Maxim MAX768 Low-noise, dual-output, regulated charge pump for gaasfet, lcd, and vco supply Datasheet

19-1174; Rev 0; 12/96
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
____________________________Features
♦ Dual Positive/Negative Regulated Outputs:
±5VOUT from 3VIN
♦ 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
______________Ordering Information
PART
Dual Mode is a trademark of Maxim Integrated Products.
__________Typical Operating Circuit
VIN
(3.0V TO 5.5V)
C7
SYNC
POUT
V+
NSHDN
C5
C3
C1+
MAX768
C1
C4
C1-
Positive and Negative LCD Supply
V-
C2+
Cellular Phone
Wireless Handheld Computers
POSITIVE
OUTPUT
+5V
IN
PSHDN
Voltage-Controlled Oscillator (VCO) Supply
Wireless Handsets
Dice*
16 QSOP
Pin Configuration appears at end of data sheet.
GaAsFET Power Amp Bias
PCS and Cordless Phone
PIN-PACKAGE
0°C to +70°C
-40°C to +85°C
*Dice are specified at TA = +25°C, DC parameters only.
________________________Applications
Tuner Diode Power Supply
TEMP. RANGE
MAX768C/D
MAX768EEE
NOUT
C2
C6 NEGATIVE
OUTPUT
-5V
C2RDY
SETN
GND
SETP
OUTPUTREADY
SIGNAL
Wireless PCMCIA Cards
Modems
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
MAX768
_______________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.
MAX768
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
POUT to V+ ........................................................... -12V to +0.3V
Continuous Power Dissipation (TA = +70°C)
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
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.
ELECTRICAL CHARACTERISTICS
(VIN = +3V, SYNC = IN, SETN = SETP = GND, NSHDN = PSHDN = IN, TA = -40°C to +85°C, unless otherwise noted. Typical values
are at TA = +25°C. See Figure 2.) (Note 1)
PARAMETER
CONDITIONS
Input Voltage Range
MIN
TYP
3.0
MAX
UNITS
5.5
V
Minimum Input Start-Up Voltage
ILOAD = 0
2.5
Positive Output Voltage
0mA < ILOAD < 5mA, VIN = 3.0V to 5.5V
4.81
5.00
5.14
V
V
Negative Output Voltage
0mA < ILOAD < 5mA, VIN = 3.0V to 5.5V
-5.10
-5.00
-4.82
V
Positive Output Voltage Adjustable Range
(Note 2)
1.25
11
V
Negative Output Voltage Adjustable Range
(Note 3)
-11
-1.25
Maximum POUT, NOUT Output Currents
VIN = 3V, VPOUT ≥ 4.81V, VNOUT ≤ -4.82V
No-Load Supply Current at 100kHz
(both regulators active)
VIN = 3.0V
0.8
VIN = 5.5V
1.5
No-Load Supply Current at 100kHz
(negative regulator off)
NSHDN = GND
0.3
No-Load Supply Current at 25kHz
(both regulators active)
VSYNC = GND
0.45
Dropout Voltage (2 x VIN - |VOUT|)
2 x VIN - | VOUT |
Line Regulation
VIN = 3V to 5.5V
Load Regulation
IPOUT = 0mA to 5mA,
INOUT = 0mA to -5mA
Output Voltage Noise
CPOUT = CNOUT = 10µF,
10kHz < f < 1MHz
5
V
mA
1.4
mA
mA
0.80
mA
IPOUT = INOUT = 0.1mA
20
IPOUT = INOUT = 5mA
420
900
0.0
0.12
%/V
0.06
0.12
%/mA
-0.12
POUT
1.2
NOUT
1.7
Shutdown/SYNC Logic-Low Input Threshold
mVp-p
0.4
Shutdown/SYNC Logic-High Input Threshold
mV
2.0
V
V
SHUTDOWN
SHDN Input Bias Current
VSHDN = 3V
0.1
2
µA
Shutdown Supply Current
NSHDN = PSHDN = SYNC = GND
0.1
10
µA
2
_______________________________________________________________________________________
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
(VIN = +3V, SYNC = IN, SETN = SETP = GND, NSHDN = PSHDN = IN, TA = -40°C to +85°C, unless otherwise noted. Typical values
are at TA = +25°C. See Figure 2.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
SYNC
SYNC Frequency Range (external)
20
240
kHz
SYNC Duty Cycle (external)
40
60
%
SYNC = GND (divide by 4)
Oscillator Frequency (internal)
21.5
25
28.5
85
100
115
0.1
2
VSYNC = 3V
SYNC Input Leakage Current
kHz
µA
SET INPUT
TA = +25°C
1.217
1.25
1.283
TA = -40°C to + 85°C
1.215
1.25
1.285
TA = +25°C
-1.270
-1.25
-1.230
TA = -40°C to + 85°C
-1.275
-1.25
-1.225
0.01
0.1
µA
98
%
Positive Set-Reference Voltage
IPOUT = 0.1mA
Negative Set-Reference Voltage
INOUT = 0.1mA
SETP, SETN Input Leakage Current
VSETP = VSETN = 1.3V
RDY Output Threshold
Percent of VNOUT, INOUT = 5mA
Output Low Voltage
ISINK = 2mA
Output Off Current
VRDY = 10V
RDY OUTPUT
85
94
0.01
Maximum Sink Current
V
V
0.25
V
2
µA
10
mA
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 VIN - dropout voltage.
