Rainbow Electronics MAX768 User Manual

19-1174; Rev 0; 12/96

Low-Noise, Dual-Output, Regulated Charge Pump

for GaAsFET, LCD, and VCO Supplies

_______________General Description

The MAX768 low-noise, dual-output, regulated charge
pump provides a negative output for biasing GaAsFET
power amplifiers, and a positive output for powering
voltage-controlled oscillators (VCOs) in wireless hand­sets. The outputs can also be used to power LCDs.
Output ripple is less than 2mVp-p. The MAX768 is
intended for use in low-voltage systems where a simple
charge-pump inverter is inadequate, or where the VCO
needs more range to improve its signal-to-noise ratio.
The input range is 2.5V to 5.5V, enabling direct power
from 1Li+ and 3-cell NiMH/NiCd batteries.

The MAX768 includes a voltage-doubler charge pump,
followed by an inverting charge pump. This combina­tion produces unregulated outputs that are ±2x the
input. Two internal low-dropout linear regulators provide
the low-noise, regulated positive and negative outputs.
Output current is guaranteed to be at least 5mA per
output. The linear regulators use CMOS devices, so the
quiescent current remains independent of output load­ing (even in dropout), and the dropout voltage
approaches zero with no load current.

The MAX768 has two preset switching frequencies
(25kHz or 100kHz), or can be synchronized by an exter­nal clock from 20kHz to 240kHz. This flexibility permits
users to optimize their designs based on noise, capaci­tor size, and quiescent-supply-current criteria.

The device features Dual Mode™ operation: the output
voltage is preset to +5V and -5V, or can be adjusted by
adding external resistor dividers. Other features include
independent shutdowns and a logic output that signals
when the negative voltage has risen to within 10% of its
regulation setpoint (to protect the power amplifier
GaAsFET). The MAX768 is available in a space-saving,
16-pin QSOP, which is the same size as a standard
8-pin SO.

________________________Applications

GaAsFET Power Amp Bias
Voltage-Controlled Oscillator (VCO) Supply
Tuner Diode Power Supply
Positive and Negative LCD Supply
Cellular Phone
PCS and Cordless Phone
Wireless Handsets
Wireless Handheld Computers
Wireless PCMCIA Cards
Modems

____________________________Features

♦ Dual Positive/Negative Regulated Outputs:

±5V

♦ Output-Ready Indicator to Protect GaAsFET PAs
♦ 2.5V to 5.5V Input Voltage Range
♦ Low-Noise Output Ripple: < 2mVp-p
♦ Synchronizable Switching Frequency
♦ Uses Only Small, Low-Cost Capacitors
♦ 0.1µA Independent Shutdown Controls
♦ Adjustable Output Voltages
♦ Small 16-Pin QSOP Package

OUT

from 3V

IN

______________Ordering Information

PART

MAX768C/D
MAX768EEE -40°C to +85°C

*

Dice are specified at TA= +25°C, DC parameters only.

Pin Configuration appears at end of data sheet.

Dual Mode is a trademark of Maxim Integrated Products.

TEMP. RANGE PIN-PACKAGE

0°C to +70°C

Dice*

16 QSOP

__________Typical Operating Circuit

VIN

(3.0V TO 5.5V)

C7

C5

C6

POSITIVE
OUTPUT
+5V

NEGATIVE
OUTPUT

-5V
OUTPUT-

READY
SIGNAL

SYNC
PSHDN
NSHDN
C1+

C1

C2

C1­C2+

C2-

IN

MAX768

GND

POUT

V+

C3

C4

V-

NOUT

RDY

SETPSETN

MAX768

________________________________________________________________

Maxim Integrated Products

1

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

Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies

ABSOLUTE MAXIMUM RATINGS

VIN, C1-, SYNC, PSHDN, NSHDN to GND...............-0.3V to +6V

V+, C1+, C2+, RDY to GND...................................-0.3V to +12V

SETP to GND .......................................................... -0.3V to +3V

SETN to GND............................................................-3V to +0.3V

V-, C2- to GND ...................................................... -12V to +0.3V

OUTP, OUTN Short Circuited to GND .......................Continuous

NOUT to V- ........................................................... -0.3V to +12V

MAX768

POUT to V+ ........................................................... -12V to +0.3V

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.

