Fairchild Semiconductor ML6426X4 Datasheet

ML6426

High Bandwidth Triple Video Filters with Buffered

Outputs for RGB or YUV

GENERAL DESCRIPTION

The ML6426 are a family of triple video filters with buffered outputs. There are several versions of the ML6426, each with different passband cut-off frequencies of 6.7MHz, 12MHz, 15MHz, 24MHz, 30MHz, 36MHz, and 48MHz. Each channel contains a 4

-order Butterworth lowpass reconstruction video filter. The filter is optimized for minimum overshoot and flat group delay and guaranteed differential gain and phase at the outputs of the integrated cable drivers.

All input signals from DACs are AC coupled into the ML6426. All channels have DC restore circuitry to clamp the DC input levels during video H-sync, using an output feedback clamp. An external H-sync signal is required for this purpose.

All outputs must be AC coupled into their loads. Each output can drive 2V

P-P

into a 150Ω load. All channels

have a gain of 2 (6dB) at 1V

P-P

input levels.

FEATURES

■ 5V ±10% operation

■ RGB/YUV filters for ATSC Digital Television VESA

Standard

■ 2:1 Mux Inputs for multiple RGB/YUV inputs

■ Triple Reconstruction Filter options for 6.7, 12, 15, 24,

30, 36, and 48MHz to handle various line rates

■ Multiple ML6426 outputs can be paralleled to drive

RGB/YUV outputs at different frequencies for various line rates by means of Disable/Enable pin.

■ 6dB drivers and sync tip clamps for DC restore

■ DC restore with minimal tilt

■ 0.4% differential gain on all channels

0.4º differential phase on all channels

0.8% total harmonic distortion on all channels

■ 2kV ESD protection

BLOCK DIAGRAM

RINA/YINA

RINB/YINB

BINA/VINA

BINB/VINB

A/B MUX

GINA/UINA

GIN/UINB

OUT/YOUT

OUT/UOUT

OUT/VOUT

4th-ORDER

FILTER A

4th-ORDER

FILTER B

4th-ORDER

FILTER C

MUX

×2

TRANSCONDUCTANCE

ERROR AMP

TRANSCONDUCTANCE

ERROR AMP

TRANSCONDUCTANCE

ERROR AMP

SYNCIN

GNDO

DISABLE

CCO

GND

–

0.5V

ML6426-1 ML6426-2 ML6426-3 ML6426-4 ML6426-5 ML6426-6 ML6426-15 Filter A 6.7MHz 12MHz 24MHz 30MHz 36MHz 48MHz 15MHz Filter B 6.7MHz 12MHz 24MHz 30MHz 36MHz 48MHz 15MHz Filter C 6.7MHz 12MHz 24MHz 30MHz 36MHz 48MHz 15MHz

REV. 1.1 2/8/2001

ML6426

2 REV. 1.1 2/8/2001

PIN CONFIGURATION

PIN DESCRIPTION

PIN NAME FUNCTION

1A/B MUX Logic input pin to select between

Bank <A> and Bank <B> video inputs. This pin is internally pulled high.

A/YINA Unfiltered analog R- or Y-channel

input for Bank <A>. Sync must be provided at SYNC IN pin.

3 GND Analog ground

Analog 5V supply

B/YINB Unfiltered analog R- or Y-channel

input for Bank <B>. Sync must be provided at SYNC IN pin.

A/UINA Unfiltered analog G- or U-channel

input for Bank <A>. Sync must be provided at SYNC IN pin.

B/UINB Unfiltered analog G- or U-channel

input for Bank <B>. Sync must be provided at SYNC IN pin.

PIN NAME FUNCTION

8BINA/VINA Unfiltered analog B- or V-channel

input for Bank <A>. Sync must be provided at SYNC IN pin.

B/VINB Unfiltered analog B- or V-channel

input for Bank <B>. Sync must be provided at SYNC IN pin.

