L4973:3.5 A Switching Regulator

The L4973 is a step down monolithic power switching regulator delivering 3.5A at fixed voltages of 3.3V or 5.1V and using a simple external divider output adjustable voltage up to 50V. Realized in BCD mixed technology, the device uses an internal power D-MOS transistor (with a typical RDS(on) of 0.15Ω) to obtain very high efficiency and very fast switching times. Switching frequency up to 300KHz are achievable (the maximum power dissipation of the packages must be observed).

A wide input voltage range between 8V to 55V and output voltages regulated from 3.3V to 40V cover the majority of the today applications. Features of this new generation of DC-DC converter includes pulse by pulse current limit, hiccup mode for output short circuit protection, voltage feed forward regulation, soft start, input/output synchronization, protection against feedback loop disconnection, inhibit for zero current consumption and thermal shutdown. Packages available are in plastic dual in line, DIP- 18 (12+3+3) for standard assembly, and SO20 (12+4+4) for SMD assembly.

Key Features

  • Inhibit for zero current consumption (100mA at VCC = 24V)
  • Input/output synchronization function
  • Thermal shutdown
  • Protection against feedback disconnection
  • Soft start function
  • Output over voltage protection
  • Internal current limiting (pulse by pulse and HICCUP mode)
  • Zero load current operation (min 1mA)
  • Up to 3.5A step down converter
  • 3.3V and 5.1V (±1%) fixed output, and adjustable outputs from: 0.5V to 50V (3.3 type)5.1V to 50V (5.1 type)
  • Operating input voltage from 8V to 55V
  • Voltage feed forward
  • Precise 5.1V (1.5%) reference voltage externally available
  • Frequency adjustable up to 300kHz
Product Specifications
DescriptionVersionSize
DS0169: 3.5 A step down switching regulator18.2635 KB
Application Notes
DescriptionVersionSize
AN1126: Current sharing of the L4973 in a multiphase application1.2191 KB
AN938: Designing with L4973, 3.5 A high efficiency DC-DC converter10.11 MB
Design Notes & Tips
DescriptionVersionSize
DN0011: ST1S03 alternative topology: Using a buck in a negative buck-boost configuration1.1359 KB
Brochures
DescriptionVersionSize
Brochure Power management guide05.20164 MB
Sample & Buy
Part NumberPackagePacking TypeUnit Price (US$) *QuantityECCN (EU)ECCN (US)Country of Origin
L4973D3.3SO-20Tube1.8111000NECEAR99MALAYSIA
L4973D5.1-013TRSO-20Tape And Reel1.8611000NECEAR99MALAYSIA
L4973V3.3PDIP 18Tube1.6931000NECEAR99MALAYSIA
L4973D3.3-013TRSO-20Tape And Reel1.8111000NECEAR99MALAYSIA
L4973D5.1SO-20Tube1.8611000NECEAR99MALAYSIA
L4973V5.1PDIP 18Tube1.7781000NECEAR99MALAYSIA
Quality & Reliability
Part NumberPackageGradeRoHS Compliance GradeMaterial Declaration**
L4973D3.3SO-20IndustrialEcopack1 (*)md_z7-wspc-so20.30_a5z7-wspc-u740da6.pdf
md_z7-wspc-so20.xml
L4973D5.1-013TRSO-20IndustrialEcopack1 (*)md_z7-wspc-so20-wspc-.30-wspc-to-wspc-jedec-wspc-ms-013_c5z7-wspc-u540da6.pdf
md_z7-wspc-so20-wspc-.xml
L4973V3.3PDIP 18IndustrialEcopack1
L4973D3.3-013TRSO-20IndustrialEcopack1 (*)md_z7-wspc-so20.30_a5z7-wspc-u740da6.pdf
md_z7-wspc-so20.xml
L4973D5.1SO-20IndustrialEcopack1 (*)md_z7-wspc-so20-wspc-.30-wspc-to-wspc-jedec-wspc-ms-013_c5z7-wspc-u540da6.pdf
md_z7-wspc-so20-wspc-.xml
L4973V5.1PDIP 18IndustrialEcopack1md_d7-wspc-pdip-wspc-18-wspc-.3-wspc-cu-wspc-0.4_a5d7-wspc-u540da6.pdf
md_d7-wspc-pdip-wspc-18-wspc-.3-wspc-cu-wspc-0.4_a5d7-wspc-u540da6.xml
3.5 A step down switching regulator L4973
circuit_diagram_1546_thumbnail.png L4973
Current sharing of the L4973 in a multiphase application L4973
Designing with L4973, 3.5 A high efficiency DC-DC converter L4973
ST1S03 alternative topology: Using a buck in a negative buck-boost configuration L5986
Very low drop voltage regulators with inhibit KFXX
md_z7-wspc-so20.30_a5z7-wspc-u740da6.pdf L4973
md_z7-wspc-so20.xml L4973
md_z7-wspc-so20-wspc-.30-wspc-to-wspc-jedec-wspc-ms-013_c5z7-wspc-u540da6.pdf L4973
md_z7-wspc-so20-wspc-.xml L4973
md_d7-wspc-pdip-wspc-18-wspc-.3-wspc-cu-wspc-0.4_a5d7-wspc-u540da6.pdf L4973
md_d7-wspc-pdip-wspc-18-wspc-.3-wspc-cu-wspc-0.4_a5d7-wspc-u540da6.xml L4973