Rainbow Electronics MAX1606 User Manual

General Description

The MAX1606 is a step-up DC-DC converter that con­tains a 0.5A internal power switch and a 0.5A output
isolation switch in an 8-pin µMAX package. The IC
operates from a 2.4V to 5.5V supply voltage but can
boost battery voltages as low as 0.8V up to 28V.

The MAX1606 uses a unique control scheme that pro­vides high efficiency over a wide range of load condi­tions. An internal 0.5A MOSFET reduces external
component count, and a high switching frequency (up
to 500kHz) allows for tiny surface-mount components.
The current limit can be set to 500mA, 250mA, or
125mA, allowing the user to reduce the output ripple
and component size in low-current applications.

Additional features include a low quiescent supply cur­rent and a true shutdown mode that saves power by
disconnecting the output from the input. The MAX1606
is ideal for small LCD panels with low current require­ments but can also be used in other applications. A
MAX1606 evaluation kit is available to help speed up
design time.

________________________Applications

LCD Bias Generators

Cellular or Cordless Phones

Palmtop Computers

Personal Digital Assistants (PDAs)

Organizers

Handy Terminals

Features

♦ Adjustable Output Voltage up to 28V

♦ 20mA at 20V from a Single Li+ Battery

♦ True Shutdown (Output Disconnected from Input)

♦ Output Short-Circuit Protection

♦ 88% Efficiency

♦ Up to 500kHz Switching Frequency

♦ Selectable Inductor Current Limit

(125mA, 250mA, or 500mA)

♦ 0.1µA Shutdown Current

♦ 8-Pin µMAX Package

MAX1606

28V Internal Switch LCD Bias Supply

with True Shutdown

________________________________________________________________ Maxim Integrated Products 1

Pin Configuration

V

IN

= 0.8V TO 5.5V

V

CC

= 2.4V TO 5.5V

V

OUT

= V

IN

TO 28V

ON

OFF

SHDN

V

CC

LIM

SW

BATT

GND

LX

FB

MAX1606

Typical Operating Circuit

19-1744; Rev 0; 7/00

For free samples and the latest literature, visit www.maxim-ic.com or phone [phone].
For small orders, phone [phone].

Ordering Information

PART TEMP. RANGE PIN-PACKAGE

MAX1606EUA -40°C to +85°C8 µMAX

TOP VIEW

BATT

1

FB

2

3

V

CC

4

8

SW

7

MAX1606

µMAX

SHDN

6

LIM

5

LXGND

MAX1606

28V Internal Switch LCD Bias Supply
with True Shutdown

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= 3.3V, VCC= BATT = SHDN, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +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.

VCC, FB, BATT, SW to GND .....................................-0.3V to +6V

BATT to SW ..............................................................-0.3V to +6V

SHDN, LIM to GND.....................................-0.3V to (V

CC

+ 0.3V)

LX to GND ..............................................................-0.3V to +30V

Current into LX or BATT..............................................600mA

RMS

Current out of SW .......................................................600mA

RMS

Output Short-Circuit Duration ........................................Indefinite

Continuous Power Dissipation (T

A

= +70°C)

8-Pin µMAX (derate 4.1mW/°C above +70°C).............330mW

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

)

µ

VCC Supply Voltage V

BATT Input Voltage Range V

VCC Undervoltage Lockout V

VCC Quiescent Supply Current I

VCC Shutdown Supply Current SHDN = GND 0.1 1 µA

BATT Input Supply Current I
BATT Shutdown Supply Current SHDN = GND 0.1 1 µA

VCC Line Regulation ∆V

BATT Line Regulation ∆V

Load Regulation ∆V

Efficiency L1 = 100µH, V

Feedback Set Point V

Feedback Input Bias Current I

INDUCTOR CONNECTIONS (LX, SW)

LX Voltage Range V

LX On-Resistance R

LX Leakage Current VLX = 28V 2 µA

Maximum LX On-Time t

Minimum LX Off-Time t

SW Leakage Current SW = GND, V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CC

