
N-Channel On-Resistance RDS(ON) VOUT forced to 3.3V 1.0 Ω
P-Channel On-Resistance RDS(ON) VOUT forced to 3.3V 2.0 Ω
N-Channel Switch Current Limit ILIM VOUT forced to 3.3V 400 620 mA
Switch Maximum On-Time tON 3.5 6.5 µs
Synchronous Rectifier Zero-
Crossing Current VOUT forced to 3.3V 5 35 mA
Quiescent Current into OUT (Notes 3,4) 3.6 µA
VIL MAX1723/MAX1724 75
SHDN Voltage Threshold VIH MAX1723/MAX1724 800 mV
ELECTRICAL CHARACTERISTICS
(VBATT = 1.2V, VOUT = 3.3V (MAX1722/MAX1723), VOUT = VOUT(NOM) (MAX1724), SHDN = OUT, RL= ∞, TA= -40°C to +85°C,
unless otherwise noted.) (Note 1)
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
4 _______________________________________________________________________________________
Typical Operating Characteristics
(Figure 3 (MAX1723), Figure 7 (MAX1722), Figure 8 (MAX1724), VBATT = VIN = 1.5V, L = 10µH, CIN = 10µF, COUT = 10µF, TA= +25°C,
unless otherwise noted.)
0
40
120
80
160
200
021345
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE
MAX1722 toc04
INPUT VOLTAGE (V)
IOUT(MAX) (mA)
VOUT = 2.5V
VOUT = 5.0V
VOUT = 3.3V
10 100
0.8
1.0
1.2
1.4
1.6
2.0
1.8
2.2
2.4
0.01 0.1 1
STARTUP VOLTAGE
vs. LOAD CURRENT
MAX1722 toc05
LOAD CURRENT (mA)
STARTUP VOLTAGE (V)
0.6
RESISTIVE LOAD
VOUT = 5.0V
0
0.4
0.2
0.8
0.6
1.2
1.0
1.4
1.8
1.6
2.0
1.0 2.0 2.5 3.01.5 3.5 4.0 4.5 5.0 5.5
MAX1722 toc06
QUIESCENT CURRENT (µA)
OUTPUT VOLTAGE (V)
QUIESCENT CURRENT INTO OUT
vs. OUTPUT VOLTAGE
NO LOAD
100
0.01 0.1 1 10 100 1000
EFFICIENCY vs. LOAD CURRENT
(VOUT = 5.0V)
MAX1722 toc01
LOAD CURRENT (mA)
EFFICIENCY (%)
60
80
50
70
90 VIN = 2.0V VIN = 3.3V VIN = 4.0V
VIN = 1.5V
VIN = 1.0V
L = DO1606
100
0.01 0.1 1 10 100 1000
EFFICIENCY vs. LOAD CURRENT
(VOUT = 3.3V)
MAX1722 toc02
LOAD CURRENT (mA)
EFFICIENCY (%)
60
80
50
70
90 VIN = 2.0V VIN = 2.5V
VIN = 1.5V
VIN = 1.0V
L = DO1606
100
0.01 0.1 1 10 100 1000
EFFICIENCY vs. LOAD CURRENT
(VOUT = 2.5V)
MAX1722 toc03
LOAD CURRENT (mA)
EFFICIENCY (%)
60
80
50
70
90
VIN = 1.5V
VIN = 2.0V
VIN = 1.0V L = DO1606
0
0.4
0.2
0.8
0.6
1.0
1.2
-40 85
STARTUP VOLTAGE vs.
TEMPERATURE
MAX1722 toc07
TEMPERATURE (°C)
STARTUP VOLTAGE (V)
10-15 35 60
NO LOAD
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
_______________________________________________________________________________________ 5
Pin Description
1ms/div
VSHDN
1V/div
5V
0
0
2V
SHUTDOWN RESPONSE
MAX1722 toc10
VIN = 3.3V, VOUT = 5.0V, ROUT = 100Ω
VOUT
2V/div
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
-40 -15 10 35 60 85
SHUTDOWN INPUT THRESHOLD
vs. TEMPERATURE
MAX1722 toc11
TEMPERATURE (°C)
SHUTDOWN THRESHOLD (mV)
RISING EDGE
FALLING EDGE
Typical Operating Characteristics (continued)
(Figure 3 (MAX1723), Figure 7 (MAX1722), Figure 8 (MAX1724), VBATT = VIN = 1.5V, L = 10µH, CIN = 10µF, COUT = 10µF, TA= +25°C,
unless otherwise noted.)
