Rainbow Electronics MAX865 User Manual

_______________General Description

The MAX865 is a CMOS charge-pump DC-DC convert­er in an ultra-small µMAX package. It produces positive
and negative outputs from a single positive input, and
requires only four capacitors. The charge pump first
doubles the input voltage, then inverts the doubled volt­age. The input voltage ranges from +1.5V to +6.0V.

The internal oscillator is guaranteed to be between
20kHz and 38kHz, keeping noise above the audio
range while consuming minimal supply current. A 75Ω
output impedance permits useful output currents up to
20mA.

The MAX865 comes in a 1.11mm-high, 8-pin µMAX
package that occupies half the board area of a stan­dard 8-pin SOIC. For a device with selectable frequen­cies and logic-controlled shutdown, refer to the MAX864
data sheet.

________________________Applications

Low-Voltage GaAsFET Bias in Wireless Handsets
VCO and GaAsFET Supplies
Split Supply from 3 Ni Cells or 1 Li+ Cell
Low-Cost Split Supply for Low-Voltage

Data-Acquisition Systems
Split Supply for Analog Circuitry
LCD Panels

____________________________Features

♦ 1.11mm-High µMAX Package
♦ Compact: Circuit Fits in 0.08in

2

♦ Requires Only Four Capacitors
♦ Dual Outputs (positive and negative)
♦ +1.5V to +6.0V Input Voltage
♦ 20kHz (min) Frequency (above the audio range)

MAX865

Compact, Dual-Output Charge Pump

________________________________________________________________

Maxim Integrated Products

1

1
2
3
4

8
7
6
5

C1+
V+
IN

GND

V-

C2-

C2+

C1-

MAX865

µMAX

TOP VIEW

__________________Pin Configuration

MAX865

C1+

V+

GND

GND

+VIN to ±2V

IN

CONVERTER

V-

IN

GND

C1-

C2+

C2-

+2*V

IN

V

IN

(+1.5V to +6.0V)

-2*V

IN

__________Typical Operating Circuit

19-0472; Rev 1; 7/97

PART

MAX865C/D
MAX865EUA -40°C to +85°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

Dice
8 µMAX

______________Ordering Information

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone] ext. 3468.

100

90

0

0 2 8 10 18

EFFICIENCY vs. OUTPUT CURRENT

(V

IN

= 5V)

30
20
10

80
70

MAX865-01

OUTPUT CURRENT (mA)

EFFICIENCY (%)

4 6 12 14

50
40

60

16

V-

V+

100

90

0

0 1 3 4 8

EFFICIENCY vs. OUTPUT CURRENT

(V

IN

= 3.3V)

30
20
10

80
70

MAX865-02

OUTPUT CURRENT (mA)

EFFICIENCY (%)

2 5 6

50
40

60

7

V-

V+

100

90

0

0

1.0

2.5

EFFICIENCY vs. OUTPUT CURRENT

(V

IN

= 2V)

30
20
10

80
70

MAX865-03

OUTPUT CURRENT (mA)

EFFICIENCY (%)

0.5 1.5

50
40

60

2.0

V-

V+

__________________________________________Typical Operating Characteristics

(Circuit of Figure 1, VIN= 5V, TA= +25°C, unless otherwise noted.)

MAX865

Compact, Dual-Output Charge Pump

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN= 5V, C1 = C2 = C3 = C4 = 3.3µF, TA= T

MIN

to T

MAX

, 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.

V+ to GND.................................................................+12V, -0.3V

IN to GND.................................................................+6.2V, -0.3V

V- to GND..................................................................-12V, +0.3V

V- Output Current .............................................................100mA

V- Short-Circuit to GND ................................................Indefinite

Continuous Power Dissipation (T

A

= +70°C)

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

Operating Temperature Range

MAX865EUA.....................................................-40°C to +85°C

Storage Temperature Range.............................-65°C to +160°C

Lead Temperature (soldering, 10sec).............................+300°C

T

A

= +25°C

R

LOAD

= 10kΩ

R

LOAD

= 10kΩ

IL= 5mA

V+ = 10V (forced),
IV-= 1mA

IV+= 1mA,
IV-= 0mA

TA= -40°C to +85°C (Note 1)
TA= +25°C
TA= -40°C to +85°C (Note 1)

