GENNUM CORPORATION P.O. Box 489, Stn. A, Burlington, Ontario, Canada L7R 3Y3

Tel. +1 (905) 632-2996 Fax. +1 (905) 632-5946 E-mail: info@gennum.com

www.gennum.com

Revision Date: June 2004

Document No. 22213 - 2

DATA SHEET

GS90

KEY FEATURES

· SMPTE 259M and SMPTE 344M compliant

· dual coaxial cable driving outputs

· 50

differential PECL input

· single 3.3V power supply operation

· space-saving 8-lead SOIC

· operating temperature range: 0°C to 70°C

· pin compatible with GS1528 HD-LINX

II multirate SDI

dual slew-rate cable driver

· Pb-free and Green

APPLICATIONS

SMPTE 259M Coaxial Cable Serial Digital Interfaces

DESCRIPTION

The GS9068 is a second generation high-speed bipolar
integrated circuit designed to drive one or two 75

co-axial

cables at data rates up to 540Mb/s.

The GS9068 accepts a LVPECL level differential input,
which may be AC coupled. External biasing resistors at the
inputs are not required.

Power consumption is typically 160mW using a +3.3V DC
power supply.

GS9068 FUNCTIONAL BLOCK DIAGRAM

SDO

SET

SDO

SDI

BANDGAP REFERENCE AND BIASING CIRCUIT

OUTPUT STAGE &

CONTROL

INPUT

DIFFERENTIAL

PAIR

GS9068

SD SDI Cable Driver

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GS90

TABLE OF CONTENTS

1. PIN OUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.1 PIN ASSIGNMENT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2 PIN DESCRIPTIONS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2. ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2.1 ABSOLUTE MAXIMUM RATINGS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2.2 DC ELECTRICAL CHARACTERISTICS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2.3 AC ELECTRICAL CHARACTERISTICS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3. DETAILED DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6

3.1 SERIAL DIGITAL INPUT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.2 SERIAL DIGITAL OUTPUT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.3 OUTPUT RETURN LOSS MEASUREMENT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.4 OUTPUT AMPLITUDED ADJUSTMENT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4. APPLICATION REFERENCE DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4.1 PCB LAYOUT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4.2 TYPICAL APPLICATION CIRCUIT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6. PACKAGE & ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6.1 PACKAGE DIMENSIONS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6.2 ORDERING INFORMATION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

7. REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

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2. ELECTRICAL CHARACTERISTICS

2.1 ABSOLUTE MAXIMUM RATINGS

= 25°C unless otherwise indicated

PARAMETER

VALUE

Supply Voltage

-0.5V to 3.6 V

Input ESD Voltage

500V

Storage Temperature Range

-50°C < T

< 125°C

Input Voltage Range (any input)

-0.3 to (V

+0.3)V

Operating Temperature Range

0°C to 70°C

Power Dissipation

300mW

Lead Temperature (soldering, 10 sec)

260°C

2.2 DC ELECTRICAL CHARACTERISTICS

= 3.3V, V

=0V, T

= 0°C to 70°C, 270Mb/s unless otherwise shown

PARAMETER

SYMBOL

CONDITIONS

MIN

TYPICAL

MAX

UNITS

TEST

LEVEL

Supply Voltage

3.1

3.3

3.5

Power
Consumption

160

Supply Current

Output Voltage

Common mode

SDO(SE)

Input Voltage

Common mode

1.6 +

SDI(DIFF)

2.3 AC ELECTRICAL CHARACTERISTICS

= 3.3V, V

=0V, T

= 0°C to 70°C, 270Mb/s unless otherwise shown

PARAMETER

SYMBOL

CONDITIONS

MIN

TYPCAL

MAX

UNITS

TEST

LEVEL

Serial input data rate

SDI

540

Mb/s

Input Voltage Swing

SDI(DIFF)

Differential

300

2000

p-p

Output Voltage Swing

SDO(SE)

Single Ended into 75

external

load

SET

= 750

750

800

850

p-p

Additive jitter

Rise/Fall time

, t

20% - 80%

400

800

Mismatch in rise/fall time

Duty cycle distortion

100

Overshoot

Output Return Loss

ORL

TEST LEVELS

1. Production test at room temperature and nominal supply voltage with

guardbands for supply and temperature ranges.

