GS2978 HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
1 of 15GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
37186 - 7 March 2009
www.gennum.com
Features
• SMPTE 424M, SMPTE 292M, SMPTE 344M and SMPTE
259M compliant
• Dual coaxial cable driving outputs with selectable
slew rate
•50Ω differential PECL input
• Pb-free and RoHS compliant
• Seamless interface to other HD-LINX® III family
products
• Single 3.3V power supply operation
• Operating temperature range: 0°C to 70°C
Applications
• SMPTE 424M, SMPTE 292M, SMPTE 344M and SMPTE
259M Coaxial Cable Serial Digital Interfaces.
Description
The GS2978 is a high-speed BiCMOS integrated circuit
designed to drive one or two 75Ω co-axial cables.
The GS2978 may drive data rates up to 2.97Gb/s and
provides two selectable slew rates in order to achieve
compliance to SMPTE 424M, SMPTE 259M, SMPTE 344M
and SMPTE 292M.
The GS2978 accepts a LVPECL level differential input that
may be AC coupled. External biasing resistors at the inputs
are not required.
Power consumption is typically 168mW using a 3.3V
power supply. The GS2978 is Pb-free, and the
encapsulation compound does not contain halogenated
flame retardant.
This component and all homogeneous subcomponents are
RoHS compliant.
Functional Block Diagram
SDO
RSET
SDO
DDI
DDI
SD/HD
BANDGAP REFERENCE AND BIASING CIRCUIT
OUTPUT STAGE &
CONTROL
INPUT
DIFFERENTIAL
PAIR
DISABLE
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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Revision History
Version ECR PCN Date Changes and/or Modifications
7 151357 −March 2009 Added 2.5k reel option to section 6.6 Ordering Information. Added
maximum power consumption value to Table 2-1: DC Electrical
Characteristics.
6 150277 −August 2008 Updated data sheet format. Added Tape & Reel Part Number to 6.6
Ordering Information.
5 147849 −October 2007 Changed minimum value of differential input signal amplitude in
Section 4.1.
4 147552 −September
2007
Changed Input Voltage Swing in Table 2-2: AC Electrical Characteristics.
3 146309 −July 2007 Corrected part number typo in Ordering Information on page 14.
2 144827 41693 April 2007 Added Table 4-1: RSET vs. VOD.
1 142318 – November 2006 Converting to Data Sheet. Added section 6.4 Solder Reflow Profiles.
Added typical ORL values in AC Electrical Characteristics.
0 140608 – May 2006 Changed to Preliminary Data Sheet. Removed references to trial
publication for SMPTE 424M. Modified IIH/IILconditions to 10μA in DC
Electrical Characteristics and additive jitter in AC Electrical
Characteristics. Added section 4.3 Output Return Loss Measurement.
B 139766 – March 2006 Corrected pad standoff height and tolerances for pad width & package
dimension. Corrected pad shape.
A 138454 – February 2006 New document.
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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Contents
Features.................................................................................................................................................................1
Applications.........................................................................................................................................................1
Description...........................................................................................................................................................1
Revision History .................................................................................................................................................2
1. Pin Out...............................................................................................................................................................4
1.1 Pin Assignment ..................................................................................................................................4
1.2 Pin Descriptions ................................................................................................................................4
2. Electrical Characteristics ............................................................................................................................5
2.1 Absolute Maximum Ratings ..........................................................................................................5
2.2 DC Electrical Characteristics ........................................................................................................5
2.3 AC Electrical Characteristics ........................................................................................................6
3. Input/Output Circuits ..................................................................................................................................7
4. Detailed Description.....................................................................................................................................8
4.1 Input Interfacing ...............................................................................................................................8
4.2 Output Interfacing ...........................................................................................................................8
4.2.1 Output Amplitude (RSET) ..................................................................................................9
4.2.2 Output Disable.......................................................................................................................9
4.3 Output Return Loss Measurement ..............................................................................................9
5. Application Information .......................................................................................................................... 10
5.1 PCB Layout ....................................................................................................................................... 10
5.2 Typical Application Circuit ........................................................................................................ 10
6. Package & Ordering Information .......................................................................................................... 11
6.1 Package Dimensions ..................................................................................................................... 11
6.2 Recommended PCB Footprint ................................................................................................... 12
6.3 Packaging Data ............................................................................................................................... 12
6.4 Solder Reflow Profiles .................................................................................................................. 13
6.5 Marking Diagram ........................................................................................................................... 14
6.6 Ordering Information ................................................................................................................... 14
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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1. Pin Out
1.1 Pin Assignment
Figure 1-1: 16-Pin QFN
1.2 Pin Descriptions
Center Pad
(bottom of package)
GS2978
(top view)
1
V
EE
DDI
DDI
2
3
4
SDO
SDO
VCC
12
11
10
9
57
68
NC
NC
NC
NC
13
14
15
16
NC
DISABLE
NC
RSET
SD/HD
RSVD
Table 1-1: Pin Descriptions
Pin Number Name Timing Type Description
1,2 DDI, DDI Analog Input Serial digital differential input.
