2.5 A switch step down switching regulator

Topologie: Buck
Eingangsspannung (min.): 4.40 V
Eingangsspannung (max.): 36.00 V

Erstveröffentlichung am 07.01.2008, Version 16 vom


The L5973D is a step down monolithic power switching regulator with a minimum switch current limit of 2.5 A so it is able to deliver more than 2 ADC current to the load depending on the application conditions.The output voltage can be set from 1.235 V to 35 V. The high current level is also achieved thanks to an SO8 package with exposed frame, that allows to reduce the Rth(j-amb) down to approximately 40 °C/W.The device uses an internal P-channel D-MOS transistor (with a typical Rdson of 250 mΩ) as switching element to minimize the size of the external components.An internal oscillator fixes the switching frequency at 250 kHz. Having a minimum input voltage of 4 V only, it is particularly suitable for 5 V bus, available in all computer related applications.Pulse by pulse current limit with the internal frequency modulation offers an effective constant current short circuit protection.


  • 2.5 A internal switch
  • Operating input voltage from 4 V to 36 V
  • 3.3 V / (±2%) reference voltage
  • Output voltage adjustable from 1.235 V to 35 V
  • Low dropout operation: 100 % duty cycle
  • 250 kHz internally fixed frequency
  • Voltage feedforward
  • Zero load current operation
  • Internal current limiting
  • Inhibit for zero current consumption
  • Synchronization
  • Protection against feedback disconnection
  • Thermal shutdownRemarks:-Refer page no 17Table 5.Inductor selection


  Artikel Nr. SPEC Produktserie L1
IR 1
RDC1 typ
RDC1 max.
fres 1
Montageart Muster
74456122 PDF WE-PD4 SMT-Speicherdrossel 22 2.6 3.1 0.071 0.095 14 SMT
74456133 PDF WE-PD4 SMT-Speicherdrossel 33 2.3 2.6 0.094 0.12 13 SMT
74456115 PDF WE-PD4 SMT-Speicherdrossel 15 2.9 3.6 0.043 0.06 17 SMT