MAX5140 View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

MAX5140

8-Bit, Ultra-High-Speed DAC

Maxim Integrated 

8-Bit, Ultra-High-Speed DAC

In video applications, the outputs can drive a doubly

terminated 50Ω or 75Ω load to standard video levels. In

the standard configuration shown in Figure 7, the out-

put voltage is the product of the output current and

load impedance and is between 0V and -1.07V. Out-

(Figure 5) provides a video output waveform with the

Sync pulse bottom at -1.07V. Out+ is inverted with Sync

up.

Typical RGB Graphics System

In an RGB graphics system, the color displayed is

determined by the combined intensities of the red,

green, and blue (RGB) DAC outputs. A change in gain

or offset in any of the RGB outputs affects the apparent

hue displayed on the CRT screen. Thus, it is very

important that the DAC’s outputs track each other over

a wide range of operating conditions. Since the DAC

output is proportional to the product of the reference

and digital input code, use a common reference to

drive all three DACs in an RGB system to minimize

RGB DAC-to-DAC mismatch and improve TC tracking.

The MAX5140 contains an internal precision-bandgap

reference that completely eliminates the need for an

external reference. The reference can supply up to

50µA to an external load, such as two other DAC refer-

ence inputs.

The circuits shown in Figure 8 show how a single

MAX5140 can be used as a master reference in a sys-

tem with multiple DACs (such as RGB). The other DACs

are simply slaved from the MAX5140’s reference

output.

Figure 6. CONV, CONV Switching Levels

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