3V
EE – Power Most negative power supply connection. Connect to GND.
4R
SET Analog Input External output amplitude control resistor.
5,8,13,14,
15,16
NC––No Connect. Not bonded internally.
7RSVD – Reserved Do not connect.
6DISABLE Non
Synchronous
Input Serial output disable. When asserted LOW, the SDO/SDO output
driver is powered off. SDO/SDO will float to VCC through the pull-up
resistor.
9V
CC – Power Most positive power supply connection. Connect to +3.3V.
10 SD/HD Non
Synchronous
Input Output slew rate control. When set HIGH, the output will meet
SMPTE 259M rise/fall time specifications. When set LOW, the serial
outputs will meet SMPTE424M and SMPTE 292M rise/fall time
specifications.
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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2. Electrical Characteristics
2.1 Absolute Maximum Ratings
2.2 DC Electrical Characteristics
11,12 SDO, SDO Analog Output Serial digital differential output.
–Center Pad – Power Connect to most negative power supply plane following the
recommendations in Recommended PCB Footprint on page 12.
Table 1-1: Pin Descriptions
Pin Number Name Timing Type Description
Parameter Value
Supply Voltage -0.5V to 3.6 VDC
Input ESD Voltage 4kV
Storage Temperature Range -50°C < Ts < 125°C
Input Voltage Range (any input) -0.3 to (VCC +0.3)V
Operating Temperature Range 0°C to 70°C
Solder Reflow Temperature 260°C
NOTE: Absolute Maximum Ratings are those values beyond which damage to the device may
occur. Functional operation under these conditions or at any other condition beyond those
indicated in the AC/DC Electrical Characteristic sections is not implied.
Table 2-1: DC Electrical Characteristics
VCC = 3.3V ±5%; TA = 0°C to 70°C, unless otherwise shown
Parameter Symbol Conditions Min Typ Max Units
Supply Voltage VCC – 3.135 3.3 3.465 V
Power Consumption PDTA = 25°C,
SDO/SDO enabled
– 168 180 mW
TA = 25°C,
SDO/SDO disabled
–96 –mW
Supply Current IsTA = 25°C,
SDO/SDO enabled
–51 –mA
TA = 25°C,
SDO/SDO disabled
–29 –mA
Output Voltage VCMOUT Common mode – VCC - VOUT –V
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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2.3 AC Electrical Characteristics
Input Voltage VCMIN Common mode 1.4 + ΔVDDI/2 – VCC - ΔVDDI/2 V
SD/HD, DISABLE Input VIH I
IH <= 10 μA2.0– –V
VIL IIL <= 10 μA––0.8V
Table 2-1: DC Electrical Characteristics
VCC = 3.3V ±5%; TA = 0°C to 70°C, unless otherwise shown
Parameter Symbol Conditions Min Typ Max Units
Table 2-2: AC Electrical Characteristics
VCC = 3.3V ±5%; TA = 0°C to 70°C, unless otherwise shown
Parameter Symbol Conditions Min Typ Max Units Notes
Serial input data rate DRSDO –––2.97Gb/s 1
Additive jitter – 2.97Gb/s – 22 – psp-p –
–1.485Gb/s – 20 – psp-p –
– 270Mb/s – 16 – psp-p –
Rise/Fall time tr, tfSD/HD=0 – – 135 ps 2
tr, tfSD/HD=1 400 – 800 ps 2
Mismatch in rise/fall time Utr, Utf–––35ps–
Duty cycle distortion – SD/HD=0, 2.97 Gb/s – – 27 ps 3
–SD/HD=0, 1.485 Gb/s – – 30 ps 3
–SD/HD=1 – – 100 ps 3
Overshoot – SD/HD=0, – – 10 % 3
–SD/HD=1 – – 8 % 3
Output Return Loss ORL 5 MHz – 1.485 GHz 15 20 – dB 4
1.485 GHz – 2.97 GHz 10 12 – dB 4
Output Voltage Swing VOUT RSET = 750Ω750 800 850 mVp-p 3
Input Voltage Swing UVDDI Differential 100 – 2200 mVp-p –
NOTES:
