ML6424/ML6425

5

FUNCTIONAL DESCRIPTION

The ML6424 and ML6425 are monolithic CCIR601

continuous time video filters, designed for broadcast and

professional luminance and chrominance antialias and

reconstruction applications. They are fabricated using

Micro Linear’s 1.5

µ, 4 GHz BiCMOS process. The filter

incorporates an input amplifier, programmable gain of 1x

or 2x set by the GAIN pin, a fifth order lowpass filter, a

third order allpass filter, and an output amplifier capable

of driving 75

Ω to ground. The ML6425 provides sinx/x

equalization.

The ML6424–1 is intended for application as luminance

antialias processing, the ML6424–2 for chrominance

antialias, the ML6425–1 for luma reconstruction, and the

ML6425–2 for chroma reconstruction.

Input signals can be applied either through an AC coupling

capacitor (MODE = High/Low) or directly to the input pin

(MODE = float). With MODE = High, Y-Channel signal

6

7

ML6424-1

12

MODE

+5V

Y

4

PULSE I/O

6

7

ML6424-2

12

MODE

U

4

PULSE I/O

6

7

ML6424-2

12

MODE

V

75

Ω

1

µF

1

µF

1

µF

75

Ω

75

Ω

4

PULSE I/O

can be applied to the input and the PULSE I/O pin

generates a clamping pulse for the U/V channel. When

MODE = Low, U/V channel signal can be applied to the

input. In this case, the PULSE I/O pin can take the pulse

signal generated from the PULSE I/O pin of the other chip

in the Y-channel. In the case of direct coupling, RANGE

should be adjusted according to the input signal range.

When RANGE is low, the input signal range is 0.5V to

1.5V. When the input signal goes down to 0V, RANGE

should be tied high. In this case, an offset is added to the

input so that the filter can process the 0V DC level.

The output amplifier is designed to drive up to 20mA peak

into a 75

Ω load, or 17mA peak into a 150Ω load. Load

resistance less than 75

Ω and/or output voltage above 1.5V

into 75

Ω (2.5V into 150Ω) may cause signal distortion.

Good high frequency decoupling is required between

each power supply pin and ground, otherwise oscillations

and/or excessive crosstalk may occur.

Figure 1. YUV Filter with Sync on Y Input

and Auto Clamp On

6

7

ML6424-1

12

MODE

+5V

Y

4

PULSE I/O

6

7

ML6424-2

12

MODE

U

4

PULSE I/O

6

7

ML6424-2

12

MODE

V

75

Ω

1

µF

1

µF

1

µF

75

Ω

75

Ω

4

PULSE I/O

Figure 2. YUV Filter with External Sync for U/V