Continuous Power Dissipation (T

QSOP (derate 8.70mW/°C above +70°C)......................696mW

Operating Temperature Range

MAX768EEE.......................................................-40°C to +85°C

Maximum Junction Temperature .....................................+150°C

Storage Temperature Range.............................-65°C to +165°C

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

ELECTRICAL CHARACTERISTICS

(VIN= +3V, SYNC = IN, SETN = SETP = GND, NSHDN = PSHDN = IN, TA= -40°C to +85°C, unless otherwise noted. Typical values

= +25°C. See Figure 2.) (Note 1)

are at T

A

CONDITIONS

I

Minimum Input Start-Up Voltage

No-Load Supply Current at 100kHz
(both regulators active)

No-Load Supply Current at 100kHz
(negative regulator off)

No-Load Supply Current at 25kHz
(both regulators active)

Dropout Voltage (2 x VIN- |V

Output Voltage Noise

SHUTDOWN

SHDN Input Bias Current

OUT

)

|

= 0

LOAD

0mA < I
0mA < I
(Note 2)
(Note 3)
VIN= 3V, V
VIN= 3.0V
VIN= 5.5V 1.5

NSHDN = GND

V

SYNC

2 x VIN- | V
VIN= 3V to 5.5V

I

POUT

I

NOUT

C

POUT =CNOUT

10kHz < f < 1MHz

V

SHDN

NSHDN = PSHDN = SYNC = GND

< 5mA, VIN= 3.0V to 5.5V V4.81 5.00 5.14Positive Output Voltage

LOAD

< 5mA, VIN= 3.0V to 5.5V

LOAD

≥ 4.81V, V

POUT

= GND mA0.45 0.80

I

POUT

OUT

|

I

POUT

= 0mA to 5mA,
= 0mA to -5mA

=

10µF,

= 3V

NOUT

= I
= I

NOUT
NOUT

POUT
NOUT

≤ -4.82V

= 0.1mA
= 5mA

= +70°C)

A

0.8 1.4

20

420 900

1.2

1.7

UNITSMIN TYP MAXPARAMETER

%/mA0.06 0.12Load Regulation

mVp-p

V3.0 5.5Input Voltage Range
V2.5

V-5.10 -5.00 -4.82Negative Output Voltage
V1.25 11Positive Output Voltage Adjustable Range
V-11 -1.25Negative Output Voltage Adjustable Range

mA5Maximum POUT, NOUT Output Currents
mA

mA0.3

mV

%/V-0.12 0.0 0.12Line Regulation

V0.4Shutdown/SYNC Logic-Low Input Threshold
V2.0Shutdown/SYNC Logic-High Input Threshold

µA0.1 2
µA0.1 10Shutdown Supply Current

2 _______________________________________________________________________________________

Low-Noise, Dual-Output, Regulated Charge Pump

RDY

for GaAsFET, LCD, and VCO Supplies

ELECTRICAL CHARACTERISTICS (continued)

(VIN= +3V, SYNC = IN, SETN = SETP = GND, NSHDN = PSHDN = IN, TA= -40°C to +85°C, unless otherwise noted. Typical values

= +25°C. See Figure 2.) (Note 1)

are at T

A

CONDITIONS

SYNC

Oscillator Frequency (internal)

