Rainbow Electronics MAX1759 User Manual

General Description

The MAX1759 is a buck/boost regulating charge pump
that generates a regulated output voltage from a single
lithium-ion (Li+) cell, or two or three NiMH or alkaline
cells for small hand-held portable equipment. The
MAX1759 operates over a wide +1.6V to +5.5V input
voltage range and generates a fixed 3.3V or adjustable
(2.5V to 5.5V) output (Dual Mode™). Maxim’s unique
charge-pump architecture allows the input voltage to be
higher or lower than the regulated output voltage.
Despite its high 1.5MHz operating frequency, the
MAX1759 maintains low 50µA quiescent supply current.

Designed to be an extremely compact buck/boost con­verter, this device requires only three small ceramic
capacitors to build a complete DC-DC converter capa­ble of generating a guaranteed 100mA (min) output
current from a +2.5V input. For added flexibility, the
MAX1759 also includes an open-drain power-OK
(POK) output that signals when the output voltage is in
regulation.

The MAX1759 is available in a space-saving 10-pin
µMAX package that is 1.09mm high and half the size of
an 8-pin SO.

Applications

Li+ Battery-Powered Applications

Miniature Equipment

Backup Battery Boost Converters

Translators

Features

♦ Regulated Output Voltage (Fixed 3.3V or

Adjustable 2.5V to 5.5V)

♦ 100mA Guaranteed Output Current

♦ +1.6V to +5.5V Input Voltage Range

♦ Low 50µA Quiescent Supply Current

♦ 1µA Shutdown Mode

♦ Load Disconnected from Input in Shutdown

♦ High 1.5MHz Operating Frequency

♦ Uses Small Ceramic Capacitors

♦ Short-Circuit Protection and Thermal Shutdown

♦ Small 10-Pin µMAX Package

MAX1759

Buck/Boost Regulating

Charge Pump in µMAX

________________________________________________________________ Maxim Integrated Products 1

Typical Operating Circuit

19-1600; Rev 1; 6/00

PART

MAX1759EUB -40°C to +85°C

TEMP. RANGE PIN-PACKAGE

10 µMAX

Pin Configuration

Ordering Information

Dual Mode is a trademark of Maxim Integrated Products.

For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

C

X

IN

+1.6V TO +5.5V

C

IN

ON

OFF

CXN CXP

IN

MAX1759

SHDN

OUT

POK

PGNDGNDFB

OUT

3.3V AT 100mA

POWER OK

TOP VIEW

1

POK

C

OUT

SHDN

2

3

IN

4

5

10

FB

9

MAX1759

µMAX

OUT

8

CXP

7

CXNIN

PGNDGND

6

MAX1759

Buck/Boost Regulating
Charge Pump in µMAX

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1, VIN= V

SHDN

= 2V, FB = PGND = GND, CIN= 10µF, CX= 0.33µF, C

OUT

= 10µF, TA= 0°C to +85°C, unless oth-

erwise noted. Typical values are at T

A

= +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.

IN, OUT, FB, POK, SHDN to GND............................-0.3V to +6V

PGND to GND.....................................................................±0.3V

CXN to GND ................................................-0.3V to (V

IN

+ 0.3V)

CXP to GND................-0.3V to (the greater of V

IN

or V

OUT

) + 1V

OUT Short to GND .........................................................Indefinite

Continuous Power Dissipation (T

A

= +70°C)

