LT1965 Series
1.1A, Low Noise,
Low Dropout Linear Regulator
FEATURES
DESCRIPTION
TheLT®1965seriesarelownoise, lowdropoutlinearregu-
lators. The devices supply 1.1A of output current with a
310mVtypicaldropoutvoltage.Operatingquiescentcurrent
is 500μA for the adjustable version, reducing to <1μA in
shutdown. Quiescentcurrentiswellcontrolled;itdoesnot
rise in dropout as with many other regulators. The LT1965
regulators have very low output noise which makes them
ideal for sensitive RF and DSP supply applications.
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Output Current: 1.1A
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Dropout Voltage: 310mV
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Low Noise: 40μV
(10Hz to 100kHz)
RMS
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500μA Quiescent Current (Adjustable Version)
Wide Input Voltage Range: 1.8V to 20V
No Protection Diodes Needed
Controlled Quiescent Current in Dropout
Adjustable Output from 1.20V to 19.5V
Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3.3V
< 1μA Quiescent Current in Shutdown
Stable with 10μF Output Capacitor
Stable with Ceramic, Tantalum or Aluminum
Electrolytic Capacitors
Reverse Battery Protection
No Reverse Current
Current Limit with Foldback Protection
Thermal Limiting
Output voltage ranges from 1.20V to 19.5V. The LT1965
regulators are stable with output capacitors as low as
10μF. Internal protection circuitry includes reverse battery
protection, currentlimitingwithfoldback, thermallimiting
and reverse current protection. The LT1965 series are
available in fixed output voltages of 1.5V, 1.8V, 2.5V, 3.3V,
andasanadjustabledevicewitha1.20Vreferencevoltage.
The package offerings include the 5-lead TO-220, 5-lead
DD-PAK as well as the thermally enhanced 8-lead MSOP
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5-Lead TO-220, DD-PAK, Thermally Enhanced 8-Lead
MSOP and 8-Lead 3mm × 3mm DFN Packages
and low-profile (0.75mm) 8-lead 3mm × 3mm DFN.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
APPLICATIONS
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Logic Power Supplies
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Post Regulator for Switching Supplies
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Low Noise Instrumentation
TYPICAL APPLICATION
Dropout Voltage
3.3V to 2.5V Regulator
400
T
= 25°C
J
350
300
250
200
150
100
50
2.5V
1.1A
IN
OUT
LT1965-2.5
+
> 3V
+
V
IN
10μF*
10μF*
TO 20V
SHDN SENSE
GND
*CERAMIC, TANTALUM OR
ALUMINUM ELECTROLYTIC
1965 TA01
0
0
0.2
0.6
0.8
1
1.2
0.4
OUTPUT CURRENT (A)
1965 TA01b
1965fa
1