SYNC = GND (divide by 4)
V

= 3V

SYNC

SET INPUT

Positive Set-Reference Voltage

Negative Set-Reference Voltage

I

POUT

I

NOUT

V

SETP

= 0.1mA

= 0.1mA

= V

SETN

TA= +25°C
TA= -40°C to + 85°C
TA= +25°C
TA= -40°C to + 85°C

= 1.3V

OUTPUT

RDY Output Threshold

Percent of V
I

= 2mA V0.25Output Low Voltage

SINK

V

= 10V

RDY

NOUT

, I

NOUT

= 5mA

Note 1: Parameters to -40°C are guaranteed by design, not production tested.
Note 2: Maximum output voltage range is from the positive reference voltage to 2 x V
Note 3: Maximum output voltage range is from the negative reference voltage to -2 x V

21.5 25 28.5
85 100 115

1.217 1.25 1.283

1.215 1.25 1.285

-1.270 -1.25 -1.230

-1.275 -1.25 -1.225

- dropout voltage.

IN

+ dropout voltage.

IN

UNITSMIN TYP MAXPARAMETER

MAX768

kHz20 240SYNC Frequency Range (external)

%40 60SYNC Duty Cycle (external)

kHz

µA0.1 2SYNC Input Leakage Current

V

V

µA0.01 0.1SETP, SETN Input Leakage Current

%85 94 98

µA0.01 2Output Off Current

mA10Maximum Sink Current

__________________________________________Typical Operating Characteristics

(SYNC = IN, TA = +25°C, unless otherwise noted.)

mV

OUTPUT VOLTAGE

RMS

0.30

)

RMS

0.20

0.10

OUTPUT VOLTAGE (mV

0

vs. OUTPUT CURRENT

IN = 3.0V

NOUT = -5V

POUT = +5V

0 5 15 25

10 20

OUTPUT CURRENT (mA)

_______________________________________________________________________________________ 3

5.2

MAX768-TOC01

5.0

4.8

4.6

4.4

OUTPUT VOLTAGE (V)

4.2

4.0

POUT OUTPUT VOLTAGE 

vs. OUTPUT CURRENT

ONLY POUT LOADED

0 5 15 30





10 20 25

OUTPUT CURRENT (mA)

IN = 4.0V

IN = 3.0V

-4.2

-4.3

MAX768-TOC02

-4.4

-4.5

-4.6

-4.7

OUTPUT VOLTAGE (V)

-4.8

-4.9

-5.0

NOUT OUTPUT VOLTAGE vs. 

OUTPUT CURRENT

ONLY NOUT LOADED

0 5 15 30

OUTPUT CURRENT (mA)





IN = 3.0V

IN = 4.0V

10 20 25

MAX768-TOC03

Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies

____________________________Typical Operating Characteristics (continued)

(SYNC = IN, TA = +25°C, unless otherwise noted.)

4

MAX768

3

2

SUPPLY CURRENT (mA)

1

0

0 40 120 320

SHDN SUPPLY CURRENT

20

vs. SYNC FREQUENCY

18
16
14
12
10

SHDN SUPPLY CURRENT (µA)

90
80
70
60
50
40

EFFICIENCY (%)

30
20
10

0

V

IN

8
6

4
2
0

-40 -15 35 85

EFFICIENCY vs. LOAD CURRENT

(NOUT ONLY LOADED)

V

IN

0.1 1 10 100
LOAD CURRENT (mA)

SUPPLY CURRENT

VIN = 5.0V

V

= 3.3V

IN

16080 200 240 280

SYNC FREQUENCY (kHz)

vs. TEMPERATURE

= 5.0V

V

= 3.3V

IN

TEMPERATURE (°C)

= 3.0V

V

= 4.0V

IN

CHARGE-PUMP FREQUENCY

115

100

MAX768-TOC04

85

70

55

40

CHARGE-PUMP FREQUENCY (kHz)

25

10

0.40

0.35

MAX768-TOC07

0.30

0.25

0.20

0.15

0.10

SHDN SUPPLY CURRENT (µA)

0.05
0

MAX768 TOC10

EFFICIENCY (%)

