ViewSonic VG920-1, Service Manual

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4.4 INTRODUCTION OF IC
STUM56AK(U401): integrate ADC, OSD, SCALER, MCU, LVDS, convert analog RGB
into digital and room and shrink scaling output to LCD panel.
PIN Function:
AIC1084-33PM (U702): DC power convert, used to 5v convert 3.3v.
LT1117-18(U701): DC power convert, used to 5v convert 3.3v.
Pin Symbol Description
70 SDO SPI flash serial data output; Input w/5V-tolerant
71 CSZ SPI flash chip select; output
72 SCK SPI flash serial select; output
73 SDI SPI flash serial data input; output
65 DDCA_SDA/RS232_TX DDC data for analog interface; 4mA driving
strength/UART transmitter/GPIO; I/O w/5V-tolrant
66 DDCA_SDA/RS232_RX DDC data for analog interface/UART
transmitter/GPIO;Input w/5V-tolrant
36 DDCD_SDA DDC data for DVI interface; 4mA driving strength;
I/O w/5V-tolerant
37 DDCD_SCL DDC clock for DVI interface; Input w/5V-tolerant
19 RST Chip reset; High reset; Input w/5V-tolerant
22 RSTN Chip reset; Low reset; Input w/5W-toerant
11 VCTRL Regulator control; Output
63 HSYNCO Analog HSYNC input
64 VSYNCO Analog VSYNC input
62 REFP Internal ADC top de-coupling pin
61 REFM Internal ADC bottom de-coupling pin
51 REXT
External resistor 390 ohm to AVDD ＿ DVI
21 PWM1 PWM1; 4mA driving strength; Output
29 PWM0 PWM0; 4mA driving strength; Output
4 BYPASS For External Bypass Capacitor
33 XIN Xin; Crystal Oscillator Input
34 XOUT Xout; Crystal Oscillator Output
44
、
50 AVDD
＿
DVI
DVI Power 3.3V
60
AVDD
＿
ADC
ADC Power 3.3V
52
AVDD
＿
PLL
PLL Power 3.3V
34
AVDD
＿
MPLL
MPLL Power 3.3V
14
、
67
、
95
、
103 、 115
VDDP Digital Output Power 3.3V
13
、
38
、
41
、
47
、
96
、
116
VDDC Digital Core Power 1.8V
15
ViewSonic Corporation
Co
nfidential - Do Not Copy VG920-1