ADV7482WBBCZ datasheet(18/20 Pages) AD

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ADV7482

Data Sheet

Figure 13. Typical Fully Differential Input Resistor Divider Network

The ADC features three clocking rates that allow 4×

oversampling per channel for CVBS mode, Y/C mode, and

YPbPr mode.

The fully differential AFE of the ADV7482 provides inherent

small and large signal noise rejection, improved electromagnetic

interference (EMI) protection, and the ability to absorb ground

bounce. Support is provided for both true differential and

pseudo differential signals.

The main AFE features include

•

A single 172 MHz, 10-bit ADC that enables true 8-bit

video decoding.

•

8-channel analog input mux that enables multiple source

connections without the requirement of an external mux.

•

A current clamp control loop that ensures that any dc

offsets are removed from the video signal entering the SDP.

•

Diagnostic capability on all differential inputs.

•

Support for 4 V common-mode input range.

•

Support for analog input signals up to 1 V p-p.

•

Support for single-ended, pseudo differential, and fully

differential inputs.

SHORT TO BATTERY DIAGNOSTICS

In differential mode, the ADV7482 is protected against STB

events by ac coupling capacitors (see Figure 12 and Figure 13).

The input network resistors are sized to reduce the current flow

during an STB event, thus preventing damage to the resistors.

Note that the input network resistors and the ac coupling

capacitors must be chosen with ratings guaranteeing they are

able to withstand the high voltage of STB events.

The four diagnostic inputs of the ADV7482 provide diagnostic

capability for all differential inputs. The ADV7482 can detect an

STB event on either the positive or the negative composite input

and trigger an interrupt. The 75 Ω (pseudo differential) or 150 Ω

(fully differential) parallel termination resistor enables one

DIAGx pin to sense an STB event on either input, because there

is a minimal voltage drop across the resistor.

Figure 14. Diagnostic Connection for Differential Inputs

Resistors R4 and R5 divide down the voltage at the input

connector to protect the DIAGx pin from an STB event. The

DIAGx pin circuitry compares this voltage to a programmable

reference voltage, known as the diagnostic slice level. When the

diagnostic slice level is exceeded, an STB event has occurred.

R4 and R5 are sized to allow the use of low cost, small footprint

resistors that are tolerant of STB events.

Use the following equation to find the STB voltage for a selected

diagnostic slice level.

_SLICE_LEV

DIAGNOSTIC

STB_TRIGGE

where:

VSTB_TRIGGER is the minimum voltage required at the input

connector to trigger the STB interrupt on the ADV7482.

DIAGNOSTIC_SLICE_LEVEL is the programmable reference

voltage.

For example, with a diagnostic slice level programmed to

1.125 V, an R4 value of 9.1 kΩ, and an R5 value of 1 kΩ, the

minimum voltage required at the input connector to trigger the

STB interrupt is approximately 11.4 V.

When the DIAGx pin voltage exceeds the diagnostic slice level

voltage, a hardware interrupt is triggered and indicated by one

of the interrupt pins. A readback register specifies the input on

which the STB event occurred.

STANDARD DEFINITION PROCESSOR

The ADV7482 is capable of decoding a large selection of

baseband video signals in composite (both single-ended and

differential), S-Video, and component formats. The video

standards supported by the video processor include

• PAL B, PAL D, PAL G, PAL H, PAL I, PAL M, PAL N,

PAL Nc, and PAL 60

• NTSC J, NTSC M, and NTSC 4.43

• SECAM B, SECAM D, SECAM G, SECAM K, and SECAM L

The ADV7482 can automatically detect the video standard and

process it accordingly.

The ADV7482 has a five-line adaptive 2D comb filter that

provides superior chrominance and luminance separation when

decoding a composite video signal. This highly adaptive filter

automatically adjusts its processing mode according to the

AINx

AINy

ANALOG INPUT

CVBS_P

CVBS_N

1.3kΩ

150Ω

430Ω

100nF

AINx

AINy

ANALOG INPUT

CVBS_P

CVBS_N

1.3k

150

430

DIAGx

100nF

Rev. 0 | Page 18 of 20

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