1. The input coupling capacitor must be set accordingly for lower data rates.
2. Rise/Fall time measured between 20% and 80%.
3. Single Ended into 75Ω external load.
4. ORL depends on board design. The GS2978 achieves this specification on Gennum's evaluation boards.
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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3. Input/Output Circuits
Figure 3-1: Differential Input Stage (DDI/DDI)
Figure 3-2: Differential Output Stage (SDO/SDO)
Figure 3-3: Slew Rate Select Input Stage
V
CC
V
CC
DDI DDI
10k 10k
5k
10k
Vcc
IREF
SDO SDO
SD/HD
VCC
On Chip
Reference
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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4. Detailed Description
4.1 Input Interfacing
D
DI/DDI are high impedance differential inputs. The equivalent input circuit is shown in
Figure 3-1
.
Several conditions must be observed when interfacing to these inputs:
• The differential input signal amplitude must be between 100 and 2200mVpp.
• The common mode voltage range must be as specified in the DC Electrical
Characteristics on page 5.
• For input trace lengths longer than approximately 1cm, the inputs should be
terminated as shown in the Typical Application Circuit.
The GS2978 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.
SD/HD Input Pin
The GS2978 SDO rise and fall times can be set to comply with both SMPTE 259M/344M
and SMPTE 424M / SMPTE 292M. For all SMPTE 259M standards, or any data rate that
requires longer rise and fall time characteristics, the SD/HD pin must be set HIGH by the
application layer. For SMPTE 424M and SMPTE 292M standards and signals which
require faster rise and fall times, this pin should be set LOW.
4.2 Output Interfacing
The GS2978 outputs are current mode, and will drive typically 800mV into a 75Ω load.
These outputs are protected from accidental static damage with internal ESD protection
diodes.
In order for a DDI output circuit using the GS2978 to meet this specification, the output
application circuit shown in Typical Application Circuit on page 10 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 device. This value is chosen
to ensure that pathological signals can be coupled without a significant DC component
occurring. Please see Application Information on page 10 for more details.
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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4.2.1 Output Amplitude (RSET)
The output amplitude of the GS2978 can be adjusted by changing the value of the RSET
resistor as shown in Table 4-1. For an 800mVp-p output with a nominal ±7% tolerance, a
value of 750Ω is required. A ±1% SMT resistor should be used.
The RSET resistor is part of the high speed output circuit of the GS2978. The resistor
should be placed as close as possible to the RSET pin. In addition, the PCB capacitance
should be minimized at this node by removing the PCB groundplane beneath the RSET
resistor and the RSET pin.
4.2.2 Output Disable
The serial output disable (DISABLE), disables power to the current mode serial digital
output driver. When asserted LOW, the SDO/SDO output driver is powered off.
SDO/SDO will float to VCC through the pull-up resistor.
NOTE: If the DISABLE pin is left as a No Connect (NC), the SDO/SDO outputs are still
active.
4.3 Output Return Loss Measurement
To perform a practical return loss measurement, it is necessary to force the GS2978
output to a DC high or low condition. The actual measured return loss will be based on
the outputs being static at VCC or VCC-1.6V. Under normal operating conditions the
outputs of the device swing between VCC-0.4V and VCC-1.2V.
Table 4-1: RSET vs. VOD
RSET R (Ω)Output Swing (mVp-p)
995 608
824 734
750 800
680 884
573 1040
NOTE: For reliable operation of the GS2978 over the full temperature range, do not use an
RSET value below 573Ω.
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
37186 - 7 March 2009
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5. Application Information
5.1 PCB Layout
Special attention must be paid to component layout when designing serial digital
interfaces for HDTV.
An FR-4 dielectric can be used, however, controlled impedance transmission lines are
required for PCB traces longer than approximately 1cm. Note the following PCB artwork
features used to optimize performance:
• The PCB trace width for HD rate signals is closely matched to SMT component
width to minimize reflections due to changes in trace impedance.
• The PCB ground plane is removed under the GS2978 output components to
minimize parasitic capacitance.
• The PCB ground plane is removed under the GS2978 RSET pin and resistor to
minimize parasitic capacitance.
• Input and output BNC connectors are surface mounted in-line to eliminate a
transmission line stub caused by a BNC mounting via high speed traces which are
curved to minimize impedance variations due to change of PCB trace width.