-0.05

90
80
70
60
50
40
30
20
10

0

6010

vs. SUPPLY VOLTAGE

SYNC = IN

SYNC = GND

2.5 3.0 4.0 6.0

SHDN SUPPLY CURRENT

-40 -15 35 85

EFFICIENCY vs. OUTPUT CURRENT

(POUT ONLY LOADED)

V

IN

0.1 1 10 100
OUTPUT CURRENT (mA)

4.53.5 5.0 5.5

SUPPLY VOLTAGE (V)

vs. TEMPERATURE

V

IN

TEMPERATURE (°C)

= 3.0V

V

= 4.0V

IN

= 5.0V

V

IN

V

IN

= 4.0V
= 3.3V

6010

120

MAX768-TOC05

100

CHARGE-PUMP FREQUENCY (kHz)

MAX768-TOC08

SUPPLY CURRENT (mA)

MAX768 TOC11

EFFICIENCY (%)

CHARGE-PUMP FREQUENCY

vs. TEMPERATURE

V

= 3.3V

IN

SYNC = IN

80

60

40

20

0

-55 -35 5 125

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2
0

2.5 3.0 4.0 6.0

90
80
70
60
50
40
30
20
10

0

0.1 1 10 100

SYNC = GND

25-15 45 8565 105

TEMPERATURE (°C)

SUPPLY CURRENT

vs. SUPPLY VOLTAGE (NO LOAD)

f = 100kHz

f = 25kHz

SUPPLY VOLTAGE (V)

EFFICIENCY vs. OUTPUT CURRENT

LOAD BETWEEN POUT AND NOUT

V

= 3.0V

IN

OUTPUT CURRENT (mA)

5.04.5 5.53.5

V

= 4.0V

IN

MAX768-TOC06

MAX768-TOC09

MAX768 TOC12

4 _______________________________________________________________________________________

Low-Noise, Dual-Output, Regulated Charge Pump

for GaAsFET, LCD, and VCO Supplies

_____________________________Typical Operating Characteristics (continued)

(SYNC = IN, TA = +25°C, unless otherwise noted.)

POUT MAXIMUM OUTPUT CURRENT 

140

120

100

80

60

40

MAXIMUM OUTPUT CURRENT (mA)

20

0

vs. SUPPLY VOLTAGE

ONLY POUT LOADED

2.5 3.0 4.0
SUPPLY VOLTAGE (V)



MAX768-TOC13

5.04.53.5

TIME TO EXIT SHUTDOWN

NOUT MAXIMUM OUTPUT CURRENT 

vs. SUPPLY VOLTAGE

90

ONLY NOUT LOADED

80
70
60
50
40
30

20

MAXIMUM OUTPUT CURRENT (mA)

10

0

2.5 3.0 4.0 5.0

MAX768-TOC15





SUPPLY VOLTAGE (V)

+3V,

PSHDN = NSHDN

+5V, V

POUT

0V

MAX768-TOC14

4.53.5

MAX768

-5V, V

NOUT

0V,

RDY

1ms/div

POUT OUTPUT NOISE AND RIPPLE

POUT = +5V AT 5mA
IN = 3.0V

500µs/div

MAX768-TOC16



V

500µV/div

POUT,

AC COUPLED

NOUT OUTPUT NOISE AND RIPPLE

NOUT = -5V AT 5mA
IN = 3.0V

500µs/div



_______________________________________________________________________________________ 5

MAX768-TOC17

V

, 500µV/div

NOUT

AC COUPLED

Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies

______________________________________________________________Pin Description

PIN

MAX768

NAME FUNCTION

1 C1- Negative Terminal of the Doubler Charge-Pump Capacitor. See Table 2 for capacitor selection.
2 GND Ground
3 C2- Negative Terminal of the Inverter Charge-Pump Capacitor
4 V- Inverter Charge-Pump Output. See Table 2 for capacitor selection.
5 NOUT Negative Regulator Output. See Table 2 for capacitor selection.