BATT

UVLO

CC

BATT

LNR

LNR

LDR

FB

FB

LX(MAX

(Note 1) 2.4 5.5 V

(Note 1) 0.8 5.5 V

VCC falling, 30mV typical hysteresis 2.0 2.2 2.37 V

VFB = 1.3V 160 320 µA

VFB = 1.3V 20 40 µA

V

= 18V, I

OUT

= V

V

CC

LIM

V

= 18V, I

OUT

= V

V

CC

LIM

V

= 18V, VCC = V

OUT

I

= 0mA to 20mA

LOAD

= 1mA, V

LOAD

= 2.4V to 5.5V

= 1mA,

LOAD

= 3.3V, V

BATT

BATT

BATT

= 3.6V, I

= 3.6V,

BATT

= 0.8V to 5.5V

= V

= 3.3V,

LIM

= 10mA 88 %

LOAD

0.1 %/V

0.05 %/V

0.05 %/mA

1.225 1.25 1.275 V

VFB = 1.3V 5 100 nA

LX

LIM = V

CC

0.40 0.50 0.56

LIM = floating 0.20 0.25 0.285LX Switch Current Limit I

28 V

LIM = GND 0.10 0.125 0.15

LX

ON

OFF

VCC = 5V, I

VCC = 3.3V, ILX = 100mA 1 2

VFB > 1.1V 0.8 1.0 1.2

VFB < 0.8V (soft-start) 3.9 5.0 6.0

= 100mA 0.8

LX

10 13 16 µs

= 5.5V 1

BATT

A

Ω

µs

A

)

MAX1606

28V Internal Switch LCD Bias Supply

with True Shutdown

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS

(VCC= 3.3V, VCC= BATT = SHDN, TA= -40°C to +85°C, unless otherwise noted.) (Note 2)

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 3.3V, VCC= BATT = SHDN, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

)

CONTROL INPUTS (SHDN, LIM)

SHDN Input Threshold

SHDN Input Bias Current I

LIM Input Low Level 2.4V ≤ VCC ≤ 5.5V 0.4 V

LIM Input Float Level

LIM Input High Level 2.4V ≤ VCC ≤ 5.5V

LIM Input Bias Current I

PMOS ISOLATION SWITCH (BATT to SW)

PMOS Current Limit V

PMOS On-Resistance R

Soft-Start Time t

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

V

IH

V

IL

SHDN

LIM

DS(ON

SS

2.4V ≤ VCC ≤ 5.5V

2.4V ≤ VCC ≤ 5.5V

VCC = 5.5V, V

2.4V ≤ V
I

LIM

SHDN = VCC, LIM = GND or V
SHDN = GND 0.1 1

C C

VCC = 2.5V, V

VCC = 2.5V, V
R

SW

≤ 5.5V,

CC

= ±0.5µA

= 2.5V, V

= 50Ω to GND

= 0 to 5.5V -1 1 µA

SHDN

CC

= 1.5V 0.65 0.85 1.5 A

BATT

= 1.5V, ISW = 100mA 0.25 0.4 Ω

BATT

= 1.5V,

BATT

0.8 ×
V

CC

( V

/ 2)

C C

- 0.25V

V

CC

- 0.4V

-2 2

0.3 ms

0.2 ×
V

CC

( V

/ 2)

C C

+ 0.25V

V

V

V

µA

VCC Supply Voltage V

BATT Input Voltage Range V

VCC Undervoltage Lockout V

VCC Quiescent Supply Current I

VCC Shutdown Supply Current SHDN = GND 1 µA

BATT Input Supply Current I
BATT Shutdown Supply Current SHDN = GND 1 µA

Feedback Set Point V

Feedback Input Bias Current I

INDUCTOR CONNECTIONS (LX, SW)

LX Voltage Range V

LX Switch Current Limit I

LX On-Resistance R

LX Leakage Current VLX = 28V 2 µA

Maximum LX On-Time t

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CC

BATT

UVLO

CC

BATT

FB

FB

LX

LX(MAX

ON

(Note 1) 2.4 5.5 V

(Note 1) 0.8 5.5 V

VCC falling, 30mV typical hysteresis 2.0 2.37 V

VFB = 1.3V 360 µA

VFB = 1.3V 40 µA

1.215 1.285 V

VFB = 1.3V 100 nA

LIM = V

CC

LIM = floating 0.18 0.30

LIM = GND 0.08 0.17

VCC = 3.3V, ILX = 100mA 2 Ω

LX

0.35 0.58

917µs

28 V

A