Rainbow Electronics MAX1724 User Manual

General Description

The MAX1722/MAX1723/MAX1724 compact, high-effi­ciency, step-up DC-DC converters are available in tiny, 5­pin thin SOT23 packages. They feature an extremely low

1.5µA quiescent supply current to ensure the highest pos­sible 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 fea­ture 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).

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

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 Battery­Powered 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

PIN­PACKAGE

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

10µH

IN

0.8V TO 5.5V

BATT

LX

TOP VIEW

15LXBATT

MAX1724

ON

OFF

SHDN

OUT

GND

OUT

3.3V AT
UP TO 150mA

GND

MAX1722

2

34

THIN SOT23-5

OUTFB

MAX1722/MAX1723/MAX1724

1.5µA IQ, Step-Up DC-DC Converters
in Thin SOT23-5

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V

BATT

= 1.2V, V

OUT

= 3.3V (MAX1722/MAX1723), V

OUT

= V

OUT(NOM)

(MAX1724), SHDN = OUT, RL= ∞, TA= 0°C to +85°C,

unless otherwise noted. Typical values are at T

A

= +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 (V

OUT

+ 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 V

OUT

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

V

IN

0.91 5.5
V

1.2 5.5

4.950 5.0 5.050

4.875 5.125

Output Voltage Range V

OUT

2 5.5

V

Feedback Voltage V

FB

1.223 1.235 1.247
V

1.210 1.260

Feedback Bias Current I

FB

1.5 20
nA

2.2

N-Channel On-Resistance R

DS(ON)

0.5 1.0

Ω

P-Channel On-Resistance R

DS(ON)

1.0 2.0

Ω

N-Channel Switch Current Limit I

LIM

400 500 600

mA

Switch Maximum On-Time t

ON

3.5 5 6.5

µs

Synchronous Rectifier Zero­Crossing Current

52035

mA

CONDITIONS

MAX1724EZK50

MAX1724EZK27

TA= +25°C,
RL= 3kΩ

MAX1724EZK30

MAX1722/MAX1723

MAX1722/MAX1723

MAX1724EZK33

MAX1722/MAX1723

MAX1722/MAX1724

V

OUT

forced to 3.3V

TA= +25°C

V

OUT

forced to 3.3V

V

OUT

forced to 3.3V

V

OUT

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)

(V

BATT

= 1.2V, V

OUT

= 3.3V (MAX1722/MAX1723), V

OUT

= V

OUT(NOM)

(MAX1724), SHDN = OUT, RL= ∞, TA= 0°C to +85°C,

unless otherwise noted. Typical values are at T

A

= +25°C.) (Note 1)

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).

V

IL

MAX1723/MAX1724

TA= +85°C

TA= +25°C

TA= +85°C

TA= +25°C

0.001 0.5

SHDN Voltage Threshold

V

IH

500 800

mV

Shutdown Current into BATT

0.01

µA

SHDN Input Bias Current

7

nA

MAX1724 (Note 4)

MAX1723/MAX1724,
V

SHDN

= 5.5V

PARAMETER SYMBOL

MIN TYP MAX

UNITSCONDITIONS

MAX1723/MAX1724

75 400

2 100

ELECTRICAL CHARACTERISTICS

(V

BATT

= 1.2V, V

OUT

= 3.3V (MAX1722/MAX1723), V

OUT

= V

OUT(NOM)

(MAX1724), SHDN = OUT, RL= ∞, TA= -40°C to +85°C,

unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

O utp ut V ol tag eV

O utp ut V ol tag e Rang eV

Feedback Voltage V

N-Channel On-Resistance

P-Channel On-Resistance

N-Channel Switch Current Limit I

Switch Maximum On-Time t

Synchronous Rectifier Zero­Crossing Current

Quiescent Current into OUT (Notes 3,4) 3.6 µA

SHDN Voltage Threshold

OUT

OUT

FB

R

DS(ON)

R

DS(ON)

LIM

ON

V

V

MAX1724EZK27 2.633 2.767

MAX1724EZK30 2.925 3.075

MAX1724EZK33 3.218 3.383

MAX1724EZK50 4.875 5.125

MAX1722/MAX1723 2 5.5 V

MAX1722/MAX1723 1.200 1.270 V

V

OUT

V

OUT

V

OUT

V

OUT

MAX1723/MAX1724 75

IL

MAX1723/MAX1724 800

IH

forced to 3.3V 1.0 Ω
forced to 3.3V 2.0 Ω

forced to 3.3V 400 620 mA

forced to 3.3V 5 35 mA

3.5 6.5 µs

V

mV

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), V

BATT

= VIN= 1.5V, L = 10µH, CIN= 10µF, C

OUT

= 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)

I

OUT(MAX)

(mA)

V

OUT

= 2.5V

V

OUT

= 5.0V

V

OUT

= 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
V

OUT

= 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

(V

OUT

= 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

(V

OUT

= 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

(V

OUT

= 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

1µs/div

I

LX

500mA/div

V

OUT

50mV/div

V

LX

2V/div

SWITCHING WAVEFORMS

MAX1722 toc08

I

OUT

= 50mA, V

OUT

= 5.0V, VIN = 3.3V