2. Production test at room temperature and nominal supply voltage with

guardbands for supply and temperature ranges using correlated test.

3. Production test at room temperature and nominal supply voltage.

4. QA sample test.

5. Calculated result based on Level 1, 2, or 3.

6. Not tested. Guaranteed by design simulations.

7. Not tested. Based on characterization of nominal parts.

8. Not tested. Based on existing design/characterization data of similar

product.

9. Indirect test.

10. Wafer Probe

CAUTION

The GS9068 is sensitive to electrostatic discharge. Use
extreme caution, observing all ESD-prevention practices,
during handling and assembly. The SDI inputs of the GS9068
must be protected from electrostatic discharge and electrical
overstress during the handling and operation of circuit
assemblies containing the device.

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3. DETAILED DESCRIPTION

3.1 SERIAL DIGITAL INPUT

SDI/SDI are high impedance differential inputs. Several
conditions must be observed when interfacing to these
inputs:

1. The differential input signal amplitude must be between

300 and 2000mVpp.

2. For DC coupling to the device, the common mode

voltage must be between 1.6+

SDI(DIFF)

and VCC-

SDI(DIFF)

3. For input trace lengths longer than approximately 1cm,

the inputs should be terminated as shown in the Typical
Application Circuit.

The GS9068 inputs are self-biased, allowing for simple AC
coupling to the device. For serial digital video, a minimum
capacitor value of 4.7µF should be used to allow coupling
of pathological test signals. A tantalum capacitor is
recommended.

3.2 SERIAL DIGITAL OUTPUT

The GS9068 outputs are current mode and will drive 800mV
into a 75

load. These outputs are protected from accidental

static damage with internal static protection diodes.

The SMPTE 259M standard requires that the output of a
cable driver have a source impedance of 75

and a return

loss of at least 15dB between 5MHz and 540MHz. In order
for an SDI output circuit using the GS9068 to meet this
specification, the output circuit shown in the Typical
Application Circuit is recommended.

The value of L

COMP

will vary depending on the PCB layout,

with a typical value of 5.6nH. A 4.7µF capacitor is used for
AC coupling the output of the GS9068. This value is chosen
to ensure that pathological signals can be coupled without
a significant DC component occurring.

See Section 4, Application Reference Design, for more
details.

When measuring return loss at the GS9068 output, it is
necessary to take the measurement for both a logic high
and a logic low output condition. This is because the output
protection diodes act as a varactor (voltage controlled
capacitor) as shown in Figure 1. Consequently, the output
capacitance of the GS9068 is dependent on the logic state
of the output.

Fig. 1 Static Protection Diodes

3.3 OUTPUT RETURN LOSS MEASUREMENT

To perform a practical return loss measurement, it is
necessary to force the GS9068 output to a DC high or low
condition. The actual return loss will be based on the
outputs being static at V

or V

-1.6V. Under normal

operating conditions the outputs of the GS9068 swing
between V

-0.4V and V

-1.2V, so the measured value of

return loss will not represent the actual operating return
loss.

A simple method of calculating the values of actual
operating return loss is to interpolate the two return loss
measurements. In this way, the values of return loss are
estimated at V

-0.4V and V

-1.2V based on the

measurements at V

and V

-1.6V.

The two values of return loss (high and low) will typically
differ by several decibels. If the measured return loss is R

for logic high and R

for logic low, then the two values can

be interpolated as follows:

= R

- (R

-R

)/4, and

= R

+(R

-R

)/4,

where R

is the interpolated logic high value and R

is the

interpolated logic low value.

For example, if R

= -18dB and R

= -14dB, then the

interpolated values are R

= -17dB and R

= -15dB.

SDO

Part Number GS9068