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LINEAR LT3439 Data Sheet

Summary

This isolated, push-pull DC/DC transformer driver delivers ultralow noise with advanced slew rate control to drastically reduce conducted and radiated EMI. Featuring robust protection circuitry and low quiescent current, it is engineered for high reliability in critical power systems. The manual provides comprehensive electrical characteristics and application guidance, making the LT3439 ideal for precision instruments, medical devices, and radio/telecom supplies requiring clean, stable DC regulation.

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查询LT3439供应商

LT3439

Slew Rate Controlled Ultralow Noise1A Isolated DC/DC Transformer Driver

FEATURES DESCRIPTIO Reduced Conducted and Radiated EMI The LT®3439 is a push-pull DC/DC transformer driver that Single Resistor Control of Output Switch Voltage reduces conducted and radiated electromagnetic interfer- and Current Slew Rates ence (EMI). Ultralow noise and EMI are achieved by Cross Conduction Prevention Circuitry controlling the output switch voltage and current slew Two 1A Current Limited Power Switches rates. Slew rates are user adjustable to optimize output Low Minimum Supply Voltage: 2.8V noise versus efficiency. The LT3439 can reduce high Low Shutdown Current: <20µA frequency harmonic content by as much as 40d B with only 50% Duty Cycle a minor decrease in efficiency. 20k Hz to 250k Hz Oscillator Frequency

The LT3439 includes two 1A current limited power switches

Synchronizable to 300k Hz

to ensure start-up under heavy loads. It also includes an

Overcurrent and Overtemperature Protected

oscillator that can be synchronized to an external clock for more accurate placement of switcher harmonics. Protec- APPLICATIO S tion features include current limiting, undervoltage lock- out, thermal shutdown and cross conduction prevention

Low Noise Isolated Supplies circuitry. Radio and Telecom Supplies

The LT3439 is available in a thermally enhanced 16-pin

Distributed Supplies

TSSOP with an exposed backside.

Medical Instruments

, LTC and LT are registered trademarks of Linear Technology Corporation.

Precision Instruments Low Noise Filament Supplies

TYPICAL APPLICATIO Low Noise 5V to 5V Push-Pull DC/DC Transformer

5V Output Noise

OPTIONAL

VIN L1 33µH VOUT

13CIN C1 C2

10V VIN

SHDN COL A 200µV/DIV

LT3439 SYNC COL B CT D2

CIN: MURATA GRM235Y5V226Z10

RT RSL C1, C2: TDK C4532X5R0J476M D1, D2: MBR0520

16.9k GND PGND

20m V/DIV

34k L1: TDK SLF6028T-330MR69

1, 16 T1: COILTRONICS 15835

3439 TA01

5µs/DIV 3439 TA01b

sn3439 3439fs

Page Summary Contents For LINEAR LT3439 Data Sheet

Page 1 查询LT3439供应商 LT3439 Slew Rate Controlled Ultralow Noise1A Isolated DC/DC Transformer Driver FEATURES DESCRIPTIO Reduced Conducted and Radiated EMI The LT®3439 is a push-pull DC/DC transformer driver th...
Page 2 LT3439 ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW VIN Voltage 20V ORDER PART COL A, COL B Voltage 35V PGND PGND NUMBER NC NC SHDN, SYNC Voltage 20V COL A COL B LT3439EFE Maximum...
Page 3 IN PU VO LT AG (V CU RR EN LI IT (A SW IT CH OL TA GE (V LT3439 TYPICAL PERFOR A CE CHARACTERISTICS Minimum Input Voltage Supply Current in Shutdown Mode Oscillator Frequency vs Temperature vs Tempera...
Page 4 LT3439 PI FU CTIO S PGND (Pins 1, 16): Power ground is connected to the RT (Pin 7): The oscillator resistor pin is used to set the emitter of the power switches via an internal sense resis- charge and...
Page 5 LT3439 BLOCK DIAGRA T1 VOUT VIN COUT SHDN VIN COLALT3439 COLB REGULATOR OUTPUT DRIVERS CONTROL INTERNAL VCC QB CT OSCILLATOR RSENSE PGND GND RSL 3439 BD OPERATIO Push-Pull Topology eventually cause th...
Page 6 LT3439 OPERATIO vary from 2.8V to 17.5V with very little change in device Overtemperature Protection performance. When the part is in shutdown mode, the When the IC has exceeded the maximum temperatur...
Page 7 LT3439 APPLICATIO S I FOR ATIO Oscillator SYNC + VON SHDN= The oscillator can be synchronized to an external clock.   Set the RC timing components for an oscillator frequency 10% below the desire...
Page 8 LT3439 APPLICATIO S I FOR ATIO mean greater switching losses in the internal output Table 1 switches. However, efficiency is only modestly reduced NOMINAL NOMINAL INPUT OUTPUT OUTPUT COILTRONICS for a...
Page 9 LT3439 APPLICATIO S I FOR ATIO current. This can be accomplished by adding more turns of the switching cycle do not match, the transformer’s flux onto a given core or selecting a new core with a highe...
Page 10 LT3439 APPLICATIO S I FOR ATIO The primary inductance is then calculated: Optional LC Filter An optional LC filter, as shown on the Typical Application on the first page of this data sheet, should be ...
Page 11 LT3439 TYPICAL APPLICATIO Low Noise 5V to ±12V Push-Pull DC Transformer OPTIONAL BYP C7 LT1761-BYP VOUT IN OUT 12V 80m A ADJGND VIN T1 5V SHDN COLA LT3439 SYNC COLB CT OPTIONAL BYP C8 RT RSL D4 0.01µF...
Page 12 LT3439 TYPICAL APPLICATIO Low Noise 12V to –12V, 6W Push-Pull DC Transformer OPTIONAL LT1175 L2 IN VIN 33µH ILIM2 VOUT 12V ILIM4 OUT –12V SENSEGND SHDN COLA 3439 TA03 LT3439 D2 SYNC COLB 150k 324k CT ...

Manual Details

Brand Linear
Pages 12
File Size 187.19 KB
Published June 16, 2026
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Frequently Asked Questions

What is the typical output noise level of the LT3439?

The manual does not specify a single typical output noise figure, but it features Ultralow noise and EMI reduction.

What are the operational temperature limits for this device?

The operating junction temperature range is –40°C to 125°C. The storage temperature range is –65°C to 150°C.

How can the LT3439 reduce Electromagnetic Interference (EMI)?

It achieves ultralow noise and EMI reduction using a Cross Conduction Prevention Circuitry and two adjustable current slew rates.

What is the standby power consumption of the unit?

The supply current in shutdown mode (VIN(SHDN)IN) is specified as <20mA.