Datasheet LT1683 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Slew Rate Controlled Ultralow Noise Push-Pull DC/DC Controller |
| Pages / Page | 26 / 1 — FEATURES. DESCRIPTION. Greatly Reduced Conducted and Radiated EMI. Low … |
| File Format / Size | PDF / 419 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Greatly Reduced Conducted and Radiated EMI. Low Switching Harmonic Content
Model Line for this Datasheet
Text Version of Document
LT1683 Slew Rate Controlled Ultralow Noise Push-Pull DC/DC Controller
FEATURES DESCRIPTION
n
Greatly Reduced Conducted and Radiated EMI
The LT®1683 is a switching regulator control er designed to n
Low Switching Harmonic Content
lower conducted and radiated electromagnetic interference n
Independent Control of Output Switch Voltage and
(EMI). Ultralow noise and EMI are achieved by controlling
Current Slew Rates
the voltage and current slew rates of external N-channel n
Greatly Reduced Need for External Filters
MOSFET switches. Current and voltage slew rates can n Dual N-Channel MOSFET Drivers be independently set to optimize harmonic content of n 20kHz to 250kHz Oscillator Frequency the switching waveforms vs efficiency. The LT1683 can n Easily Synchronized to External Clock reduce high frequency harmonic power by as much as n Regulates Positive and Negative Voltages 40dB with only minor losses in efficiency. n Easier Layout Than with Conventional Switchers The LT1683 utilizes a dual output (push-pull) current mode architecture optimized for low noise topologies.
APPLICATIONS
The IC includes gate drivers and all necessary oscillator, n Power Supplies for Noise Sensitive Communication control and protection circuitry. Unique error amp circuitry Equipment can regulate both positive and negative voltages. The oscil- n EMI Compliant Offline Power Supplies lator may be synchronized to an external clock for more n Precision Instrumentation Systems accurate placement of switching harmonics. n Isolated Supplies for Industrial Automation Protection features include gate drive lockout for low V n IN, Medical Instruments opposite gate lockout, soft-start, output current limit, n Data Acquisition Systems short-circuit current limiting, gate drive overvoltage clamp L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and DirectSense is a trademark of Linear Technology Corporation. All other trademarks are the and input supply undervoltage lockout. property of their respective owners.
TYPICAL APPLICATION Ultralow Noise 48V to 5V DC/DC Converter
48V 510Ω 51k 39µF 0.5W 63V MIDCOM 31244 FZT853 1N4148 10µF MBR0530 OPTIONAL 20V MBRS340 2N3904 22µH B 22µH A 5V/2A 8.2V
5V Output Noise
150µF 2×100µF 68µF 11V OS-CON POSCAP
(Bandwidth = 100MHz)
20V 17 3 VIN GCL 23.2k 5pF 10pF 14 2 200V SHDN CAP A 5 976Ω V5 1 MBRS340 6 GATE A 1.2nF SYNC 5pF 10pF A 200µVP-P 7 18 200V 200µV/DIV CT CAP B LT1683 16.9k 8 19 30pF RT GATE B B 25k 3.3k 16 4 Si9422 Si9422 R 20mV/DIV VSL CS 25k 3.3k 15 0.1Ω RCSL 20 PGND 1.5k 12 7.50k VC 9 FB 5µs/DIV 1683 TA01a 0.22µF 22nF SS GND NFB 30pF 2.49k 13 11 10 10nF 1683 TA01 1683fd 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Test Circuits Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
FEATURES DESCRIPTION
n
Greatly Reduced Conducted and Radiated EMI
The LT®1683 is a switching regulator control er designed to n
Low Switching Harmonic Content
lower conducted and radiated electromagnetic interference n
Independent Control of Output Switch Voltage and
(EMI). Ultralow noise and EMI are achieved by controlling
Current Slew Rates
the voltage and current slew rates of external N-channel n
Greatly Reduced Need for External Filters
MOSFET switches. Current and voltage slew rates can n Dual N-Channel MOSFET Drivers be independently set to optimize harmonic content of n 20kHz to 250kHz Oscillator Frequency the switching waveforms vs efficiency. The LT1683 can n Easily Synchronized to External Clock reduce high frequency harmonic power by as much as n Regulates Positive and Negative Voltages 40dB with only minor losses in efficiency. n Easier Layout Than with Conventional Switchers The LT1683 utilizes a dual output (push-pull) current mode architecture optimized for low noise topologies.
APPLICATIONS
The IC includes gate drivers and all necessary oscillator, n Power Supplies for Noise Sensitive Communication control and protection circuitry. Unique error amp circuitry Equipment can regulate both positive and negative voltages. The oscil- n EMI Compliant Offline Power Supplies lator may be synchronized to an external clock for more n Precision Instrumentation Systems accurate placement of switching harmonics. n Isolated Supplies for Industrial Automation Protection features include gate drive lockout for low V n IN, Medical Instruments opposite gate lockout, soft-start, output current limit, n Data Acquisition Systems short-circuit current limiting, gate drive overvoltage clamp L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and DirectSense is a trademark of Linear Technology Corporation. All other trademarks are the and input supply undervoltage lockout. property of their respective owners.
TYPICAL APPLICATION Ultralow Noise 48V to 5V DC/DC Converter
48V 510Ω 51k 39µF 0.5W 63V MIDCOM 31244 FZT853 1N4148 10µF MBR0530 OPTIONAL 20V MBRS340 2N3904 22µH B 22µH A 5V/2A 8.2V
5V Output Noise
150µF 2×100µF 68µF 11V OS-CON POSCAP
(Bandwidth = 100MHz)
20V 17 3 VIN GCL 23.2k 5pF 10pF 14 2 200V SHDN CAP A 5 976Ω V5 1 MBRS340 6 GATE A 1.2nF SYNC 5pF 10pF A 200µVP-P 7 18 200V 200µV/DIV CT CAP B LT1683 16.9k 8 19 30pF RT GATE B B 25k 3.3k 16 4 Si9422 Si9422 R 20mV/DIV VSL CS 25k 3.3k 15 0.1Ω RCSL 20 PGND 1.5k 12 7.50k VC 9 FB 5µs/DIV 1683 TA01a 0.22µF 22nF SS GND NFB 30pF 2.49k 13 11 10 10nF 1683 TA01 1683fd 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Test Circuits Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
