Rainbow Electronics MAX889 User Manual

General Description

The MAX889 inverting charge pump delivers a regulated
negative output voltage at loads of up to 200mA. The
device operates with inputs from 2.7V to 5.5V to produce
an adjustable, regulated output from -2.5V to -VIN.

The MAX889 is available with an operating frequency of
2MHz (T version), 1MHz (S version), or 0.5MHz (R ver­sion). The higher switching frequency devices allow the
use of smaller capacitors for space-limited applica­tions. The lower frequency devices have lower quies­cent current.

The MAX889 also features a 0.1µA logic-controlled
shutdown mode and is available in an 8-pin SO pack­age. An evaluation kit, MAX889SEVKIT, is available.

________________________Applications

TFT Panels

Hard Disk Drives

Camcorders

Digital Cameras

Measurement Instruments

Battery-Powered Applications

Features

♦ 200mA Output Current

♦ Up to 2MHz Switching Frequency

♦ Small Capacitors (1µF)

♦ +2.7V to +5.5V Input Voltage Range

♦ Adjustable Regulated Negative Output

(-2.5V to -V

IN

)

♦ 0.1µA Logic-Controlled Shutdown
♦ Low 0.05Ω Output Resistance (in regulation)

♦ Soft-Start and Foldback Current Limited

♦ Short-Circuit and Thermal Shutdown Protected

♦ 8-Pin SO Package

MAX889

High-Frequency, Regulated,

200mA, Inverting Charge Pump

________________________________________________________________ Maxim Integrated Products 1

Pin Configuration

MAX889

IN

INPUT +2.7V TO +5.5V

REGULATED

NEGATIVE

OUTPUT

(UP TO -1 × V

IN

,

UP TO 200mA)

FB

OUT

GNDAGND

CAP+

ON

OFF

SHDN

CAP-

Typical Operating Circuit

19-1774; 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-

SWITCHING

FREQUENCY

8 SO 2MHz

8 SO 1MHz

8 SO 0.5MHz

EVALUATION KIT

AVAILABLE

PACKAGE

MAX889TESA -40°C to +85°C
MAX889SESA -40°C to +85°C
MAX889RESA -40°C to +85°C

TOP VIEW

IN

1

2

GND

3

4

87AGND

MAX889

SO

FBCAP+

SHDN

6

OUTCAP-

5

MAX889

High-Frequency, Regulated,
200mA, Inverting Charge Pump

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN= V

SHDN

= +5V, capacitors from Table 1, 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.

IN to GND .................................................................-0.3V to +6V

FB, SHDN, CAP+ to GND............................-0.3V to (V

IN

+ 0.3V)

AGND to GND .......................................................-0.3V to +0.3V

OUT to GND .............................................................-6V to +0.3V

CAP- to GND ............................................(V

OUT

- 0.3V) to +0.3V

Continuous Output Current ...............................................250mA

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

Continuous Power Dissipation (T

A

= +70°C)

8-Pin SO (derate 5.88mW/°C above +70°C)...............471mW

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

PARAMETER

CONDITIONS

Supply Voltage Range V

IN

R

LOAD

= 100Ω 2.7

V

Output Voltage Range V

OUT

R

LOAD

= 100Ω

V

VIN = 5V, V

OUT

= -3.3V

Maximum Output Current

VIN = 3.3V, V

OUT

= -2.5V

mA

MAX889R 6 12

MAX889S 12 24

Quiescent Supply
Current (Free-Run Mode)

)

No load, VFB = V

IN

MAX889T 24 48

mA

MAX889R 3.3 7

MAX889S 5.5 12

Quiescent Supply
Current (Regulated Mode)

)

-3.3V
MAX889T 11 22

mA

Shutdown Supply Current I

SHDN

V

SHDN

= 0 0.1 50 µA

Open-Loop Output
Resistance (Free-Run Mode)

R

O

VFB = V

IN

2.0

Ω

Output Resistance

R

O(REG1)