Note 3: Maximum output voltage range is from the negative reference voltage to -2 x VIN + dropout voltage.
__________________________________________Typical Operating Characteristics
(SYNC = IN, TA = +25°C, unless otherwise noted.)
0.20
NOUT = -5V
POUT = +5V
0.10
5.0
-4.2
4.8
IN = 3.0V
4.6
4.4
MAX768-TOC03
IN = 4.0V
MAX768-TOC02
ONLY POUT LOADED
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (mVRMS)
IN = 3.0V
NOUT OUTPUT VOLTAGE vs.
OUTPUT CURRENT
5.2
MAX768-TOC01
0.30
POUT OUTPUT VOLTAGE
vs. OUTPUT CURRENT
ONLY NOUT LOADED
-4.3
OUTPUT VOLTAGE (V)
mVRMS OUTPUT VOLTAGE
vs. OUTPUT CURRENT
-4.4
-4.5
IN = 3.0V
-4.6
-4.7
-4.8
4.2
0
-4.9
4.0
0
5
10
15
OUTPUT CURRENT (mA)
20
25
IN = 4.0V
-5.0
0
5
10
15
20
OUTPUT CURRENT (mA)
25
30
0
5
10
15
20
25
30
OUTPUT CURRENT (mA)
_______________________________________________________________________________________
3
MAX768
ELECTRICAL CHARACTERISTICS (continued)
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
MAX768
____________________________Typical Operating Characteristics (continued)
(SYNC = IN, TA = +25°C, unless otherwise noted.)
VIN = 5.0V
2
VIN = 3.3V
1
55
40
SYNC = GND
25
120 160 200 240 280 320
80
60
40
SYNC = GND
20
0
2.5
3.0
4.0
3.5
4.5
5.0
5.5
6.0
-55 -35 -15
25
45
65
85 105 125
SHDN SUPPLY CURRENT
vs. TEMPERATURE
SUPPLY CURRENT
vs. SUPPLY VOLTAGE (NO LOAD)
8
6
4
2
0.30
0.25
0.20
VIN = 5.0V
0.15
0.10
0.05
35
60
1.2
f = 100kHz
1.0
0.8
f = 25kHz
0.6
0.2
VIN = 3.3V
-40
85
1.4
0.4
VIN = 4.0V
-0.05
10
1.6
0
0
MAX768-TOC09
0.35
VIN = 3.3V
-15
1.8
MAX768-TOC08
0.40
MAX768-TOC07
10
-15
10
35
60
0
85
2.5
3.0
4.0
3.5
4.5
5.0
5.5
TEMPERATURE (°C)
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
EFFICIENCY vs. LOAD CURRENT
(NOUT ONLY LOADED)
EFFICIENCY vs. OUTPUT CURRENT
(POUT ONLY LOADED)
EFFICIENCY vs. OUTPUT CURRENT
LOAD BETWEEN POUT AND NOUT
VIN = 3.0V
EFFICIENCY (%)
70
60
VIN = 4.0V
40
30
VIN = 4.0V
40
30
60
40
30
20
20
10
10
10
0
0
10
LOAD CURRENT (mA)
100
VIN = 4.0V
50
20
1
VIN = 3.0V
70
60
50
80
6.0
MAX768 TOC12
80
EFFICIENCY (%)
VIN = 3.0V
90
MAX768 TOC11
80
50
90
MAX768 TOC10
90
0.1
5
SHDN SUPPLY CURRENT
vs. TEMPERATURE
12
70
80
TEMPERATURE (°C)
14
-40
SYNC = IN
SUPPLY VOLTAGE (V)
VIN = 5.0V
16
100
SYNC FREQUENCY (kHz)
SHDN SUPPLY CURRENT (µA)
SHDN SUPPLY CURRENT (µA)
70
VIN = 3.3V
SUPPLY CURRENT (mA)
40
20
18
EFFICIENCY (%)
85
120
10
0
4
100
MAX768-TOC06
SYNC = IN
0
CHARGE-PUMP FREQUENCY
vs. TEMPERATURE
MAX768-TOC05
MAX768-TOC04
3
115
CHARGE-PUMP FREQUENCY (kHz)
SUPPLY CURRENT (mA)
4
CHARGE-PUMP FREQUENCY
vs. SUPPLY VOLTAGE
CHARGE-PUMP FREQUENCY (kHz)
SUPPLY CURRENT
vs. SYNC FREQUENCY
0
0.1
1
10
OUTPUT CURRENT (mA)
100
0.1
1
10
OUTPUT CURRENT (mA)
_______________________________________________________________________________________
100
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
(SYNC = IN, TA = +25°C, unless otherwise noted.)
