DESCRIPTIONThe

ADV7125 (ADV®) is a triple high speed, digital-to-analog converter (DAC) on a single monolithic chip. It consists of three high speed, 8-bit video DACs with complementary outputs, a standard TTL input interface, and a high impedance, analog output current source.The ADV7125 has three separate 8-bit-wide input ports. A single +5 V/+3.3 V power supply and clock are all that are required to make the device functional. The ADV7125 has additional video control signals, composite SYNC and BLANK, as well as a power save mode.The ADV7125 is fabricated in a 5 V CMOS process. Its monolithic CMOS construction ensures greater functionality with lower power dissipation. The ADV7125 is available in 48-lead LQFP and 48-lead LFCSP packages.

ADV7125JSTZ330 is available in a 3.3 V option only.

 

PRODUCT HIGHLIGHTS

1.330 MSPS (3.3 V only) throughput.

2.Guaranteed monotonic to eight bits.

3.Compatible with a wide variety of high resolution color graphics systems, including RS-343A and RS-170.

 

FEATURE

S330 MSPS throughput rateTriple 8-bit DACsRS-343A-/RS-170-compatible outputComplementary outputsDAC output current range: 2.0 mA to 26.5 mATTL-compatible inputsInternal reference (1.235 V)Single-supply +3.3 V operation48-lead LQFP and LFCSP Low power dissipation (30 mW minimum at 3 V)Low power standby mode (6 mW typical at 3 V)Industrial temperature range (−40°C to +85°C)RoHS compliant packagesQualified for automotive applications

 

APPLICATIONS

Digital video systems

High resolution color graphics

Digital radio modulation

Image processing

Instrumentation

Video signal reconstruction

Automotive infotainment units

 

ELECTRICAL CHARACTERISTICS

3.3 V: VAA = 3.0 V to 3.6 V, VREF = 1.235 V, RSET = 560 Ω, CL = 10 pF. All specifications TMIN to TMAX,1 unless otherwise noted, TJ MAX = 110°C.

TIMING SPECIFICATIONS

3.3 V: VAA = 3.0 V to 3.6 V,1 VREF = 1.235 V, RSET = 560 Ω, CL = 10 pF. All specifications TMIN to TMAX,2 unless otherwise noted, TJ MAX = 110°C.

 

CIRCUIT DESCRIPTION AND OPERATION

The ADV7125 contains three 8-bit DACs, with three input channels, each containing an 8-bit register. Also integrated on board the device is a reference amplifier. The CRT control functions, BLANK and SYNC, are integrated on board the ADV7125.

 

CLOCK INPUT

The CLOCK input of the ADV7125 is typically the pixel clock rate of the system. It is also known as the dot rate. The dot rate, and thus the required CLOCK frequency, is determined by the on-screen resolution, according to the following equation:

Dot Rate = (Horiz Res) × (Vert Res) × (Refresh Rate)/(Retrace Factor)

where:

Horiz Res is the number of pixels per line.

Vert Res is the number of lines per frame.

Refresh Rate is the horizontal scan rate. This is the rate at which the screen must be refreshed, typically 60 Hz for a noninterlaced system, or 30 Hz for an interlaced system.Retrace Factor is the total blank time factor. This takes into account that the display is blanked for a certain fraction of the total duration of each frame (for example, 0.8).

Therefore, for a graphics system with a 1024 × 1024 resolution, a noninterlaced 60 Hz refresh rate, and a retrace factor of 0.8,

Dot Rate = 1024 × 1024 × 60/0.8 = 78.6 MHz

The required CLOCK frequency is thus 78.6 MHz. All video data and control inputs are latched into the ADV7125 on the rising edge of CLOCK, as previously described in the Digital Inputs section. It is recommended that the CLOCK input to the ADV7125 be driven by a TTL buffer (for example, the 74F244).

NOTES：

1.OUTPUTS CONNECTED TO A DOUBLY TERMINATED 75Ω LOAD.
2.VREF = 1.235V, RSET = 530Ω.
3.RS-343 LEVELS AND TOLERANCES ASSUMED ON ALL LEVELS.
4.Z = RoHS Compliant Part.

 

AUTOMOTIVE PRODUCTS

The ADV7125W models are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. Note that these automotive models may have specifications that differ from the commercial models; therefore, designers should review the Specifications section of this data sheet carefully. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for these models.