PI3VST01 Datasheet, PDF (4/7 Pages) Pericom Semiconductor Corporation – HPD signal Generator for VGA

PI3VST01
HPD signal Generator for VGA
Dynamic Electrical Characteristics over Operating Range
(TA=-40º to+85ºC, V_DD3 =3.3V±10%, GND=0V, V_DD5 = 5.0V±10%)
Parameters Description
Test Conditions
Min.
Typ. Max.
Units
OFF Isolation,
OIRR
f = 250MHz
-
BIN to BOUT
-46
-
dB
Bandwidth –3dB,
BW
BIN to BOUT
-
2.0
-
GHz
Propagation Delay,
tPD
BIN to BOUT
-
90
-
ps
Freq = 10MHz (VGA) -0.3
with 75-Ohm load
ILOSS
Insertion Loss for B path
Freq = 100MHz (XGA) -0.33
dB
Freq = 300MHz (UXGA) -0.4
Capacitance (TA = 25°C, f = 1MHz)
Parameters Description
Test Conditions
Typ. Units
COFF
CON
Capacitance, Switch OFF
Switch Capacitance between BIN and BOUT,
Switch ON
2.4
pF
5.6
pF
Applications
VGA-DACs in chipsets as well as video chips (MXM, GPU, DP-to-VGA, PCIe, etc.) typically dissipate about 170 mW.
The VGA standard does not have a monitor detect feature, so the DAC dissipates power whether the monitor is connected or not.
PI3VST01 provides an HPD_OUT signal that detects the presence of a monitor. This HPD_OUT signal can be routed to the
chipset, directly, or through an MPU, to turn off the VGA DAC when a monitor is not connected. Using the PI3VST01, the system
can save 170 mW when the monitor is not connected.
PI3VST01 can also be used to enable automatic switching between two monitors. Another Pericom product, PI3V724 integrates 2
monitor detection circuits with a 1:2 VGA switch and offers both automatic and manual monitor switching.
VGA Termination
PI3VST01 can support two different termination schemes:
1. Case_75//75: Reverse termination for the monitor is provided by a 75 Ohm resistor at the connector, as per the VESA VSIS
specification.
2. Case_150//75: Reverse termination for the monitor is split between a 150 Ohm resistor at the connector and a 150 Ohm resistor
at the video DAC, as required by some chipsets.
An external resistor must be supplied between the Rref pin and ground to tell the detection circuit which termination scheme is
being used. Values for this resistor are shown below.
Rref
Application Case Supported
330Kohm +/-5% Case _150//75
200Kohm +/-5% Case _75//75
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15-0090
4
www.pericom.com 07/08/15