MAX1724MAX1722 MAX1723
OUT
LX
FB
GND
SHDN
BATT
NAME
4
5
—
2
3
1
Power Output. OUT also provides bootstrap power to the IC.44
Internal N-channel MOSFET Switch Drain and P-Channel Synchronous
Rectifier Drain
55
Feedback Input to Set Output Voltage. Use a resistor-divider network to
adjust the output voltage. See Setting the Output Voltage section.
33
Ground22
PIN
Shutdown Input. Drive high for normal operation. Drive low for shutdown.1—
Battery Input and Damping Switch Connection—1
FUNCTION
200µs/div
A
A: VOUT, 50mV/div
B: IOUT, 20mA/div
B
LOAD-TRANSIENT RESPONSE
MAX1722 toc09
3.3V
50mA
0
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
6 _______________________________________________________________________________________
Detailed Description
The MAX1722/MAX1723/MAX1724 compact, high-effi-
ciency, step-up DC-DC converters are guaranteed to
start up with voltages as low as 0.91V and operate with
an input voltage down to 0.8V. Consuming only 1.5µA of
quiescent current, these devices include a built-in syn-
chronous rectifier that reduces cost by eliminating the
need for an external diode and improves overall efficien-
cy by minimizing losses in the circuit (see Synchronous
Rectification section). The MAX1722/MAX1724 feature a
clamp circuit that reduces EMI due to inductor ringing.
The MAX1723/MAX1724 feature an active-low shutdown
that reduces quiescent supply current to 0.1µA. The
MAX1722/MAX1723 have an adjustable output voltage,
while the MAX1724 is available with four fixed-output
voltage options (see Selector Guide). Figure 1 is the
MAX1723 simplified functional diagram and Figure 2 is
the MAX1724 simplified functional diagram.
PFM Control Scheme
A forced discontinuous, current-limited, pulse-frequency-
modulation (PFM) control scheme is a key feature of the
MAX1722/MAX1723/MAX1724. This scheme provides
ultra-low quiescent current and high efficiency over a
wide output current range. There is no oscillator; the
inductor current is limited by the 0.5A N-channel cur-
rent limit or by the 5µs switch maximum on-time.
Following each on cycle, the inductor current must
ramp to zero before another cycle may start. When the
error comparator senses that the output has fallen
below the regulation threshold, another cycle begins.
Synchronous Rectification
The internal synchronous rectifier eliminates the need
for an external Schottky diode, thus reducing cost and
board space. While the inductor discharges, the P-
channel MOSFET turns on and shunts the MOSFET
body diode. As a result, the rectifier voltage drop is sig-
nificantly reduced, improving efficiency without the
addition of external components.
Low-Voltage Startup Circuit
The MAX1722/MAX1723/MAX1724 contain a low-volt-
age startup circuit to control DC-DC operation until the
output voltage exceeds 1.5V (typ). The minimum start-
P
N
CONTROL
LOGIC
STARTUP
CIRCUITRY
DRIVER
GND
FB
OUT
LX
CURRENT
LIMIT
1.235V REFERENCE
ERROR
COMPARATOR
ZERO-
CROSSING
DETECTOR
MAX1723
SHDN
Figure 1. MAX1723 Simplified Functional Diagram
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
_______________________________________________________________________________________ 7
up voltage is a function of load current (see Typical
Operating Characteristics). This circuit is powered from
the BATT pin for the MAX1722/MAX1724, guaranteeing
startup at input voltages as low as 0.91V. The MAX1723
lacks a BATT pin; therefore, this circuit is powered
through the OUT pin. Adding a Schottky diode in paral-
lel with the P-channel synchronous rectifier allows for
startup voltages as low as 1.2V for the MAX1723
(Figure 3). The external Schottky diode is not needed
for input voltages greater than 1.8V. Once started, the
output maintains the load as the battery voltage
decreases below the startup voltage.
Shutdown (MAX1723/MAX1724)
The MAX1723/MAX1724 enter shutdown when the
SHDN pin is driven low. During shutdown, the body
diode of the P-channel MOSFET allows current to flow
from the battery to the output. VOUT falls to approxi-
mately VIN - 0.6V and LX remains high impedance.
