ST ISA043V1 User Manual

1.5 A /1.2 V high frequency synchronous buck converter
demonstration board based on the ST1S06

Features

■ Adjustable current-mode pulse width

modulation (PWM) synchronous, step-down
DC-DC converter with inhibit function

■ Input voltage, Vin: 2.5 V to 5.5 V

■ Output voltage, Vout: 1.2 V

■ Output current, Iout: 1.5 A

■ Switching frequency: 1.5 MHz

■ RoHS compliant

Description

This demonstration board, based on the ST1S06,
is an adjustable current-mode PWM synchronous,
step-down DC-DC converter with inhibit function.
It is optimized for powering all low-voltage
applications and, more generally, to replace the
high-current linear solution when the power
dissipation may cause overheating of the
application environment.

It provides up to 1.5 A over an input voltage range
of 2.5 V to 5.5 V.

STEVAL-ISA043V1

Data brief

STEVAL-ISA043V1

capacitors results in a low, predictable output
ripple. To clamp the error amplifier reference
voltage, this device includes a soft-start control
block generating a voltage ramp.

The ST1S06 is available in a 6L-DFN 3x3
package.

A high switching frequency (1.5 MHz) enables the
use of tiny surface-mounted components (SMD).
In addition to the resistor divider used to set the
output voltage value, only an inductor and two
capacitors are required.

Moreover, low output ripple is guaranteed by the
current-mode PWM topology and by the use of
low series resistance (ESR) SMD ceramic
capacitors.

The device is thermal protected and current
limited to prevent damage due to accidental short­circuits.

It is a complete 1.5 A switching regulator with its
internal compensation eliminating the need for
additional components.

The constant-frequency, current-mode, PWM
architecture and stable operation with ceramic

November 2010 Doc ID 18210 Rev 1 1/4

For further information contact your local STMicroelectronics sales office.

www.st.com

4

Circuit schematic STEVAL-ISA043V1

1 Circuit schematic

Figure 1. Circuit schematic

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2/4 Doc ID 18210 Rev 1