POUT MAXIMUM OUTPUT CURRENT
vs. SUPPLY VOLTAGE
100
80
60
40
20
MAX768-TOC14
120
MAXIMUM OUTPUT CURRENT (mA)
ONLY POUT LOADED
MAXIMUM OUTPUT CURRENT (mA)
90
MAX768-TOC13
140
NOUT MAXIMUM OUTPUT CURRENT
vs. SUPPLY VOLTAGE
ONLY NOUT LOADED
80
70
60
50
40
30
20
10
0
0
2.5
3.0
3.5
4.0
4.5
2.5
5.0
3.0
SUPPLY VOLTAGE (V)
3.5
4.0
4.5
5.0
SUPPLY VOLTAGE (V)
TIME TO EXIT SHUTDOWN
MAX768-TOC15
+3V, PSHDN = NSHDN
+5V, VPOUT
0V
-5V, VNOUT
0V, RDY
1ms/div
POUT OUTPUT NOISE AND RIPPLE
NOUT OUTPUT NOISE AND RIPPLE
MAX768-TOC16
MAX768-TOC17
VPOUT, 500µV/div
AC COUPLED
VNOUT, 500µV/div
AC COUPLED
500µs/div
POUT = +5V AT 5mA
IN = 3.0V
500µs/div
NOUT = -5V AT 5mA
IN = 3.0V
_______________________________________________________________________________________
5
MAX768
_____________________________Typical Operating Characteristics (continued)
MAX768
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
______________________________________________________________Pin Description
6
PIN
NAME
1
C1-
FUNCTION
2
GND
3
C2-
4
V-
5
NOUT
Negative Regulator Output. See Table 2 for capacitor selection.
6
SETN
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.
7
NSHDN
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.
8
PSHDN
Positive-Supply Shutdown Input. Pull PSHDN low to turn off the positive regulator. If NSHDN is also low,
the part completely shuts down.
9
SYNC
Clock Synchronizing Input. Connect an external 20kHz ≤ fCLK ≤ 240kHz to SYNC to synchronize the
MAX768 to that frequency. Connect SYNC to GND to select the internal 25kHz clock, or to IN for the internal 100kHz clock.
10
RDY
Output-Ready Indicator. This open-drain output pulls to GND when the negative output voltage (NOUT) is
within 10% of the regulation voltage.
11
SETP
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.
12
POUT
Positive Regulator Output. See Table 2 for capacitor selection.
13
V+
14
C1+
15
IN
16
C2+
Negative Terminal of the Doubler Charge-Pump Capacitor. See Table 2 for capacitor selection.
Ground
Negative Terminal of the Inverter Charge-Pump Capacitor
Inverter Charge-Pump Output. See Table 2 for capacitor selection.
Doubler Charge-Pump Output. See Table 2 for capacitor selection.
Positive Terminal of the Doubler Charge-Pump Capacitor. See Table 2 for capacitor selection.
Supply (3V to 5.5V). Bypass IN with 4.7µF to GND.
Positive Terminal of the Inverter Charge-Pump Capacitor. See Table 2 for capacitor selection.
_______________________________________________________________________________________
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
MAX768
IN
V+
POUT
P
MAX768
C1+
VOLTAGE
DOUBLER
SETP
CONNECT TO GND
TO SET VPOUT = +5V
C1SHDN
PSHDN
SYNC
+1.25V
REF
-1.25V
NSHDN
GND
N
RDY
C2+
VOLTAGE
INVERTER
SETN
CONNECT TO GND
TO SET VNOUT = -5V
C2V-
NOUT
N
Figure 1. Functional Diagram
_______________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 2VIN by a capacitor charge pump and
then stored in the V+ reservoir capacitor. Next, the voltage at V+ is inverted to -2VIN and 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 overdriven with an external clock in the 20kHz to 240kHz
range. The clock must have a 40% to 60% duty cycle.
__________Applications Information
Setting the Output Voltage
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.