Shutdown can be pulled as high as 6V, regardless of
the voltage at BATT or OUT. For normal operation, con-
nect SHDN to the input.
P
N
CONTROL
LOGIC
STARTUP
CIRCUITRY
DAMPING
SWITCH
DRIVER
GND
SHDN
R1
R2
BATT
LX
OUT
CURRENT
LIMIT
MAX1724
ERROR
COMPARATOR
ZERO-
CROSSING
DETECTOR
1.235V REFERENCE
Figure 2. MAX1724 Simplified Functional Diagram
Figure 3. MAX1723 Single-Cell Operation
VOUT = 3.6V
1.2V TO VOUT
D1
10µH
10µF
R2
2.37MΩ
R1
1.24MΩ
10µF
LX
OUT
SHDN
GND FB
MAX1723
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
8 _______________________________________________________________________________________
BATT/Damping Switch
(MAX1722/MAX1724)
The MAX1722/MAX1724 include an internal damping
switch (Figure 4) to minimize ringing at LX and reduce
EMI. When the energy in the inductor is insufficient to
supply current to the output, the capacitance and
inductance at LX form a resonant circuit that causes
ringing. The damping switch supplies a path to quickly
dissipate this energy, suppressing the ringing at LX.
This does not reduce the output ripple, but does
reduce EMI with minimal impact on efficiency. Figures
5 and 6 show the LX node voltage waveform without
and with the damping switch, respectively.
Design Procedure
Setting the Output Voltage
(MAX1722/MAX1723)
The output voltage can be adjusted from 2V to 5.5V
using external resistors R1 and R2 (Figure 7). Since FB
leakage is 20nA (max), select feedback resistor R1 in
the 100kΩto 1MΩrange. Calculate R2 as follows:
where VFB = 1.235V.
RR
V
V
OUT
FB
21 1 =−
MAX1722
MAX1724
PDRV
DAMP
NDRV
TIMING
CIRCUIT
OUT
VOUT
VIN
BATT
LX
DAMPING
SWITCH
GND
P
N
1µs/div
1V/div
1µs/div
1V/div
Figure 6. LX Ringing With Damping Switch (MAX1722/MAX1724)
Figure 5. LX Ringing Without Damping Switch (MAX1723)
Figure 4. Simplified Diagram of Damping Switch
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
_______________________________________________________________________________________ 9
Inductor Selection
The control scheme of the MAX1722/MAX1723/
MAX1724 permits flexibility in choosing an inductor. A
10µH inductor value performs well in most applications.
Smaller inductance values typically offer smaller physi-
cal size for a given series resistance, allowing the
smallest overall circuit dimensions. Circuits using larger
inductance values may start up at lower battery volt-
ages, provide higher efficiency, and exhibit less ripple,
but they may reduce the maximum output current. This
occurs when the inductance is sufficiently large to pre-
vent the maximum current limit (ILIM) from being
reached before the maximum on-time (tON(MAX))
expires.
For maximum output current, choose the inductor value
so that the controller reaches the current-limit before
the maximum on-time is triggered:
where the maximum on-time is typically 5µs, and the
current limit (ILIM) is typically 500mA (see Electrical
Characteristics table).
For larger inductor values, determine the peak inductor
current (IPEAK) by:
The inductor’s incremental saturation current rating should
be greater than the peak switching current. However, it is
generally acceptable to bias the inductor into saturation
by as much as 20%, although this will slightly reduce effi-
ciency. Table 1 lists suggested inductors and suppliers.
