LX7720 Daughter Board User's Manual
June 2020
LX7720 Daughter Board rev 2.1
10
© 2020 Microsemi Corporation
4
LX7720 Daughter Board Configuration Options
4.1
VGS Gate Driver Supply (15V) Regulator Settings
The header J32 selects either the on-board 15V regulator, or an external 10V to 18V power supply connected to J31
(Table 2, Figure 9).
Table 2. VGS Gate Driver Supply (15V) Link Settings
VGS Regulator Source
J32 Link
J31 Connector
VGS is 15V using on-board regulator U3 supplied by external
24V AC adapter connected to DC power socket J11
Link 1 to 2 or insert ammeter
to measure VGS current
Open
VCC is external 4.5V to 5.5V at connector J30
Open
External 10V to 18V power supply
D11
STPS5L60S
BOOT
1
VIN
2
EN
3
SS/TR
4
RT/CLK
5
PWRGD
6
VSENSE
7
COMP
8
GND
9
PH
10
EPA
D
11
U3
TPS54160ADRCR
TP1
VIN_JCK
VGS_R
C57
2.2uF/100V/1210
C58
2.2uF/100V/1210
C59
2.2uF/100V/1210
C60
2.2uF/100V/1210
R44
332K/1%/0805
R46
56.2K/1%/0805
C61
0.01uF/100V/0805
R47
165K/1%/0805
R48
76.8K/1%/0805
C63
2700pF/50V/0805
C62
5.6pF/50V/0805
L2
33uH/2.7A
MSS1260-333MLB
C56
33uF/25V/1206
R45
178K/1%/0805
VGS
C52
0.1uF/25V/0805
C53
1uF/25V/0805
C54
4.7uF/25V/0805
C55
10uF/25V/0805
15V
R50
100K/0805
C70
33uF/25V/1206
D14
LTST-C190GKT
GREEN,10mA
1
2
J31
OSTOQ027150
1
2
J32
HDR_2_100MIL
VGS_R
C51
0.1uF/50V/0805
R49
10K/1%/0805
R56
1K/1%/0805
VGS
.
.
.
Figure 9. VGS Gate Driver Supply (15V) Regulator Schematic
4.2
VDD Logic Supply (3.3V) Regulator Settings
The headers J36, J19, and J16 select either the on-board 3.3V regulator and its power source, or an external 2.7V to 3.6V
power supply connected to J18 (Table 3, Figure 10).
While the LX7720 allows a logic supply range of 2.1V to 5.5V, the LX7720 daughter board's allowed range is 2.7V to
3.6V. This limitation is due to the supply range of the ASVMPC-27.000MHZ-LR-T 27MHz oscillator module Y2, and the
SN74LVTH16245A bus transceivers that interface both the 2x20 pin controller interface header J20 and the RTG4
interface FMC connector J10.
Table 3. VDD Logic Supply (3.3V) Regulator Link Settings
VDD Regulator Source
J36 Link
J19 Link
J16 Link
J18 Connector
VDD is on-board 3.3V using regulator U4 supplied by VGS rail
Link 2 to 1
Open
VDD is on-board 3.3V using regulator U4 supplied by 12V
from FMC connector J10 pins C35 and C36 (RTG4 board)
Link 2 to 3
Link 2 to 3
Open
VDD is external 3.3V from FMC connector J10 pins C39, D32,
D36, D38, and D40 (RTG4 board) Regulator U4 is unpowered
Open
Link 2 to 1
Link 1 to 2 or
insert ammeter
to measure
VDD current
Open
VDD is external 2.7V to 3.6V at connector J18
Regulator U4 is unpowered
Open
Open
Open
External 2.7V to
3.6V power supply
