Data Brief
For further information contact your local STMicroelectronics sales office.
March 2009 Rev 1 1/6
6
Features
■ 1 A DC output current
■ 2.9 V to 18 V input voltage
■ Output voltage adjustable from 0.6 V to 16 V
■ 250 kHz switching frequency, programmable
up to 1 MHz
■ Internal soft-start and inhibit
■ Low dropout operation: 100 % duty cycle
■ Zero-load current operation
■ Over-current and thermal protection
■ VFQFPN8 3 mm x 3 mm package
Description
The EVAL5981 demonstration board provides the
design engineer with a fully functional step-down
switching regulator with an output current of up to
1 A. The L5981 integrates STMicroelectronics
step-down switching regulator, together with all
the external components required for a typical
application.
The rated voltage of the input capacitor and the
Schottky diode rectifier repetitive peak reverse
voltage are both 25 V, making the board capable
of covering the entire 2.9 V - 18 V input voltage
range of the L5981 device.
The board features an external resistor divider
(R1 and R2) designed for an output voltage
of 3.3 V.
The output voltage can be set to a level from 0.6 V
up to the rated voltage of the output capacitor
(16 V).
The compensation network on the demonstration
board allows the use of MLCC as output filter to
keep the loop stable. The inductor saturation
current and forward current of the Schottky diode
are within the current limit values.
The switching frequency on the demonstration
board is set to 500 kHz by means of the R5
resistor connected to pin Fsw.
EVAL5981
EVAL5981
1 A step-down switching regulator demonstration board
based on the L5981
www.st.com
