Fairchild Semiconductor ML6427 Datasheet

August 1999

PRELIMINARY

ML6427

75W Quad Video Cable Drivers and Filters

with Switchable Inputs

GENERAL DESCRIPTION

The ML6427 is a quad 4th-order Butterworth lowpass reconstruction filter plus quad video amplifier optimized for minimum overshoot and flat group delay. Each filter channel has a two-input multiplexer that switches between two groups of quad video signals. Applications driving SCAR T and EVC cables are supported for composite, component, and RGB video.

input signals from DACs are A C coupled into the

P-P

ML6427 where they are DC restored. Outputs are AC coupled and drive 2V

into a 150W load. The ML6427

P-P

can provide DC coupled outputs for certain applications. A fifth unfiltered channel is provided to support an

additional analog composite video input. A sw apping multiplexer between the two composite channels allows the distribution amplifiers to output from either input.

Several ML6427s can be arranged in a master-slave configuration where an external sync can be used for CV and RGB outputs.

BLOCK DIAGRAM

FEATURES

■ Cable drivers for P eritel (SCART), Enhanced Video

Connector (EVC), and standard video connectors, 75W cable drivers for CV, S-video, and RGB

■ 7.1MHz CV, RGB, and S-video, NTSC or PAL filters

with mux inputs and output channel mux

■ Quad reconstruction filter or dual anti-aliasing filter

■ 43dB stopband attenuation at 27MHz

■ 1dB flatness up to 4.8MHz

■ 12ns group delay flatness up to 10MHz

■ 0.4% differential gain, 0.4º differential phase on all

channels

■ 0.4% total harmonic distortion on all channels

■ Master-sla ve configur ation allo ws up to 8 multiplexed,

filtered output signals

SYNCIN

SYNCOUT

INF

RINA/Y4

RINB/Y5

GINA/Y6

GINB/Y2

BINA/C1

BINB/C2

A/B MUX

A/Y2*

B/Y3*

UNFILTERED CHANNEL

SYNC

TIMER

SYNC TIMER

REQUIRED SYNC STRIP

MUX

TRANSCONDUCTANCE

ERROR AMP

TRANSCONDUCTANCE

ERROR AMP

TRANSCONDUCTANCE

ERROR AMP

TRANSCONDUCTANCE

ERROR AMP

*CAN ALSO INPUT SYNC ON GREEN SIGNALS

+ –

CCO

ERROR AMP

4th-ORDER

0.5V 4th-ORDER

0.75V

FILTER

SWAP CVUV

+ –

0.5V

17 6 1314

RGB

CCO

TRANSCONDUCTANCE

SWAP

MUX

SWAP CVF

×2

1/Y

OUT

OUT/YOUT

OUT/COUT

GNDGNDO

519

ML6427

PIN CONFIGURATION

A/B MUX

INU

INF

RINA/Y4

RINB/Y5

GINA/Y6

GINB/Y7

BINA/C1

BINB/C2

/Y1

A/Y2

B/Y3

GND

ML6427

24-Pin SOIC (S24)

TOP VIEW

SYNCOUT

SYNCIN

CCO

1/Y

OUT

2/Y

OUT

GNDO

OUT/YOUT

RGB

CCO

OUT/YOUT

OUT/COUT

SWAP CVU

SWAP CVF

OUT

PIN DESCRIPTION

ML6427

PIN NAME FUNCTION

1A/B MUX Logic input pin to select between

Bank <A> or of the CV, RGB, or Y/C inputs. Internally pulled high.

2CV

/Y1 Unfiltered analog composite video

INU

or luma video input. Internally pulled high. A composite or luma or green signal must be present on either the CV

A/Y2 or the CV

INF

Y3 input to provide necessary sync signals to other channels (R, G, B, Y, C). Otherwise, sync must be provided at SYNCIN. For RGB applications the green channel with sync can be used as an input to this pin (see RGB Applications section).

3CV

A/Y2 Filtered analog composite video or

INF

luma video input for Bank <A>. Note that SYNC is stripped from this signal for the other channels. A composite or luma or green signal must be present on either the CV

A/Y2 or the CV

INF

B/Y3 input

INF

to provide necessary sync signals to other channels (R, G, B, Y, C). Otherwise, sync must be provided at SYNCIN. For RGB applications the green channel with sync can be used as an input to this pin (see RGB Applications section).

INF

PIN NAME FUNCTION

12 BINB/C2 Filtered analog BLUE video or

chroma video input for Bank

13 SWAP CVF Logic input pin to select whether

the outputs of CV CV

OUT

2/Y

OUT

1/Y

OUT

A and

B are from filtered or unfiltered CV sources. See Table 1. Internally pulled low .

14 SWAP CVU Logic input pin to select whether

the outputs of CV CV

OUT

2/Y

OUT

1/Y

OUT

A and

B are from filtered or unfiltered CV sources. See Table 1. Internally pulled low .