10-Pin µMAX (derate 5.6mW/°C above +70°C) .........444mW

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

I

LOAD,MAX

Thermal Shutdown Hysteresis

20

°C

Efficiency

90

%VIN= 3.6V, I

LOAD

= 10mA

PARAMETER SYMBOL MIN TYP MAX UNITS

Transient Load Current

200

mA

Maximum Output Current

100

mA

3.17 3.3 3.43

Output Voltage V

OUT

3.17 3.3 3.43

V

Quiescent Supply Current I

Q

50 90

85 180

µA

Shutdown Supply Current I

Q,SHDN

15

µA

Leakage Current into OUT in
Shutdown

15

µA

Input Undervoltage Lockout
Voltage

Input Voltage Range V

IN

1.6 5.5

V

V

UVLO

0.6 1.0 1.4

V

Output Voltage Adjustment Range

2.5 5.5

V

SHDN Logic Input Voltage

V

IL

0.25 · V

IN

V

V

IH

0.7 · V

IN

SHDN Input Leakage Current

I

SHDN

-1 1

µA

FB Regulation Voltage V

FB

1.205 1.235 1.265

V

FB Input Current

25 200

nA

FB Dual-Mode Threshold

100 50

mV

200 100

mV

POK Trip Voltage

1.0 1.1 1.2

V

POK Output Low Voltage V

OL

5100

mV

POK Leakage Current

0.01 0.2

µA

Switching Frequency f

OSC

1.2 1.5 1.8

MHz

Output Short-Circuit Current

110

mA

Thermal Shutdown Temperature

160

°C

CONDITIONS

1.6V ≤ VIN≤ 5.5V

I

LOAD

≤ 100mA (RMS)

1.6V ≤ VIN≤ 5.5V

2.5V ≤ VIN≤ 5.5V

2.5V ≤ VIN≤ 5.5V, 1mA ≤ I

LOAD

≤ 100mA

2V ≤ VIN≤ 5.5V, 1mA ≤ I

LOAD

≤ 50mA

VIN= V

SHDN

= 4V, VFB= 0, stepping down

VIN= V

SHDN

= 2V, VFB= 0, stepping up

V

SHDN

= 5.5V

VIN= 1.65V, V

OUT

= 3.3V

1.6V ≤ VIN≤ 5.5V, V

SHDN

= 0

VIN= 2V, V

OUT

= 3.3V, V

SHDN

= 0

VFB= 1.27V

Internal feedback

External feedback

Falling edge at FB

I

SINK

= 0.5mA, VIN= 2V

V

POK

= 5.5V, VFB= 1.27V

1.6V ≤ VIN≤ 5.5V

1.6V ≤ VIN≤ 5.5V, VFB= 1V

V

OUT

= 0, 2.5V ≤ VIN≤5.5V, foldback current limit

Rising temperature

MAX1759

Buck/Boost Regulating

Charge Pump in µMAX

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1, VIN= V

SHDN

= 2V, FB = PGND = GND, CIN= 10µF, CX= 0.33µF, C

OUT

= 10µF, TA= -40°C to +85°C, unless oth-

erwise noted.) (Note 1)

Note 1: Specifications to -40°C are guaranteed by design and are not production tested.

PARAMETER

SYMBOL MIN MAX UNITS

Quiescent Supply Current I

Q

90

Maximum Output Current I

LOAD,MAX

100

mA

Output Voltage Adjustment
Range

2.5 5.5

V

3.15 3.45

V

180

µA

Shutdown Supply Current I

Q,SHDN

6

µA

Leakage Current into OUT in
Shutdown

5

µA

SHDN Input Logic Voltage

V

IL

0.2 · V

IN

V

Input Undervoltage Lockout
Voltage

Input Voltage Range V

IN

1.6 5.5

V

V

UVLO

0.6 1.4

V

Output Voltage V

OUT

3.15 3.45

V

V

IH

0.7 · V

IN

V

SHDN Input Leakage Current

I

SHDN

-1 1

µA

FB Regulation Voltage V

FB

1.205 1.265

V

FB Input Bias Current

200

nA

FB Dual Mode Threshold

40

mV

200

mV

POK Trip Voltage

1.0 1.2

V

POK Output Low Voltage V

OL

100

mV

POK Leakage Current

0.2

µA

Switching Frequency f

OSC

1.1 1.9

MHz

CONDITIONS

1.6V ≤ VIN≤ 5.5V

VIN= V

SHDN

= 4V, VFB= 0

V

SHDN

= 5.5V

2.5V ≤ VIN≤ 5.5V

1.6V ≤ VIN≤ 5.5V

2.5V ≤ VIN≤ 5.5V, 0 ≤ I

LOAD

≤ 100mA

VIN= V

SHDN

= 2.5V, VFB= 0

1.6V ≤ VIN≤ 5.5V, V

SHDN

= 0

VIN= 1.65V, V

OUT

= 3.3V

VFB= 1.27V

VIN= 2V, V

OUT

= 3.3V, V

SHDN

= 0

1.6V ≤ VIN≤ 5.5V

Internal feedback

External feedback

Falling edge at FB

I

SINK

= 0.5mA, VIN= 2V

V

POK

= 5.5V

1.6V ≤ VIN≤ 5.5V, VFB= 1V

2V ≤ VIN≤ 5.5V, 0 ≤ I

LOAD

≤ 50mA