ViewSonic VX910 Service Manual page 23

e) On chip TMDS receiver: The MST8131A integrated DVI receiver, which operates up to 135MHz
and can directly connect to all DVI compliant transmitters. The TMDS signals are connected to
MST8131A as described bellow:
Pin Name
R+
R-
G+
G-
B+
B-
CK+
CK-
f) PWM controlling function (Pin 73~74): The MST8131A has two dedicated PWM outputs of
PWM0 and PWM1 to control audio volume and back light brightness.
g) Serial interface ports (pin 70 and pin 71): This serial interface ports communicate with MCU
and support up to 400Kbit per second transmit rate.
h) Panel interface (Pin 1, Pin 102, Pin 103, Pin 106, Pin 107, Pin 120~ Pin 125, Pin 108~113,
and Pin 128) : The MST1831A driver interface is highly programmable. It supports dual bus / dual
port for SXGA drivers.
6.1.2 Power Regulator AIC1563 (U21), LT1117 (U22, U23): The AIC1563 is a monolithic control IC
containing the primary functions required for DC-to-DC converters. The device consists of an
internal temperature compensated reference, comparator, controlled duty cycle.
Oscillator with an active current sense circuit, desired output voltage are determined by the equation,
Volt = 1.25 *(1 + R66 / R67), in this case, the output voltage are 5 Volts
The AIC1117 is a low dropout positive adjustable regulator with minimum of 800mA output current
capability. So it is well suited for 3.3 V and 2.5 V Regulator.
U10 as a 2.5V regulator, Desired output voltage are determined by the equation
Volt=1.25 x (1 + R84/R83)= 2.5
U11 as a 3.3V regulator, Desired output voltage are determined by the equation
Volt=1.255 x (1+ R86/R85)= 3.3
ViewSonic Corporation
Pin NO.
40
41
43
44
46
47
49
50
20
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VX910