6 SETN

7

NSHDN

8

PSHDN

9 SYNC

10

11 SETP
12 POUT Positive Regulator Output. See Table 2 for capacitor selection.

13 V+ Doubler Charge-Pump Output. See Table 2 for capacitor selection.
14 C1+ Positive Terminal of the Doubler Charge-Pump Capacitor. See Table 2 for capacitor selection.
15 IN Supply (3V to 5.5V). Bypass IN with 4.7µF to GND.
16 C2+ Positive Terminal of the Inverter Charge-Pump Capacitor. See Table 2 for capacitor selection.

RDY

Set Negative Output Voltage Input. Connect SETN to GND for factory-preset -5V. Connect a resistor
divider between NOUT, SETN, and GND for custom output voltage setting.

Negative-Supply Shutdown Input. Pull NSHDN low to turn off the inverting charge pump, the negative reg­ulator, and the bias-ready indicator. If PSHDN is also low, the part completely shuts down.

Positive-Supply Shutdown Input. Pull PSHDN low to turn off the positive regulator. If NSHDN is also low,
the part completely shuts down.

Clock Synchronizing Input. Connect an external 20kHz ≤ f
MAX768 to that frequency. Connect SYNC to GND to select the internal 25kHz clock, or to IN for the inter­nal 100kHz clock.

Output-Ready Indicator. This open-drain output pulls to GND when the negative output voltage (NOUT) is
within 10% of the regulation voltage.

Set Positive Output Voltage Input. Connect SETP to GND for factory-preset +5V output. Connect a resistor
divider between POUT, SETP, and GND for custom output voltage setting.

≤ 240kHz to SYNC to synchronize the

CLK

6 _______________________________________________________________________________________

Low-Noise, Dual-Output, Regulated Charge Pump

for GaAsFET, LCD, and VCO Supplies

IN

V+

P

POUT

MAX768

C1+

VOLTAGE 
DOUBLER

C1-

SHDN

Figure 1. Functional Diagram

PSHDN

SYNC

NSHDN

C2+

C2-

VOLTAGE 
INVERTER

V-

_______________Detailed Description

The MAX768 requires only seven external capacitors to
implement a regulated voltage doubler/inverter. These
can be ceramic or polarized electrolytic capacitors rang­ing from 2.2µF to 47µF. Figure 1 is a functional diagram of
the MAX768. The applied input voltage (VIN) is first dou­bled to a value of 2VINby a capacitor charge pump and
then stored in the V+ reservoir capacitor. Next, the volt­age at V+ is inverted to -2VINand stored at the V- reser­voir capacitor. The voltages at V+ and V- are then linear
regulated and appear at POUT and NOUT, respectively.
The ripple noise induced by the doubling and inverting
charge pump is reduced by the linear regulators to

1.2mVp-p for POUT and 1.7mVp-p for NOUT. In addition,
the linear regulator’s excellent AC rejection attenuates
noise from the incoming supply. A minimum of 5mA is
available at each output. When NOUT is more negative
than 90% of the regulated output voltage, the open-drain
RDY output pulls to GND.

The charge pump operates in three modes: when SYNC
= GND, the charge pump operates at 25kHz; when
SYNC = IN, it operates at 100kHz, or SYNC can be over-
driven with an external clock in the 20kHz to 240kHz
range. The clock must have a 40% to 60% duty cycle.

MAX768

SETP

+1.25V

REF

-1.25V

N

CONNECT TO GND
TO SET V

GND

N

RDY

SETN
CONNECT TO GND

TO SET V

NOUT

POUT

NOUT

= +5V

= -5V

__________Applications Information

Connect SETP or SETN directly to GND to select a fixed
+5V or -5V output voltage, respectively (Figure 2).
Select an alternative voltage for either output by con­necting SETP or SETN to the midpoint of a resistor volt­age divider from POUT or NOUT, respectively, to GND
(Figure 3). (2 x VIN) must be 1.0V above the absolute
value of the output voltage to ensure proper regulation.
Calculate the output voltage from the formulas below.
Choose R1 and R3 at between 100kΩ to 400kΩ.

where V

PSET REF

V

NSET REF

= -1.25V (typical).

