13
ASC Breakout Board
Closed Loop Trimming (Not Populated)
The ASC provides four Closed Loop Trim (CLT) cells which are used to accurately trim and margin power supplies.
The ASC Breakout Board provides four DC-DC converter and trimming circuit footprints on the breakout board.
Table 4 lists the components and signal associated with CLT operation on the ASC Breakout Board.
Table 4. Closed Loop Trim Components & Signals
Component / Signals
Ref. Des.
Schematic-
Sheet
Description
Components Not Populated on Breakout Board
DC-DC Converter
DCDC1_A /
DCDC1_B
3
Dual-foo12 V input adjustable output power
supply. Trim circuit shown in schematic for DCDC1_A
(NQR002A0X4Z) at 5 V output.
DC-DC Converter
DCDC2_A /
DCDC2_B
3
Dual-foo12 V input adjustable output power
supply. Trim circuit shown in schematic for DCDC2_A
(NQR002A0X4Z) at 3.3 V output.
DC-DC Converter
DCDC3_A /
DCDC3_B
4
Dual-foo5 V input adjustable output power
supply. Trim circuit shown in schematic for DCDC3_A
(NQR002A0X4Z) at 2.5 V output.
DC-DC Converter
DCDC4_A /
DCDC4_B
4
Dual-foo5 V input adjustable output power
supply. Trim circuit shown in schematic for DCDC4_A
(NQR002A0X4Z) at 1.2 V output.
N-Channel MOSFET – SOT-23
Q1, Q2
3
FDV301N N-Channel MOSFET. Inverts the DC-DC
enable signal from ASC GPIO8 / GPIO9 and shifts
the level up to +12 V.
Green Indicator LED
D19, D20, D21,
D22
3, 4
LED indicates output of DC-DC is active.
LED Bias Resistor
R86, R88, R90,
R92
3, 4
470
Ω
resistor limits the LED current.
NPN Transistor – SOT-23
Q13, Q14, Q15,
Q16
3, 4
2N3904 NPN Transistor drives LED on when DC-DC
output is active.
NPN Bias Resistor
R85, R87, R89,
R91
3, 4
4.7 k
Ω
resistor limits the base current of NPN transis-
tor.
Tantalum Cap
C5, C7, C9, C11 3, 4
6.8 µF, 20 V capacitor DC-DC input filter.
Tantalum Cap
C6, C8, C10,
C12
3, 4
10 µF, 6.8 V capacitor DC-DC output filter.
DC-DC Output Load Resistor
R22,R31, R39,
R47
3, 4
1k, 680, 470 and 330
Ω
resistors pull DC-DC outputs
down to zero when disabled.
DCDC1 Trim Resistors
R17 – R21
3
Resistor values based on Platform Designer Trim Cal-
culator for DCDC1_A at 5 V.
DCDC2 Trim Resistors
R26 – R30
3
Resistor values based on Platform Designer Trim Cal-
culator for DCDC2_A at 3.3 V.
DCDC3 Trim Resistors
R34 – R38
4
Resistor values based on Platform Designer Trim Cal-
culator for DCDC3_A at 2.5 V.
DCDC4 Trim Resistors
R42 – R46
4
Resistor values based on Platform Designer Trim Cal-
culator for DCDC4_A at 1.2 V.
Phoenix 4-Terminal Connector
DCDC1-4
J4, J5, J7, J9
3, 4
Wire to board connectors to apply off-board loads to
DC-DC with remote sensing.
Signals
LED8
2, 3
DCDC1 control signal from GPIO8. Safe state is high.
Inverted via Q1.
LED9
2, 3
DCDC2 control signal from GPIO9. Safe state is high.
Inverted via Q1.
LED4
2, 4
DCDC3 control signal from GPIO4. Safe state is low.