1
1
2
2
3
3
4
4
5
5
6
6
D
D
C
C
B
B
A
A
7
200 Scenic View Dr.
Cumberland, RI 02864
7
8/4/2020
Sheet:
of
NK49-Power.SchDoc
NK49-MAIN.PrjPcb
Originally Drawn By:
Project:
Sheet:
Variant:
Production
Last Modified By:
Last Modified:
Copyright 2019, inMusic Brands
All Rights Reserved
Rev I
D36
MBRA340T3G
TP27
TP26
D33
USBLC6-2
R346
C
266
USB-A
GND
USB1_D1_N
USB1_D1_P
90ohms@100MHz
J20
TYPE-B-2.0
USB1_D2_N
USB1_D2_P
D34
USBLC6-2
R348
C
275
USB-B
GND
USB2_D1_N
USB2_D1_P
90ohms@100MHz
J22
TYPE-B-2.0
USB2_D2_N
USB2_D2_P
L4
0.0nH
L7
0.0nH
+8V0
-8V0
VERTICAL
J30
SIL UNSHROUDED 3.96mm
VERTICAL
J29
SIL UNSHROUDED 3.96mm
+28-C
GND
+28-B
GND
90 ohms differential impedance between
USB_D_N & USB_D_P on PCB and cable.
GND
GND
GND
1.6A 250V
1A 250V
F1
1.6A 250V
+28-A
+28-B
+28-C
From
Universal AC
Mains
+28V, 150W
Fuse Time Lag
150% for 1 Hour
210% for 2 Minutes
1.5A To Left Platter
1.5A To Right Platter
To Center Board
+3V3
VERTICAL
J31
SIL SHROUDED 2.0mm
GND
+3V3
PMIC_ON_REQ
5
USB1_D_N
5
USB1_D_P
5
USB2_D_N
5
USB2_D_P
5
USB1_VBUS
5
USB2_VBUS
5
USB1_D_N
USB1_D_P
USB2_D_N
USB2_D_P
1
2
L13
130uH
L14
130uH
ESD
ESD
ESD
Star Ground to J32-3/4
+28-A
TP24
TP23
U38
RT7272B
L9
22uH
C167
GND
L15A
47uH
L15B
47uH
+28-A
TP25
U40
RT7272B
C207
GND
GND
L12
10uH
L16
10uH
+3V3
+28-A
D55
MBRS140T3
U25
NJM2387
GND
Q39
2222A
GND
FAN_PWM
5
VERTICAL
J33
SIL SHROUDED 2.0mm
24V-FAN
Fan: 24 V; 33 mA; 40x40x20 mm
Sunon MF40202V2-10000-A99
R298
+5V0
GND
U37
1117S50
TP22
+5V0
GND
+3V3
MTG2
MTG3
MTG4
MTG1
GND
+3V3
GND
+3V3
GND
GND
GND
J18
GROUND LUG
GND
J32
SIL UNSHROUDED 3.96mm
TP31
TP32
TP49
TP58
TP60
TP59
TP61
TP62
TP63
CHANGE LOG:
1) Reduced post DAC gain by 1.4 dB to match DAC
R168, R183, R63, R162, R188, R197
2) Adjusted SPI termination at J13 to improve signal quality and reduce EMI.
Replaced the following with RC network:
L29,L28,L27, L17, L18, L19, L20, L21, L22, L23
3) Removed FET switch for 3V3SW. Supplies will come up together to avoid boot failure.
Delete the following: R368, D37, Q34, R366, Q32
3V3SW to +3V3
4) Reduced C162 codec reset cap to 100pf (was delaying muting)
5) Added test points to JTAG header
6) Fixed audio output mute
7) Add caps to 3 signals on both J11 and J12
8) Removed left and right PLT0/1
9) Added RST to +3.3V buck enable to prevent fast power cycle erro
D37
MURS160
D35
MURS160
MTG1, MTG2, MTG3, MG4 must connect to Earth GND via stand offs to bottom chassis
Chassis bottom must be Earth grounded
NOTE:
Do not stuff R232, R233, R369, R370
C317
R236
Vth=1.25V
3.3V Buck turn-on 200ms
3.3V to fully discharge before restart
GND
Enables buck at 2.5V
R263 not fitted
D56
5.1V
U42
LM3704
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