STEVAL-ISA067V1
Dual step-down controller with auxiliary voltages demonstration
board based on the PM6681A for industrial system power
Features
■ 5.5 V to 36 V input voltage range
■ V
■ V
■ 0.9 - 3.3 V adjustable LDO delivers 100 mA
■ 5 V LDO delivers 100 mA peak current
■ 1.237 V ± 1% reference voltage available
■ Loss-less current sensing using low-side
■
■ Soft-start internally fixed at 2 ms
■ Soft output discharge
■ Latched UVP
■ Non-latched OVP
■ Selectable pulse-skipping at light loads
■ Selectable minimum frequency (33 kHz) in
■ 4 mW maximum quiescent power
■ Independent power-good signals
■ Output voltage ripple compensation
■ RoHS compliant
out1
: 3.3 V, I
> 2.5 A (or adjustable output
out1
voltage)
out2
: 1.8 V, I
> 2.5 A (or adjustable output
out2
voltage)
peak current
MOSFET R
DS(on)
Negative current limit
pulse-skip mode
STEVAL-ISA067V1
respectively. Each switching section delivers more
than 2.5 A output current.
An internal linear regulator provides a fixed 5 V
output voltage. Another internal linear regulator
provides an adjustable output voltage (default 2.5
V). Both linear regulators can deliver up to 100
mA peak current.
Data brief
Description
This demonstration board is based on the
PM6681A, a dual step-down controller with
adjustable output voltages that can be used in
industrial power systems. The PM6681A
demonstration board allows testing all the
device's functions and provides two switching
sections, with (typically) 3.3 V (OUT1) and 1.8 V
(OUT2) outputs from 5.5 V to 36 V input voltage.
The typical operating switching frequency of the
two available sections is 200 kHz/300 kHz,
April 2009 Doc ID 15643 Rev 1 1/4
For further information contact your local STMicroelectronics sales office.
www.st.com
4
Circuit schematic STEVAL-ISA067V1
1 Circuit schematic
Figure 1. Schematic diagram
2/4 Doc ID 15643 Rev 1
AM01437v1
STEVAL-ISA067V1 Revision history
2 Revision history
Table 1. Document revision history
Date Revision Changes
29-Apr-2009 1 Initial release.
Doc ID 15643 Rev 1 3/4
STEVAL-ISA067V1
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4/4 Doc ID 15643 Rev 1
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