Setting the Output Voltage

R2 = R1

()

R4 = R3

()



V

POUT



V



PSET REF



V



V



NSET REF

NOUT

−

−

1






1






= 1.25V (typical) and

_______________________________________________________________________________________ 7

Low-Noise, Dual-Output, Regulated Charge Pump

PSHDN

NSHDN

for GaAsFET, LCD, and VCO Supplies

Table 1. Shutdown-Control Logic

POUT

MAX768

Positive output active11

Positive output inactive10

STATUS

Table 2. Charge-Pump Capacitor Selection (Figure 2)

NOUT

STATUS

Negative output active
Negative output inactive 0.7Positive output active01
Negative output active 0.3
Shutdown (low-power mode) 0.0001Shutdown (low-power mode)00

SUPPLY

CURRENT

(mA)

0.8

SYNC

INPUT

FREQUENCY

(kHz)

25GND

100IN

20 to 240External Clock

C1, C2, C3, C4 C5, C6 C7

10µF

2.2µF

C = 220µF/f (kHz)

Shutdown

The MAX768 has two active-low, TTL logic-level shut­down inputs: PSHDN and NSHDN. When both inputs
are pulled low, the MAX768 shuts down and the supply
current is reduced to 10µA max over temperature.
Pulling PSHDN low turns off the positive linear regula­tor; the doubler charge pump remains active. Pulling
the NSHDN input low while PSHDN remains high turns
off the inverter charge pump, the negative linear regula­tor, and the output-ready indicator (Table 1).

Capacitors

The overall dropout voltage is a function of the charge
pump’s output resistance and the voltage drop across
the linear regulator. The charge-pump output resistance
is a function of the switching frequency and the capaci­tor’s ESR value. Therefore, minimizing the charge-pump
capacitors’ ESR minimizes dropout voltage.

R 84 8 C1 C3

=+

POUT ESR ESR

R 84 8 C1 4 C2

=+

NOUT ESR ESR

(C4 )

()
()

ESR

+

()

+

()

2

++

fC1

OSC OSC

fC2

+

fC1

OSC

+

1

2

CAPACITORS

V

IN

C2

C4

10µF

C1­GND

C2-

V­NOUT
SETN

NSHDN

PSHDN

MAX768

C2+

C1+

POUT

SETP

RDY

SYNC

4.7µF

C1

IN

C3

V+

C7

+5V

C5

TO
V

IN

C6

-5V

See Table 2 for capacitor selection. All capacitors

SEE TABLE 2 FOR CAPACITOR VALUES

should be either surface-mount ceramic chip or tanta­lum. External capacitor values may be adjusted to opti­mize size, performance, and cost.

8 _______________________________________________________________________________________

Figure 2. MAX768 Standard Application Circuit

Low-Noise, Dual-Output, Regulated Charge Pump

for GaAsFET, LCD, and VCO Supplies

R2

= (1.25) (1+ )

V

V

IN

C1

C2

Figure 3. MAX768 Adjustable Configuration

IN
SYNC

C1+

C1­C2+

C2-

NSHDN

PSHDN

POUT

SETP

MAX768

GND

SETN

NOUT

RDY

POUT

R2

V

R1

R3

R4

NOUT

V+

V-

Switching-Frequency Control

For applications sensitive to the MAX768’s internal
switching frequency, connect an external TTL/CMOS
(within IN and GND) clock to SYNC. The clock must be
a 20kHz to 240kHz square wave between 40% and
60% duty cycle.