V

OUT

regulated to -3.3V

Ω

SHDN, FB Input Bias Current ±1 µA

FB Input Offset Voltage I

LOAD

= 0 ±3

mV

Load Regulation I

OUT

= 0 to 200mA 10 mV

IN Undervoltage Lockout
Threshold

V

IN

rising (30mV hysteresis) 2.3

V

SHDN Logic High V

IH

SHDN Logic Low V

IL

VIN = +2.7V to +5.5V

V

MAX889R

0.5

0.62

MAX889S

1

Switching Frequency f

OSC

MAX889T 1.5 2

Thermal Shutdown Threshold

Junction temperature rising
(15°C hysteresis)

160 °C

SYMBOL

MIN TYP MAX UNITS

-2.5 -V

I

OUT(MAX)1

I

OUT(MAX)2

I

Q(FREE-RUN

200

145

5.5

IN

I

Q(REGULATED

No load, V

regulated to

OUT

0.7 x V

0.375

0.75

0.05

IN

0.3 x V

4.5

±35

2.6

1.25

2.5

IN

MHz

MAX889

High-Frequency, Regulated,

200mA, Inverting Charge Pump

_______________________________________________________________________________________ 3

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

ELECTRICAL CHARACTERISTICS

(VIN= V

SHDN

= +5V, capacitors from Table 1, TA= -40°C to +85°C, unless otherwise noted.) (Note 1)

PARAMETER

CONDITIONS

UNITS

Supply Voltage Range V

IN

R

LOAD

= 100Ω 2.7

V

Output Voltage Range V

OUT

R

LOAD

= 100Ω

V

VIN = 5V, V

OUT

= -3.3V

Maximum Output Current

VIN = 3.3V, V

OUT

= -2.5V

mA

MAX889R 12

MAX889S 24

Quiescent Supply
Current (Free-Run Mode)

)

No load, VFB = V

IN

MAX889T 48

mA

MAX889R 7

MAX889S 12

Quiescent Supply
Current (Regulated Mode)

)

-3.3V
MAX889T 22

mA

Shutdown Supply Current I

SHDN

V

SHDN

= 0 50 µA

Open-Loop Output
Resistance (Free-Run Mode)

R

O

VFB = V

IN

Ω

SHDN FB Input Bias Current ±1 µA

FB Input Offset Voltage I

LOAD

= 0

mV

IN Undervoltage Lockout
Threshold

V

IN

rising (30mV hysteresis) 2.3

V

SHDN Logic High V

IH

SHDN Logic Low V

IL

VIN = +2.7V to +5.5V

V

MAX889R

0.62

MAX889S

Switching Frequency f

OSC

MAX889T 1.5

MHz

Typical Operating Characteristics

(Circuit of Figure 1, VIN= V

SHDN

= +5V, capacitors from Table 1, TA= +25°C, unless otherwise noted.)

OUTPUT VOLTAGE

vs. LOAD CURRENT

MAX889 toc01

OUTPUT LOAD CURRENT (mA)

OUTPUT VOLTAGE (V)

-3.33

-3.32

-3.31

-3.30

-3.29

-3.28

-3.27

-3.26

-3.25

0 200 400 600 800

MAX889T

MAX889S

MAX889R

0

10

20

30

40

MAX889R

OUTPUT RIPPLE

vs. LOAD CURRENT vs. C

OUT

MAX889 toc02

LOAD CURRENT (mA)

OUTPUT RIPPLE (mV)

0 150 20050 100 250 300 350

C

OUT

= 22µF

C

OUT

= 47µF

C

OUT

= 10µF

0

10

20

30

40

MAX889S

OUTPUT RIPPLE

vs. LOAD CURRENT vs. C

OUT

MAX889 toc03

LOAD CURRENT (mA)

OUTPUT RIPPLE (mV)

0 150 20050 100 250 300 350

C

OUT

= 4.7µF

C

OUT

= 22µF

C

OUT

= 10µF

SYMBOL

I

OUT(MAX)1

I

OUT(MAX)2

I

Q(FREE-RUN

I

Q(REGULATED

No load, V

regulated to

OUT

MIN MAX

-2.5 -V

200

145

0.7 x V

IN

0.3 x V

0.375

0.75 1.25

5.5

IN

4.5

±35

2.6

IN

2.5