Maximum Output Current
The maximum output current depends on the peak induc-
tor current, the input voltage, the output voltage, and the
overall efficiency (η):
II
V
V
OUT MAX PEAK BATT
OUT
()
=
1
2η
IVt
L
PEAK
BATT ON MAX
=()
LVt
I
BATT ON MAX
LIM
< ()
MAX1724
GND
BATT
OUTPUT
V
OUT (NOM)
INPUT
0.8V TO VOUT 10µH
C2
10µF
SHDN
LX
OUT
C1
10µF
OFF
ON
Figure 8. MAX1724 Standard Application Circuit
Table 1. Suggested Inductors and
Suppliers
MAX1722
GND
BATT OUTPUT
2V TO 5.5V
INPUT
0.8V TO VOUT 10µH
LX
OUT
FB
R2 10µF
R1
10µF
Figure 7. Adjustable Output Circuit
MANUFACTURER INDUCTOR PHONE
WEBSITE
Coilcraft DO1608 Series
DO1606 Series
847-639-2361
www.coilcraft.com
Murata LQH4C Series 770-436-1300
www.murata.com
Sumida
CDRH4D18 Series
CR32 Series
CMD4D06 Series
847-545-6700
www.sumida.com
Sumitomo/
Daidoo Electronics CXLD140 Series +81 (06) 6355-5733
www.daidoo.co.jp
Toko 3DF Type
D412F Type
847-297-0070
www.toko.com
For most applications, the peak inductor current equals
the current limit. However, for applications using large
inductor values or low input voltages, the maximum on-
time limits the peak inductor current (see Inductor
Selection section).
Capacitor Selection
Choose input and output capacitors to supply the input
and output peak currents with acceptable voltage rip-
ple. The input filter capacitor (CIN) reduces peak cur-
rents drawn from the battery and improves efficiency.
Low equivalent series resistance (ESR) capacitors are
recommended. Ceramic capacitors have the lowest
ESR, but low ESR tantalum or polymer capacitors offer
a good balance between cost and performance.
Output voltage ripple has two components: variations
in the charge stored in the output capacitor with each
LX pulse, and the voltage drop across the capacitor’s
ESR caused by the current into and out of the capaci-
tor:
where IPEAK is the peak inductor current (see Inductor
Selection section). For ceramic capacitors, the output
voltage ripple is typically dominated by VRIPPLE(C). For
example, a 10µF ceramic capacitor and a 10µH induc-
tor typically provide 75mV of output ripple when step-
ping up from 3.3V to 5V at 50mA. Low input-to-output
voltage differences (i.e. two cells to 3.3V) require high-
er output capacitor values.
Capacitance and ESR variation of temperature should
be considered for best performance in applications
with wide operating temperature ranges. Table 2 lists
suggested capacitors and suppliers.
PC Board Layout Considerations
Careful PC board layout is important for minimizing
ground bounce and noise. Keep the IC’s GND pin and
the ground leads of the input and output capacitors
less than 0.2in (5mm) apart using a ground plane. In
addition, keep all connections to FB
(MAX1722/MAX1723 only) and LX as short as possible.
VV V
V
VL
VVC I
RIPPLE RIPPLE C RIPPLE ESR
RIPPLE ESR
RIPPLE C
OUT BATT OUT
=+
≈
≈
()
()
() ( )
() ( )
()
PEAK ESR COUT
PEAK OUT
I R
-I-
2
1
22
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
10 ______________________________________________________________________________________
Table 2. Suggested Surface-Mount Capacitors and Manufacturers (C1 and C2)
MANUFACTURER CAPACITOR
VALUE DESCRIPTION PHONE
WEBSITE
1µF to 10µF X7R Ceramic
AVX 10µF to 330µFTAJ Tantalum Series
TPS Tantalum Series
843-448-9411
www.avxcorp.com
1µF to 22µF X5R/X7R Ceramic
10µF to 330µF T494 Tantalum SeriesKemet
68µF to 330µF T520 Tantalum Series
864-963-6300
www.kemet.com
Sanyo 33µF to 330µF TPC Polymer Series 408-749-9714
www.secc.co.jp
Taiyo Yuden 33µF to 330µF X5R/X7R Ceramic 800-368-2496
www.t-yuden.org
TDK 1µF to 10µF X7R Ceramic 847-803-6100
www.tdk.com
Vishay Sprague 10µF to 330µF594D Tantalum Series
595D Tantalum Series
203-452-5664
www.vishay.com
Chip Information
TRANSISTOR COUNT: 863
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
______________________________________________________________________________________ 11
Package Information
THIN SOT23.EPS
GND
OUTFB
15LXSHDN
THIN SOT23-5
TOP VIEW
2
34
GND
OUT
15LXBATT
MAX1724
THIN SOT23-5
2
34
SHDN
MAX1723
Pin Configurations (continued)
MAX1722/MAX1723/MAX1724
1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Package Information (continued)