10 B

OUT

Analog B or V-channel output

11 G

OUT

Analog G or U-channel output

12 V

CCO

5V power supply for output buffers

13 R

OUT

Analog R or Y-channel output

14 GNDO Analog ground

15 DISABLE Disable/Enable pin. Turns the chip off

when logic high. Internally pulled low.

16 SYNC IN Input for an external H-sync logic

signal for filter channels. CMOS level input. Active High.

ML6426

16-Pin Narrow SOIC (S16N)

TOP VIEW

A/B MUX

RINA/YINA

GND

RINB/YINB

GINA/UINA

GINB/UINB

BINA/VINA

SYNC IN

DISABLE

GNDO

OUT/YOUT

CCO

OUT/UOUT

OUT/VOUT

BINB/VINB

ML6426

REV. 1.1 2/8/2001 3

ABSOLUTE MAXIMUM RATINGS

Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied.

................................................................................

–0.3V to 7V

Junction Temperature .............................................. 150°C

ESD ..................................................................... >2000V

Analog and Digital I/O........... GND –0.3V to V

+ 0.3V

Storage Temperature Range ..................... –65°C to 150°C

Lead Temperature (Soldering, 10 sec) ..................... 260°C

Thermal Resistance (θ

) .................................... 100°C/W

OPERATING CONDITIONS

Temperature Range ....................................... 0°C to 70°C

Range ...................................................4.5V to 5.5V

ELECTRICAL CHARACTERISTICS

Unless otherwise specified, VCC = 5V±10%, TA = Operating Temperature Range (Note 1)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

GENERAL

Supply Current No Load (VCC=5.5V) 52 80 mA

Low Frequency Gain (R, G, B) VIN= 100mV

P-P

at 100KHz 5.34 6.0 6.65 dB

OUT

Output Level during Sync (R, G, B,) DURING SYNC 0.7 0.9 1.1 V

Output Capability RL = 150W, AC-coupled@1MHz 2 VP-P

CLAMP

Clamp Response Time Settled to Within 10mV, CIN = 0.1µF 10 ms

Input Signal Dynamic Range (R, G, B,) AC Coupled 1.4 V

P-P

OS Peak Overshoot (R, G, B,) 2V

P-P

Output Pulse 4.3 %

Output Load Capacitance (R, G, B,) All Outputs 35 pF

Output Load Drive Capability, per Pin One Load is 150Ω 2 loads (YUV or RGB Outputs)

dG Differential Gain (R, G, B,) All Outputs at fC/2 0.4 %

dφ Differential Phase (R, G, B,) All Outputs at fC/2 0.4 º

Output Distortion (R, G, B,) V

OUT

= 2V

P-P

at 1 MHz 0.8 %

PSRR PSRR (R, G, B,) 0.5V

P-P

(100kHz) at V

35 dB

Output Short Circuit Current (R, G, B,) Note 2 120 mA

Input Voltage Logic High DISABLE, SYNC IN 2.5 V

Input Voltage Logic Low DISABLE, SYNC IN 1.0 V

MUX

Input Mux A/B Mux 2 µs Data Valid Pin Valid Time High or Low

6.7MHz FILTER: ML6426-1

1dB

–1dB Bandwidth Flatness (R, G, B,) 25ºC 4.0 4.8 MHz

–3dB Bandwidth Flatness (R, G, B,) 25ºC 6.0 6.7 7.3 MHz

0.8fc

0.8 x fC Attenuation 1.5 dB

StopBand Rejection (All Channels ≥ 4 fC)fIN ≥ 4 fC, Note 3 –38 –42 dB

NOISE Output Noise (R, G, B,) Fullband 1.0 mV

RMS

TALK

Crosstalk Input of 0.5V

P-P

at 1 MHz –55 dB

Between any two Channels

TALK

A/B MUX Crosstalk Input of 0.5V

P-P

at 3.58/4.43MHz –54 dB

ML6426

4 REV. 1.1 2/8/2001

ELECTRICAL CHARACTERISTICS (Continued)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