15 B

OUT/COUT

Analog BLUE video output or chroma output from either BINA/C1 or BINB/C2

16 G

OUT/YOUT

D Analog GREEN video output or

luma output from either GINA/Y6 or GINB/Y7

17 V

RGB 5V po wer supply for output buffers

CCO

of the RGB drivers

18 R

OUT/YOUT

C Analog RED video output or luma

output from either RINA/Y4 or RINB/ Y5

19 GNDO Ground for output buffers

4CV

B/Y3 Filtered analog composite video or

INF

luma video input for Bank . Note that SYNC is stripped from this

signal for the other channels. 5 GND Analog ground 6V

Analog 5V supply 7RINA/Y4 Filtered analog RED video or luma

video input for Bank <A> 8RINB / Y5 Filtered analog RED video or luma

video input for Bank 9GINA/Y6 Filtered analog GREEN video or

luma video input for Bank <A>

10 GINB/Y7 Filtered analog GREEN video or

luma video input for Bank

11 BINA/C1 Filtered analog BLUE video or

chroma video input for Bank <A>

20 CV

OUT

2/Y

B Composite video output for channel

OUT

2 or luma output.

21 CV

OUT

1/Y

A Composite video output for channel

OUT

1 or luma output.

22 V

CV 5V power supply for output buffers

CCO

of the CV drivers.

23 SYNCIN Input for an external H-sync logic

signal for filtered channels. TTL or CMOS. For normal operation SYNCOUT is connected to SYNCIN.

24 SYNCOUT Logic output for H-sync detect for

A/Y2 or CV

INF

B/Y3. TTL or

INF

CMOS. For normal operation SYNCOUT is connected to SYNCIN.

ML6427

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

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

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

Thermal Resistance (qJA) ......................................80°C/W

device operation is not implied.

OPERATING CONDITIONS

..................................................................................................6V

Junction T emperature............................................. 150°C

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

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

VDD 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

I A

SYNC

CLAMP

0.5dB

Supply Current No Load (VCC = 5V) 90 mA

Low Frequency Gain (All Channels) V

= 100mV

at 300kHz 5.34 6.0 6.65 dB

P-P

Channel Sync Output Level CV/Y, R/Y, G/Y Sync Present and Clamp Settled 0.6 0.9 1.1 V

B/C Sync Present and Clamp Settled 1.2 1.4 1.5 V

Unfiltered Sync Present and Clamp Settled 0.7 1.0 1.2 V

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

0.5dB Bandwidth All Outputs 4.5 MHz (Flatness. All Filtered Channels)

–3dB Bandwidth All Outputs (With no Peaking Cap. 6.7 7.1 MHz

(Flatness. All Filtered Channels) See Figures 2 and 13)

0.8f f

0.8 x fC Attenuation, All Filtered Channels All Outputs 1.5 dB

Stopband Rejection All Filtered Channels –35 –41 dB

= 27MHz to 100MHz worst case

(See Figures 2 and 13)

Input Signal Dynamic Range (All Channels) AC Coupled 1 1.25 V

NOISE Output Noise (All Channels) Over a Frequency Band 1 mV

of 25Hz-50MHz OS Peak Overshoot (All Channels) 2V I

Output Short Circuit Current (All Channels) Note 2 120 mA

Output Load Capacitance (All Channels) Load at the Output Pin 35 pF

Output Pulse 4.3 %

P-P

dG Differential Gain (All Channels) All Outputs 0.4 % dF Differential Phase (All Channels) All Outputs 0.4 º

TALK

Output Distortion (All Channels) V

Crosstalk Input of 0.5V

OUT

= 1.8V

at 3.58/4.43MHz 0.4 %

P-P

at 3.58/4.43MHz –55 dB

P-P

on any channel to output of any

other channel

Input A/B MUX Crosstalk Input of 0.5V

Swap Mux Crosstalk Input of 0.5V

at 3.58/4.43MHz –54 dB

P-P

at 3.58/4.43MHz –52 dB

P-P

RMS

ML6427

ELECTRICAL CHARACTERISTICS (Continued)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

PSRR PSRR (All Channels) 0.5V

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.

Group Delay (All Channels) at 100kHz 60 ns

Group Delay Deviation from Flatness to 3.58MHz (NTSC) 4 ns

(All Channels) to 10MHz 1 2 ns Input Voltage Logic High A/B MUX, SWAP CVU, SWAP CVF 2.5 V

Input Voltage Logic Low A/B MUX, SWAP CVU, SWAP CVF 1 V

(100kHz) at V

P-P

to 4.43MHz (PAL) 7 ns

–39 dB

ML6427

FUNCTIONAL DESCRIPTION

The ML6427 is a quad monolithic continuous time analog video filter designed for reconstructing signals from four video D/A sources. The ML6427 is intended for use in AC coupled input and output applications.

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

into A C coupled 150W video loads with up to 35pF

P-P

of load capacitance at the output pin. They are also capable of driving a 75W load at 1V

P-P

All channels are clamped during sync to establish the appropriate output voltage swing range. Consequently the input coupling capacitors do not behave according to the conventional RC time constant. Clamping for all channels settles within 10ms of a change in video sources.

