PACVGA200 Datasheet, PDF (1/3 Pages) California Micro Devices Corp – VGA PORT COMPANION CIRCUIT

CALIFORNIA MICRO DEVICES
PACVGA200
VGA PORT COMPANION CIRCUIT
Features
• 7 channels of ESD protection for all VGA port
connector pins meeting IEC-61000-4-2 Level-4 ESD
requirements (8KV contact discharge)
• Very low loading capacitance from ESD protection
diodes on VIDEO lines, 4pF typical
• TTL to CMOS level-translating buffers with power
down mode for HSYNC and VSYNC lines
• 75 Ω termination resistors for VIDEO lines (matched
to 1% typ.)
• Bi-directional level shifting N-channel FETs provided for
DDC_CLK & DDC_DATA channels
• Compact 24-pin QSOP package
Pin Diagram
Product Description
24-PIN QSOP PACKAGE
The PACVGA200 incorporates 7 channels of ESD protection for all signal lines commonly found in a VGA port. ESD protection
is implemented with current steering diodes designed to safely handle the high surge currents encountered with IEC-1000-4-
2 Level-4 ESD Protection (8KV contact discharge). When a channel is subjected to an electrostatic discharge, the ESD current
pulse is diverted via the protection diodes into the positive supply rail or ground where it may be safely dissipated.
Separate positive supply rails are provided for the VIDEO, DDC and SYNC channels to facilitate interfacing with low voltage
Video Controller ICs and provide design flexibility in multi-supply-voltage environments.
Two non-inverting drivers provide buffering for the HSYNC and VSYNC signals from the Video Controller IC (SYNC1, SYNC2).
These buffers accept TTL input levels and convert them to CMOS output levels that swing between Ground and V_CC4. These
drivers have nominal 60Ω output impedance to match the characteristic impedance of the HSYNC & VSYNC lines of the video
cables typically used in PC applications.
Two N-channel FETs provide the level shifting function required when the DDC controller is operated at a lower supply voltage
than the monitor.
Three 75Ω termination resistors suitable for terminating the video signals from the video DAC are also provided. These
resistors have separate input pins to allow insertion of additional EMI filtering, if required, between the termination point and
the ESD protection diodes. These resistors are matched to better than 2% for excellent signal level matching for the R/G/B
signals.
When the PWR_UP input is driven LOW the SYNC inputs can be floated without causing the SYNC buffers to draw any current
from the V_CC3 supply. When the PWR_UP input is LOW the SYNC outputs are driven LOW.
An internal diode (D1 in schematic below) is also provided so that V_CC3 can be derived from V_CC4, if desired, by connecting V_CC3
to V_BIAS. In applications where V_CC4 may be powered down, diode D1 blocks any DC current paths from the DDC_OUT pins
back to the powered down V_CC4 rail via the top ESD protection diodes.
Schematic Diagram
© 2000 California Micro Devices Corp. All rights reserved. PACVGA200™ is a trademark of California Micro Devices Corp.
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215 Topaz Street, Milpitas, California 95035 Tel: [phone]
Fax: [phone]
www.calmicro.com
C0641299
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