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What is LT3990-3.3?

This electronic component, produced by the manufacturer "Linear", performs the same function as "350mA Step-Down Regulator".


LT3990-3.3 Datasheet PDF - Linear

Part Number LT3990-3.3
Description 350mA Step-Down Regulator
Manufacturers Linear　
Logo Linear Logo　


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Total 22 Pages



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FEATURES
n Low Ripple Burst Mode® Operation
2.5µA IQ at 12VIN to 3.3VOUT
Output Ripple < 5mVP-P
n Wide Input Voltage Range: 4.2V to 62V Operating
n Adjustable Switching Frequency: 200kHz to 2.2MHz
n Integrated Boost and Catch Diodes
n 350mA Output Current
n Fixed Output Voltages: 3.3V, 5V
2µA IQ at 12VIN
n Accurate Programmable Undervoltage Lockout
n FMEA Fault Tolerant (MSOP Package)
Output Stays at or Below Regulation Voltage During
Adjacent Pin Short or When a Pin is Left Floating
n Low Shutdown Current: IQ = 0.7µA
n Internal Sense Limits Catch Diode Current
n Power Good Flag
n Small, Thermally Enhanced 16-Pin MSOP
and (3mm × 3mm) DFN Packages
APPLICATIONS
n Automotive Battery Regulation
n Power for Portable Products
n Industrial Supplies
LT3990/LT3990-3.3/LT3990-5
62V, 350mA Step-Down
Regulator with 2.5µA
Quiescent Current and
Integrated Diodes
DESCRIPTION
The LT®3990 is an adjustable frequency monolithic buck
switching regulator that accepts a wide input voltage
range up to 62V, and consumes only 2.5µA of quiescent
current. A high efficiency switch is included on the die
along with the catch diode, boost diode, and the neces-
sary oscillator, control and logic circuitry. Low ripple Burst
Mode operation maintains high efficiency at low output
currents while keeping the output ripple below 5mV in a
typical application. Current mode topology is used for fast
transient response and good loop stability. A catch diode
current limit provides protection against shorted outputs
and overvoltage conditions. An accurate programmable
undervoltage lockout feature is available, producing a low
shutdown current of 0.7µA. A power good flag signals when
VOUT reaches 90% of the programmed output voltage. The
LT3990 is available in small, thermally enhanced 16-pin
MSOP and 3mm × 3mm DFN packages.
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
TYPICAL APPLICATION
5V Step-Down Converter
VIN
6.5V TO 62V
OFF ON
VIN BOOST
LT3990-5
EN/UVLO SW
PG BD
0.22µF
33µH
VOUT
5V
350mA
2.2µF
RT
374k
GND VOUT
f = 400kHz
22µF
3990 TA01a
1000
VIN = 12V
Power Loss
100
10
1
0.1
0.01
0.001
0.01 0.1 1 10
LOAD CURRENT (mA)
100
3990 TA01b
3990fa
1

line_dark_gray
LT3990-3.3 equivalent
LT3990/LT3990-3.3/LT3990-5
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted.
Maximum Load Current
600
H-GRADE
500 LIMITED BY CURRENT LIMIT
400
LIMITED BY MAXIMUM
300 JUNCTION TEMPERATURE
θJA = 45°C/W
200
100
FRONT PAGE APPLICATION
VIN = 12V
VOUT = 5V
0
–50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
3990 G10
Load Regulation
0.25
0.20
0.15
0.10
0.05
0
–0.05
–0.10
–0.15 FRONT PAGE APPLICATION
–0.20 REFERENCED FROM VOUT AT 100mA LOAD
0 50 100 150 200 250 300 350
LOAD CURRENT (mA)
3990 G11
Switch Current Limit
900
800
SWITCH PEAK CURRENT LIMIT
700
600
500
CATCH DIODE VALLEY CURRENT LIMIT
400
300
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3990 G13
vSswTitecmh pVeCrEaStAuTre(ISW = 200mA)
300
250
200
150
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3990 G16
Switching Frequency
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3990 G14
Switch VCESAT
600
500
400
300
200
100
0
0 100 200 300 400 500
SWITCH CURRENT (mA)
3990 G17
Switch Current Limit
800
700 SWITCH PEAK
CURRENT LIMIT
600
500
400 CATCH DIODE VALLEY CURRENT LIMIT
300
200
0
20 40 60 80
DUTY CYCLE (%)
100
3990 G12
Minimum
Switch On-Time/Switch Off-Time
250 LOAD CURRENT = 175mA
225
200
175
MINIMUM ON-TIME
150
125
100
75 MINIMUM OFF-TIME
50
25
0
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3990 G15
BOOST Pin Current
21
18
15
12
9
6
3
0
0 100 200 300 400 500
SWITCH CURRENT (mA)
3990 G18
3990fa
5


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Part Details

On this page, you can learn information such as the schematic, equivalent, pinout, replacement, circuit, and manual for LT3990-3.3 electronic component.


Information Total 22 Pages
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Download [ LT3990-3.3.PDF Datasheet ]

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Featured Datasheets

Part NumberDescriptionMFRS
LT3990-3.3The function is 350mA Step-Down Regulator. LinearLinear

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