Input coupling capacitors of 0.1µF are recommended for all channels. During sync a feedback error amplifier sources/sinks current to restore the DC level. The net result is that the average input current is zero. Any change in the value of the input coupling capacitors will linearly affect the clamp response times.

The RGB channels have no pulldown current sources and are essentially tilt-free. The inputs of the CV channels sink less than 1µA during active video, resulting in a tilt of less than 1mV for 220µF output capacitors. A 1000µF capacitor is recommended for TV applications to minimize tilt in the CV channels.

SWAP MULTIPLEXER CONTROL

Output pins CV

OUT

1/Y

OUTA

and CV

OUT

2/Y

B are each

OUT

independently selectable among three input sources (CV

INU

/Y1, CV

A/Y2, or CV

INF

B/Y3) depending on the

INF

state of digital inputs SWAP CVF, SWAP CVU, and A/ B MUX. This allows the two outputs to remain independent and pass straight through, or to remain independent but swapped, or for both outputs to hav e the same signal sourcing from either CV

INU

/Y1, CV

A/Y2, or CV

INF

B/Y3 (See Table 1). If SWAP CVF is forced to logic low then CV THE CV CV OR THE CV CV If SWAP CVU is high then CV from either the CV

OUT

2/Y 1/Y 2/Y

B is sourced from either the CV

OUT

B/Y3 input. If SWAP CVU is logic low then

INF

A provides video from either the CV

OUT

B/Y3 input. If SWAP CVF is logic high then

INF

provides video from the CV

OUTB

A/Y2 or the CV

INF

OUT

1/Y

OUT

INF

INU

A provides video

B/Y3 input. Both

A/Y2 OR

INF

/Y1 input.

A/Y2

SWAP CVF and SWAP CVU will pull low if they are not driven.

The ML6427 is robust and stable under all stated load and input conditions. Bypassing both V

pins directly to

ground ensures this performance. Two ML6427s can be connected in a master-sla v e sync configuration. When using this configuration (See Figure 6) only the “master” ML6427 is required to have a signal with embedded sync present on the CV absence of sync on the CV

A/Y2 and CV

INF

A/Y2 and CV

INF

B/Y3 inputs. In the

B/Y3 inputs

INF

of the “slave” ML6427 it will ha v e its SYNCIN input connected to the SYNCOUT output of the “master” ML6427.

SYNCIN AND SYNCOUT PINS

Each ML6427 has two sync detectors which control the DC restore functions. The unfiltered channel has its own detector , w hic h controls the DC restore function during the horizontal sync period of the CV

/Y1 input. The

INU

other sync detector controls the DC restore functions for the filtered channels based upon the composite or luma silgnal at the CV

A/Y2 or CV

INF

B/Y3 input.

INF

Required Setup: A composite or luma or green signal must be present on CV

A/Y2 or CV

INF

B/Y3 inputs to

INF

provide necessary sync signals to other channels (R, G, B, Y, C). Otherwise, sync must be provided at the SYNCIN pin. For RGB applications the green channel with sync can be used as an input to CV

A/Y2 or CV

INF

B/Y3.

The SYNCOUT pin provides a logic high when it detects the horizontal sync of either the CV

A/Y2 or CV

INF

B/Y3 input (note that one input is selected by the A/B MUX pin). The SYNCIN pin is an input for an external H-sync logic signal to enable or disable the internal DC restore loop for the filtered channels. When SYNCIN is logic high the DC restore function is enabled.

For normal operation the SYNCOUT pin is connected to the SYNCIN pin (see Figure 4). If neither the CV nor the CV

B/Y3 has an embedded sync an external

INF

A/Y2

sync can be applied on the SYNCIN pin. In master-slave configurations the SYNCOUT of a ML6427 master can be used as the SYNCIN of a ML6427 slave (see Figure 6).

VIDEO I/O DESCRIPTION

Each input is driven b y either a low impedance source or the output of a 75W terminated line. The input is required to be AC coupled via a 0.1µF coupling capacitor which gives a nominal clamping time of 10ms. All outputs are capable of driving an AC coupled 150W load at 2V 1V

into a 75W load. At the output pin, up to 35pF of

P-P

load capacitance can be driven without stability or slew issues. A 220µF AC coupling capacitor is recommended at the output to reduce power consumption. For DC coupled outputs see the Typical Applications section.

ANALOG MULTIPLEXER CONTROL

The four filter channels each have two input multiplexers which are paired to select between two four-channel video sources (

i.e.

, composite video plus RGB component video). If A/B MUX is forced to logic high, it will select Bank<A> of the video inputs (CV

A/Y2, RINA/Y4, GINA/

INF

Y6, BINA/C1) to be enabled. If A/B MUX is logic low then Bank of video inputs (CV B

B/C2) will be selected. If the A/B MUX is open it will

INF

B/Y3, RINB/Y5,GINB/Y7,

INF

pull to logic high.

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