5.2 Typical Application Circuit
Figure 5-1: Typical Application Circuit
SD/HD
GS2978
1
2
3
4
12
11
10
9
DDI
DDI
VEE
RSET
SDO
SDO
SD/HD
VCC
10n
75
5.6n*
4u7
BNC
VCC
75
5.6n*
10n 75
4u7
49.9
750
10n
49.9
4u7
75
BNC
VCC
4u7 VCC
* TYPICAL VALUE: VARIES WITH LAYOUT
DIFFERENTIAL
DATA INPUT
NOTE: All resistors in Ohms, capacitors in Farads,
and inductors in Henrys, unless otherwise noted.
DISABLE
6
DISABLE
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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6. Package & Ordering Information
6.1 Package Dimensions
4.00+/-0.05
B
4.00+/-0.05
2X
2X
0.15
0.15
C
C
0.10 C
16X
0.08 C
SEATING PLANE
0.85+/-0.05
0.00-0.05
0.65/2
0.65
DETAIL B
SCALE:NTS
DATUM A OR B
TERMINAL TIP
0.20 REF
DATUM B
DETAIL B
0.65
16X
0.35+/-0.05
0.10
0.05 C
AB
C
DATUM A
2.76+/-0.10
0.40+/-0.05
2.76+/-0.10
DETAIL B
CENTER TAB
PIN 1 AREA
A
C
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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6.2 Recommended PCB Footprint
The Center Pad should be connected to the most negative power supply plane (VEE) by
a minimum of 5 vias.
NOTE: Suggested dimensions only. Final dimensions should conform to customer
design rules and process optimizations.
6.3 Packaging Data
Parameter Value
Package Type 4mm x 4mm 16-pin QFN
Package Drawing Reference JEDEC M0220
Moisture Sensitivity Level 3
Junction to Case Thermal Resistance, θj-c 31.0°C/W
Junction to Air Thermal Resistance, θj-a (at zero airflow) 43.8°C/W
Psi, Ψ11.0°C/W
Pb-free and RoHS compliant Yes
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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6.4 Solder Reflow Profiles
The device is manufactured with Matte-Sn terminations and is compatible with both
standard eutectic and Pb-free solder reflow profiles. MSL qualification was performed
using the maximum Pb-free reflow profile shown in Figure 6-1.The recommended
standard Pb reflow profile is shown in Figure 6-2.
Figure 6-1: Maximum Pb-free Solder Reflow Profile (Preferred)
Figure 6-2: Standard Pb Reflow Profile
25°C
150°C
200°C
217°C
260°C
250°C
Time
Temperature
8 min. max
60-180 sec. max
60-150 sec.
20-40 sec.
3°C/sec max
6°C/sec max
25°C
100°C
150°C
183°C
230°C
220°C
Time
Temperature
6 min. max
120 sec. max
60-150 sec.
10-20 sec.
3°C/sec max
6°C/sec max
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
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6.5 Marking Diagram
6.6 Ordering Information
GS297
8
XXXXE3
YYWW
XXXX - Lot/Work Order ID
YYWW - Date Code
YY - 2-digit year
WW - 2-digit week number
Pin 1 Indicator
Part Number Package Temperature Range
GS2978 GS2978-CNE3 16-pin QFN 0°C to 70°C
GS2978 GS2978-CTE3 16-pin QFN
250pc Reel
0°C to 70°C
GS2978 GS2978-CNTE3Z 16-pin QFN
2,500pc Reel
0°C to 70°C
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Canada
Phone: +1 (613) 270-0458
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Mexico 20900
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Web Site: http://www.gennum.co.jp
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Sinyi District, Taipei City 11502
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Phone: (886) 2-8732-8879
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Canada
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DOCUMENT IDENTIFICATION
DATA SHEET
The product is in production. Gennum reserves the right to make changes to
the product at any time without notice to improve reliability, function or
design, in order to provide the best product possible.
GS2978
HD-LINX® III Multi-Rate Dual Slew-Rate Cable Driver
Data Sheet
37186 - 7 March 2009
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15
Gennum Corporation assumes no liability for any errors or omissions in this document, or for the use of the circuits or devices described herein. The sale of
the circuit or device described herein does not imply any patent license, and Gennum makes no representation that the circuit or device is free from patent
infringement.
All other trademarks mentioned are the properties of their respective owners.
GENNUM and the Gennum logo are registered trademarks of Gennum Corporation.
© Copyright 2006 Gennum Corporation. All rights reserved.
www.gennum.com
GENNUM CORPORATE HEADQUARTERS
4281 Harvester Road, Burlington, Ontario L7L 5M4 Canada
Phone: +1 (905) 632-2996 Fax: +1 (905) 632-2055
E-mail: corporate@gennum.com www.gennum.com
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