THS8136 Datasheet, PDF (4/17 Pages) Texas Instruments – TRIPLE 10-BIT 180-MSPS GRAPHICS AND VIDEO DAC

THS8136
SLES236 – NOVEMBER 2008 ........................................................................................................................................................................................... www.ti.com
DETAILED DESCRIPTION
The THS8136 is a fast well-matched triple DAC with current outputs optimized for graphics and video
applications without sacrificing is usefulness as a generic DAC. The DAC output stages are designed to provide
direct drive of doubly-terminated 75-Ω loads (37.5 Ω). The full-scale output current of all three DACs is
determined by a single resistor connecting the FSADJ pin to AV_SS (GND). A 3.8-kΩ resistor is suitable for most
applications requiring 700-mV output levels. Additional circuitry and digital input controls for analog sync and
blank level generation are provided for both RGB and YPbPr color spaces. A generic mode of operation is
provided for applications not requiring sync insertion. Figure 1 shows a block diagram of the device.
DV_DD DV_SS
COMP FSADJ VREF
R[9:0]
Bandgap
Reference
R
Register
DAC
AR
G[9:0]
Input
Formatter
G
Register
DAC
AG
B[9:0]
B
Register
DAC
AB
CLK
M1
M2
Configuration
Control
SYNC/BLANK
Control
AV_DD AV_SS
SYNC BLANK
SYNC_T
Figure 1. Functional Block Diagram
Generic DAC Mode Versus Sync Insertion Mode
When configured for sync insertion, the THS8136 provides additional dc bias on the DAC outputs to provide
headroom for negative bi-level sync insertion. Such bias might be undesirable in applications where no analog
sync insertion is required, since it results in additional power consumption and might prevent dc coupling of the
DAC outputs. In such cases, only triple DAC operation without dc bias (i.e., DAC input code 0 corresponding to
0-V output) might be preferred. Generic DAC mode is easily selected by connecting the SYNC and SYNC_T pins
to DV_DD (or logic 1) and the M1 and M2 pins to DV_SS (or logic 0). BLANK is functional in both generic mode and
sync insertion mode.
4
Submit Documentation Feedback
Product Folder Link(s): THS8136
Copyright © 2008, Texas Instruments Incorporated