LT3055_15 Datasheet, PDF (1/26 Pages) Linear Technology – 500mA, Linear Regulator with Precision Current Limit and Diagnostics

FEATURES
n _{Output Current: 500mA}
n _{Dropout Voltage: 350mV}
n _{Input Voltage Range: 1.8V to 45V}
n _{Programmable Precision Current Limit: ±10%}
n _{Output Current Monitor: 1/500th of IOUT}
n _{Programmable Minimum IOUT Monitor}
n _{Temperature Monitor: 10mV/°C}
n _{FAULT Indicator: Current Limit, Thermal Limit or}
Minimum I_OUT
n _{Low Noise: 25μVRMS (10Hz to 100kHz)}
n _{Adjustable Output (VREF = VOUT(MIN) = 0.6V)}
n _{Output Tolerance: ±2% Over Load, Line and Temperature}
n _{Stable with Low ESR, Ceramic Output Capacitors}
(3.3μF Minimum)
n _{Shutdown Current: <1μA}
n _{Reverse Battery and Thermal Limit Protection}
n _{16-Lead 4mm × 3mm DFN and MSOP Packages}
APPLICATIONS
n _{Protected Antenna Supplies}
n _{Automotive Telematics}
n _{Industrial Applications (Trucks, Forklifts, etc.)}
n _{High Reliability Applications}
n _{Noise-Sensitive RF or DSP Supplies}
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LT3055 Series
500mA, Linear Regulator
with Precision Current Limit
and Diagnostics
DESCRIPTION
The LT^®3055 series are micropower, low noise, low dropout
voltage (LDO) linear regulators. The devices supply 500mA
of output current with a dropout voltage of 350mV. A 10nF
bypass capacitor reduces output noise to 25μV_RMS in a
10Hz to 100kHz bandwidth and soft starts the reference.
The LT3055’s ±45V input voltage rating combined with its
precision current limit and diagnostic functions make the
IC an ideal choice for robust, high reliability applications.
A single resistor programs the LT3055’s current limit, ac-
curate to ±10% over a wide input voltage and temperature
range. Another resistor programs the LT3055’s minimum
output current monitor, useful for detecting open-circuit
conditions. The current monitor function sources a current
equal to 1/500th of output current. Logic fault pins assert
low if the LT3055 is in current limit (FAULT2), operating
below its minimum output current (FAULT1) or is in thermal
limit (both FAULT1 and FAULT2). PWRGD indicates output
regulation. The TEMP pin indicates average die temperature.
The LT3055 optimizes stability and transient response
with low ESR ceramic capacitors, requiring a minimum of
3.3μF. Internal protection circuitry includes current limit-
ing, thermal limiting, reverse battery protection, reverse
current protection and reverse output protection.
The LT3055 is available in fixed output voltages of 3.3V
and 5V, and as an adjustable device with an output voltage
range from 0.6V to 40V.
TYPICAL APPLICATION
+
V_IN
6V
5V Supply with 497mA Precision Current Limit, 10mA I_MIN
10µF
22nF
LT3055-5
IN
OUT
200k 200k 200k SHDN SENSE
FAULT1
FAULT2 ADJ
PWRGD
604Ω
I_MAX
(THRESHOLD = 497mA)
I_MON
0.1µF
120k
(THRESHOLD = 10mA)
TEMP
I_MIN REF/BYP
GND
5V
10nF
10µF
1k
(ADC
FULL-SCALE = 1V)
10nF
3055 TA01a
TO
µP
0.1µF ^ADC
TO
µP
ADC
Precision Current Limit, R_IMAX = 604Ω
550
V_OUT(NOMINAL) = 5V
540
530
520
510
V_IN = 7V
500
490
V_IN = 5.6V
480
470
460
450
–75 –50 –25 0 25 50 75 100 125 150 175
TEMPERATURE (°C)
3055 TA01b
For more information www.linear.com/LT3055
3055fa
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