 VPOUT

R2 = R1 
− 1
 VPSET REF 
( )
 VNOUT

R4 = R3 
− 1
 VNSET REF 
( )
where VPSET REF = 1.25V (typical) and
VNSET REF = -1.25V (typical).
_______________________________________________________________________________________
7
MAX768
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
Table 1. Shutdown-Control Logic
SUPPLY
CURRENT
(mA)
PSHDN
NSHDN
1
1
Positive output active
Negative output active
0.8
1
0
Positive output active
Negative output inactive
0.7
0
1
Positive output inactive
Negative output active
0
0
Shutdown (low-power mode)
Shutdown (low-power mode)
POUT
STATUS
NOUT
STATUS
0.3
0.0001
Table 2. Charge-Pump Capacitor Selection (Figure 2)
CAPACITORS
SYNC
INPUT
FREQUENCY
(kHz)
C1, C2, C3, C4
GND
25
10µF
IN
100
2.2µF
External Clock
20 to 240
C = 220µF/f (kHz)
C5, C6
C7
10µF
4.7µF
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).
VIN
C2
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.
RPOUT = 84 + 8(C1ESR ) + (C3ESR ) +
RNOUT = 84 + 8(C1ESR ) + 4(C2ESR ) +
(C4ESR ) +
2
fOSCC1
+
2
fOSCC1
C2+
GND
IN
C2-
C1+
V-
V+
C1
C7
C3
C4
MAX768
NOUT
POUT
SETN
SETP
+5V
C5
NSHDN
RDY
PSHDN
SYNC
TO
VIN
C6
1
-5V
fOSCC2
See Table 2 for capacitor selection. All capacitors
should be either surface-mount ceramic chip or tantalum. External capacitor values may be adjusted to optimize size, performance, and cost.
8
C1-
SEE TABLE 2 FOR CAPACITOR VALUES
Figure 2. MAX768 Standard Application Circuit
_______________________________________________________________________________________
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
POUT
IN
MAX768
VPOUT = (1.25) (1+
VIN
R2
)
R1
R2
GND
SYNC
SETP
C5
C1+
MAX768
R1
C1
MAX768
V+
C1-
NOUT
C3
C2+
GND
C2-
V-
C4
C2
NSHDN
PSHDN
R3
C6
SETN
Figure 4. A Schottky diode protects the MAX768 when a large
current flows from POUT to NOUT.
R4
NOUT
VNOUT = (-1.25) (1 +
R4
)
R3
RDY
Figure 3. MAX768 Adjustable Configuration
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.
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.
_______________________________________________________________________________________
9
MAX768
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
__________________Pin Configuration
___________________Chip Information
TRANSISTOR COUNT: 657
TOP VIEW
C1- 1
16 C2+
15 IN
GND 2
C2- 3
V- 4
SUBSTRATE CONNECTED TO GND
14 C1+
MAX768
13 V+
NOUT 5
12 POUT
SETN 6
11 SETP
NSHDN 7
10 RDY
PSHDN 8
9
SYNC
QSOP
10
______________________________________________________________________________________
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
DIM
A
A1
A2
B
C
D
E
e
H
h
L
N
S
α
D
A
e
A1
B
S
E
INCHES
MILLIMETERS
MAX
MIN
MIN
MAX
0.068
0.061
1.55
1.73
0.004 0.0098 0.127
0.25
0.061
0.055
1.40
1.55
0.012
0.008
0.20
0.31
0.0075 0.0098
0.19
0.25
SEE PIN COUNT VARIATIONS
0.157
0.150
3.81
3.99
0.25 BSC
0.635 BSC
0.244
0.230
5.84
6.20
0.016
0.010
0.25
0.41
0.035
0.016
0.41
0.89
SEE PIN COUNT VARIATIONS
SEE PIN COUNT VARIATIONS
8°
0°
0°
8°
H
h x 45°
α
A2
N
E
C
DIM PINS
D
S
D
S
D
S
D
S
16
16
20
20
24
24
28
28
INCHES
MILLIMETERS
MIN
MAX MIN
MAX
0.189 0.196 4.80
4.98
0.0020 0.0070 0.05
0.18
0.337 0.344 8.56
8.74
0.0500 0.0550 1.27
1.40
0.337 0.344 8.56
8.74
0.0250 0.0300 0.64
0.76
0.386 0.393 9.80
9.98
0.0250 0.0300 0.64
0.76
21-0055A
QSOP
QUARTER
SMALL-OUTLINE
PACKAGE
L
______________________________________________________________________________________
11
MAX768
________________________________________________________Package Information
MAX768
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
NOTES
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.
12 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600
© 1996 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.