6.7MHZ FILTER: ML6426-1 (continued)

Group Delay (R, G, B,) 100kHz 70 ns

∆T

Group Delay Deviation from Flatness to 3.58MHz 4.0 ns

(R, G, B,) to 4.43MHz 8.0 ns

to 10MHz 9 ns

2MHz FILTER: ML6426-2

1dB

–1dB Bandwidth Flatness (R, G, B,) 25ºC 7.8 9.2 MHz

–3dB Bandwidth Flatness (R, G, B,) 25ºC 10.8 12 13.2 MHz

0.8fc

0.8 x fC Attenuation 1.2 dB

StopBand Rejection (All Channels ≥ 4 fC)fIN ≥ 4 fC, Note 3 –40 dB

NOISE Output Noise (R, G, B,) Fullband 1 mV

RMS

TALK

Crosstalk Input of 0.5V

P-P

at 1 MHz –55 dB

Between any two Channels

TALK

A/B MUX Crosstalk Input of 0.5V

P-P

at 3.58/4.43MHz –54 dB

Group Delay (R, G, B,) 100kHz 40 ns

∆T

Group Delay Deviation from Flatness to 3.58MHz 1 ns

(R, G, B,) to 4.43MHz 1 n s

to 10MHz 7 ns

24MHz FILTER: ML6426-3

1dB

–1dB Bandwidth Flatness (R, G, B,) 25ºC 13.6 16 MHz

–3dB Bandwidth Flatness (R, G, B,) 25ºC 21.6 24 26.4 MHz

0.8fc

0.8 x fC Attenuation 1.7 dB

StopBand Rejection (All Channels ≥ 4 fC)fIN ≥ 4 fC, Note 3 – 40 dB

NOISE Output Noise (R, G, B,) Fullband 1.0 mV

RMS

TALK

Crosstalk Input of 0.5V

P-P

at 1 MHz –55 dB

Between any two Channels

TALK

A/B MUX Crosstalk Input of 0.5V

P-P

at 3.58/4.43MHz -54 dB

Group Delay (R, G, B,) 100kHz 22 ns

∆T

Group Delay Deviation from Flatness to 3.58MHz 1 ns

(R, G, B,) to 4.43MHz 1 n s

to 10MHz 2 ns

30MHz FILTER: ML6426-4

1dB

–1dB Bandwidth Flatness (R, G, B,) 25ºC 15.3 18 MHz

–3dB Bandwidth Flatness (R, G, B,) 25ºC 27 30 3 3 MHz

0.8fc

0.8 x fC Attenuation 1.7 dB

StopBand Rejection (All Channels ≥ 4 fC)fIN ≥ 4 fC, Note 3 –40 dB

NOISE Output Noise (R, G, B,) Fullband 1.0 mV

RMS

ML6426

REV. 1.1 2/8/2001 5

Note 1. Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions.

Note 2. Sustained short circuit protection limited to 10 seconds.

Note 3. 38dB is based on tester noise limits.

ELECTRICAL CHARACTERISTICS (Continued)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

30MHz FILTER: ML6426-4 (Continued)

