LTC1682_15 Datasheet, PDF (5/12 Pages) Linear Technology – Doubler Charge Pumps with Low Noise Linear Regulator

LTC1682/LTC1682-3.3/LTC1682-5
TYPICAL PERFOR A CE CHARACTERISTICS
V_OUT Voltage vs Temperature
5.030
5.020
5.010
V_IN = 3V
I_OUT = 10mA
5.000
4.990
LTC1682-5
3.340
3.330
3.320
3.310
LTC1682-3.3
3.300
3.290
1.240
1.238
1.236
LTC1682
1.234
–50 –25 0 25 50 75 100 125
TEMPERATURE (°C)
1682 G09
V_OUT Voltage vs Output Current
5.000
4.999
4.998
4.997
4.996
4.995
4.994
4.993
V_IN = 3.3V
T_A = 25°C
LTC1682-5
3.300
3.299
3.298
3.297
3.296
3.295
3.294
0
LTC1682-3.3
5 10 15 20 25 30 35 40 45 50
OUTPUT CURRENT (mA)
1682 G10
PIN FUNCTIONS
V_OUT (Pin 1): Low Noise Regulated Output Voltage. V_OUT
should be bypassed with a ≥ 2µF low ESR capacitor as
close to the pin as possible for best performance. The V_OUT
range is 2.5V to 5.5V.
SHDN (Pin 2): Shutdown Input. A logic low on the SHDN
pin puts the part in shutdown mode. A logic high enables
the part. To continuously enable the part connect SHDN to
V_IN. When the part is in shutdown, V_OUT will be connected
to ground via a 100Ω switch and CPO will be high
impedance disconnected from V_IN.
FB (Pin 3) (LTC1682): The voltage on this pin is compared
to the internal reference voltage (1.235V) by the error
amplifier to keep the output in regulation. An external
resistor divider is required between V_OUT and FB to adjust
the output voltage.
FILT (Pin 3) (LTC1682-3.3/LTC1682-5): This pin is used
to filter the internal voltage reference. Typically a 1nF
capacitor is connected from FILT to ground.
GND (Pin 4): System Ground.
C ^– (Pin 5): Flying Capacitor Negative Input.
V_IN (Pin 6): Input Voltage, 1.8V to 4.4V. V_IN should be
bypassed with a ≥ 2µF low ESR capacitor as close to the
pin as possible for best performance. A minimum capaci-
tance value of 0.1µF is required.
C⁺ (Pin 7): Flying Capacitor Positive Input.
CPO (Pin 8): Unregulated Charge Pump Output Voltage.
Approximately 1.95(V_IN) at low loads. Bypass with a ≥ 2µF
low ESR capacitor. If a minimum V_OUT enable time is
required, the CPO capacitor should be 2× the V_OUT
capacitor.
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