Low-Noise, Dual-Output, Regulated Charge Pump
for GaAsFET, LCD, and VCO Supplies
MAX768
______________________________________________________________Pin Description
PIN
1
2
3
4
5
6
7
8
NAME
C1-
GND
C2-
V-
NOUT
SETN
NSHDN
PSHDN
FUNCTION
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.
Negative Regulator Output. See Table 2 for capacitor selection.
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 reg-
ulator, 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
CLK
≤
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 inter-
nal 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.
Positive Regulator 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.
9
SYNC
10
11
12
13
14
15
16
RDY
SETP
POUT
V+
C1+
IN
C2+
6
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MAXIM [ MAXIM INTEGRATED PRODUCTS ]