Schottky Diodes

When under heavy loads, where POUT is sourcing into
NOUT (i.e., load current flows from POUT to NOUT,
rather than from supply to ground), do not allow NOUT
to pull above ground. In applications where large cur­rents from POUT to NOUT are likely, use a Schottky
diode (1N5817) between GND and NOUT, with the
anode connected to GND (Figure 4).

Connect a IN5817-type Schottky diode from C2- to V­to assure proper start-up.

C3

C4

= (-1.25) (1 + )

R1

GND

C5

C6

R4
R3

Figure 4. A Schottky diode protects the MAX768 when a large
current flows from POUT to NOUT.

MAX768

NOUT

Layout and Grounding

Good layout is important, primarily for good noise per­formance:

1) Mount all components as close together as possi­ble.

2) Keep traces short to minimize parasitic inductance
and capacitance. This includes connections to
SETP and SETN.

3) Use a ground plane.

Noise and Ripple Measurement

Accurately measuring output noise and ripple can be
difficult. Brief differences in ground potential between
the circuit and the oscilloscope (which result from the
charge pump’s switching action) cause ground cur­rents in the probe’s wires, inducing sharp voltage
spikes. For best results, measure directly across output
capacitor C3, C4, C5, or C6. Do not use the oscillo­scope probe’s ground lead; instead, remove the
cover’s ground lead and touch the ground ring on the
probe directly to the ground terminal of C3, C4, C5, or
C6. Or, use a Tektronix chassis-mount test jack (part
no. 131-0258) to connect your scope probe directly.
This direct connection provides the most accurate
noise and ripple measurement.

MAX768

_______________________________________________________________________________________ 9

Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies

__________________Pin Configuration

TOP VIEW

16

C2+
IN

15
14

C1+

13

V+

12

POUT

11

SETP

10

RDY

9

SYNC

MAX768

NSHDN

PSHDN

C1-

GND

C2-

NOUT

SETN

1
2
3
4

MAX768

V-

5
6
7
8

QSOP

___________________Chip Information

TRANSISTOR COUNT: 657
SUBSTRATE CONNECTED TO GND

10 ______________________________________________________________________________________

Low-Noise, Dual-Output, Regulated Charge Pump

for GaAsFET, LCD, and VCO Supplies

________________________________________________________Package Information

INCHES MILLIMETERS

DIM



D

A

e

A1

B

S

H

E

A
A1
A2

B

C

D

E

e

H

h

L
N
S

α

MAX

MIN

0.061

0.0098

0.004

0.055

0.008

0.0098

0.0075
SEE PIN COUNT VARIATIONS

0.150

0.230

0.010

0.016
SEE PIN COUNT VARIATIONS
SEE PIN COUNT VARIATIONS

0°

0.068

0.061

0.012

0.157

0.244

0.016

0.035

8°

MIN

1.55

0.127

1.40

0.20

0.19

3.81

0.635 BSC0.25 BSC

5.84

0.25

0.41

0°

MAX

1.73

0.25

1.55

0.31

0.25

3.99

6.20

0.41

0.89

8°

DIM

D
S
D
S
D
S
D
S



h x 45°

N

A2

α

SMALL-OUTLINE

E

C

L

INCHES MILLIMETERS

PINS

MIN

0.189

0.0020

0.337

0.0500

0.337

0.0250

0.386

0.0250

MAX

0.196

0.0070

0.344

0.0550

0.344

0.0300

0.393

0.0300

16
16
20
20
24
24
28
28

QSOP

QUARTER

PACKAGE

MIN

4.80

0.05

8.56

1.27

8.56

0.64

9.80

0.64

MAX

4.98

0.18

8.74

1.40

8.74

0.76

9.98

0.76

21-0055A

MAX768

______________________________________________________________________________________ 11

Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies

NOTES

MAX768

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

12

__________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 [phone]

12

__________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 [phone]

12

__________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 [phone]

12

__________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 [phone]

© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.