TALK

Crosstalk Input of 0.5V

P-P

at 1 MHz –55 dB

Between any two Channels

TALK

A/B MUX Crosstalk Input of 0.5V

P-P

at 3.58/4.43MHz -54 dB

Group Delay (R, G, B,) 100kHz 18 ns

∆T

Group Delay Deviation from Flatness to 10MHz 0.5 ns

(R, G, B,) to 27MHz 2 n s

36MHz FILTER: ML6426-5

1dB

–1dB Bandwidth Flatness (R, G, B,) 25ºC 17 20 MHz

–3dB Bandwidth Flatness (R, G, B,) 25ºC 32.4 36 39.6 MHz

0.8fc

0.8 x fC Attenuation 2dB

StopBand Rejection (All Channels ≥ 4 fC)fIN ≥ 4 fC, Note 3 –40 dB

NOISE Output Noise (R, G, B,) Fullband 1.0 mV

RMS

TALK

Crosstalk Input of 0.5V

P-P

at 1 MHz –55 dB

Between any two Channels

TALK

A/B MUX Crosstalk Input of 0.5V

P-P

at 3.58/4.43MHz –54 dB

Group Delay (R, G, B,) 100kHz 17 ns

∆T

Group Delay Deviation from Flatness to 10MHz 0.5 ns

(R, G, B,) to 30MHz 4 n s

48MHz FILTER: ML6426-6

1dB

–1dB Bandwidth Flatness (R, G, B,) 25ºC 25.5 30 MHz

–3dB Bandwidth Flatness (R, G, B,) 25ºC 43.2 48 52.8 MHz

0.8fc

0.8 x fC Attenuation 1.2 dB

StopBand Rejection (All Channels ≥ 4 fC)fIN ≥ 4 fC, Note 3 –40 dB

NOISE Output Noise (R, G, B,) Fullband 1.0 mV

RMS

TALK

Crosstalk Input of 0.5V

P-P

at 1 MHz –55 dB

Between any two Channels

TALK

A/B MUX Crosstalk Input of 0.5V

P-P

at 3.58/4.43MHz –54 dB

Group Delay (R, G, B,) 100kHz 16 ns

∆T

Group Delay Deviation from Flatness to 10MHz 0.5 ns

(R, G, B,) to 40MHz 2 n s

ML6426

6 REV. 1.1 2/8/2001

FUNCTIONAL DESCRIPTION

The ML6426 is a triple monolithic continuous time video filter designed for reconstructing video signals from an YUV/RGB video D/A source. The ML6426 is intended for use in AC coupled input and output applications.

The filters approximate a 4th-order Butterworth characteristic with an optimization toward low overshoot and flat group delay. All outputs are capable of driving 2V

P-P

into AC coupled 150Ω video loads, with up to 35pF of load capacitance. All outputs are capable of driving a 75Ω load at 1V

P-P

All channels are clamped during sync to establish the appropriate output voltage swing range (DC restore). Thus the input coupling capacitors do not behave according to the conventional RC time constant. In most applications, the ML6426's input coupling capacitors are only 0.1µF.

Figure 1. Typical Application Schematic

An external CMOS compatible H

SYNC

pulse is required

which is Active High on the SYNC IN Pin. See Figure 2.

During sync, the feedback clamp sources/sinks current to restore the DC level. The net result is that the average input current is zero. Any change in the input coupling capacitors' value will linearly affect the clamp response times.

Each channel is essentially tilt-free. Each input is clamped by a feedback amp which responds to the output during sync.

The ML6426 is robust and stable under all stated load and input conditions. Bypassing both V

pins directly to

ground ensures this performance.

5V 5V

0.1µF

220µF

75Ω

0.1µF

220µF

75Ω

220µF

75Ω

SYNC IN

0.1µF

RINA/YINA

RINB/YINB

BINA/VINA

BINB/VINB

A/B MUX

GINA/UINA

GINB/UINB

OUT/YOUT

OUT/UOUT

OUT/VOUT

4th-ORDER

FILTER A

4th-ORDER

FILTER B

4th-ORDER

FILTER C

MUX

×2

TRANSCONDUCTANCE

ERROR AMP

TRANSCONDUCTANCE

ERROR AMP

TRANSCONDUCTANCE

ERROR AMP

SYNCIN

GNDO

DISABLE

CCO

GND

–

0.5V

ACTIVE HIGH

Figure 2. SYNC IN Pulse Width

VIL = 1.0V

50% x V

SYNC IN

= 2.5V

MIN

= 2µS

+ 11 hidden pages