February 2016
DocID028953 Rev 1
1/4
For further information contact your local STMicroelectronics sales
office
www.st.com
STEVAL-ISA188V1
38 V, 1.5 A synchronous step-down switching regulator
evaluation board based on A6986F3V3
Data brief
Features
AECQ100 qualification
1.5 A DC output current
4 V to 38 V operating input voltage
Low consumption mode or low noise mode
Programmable ISKIP current
30 μA IQ at light load (LCM VIN = 12 V)
8 μA IQ-SHTDWN
Adjustable f SW (250 kHz - 2 MHz)
Fixed output voltage VOUT= 3.3 V
Embedded output voltage supervisor
Synchronization
Adjustable soft-start time
Internal current limiting
Overvoltage protection
Output voltage sequencing
Peak current mode architecture
RDS(on)HS = 180 mΩ; RDS(on)LS = 150 mΩ
Thermal shutdown
RoHS compliant
Description
The STEVAL-ISA188V1 is a product evaluation
board based on the ST synchronous step-down
switching regulator A6986F3V3, which can
deliver up to 1.5 A and, with its 100% duty cycle
ability to withstand cold crank events and wide
input operating voltage range, represents the
ideal choice for battery-powered automotive
systems. Synchronous rectification helps achieve
higher efficiency at full load as well as application
compactness, while high-frequency switching
(programmable up to 2 MHz) helps reduce the
cost and size of power passive components while
remaining outside the AM band. The device can
operate in low consumption mode (LCM), with a
quiescent current of 30 μA that ensures high
efficiency under light load, which is a requirement
in typical car body applications that are active
when a car is parked. A low noise mode (LNM)
can be selected to meet the requirements of
infotainment applications with forced PWM mode
under all load conditions. The default board
configuration is LCM active, 500 kHz switching
frequency, high ISKIP current and the switchover
feature enabled, but all of these settings can be
easily changed so the user can evaluate different
application scenarios.
Schematic diagram
2/4
DocID028953 Rev 1
1 Schematic diagram
Figure 1: STEVAL-ISA188V1 schematic circuit
signal GND
power GND
VIN_FLT
PGND
VIN_FLT
PGND
C144.7uF
C144.7uF
L1ANM
L1ANM
+
C13A NM
+
C13A NM
J5J5
R4
0R
R4
0R
R1110RR1110R
TP3
SYNCH TP3
SYNCH
C8 220pC8 220p
J3J3
L1 6.8uH
L1 6.8uH
TP8
VIN_EMI
TP8
VIN_EMI
C9 10uF
C9 10uF
R10NMR10NM
C2 1uF
C2 1uF
+
C13 NM
+
C13 NM
C6
10nF
C6
10nF
R2
NM
R2
NM
C164.7uF
C164.7uF
C4 2.2pC4 2.2p
R6 1MR6 1M
C1010uF
C1010uF
TP7 GND
TP7 GND
J2J2
TP2 RST
TP2 RST
R3 NMR3 NM
R9 NMR9 NM
TP1
SS/INH TP1
SS/INH
C11
NM
C11
NM
C1 10uF50V
C1 10uF50V
R5 NMR5 NM
R7 0RR7 0R
R1 0R1 0
C154.7uF
C154.7uF
C7 NMC7 NM
J1J1
TP6
GND TP6
GND
U1 A6986F3V3
U1 A6986F3V3
RST 1
VCC
2
SS/INH
3
SYNCH
4
FSW
5
MLF
6
COMP 7
DELAY
8
FB 9
SGND
10
PGND
11
PGND
12
LX 13
LX 14
VIN
15 VBIAS 16
EP
17
J4J4
TP4 VOUT
TP4 VOUT
L3
MPZ2012S221A
L3
MPZ2012S221A
C5
68nF
C5
68nF
L2 4.7uH
L2 4.7uH
C3
470nF
C3
470nF
R8 75kR8 75k
TP5
VIN TP5
VIN
GSPG02022016DI1510
STEVAL-ISA188V1
DocID028953 Rev 1
3/4
2 Revision history
Table 1: Document revision history
Date
Version
Changes
02-Feb-2016
1
Initial release.
STEVAL-ISA188V1
4/4
DocID028953 Rev 1
IMPORTANT NOTICE – PLEASE READ CAREFULLY
STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, enhancements, modifications, and
improvements to ST products and/or to this document at any time without notice. Purchasers should obtain the latest relevant information on ST
products before placing orders. ST products are sold pursuant to ST’s terms and conditions of sale in place at the time of order
acknowledgement.
Purchasers are solely responsible for the choice, selection, and use of ST products and ST assumes no liability for application assistance or the
design of Purchasers’ products.
No license, express or implied, to any intellectual property right is granted by ST herein.
Resale of ST products with provisions different from the information set forth herein shall void any warranty granted by ST for such product.
ST and the ST logo are trademarks of ST. All other product or service names are the property of their respective owners.
Information in this document supersedes and replaces information previously supplied in any prior versions of this document.
© 2016 STMicroelectronics – All rights reserved