CONDITIONS

0.6 1.05

V6.0Maximum Supply Voltage

V2.0 1.5Minimum Supply Voltage

%85Power Efficiency

Ω

140

Output Resistance

75 100

280

mA

1.15

Supply Current

19.5 24 32.5
kHz

18 34

Oscillator Frequency

150 200

UNITSMIN TYP MAXPARAMETER

TA= +25°C
TA= T

MIN

to T

MAX

TA= +25°C
TA= T

MIN

to T

MAX

V-, RL= ∞

V+, RL= ∞

%

90 98

Voltage Conversion Efficiency

95 99

Note 1: These specifications are guaranteed by design and are not production tested.

MAX865

Compact, Dual-Output Charge Pump

_______________________________________________________________________________________

3

10

8

-10
0 2 6 14

OUTPUT VOLTAGE vs.

OUTPUT CURRENT

-4

-6

-8

6
4

MAX865-04

OUTPUT CURRENT (mA)

OUTPUT VOLTAGE, V+, V- (V)

4 8 10

0

-2

2

12

V-

C1 = C2 = C3 = C4 = 3.3µF
V

IN

= 4.75V

V-

BOTH V+ AND
V- LOADED EQUALLY

V+

V+

400

350

0

0 20 25 50

OUTPUT VOLTAGE RIPPLE

vs. PUMP CAPACITANCE

100

50

300

MAX865-05

PUMP CAPACITANCE (µF)

OUTPUT VOLTAGE RIPPLE (mVp-p)

5 10 15 30 35

200

150

250

40 45

C1 = C2 = C3 = C4

A

B

D

E

F

C

A: V+, IN = 4.75V, V+ + |V-| = 16V
B: V+, IN = 3.15V, V+ + |V-| = 10V
C: V+, IN = 1.90V, V+ + |V-| = 6V
D: V-, IN = 4.75V, V+ + |V-| = 16V
E: V-, IN = 3.15V, V+ + |V-| = 10V
F: V-, IN = 1.90V, V+ + |V-| = 6V

7

6

0

0 20 25 50

OUTPUT CURRENT

vs. PUMP CAPACITANCE

2

1

5

MAX865-06

PUMP CAPACITANCE (µF)

OUTPUT CURRENT, V+ TO V- (mA)

5 10 15 30 35

3

4

40 45

VIN = 4.75V, V+ + |V-| = 16V

C1 = C2 = C3 = C4

VIN = 3.15V, V+ + |V-| = 10V

VIN = 1.90V, V+ + |V-| = 6V

1000

900

0

2.0 3.5 4.0 6.0

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

300
200
100

800
700

MAX865-07

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (µA)

2.5

3.0

4.5

400

600
500

5.0 5.5

C1 = C2 = C3 = C4 = 3.3µF

300

0

-55 5

25

125

OUTPUT RESISTANCE

vs. TEMPERATURE

100

50

250

MAX865-08

TEMPERATURE (°C)

OUTPUT RESISTANCE (Ω)

-35

-15

45

65

200

150

85

105

C1 = C2 = C3 = C4 = 3.3µF

V-, VIN = 3.3V

V+, VIN = 3.3V

V+, VIN = 5.0V

V-, VIN = 5.0V

27

15

-40 0 20 100

PUMP FREQUENCY
vs. TEMPERATURE

19

17

25

MAX865-09

TEMPERATURE (°C)

PUMP FREQUENCY (kHz)

-20 40

23

21

60

80

C1 = C2 = C3 = C4 = 3.3µF

VIN = 5.0V

VIN = 3.3V

VIN = 2.0V

250

0

2.0 3.0 3.5 6.0

OUTPUT RESISTANCE
vs. SUPPLY VOLTAGE

50

200

MAX865-10

SUPPLY VOLTAGE (V)

OUTPUT RESISTANCE (Ω)

2.5 4.0 4.5

150

100

5.0 5.5

C1 = C2 = C3 = C4 = 3.3µF

V-

V+

____________________________Typical Operating Characteristics (continued)

(Circuit of Figure 1, VIN= 5V, TA= +25°C, unless otherwise noted.)