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MAX768EEE+T

P1-P3P4-P6P7-P9P10-P12
_______________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 hand-
sets. 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 combina-
tion 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 load-
ing (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 exter-
nal clock from 20kHz to 240kHz. This flexibility permits
users to optimize their designs based on noise, capaci-
tor 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
OUT
from 3V
IN
♦ 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
MAX768
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
________________________________________________________________
Maxim Integrated Products
1
MAX768
POUT
V+
C3
C5
C7
POSITIVE
OUTPUT
+5V
NEGATIVE
OUTPUT
-5V
OUTPUT-
READY
SIGNAL
C6
C4
C1
C2
V-
NOUT
RDY
SYNC
V
IN
(3.0V TO 5.5V)
IN
GND
SETPSETN
PSHDN
NSHDN
C1+
C1-
C2+
C2-
__________Typical Operating Circuit
19-1174; Rev 0; 12/96
PART
MAX768C/D
MAX768EEE -40°C to +85°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
Dice*
16 QSOP
______________Ordering Information
*
Dice are specified at T
A
= +25°C, DC parameters only.
Pin Configuration appears at end of data sheet.
Dual Mode is a trademark of Maxim Integrated Products.
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
MAX768
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= +3V, SYNC = IN, SETN = SETP = GND, NSHDN = PSHDN = IN, T
A
= -40°C to +85°C, unless otherwise noted. Typical values
are at T
A
= +25°C. See Figure 2.) (Note 1)
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.
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 (T
A
= +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
0mA < I
LOAD
< 5mA, V
IN
= 3.0V to 5.5V
I
LOAD
= 0
NSHDN = PSHDN = SYNC = GND
V
SHDN
= 3V
V
IN
= 3V to 5.5V
NSHDN = GND
(Note 2)
(Note 3)
V
IN
= 3V, V
POUT
≥ 4.81V, V
NOUT
≤ -4.82V
V
IN
= 3.0V
I
POUT
= 0mA to 5mA,
I
NOUT
= 0mA to -5mA
CONDITIONS
µA0.1 10Shutdown Supply Current
µA0.1 2
SHDN Input Bias Current
V2.0Shutdown/SYNC Logic-High Input Threshold
V0.4Shutdown/SYNC Logic-Low Input Threshold
%/mA0.06 0.12Load Regulation
V-5.10 -5.00 -4.82Negative Output Voltage
V2.5
V3.0 5.5Input Voltage Range
Minimum Input Start-Up Voltage
%/V-0.12 0.0 0.12Line Regulation
mA0.3
No-Load Supply Current at 100kHz
(negative regulator off)
V1.25 11Positive Output Voltage Adjustable Range
V-11 -1.25Negative Output Voltage Adjustable Range
mA5Maximum POUT, NOUT Output Currents
mA
0.8 1.4
No-Load Supply Current at 100kHz
(both regulators active)
UNITSMIN TYP MAXPARAMETER
V
SYNC
= GND mA0.45 0.80
No-Load Supply Current at 25kHz
(both regulators active)
mV
420 900
Dropout Voltage (2 x V
IN
-
|
V
OUT
|
)
20
V
IN
= 5.5V 1.5
I
POUT
= I
NOUT
= 5mA
2 x V
IN
-
|
V
OUT
|
0mA < I
LOAD
< 5mA, V
IN
= 3.0V to 5.5V V4.81 5.00 5.14Positive Output Voltage
C
POUT
=C
NOUT
=
10µF,
10kHz < f < 1MHz
1.7
POUT
NOUT
mVp-p
1.2
Output Voltage Noise
SHUTDOWN
I
POUT
= I
NOUT
= 0.1mA
MAX768
Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= +3V, SYNC = IN, SETN = SETP = GND, NSHDN = PSHDN = IN, T
A
= -40°C to +85°C, unless otherwise noted. Typical values
are at T
A
= +25°C. See Figure 2.) (Note 1)
SYNC = GND (divide by 4)
CONDITIONS
µA0.1 2SYNC Input Leakage Current
21.5 25 28.5
%40 60SYNC Duty Cycle (external)
kHz20 240SYNC Frequency Range (external)
UNITSMIN TYP MAXPARAMETER
I
NOUT
= 0.1mA
I
POUT
= 0.1mA
V
-1.275 -1.25 -1.225
Negative Set-Reference Voltage
-1.270 -1.25 -1.230
V
1.215 1.25 1.285
Positive Set-Reference Voltage
1.217 1.25 1.283
V
RDY
= 10V
Percent of V
NOUT
, I
NOUT
= 5mA
V
SETP
= V
SETN
= 1.3V
mA10Maximum Sink Current
µA0.01 2Output Off Current
%85 94 98
RDY Output Threshold
µA0.01 0.1SETP, SETN Input Leakage Current
V
SYNC
= 3V
kHz
85 100 115
Oscillator Frequency (internal)
T
A
= +25°C
T
A
= -40°C to + 85°C
T
A
= +25°C
T
A
= -40°C to + 85°C
I
SINK
= 2mA V0.25Output Low Voltage
SYNC
SET INPUT
OUTPUT
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
IN
- dropout voltage.
Note 3: Maximum output voltage range is from the negative reference voltage to -2 x V
IN
+ dropout voltage.
__________________________________________Typical Operating Characteristics
(SYNC = IN, T
A
= +25°C, unless otherwise noted.)
0.30
IN = 3.0V
NOUT = -5V
POUT = +5V
0
0 5 15 25
mV
RMS
OUTPUT VOLTAGE
vs. OUTPUT CURRENT
0.10
MAX768-TOC01
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (mV
RMS
)
10 20
0.20
5.2
4.0
0 5 15 30
POUT OUTPUT VOLTAGE 
vs. OUTPUT CURRENT
4.2
4.8
5.0
MAX768-TOC02
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
10 20 25
4.6
4.4
IN = 4.0V
IN = 3.0V
ONLY POUT LOADED
-4.2
-5.0
0 5 15 30
NOUT OUTPUT VOLTAGE vs. 
OUTPUT CURRENT
-4.9
-4.4
-4.3
MAX768-TOC03
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
10 20 25
-4.5
-4.7
-4.8
-4.6
IN = 4.0V
IN = 3.0V
ONLY NOUT LOADED
P1-P3P4-P6P7-P9P10-P12

MAX768EEE+T

Mfr. #:
Buy MAX768EEE+T
Manufacturer:
Maxim Integrated
Description:
IC REG CHG PUMP ADJ/5V 16QSOP
Lifecycle:
New from this manufacturer.
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