GS2985
GS2985 Multi-Rate SDI Reclocker with Equalization & De-emphasis
Features
•
•
•
•
•
•
•
•
•
•
SMPTE 424M, SMPTE 292M and SMPTE 259M-C compliant
Supports DVB-ASI at 270Mb/s
Single supply operation at 3.3V or 2.5V
180mW typical power consumption (210mW with RCO
enabled) at 2.5V
Input signal equalization and output-signal de-emphasis
settings to compensate for board-trace dielectric losses
4:1 input multiplexer patented technology
Choice of dual reclocked data outputs or one reclocked data
output and one clock output
Uses standard 27MHz crystal
Cascadable crystal buffer supports multiple reclockers using
a single crystal
Differential inputs and outputs
support DC coupling to industry-standard differential
logic
on-chip 100Ω differential data input/output termination
selectable 400mVppd or 800mVppd output swing on
each output
seamless interface to other Gennum products
4 wire SPI host interface for device configuration and
monitoring
Standard logic control and status signal levels
Auto and Manual modes for rate selection
Standards indication in Auto mode
Lock Detect Output
Mute, Bypass and Autobypass functions
SD/HD indication output to control GS2978 or GS2988 dual
slew-rate cable drivers
Operating temperature range: -40°C to +85°C
Small footprint QFN package (9mm x 9mm)
Package-compatible with GS2975A
Pb-free and RoHS compliant
Description
The GS2985 is a multi-rate serial digital reclocker designed to
automatically recover the embedded clock from a digital video
signal and retime the incoming video data. It will recover the
embedded clock signal and retime the data from a SMPTE 424M,
SMPTE 292M, or SMPTE 259M-C compliant digital video signal.
A serial host interface provides the ability to configure and
monitor multiple GS2985 devices in a daisy-chain configuration.
Adjustable input trace equalization (EQ) for up to 40” of FR4 trace
losses, and adjustable output de-emphasis (DE) for up to 20” of
FR4 trace losses, can be configured via the host interface.
The GS2985 can operate in either auto or manual rate selection
mode. In Auto mode, the device will automatically detect and lock
onto incoming SMPTE SDI data signals at any supported rate. For
single rate data systems, the GS2985 can be configured to operate
in Manual mode. In both modes, the device requires only one
external crystal to set the VCO frequency when not locked and
provides adjustment free operation.
The GS2985 accepts industry-standard differential input levels
including LVPECL and CML. The differential data and clock
outputs feature selectable output swing via the host interface,
ensuring compatibility with most industry-standard, terminated
differential receivers.
The GS2985 features dual differential outputs. The second output
can be configured to emit either the recovered clock signal or the
re-timed video data. This output can also be disabled to save
power.
In systems which require passing of non-SMPTE data rates, the
GS2985 can be configured to either automatically or manually
enter a bypass mode in order to pass the signal without reclocking.
The GS2985 is Pb-free, and the encapsulation compound does not
contain halogenated flame retardant. This component and all
homogeneous sub-components are RoHS compliant.
•
•
•
•
•
•
•
•
•
•
Applications
•
SMPTE 424M, SMPTE 292M and SMPTE 259M-C coaxial
cable serial digital interfaces
GS2985 Multi-Rate SDI Reclocker with Equalization &
De-emphasis
Data Sheet
36663 - 5
July 2012
www.semtech.com
1 of 45
Proprietary & Confidential
XTAL-
XTAL+
XTAL_BUF_OUT
CP_CAP
LF+ KBB
XTAL
OSC
Buffer
LDO
Retimer
Data
Buffer
DDO0
DE0_EN
DDO0
DDI0
DDI0
Phase
Frequency
Detector
Charge
Pump
VCO
Clock/
Data
Buffer
DDO1/RCO
DE1_EN
DDO1/RCO
DDI1
DDI1
Equalizer/
Data Mux
DDI2
DDI2
DDI3
DDI3
Phase
Detector
Selectable
Divide
Selectable
Divide
LOS
Detect
SPI
1.8V
Control
LDO
HIF
SDI/EQ0_EN
DDI_SEL[1:0]
LOS
SDO/EQ1_EN
SCK/EQ2_EN
CS/EQ3_EN
SS[1:0]
AUTO/MAN
LOCKED
BYPASS
DATA/CLOCK
DDO1_DISABLE
VDD_1p8
SD/HD
AUTOBYPASS
DATA_MUTE
GS2985 Functional Block Diagram
Revision History
Version
5
ECR
158296
PCN
–
Date
July 2012
Changes and/or Modifications
Removed jumper from
Figure 5-1:
GS2985 Typical Application Circuit.
Corrected 4.15.3 section to make it
easier to follow and changed to
Semtech Template.
Corrected DRIVER_1 [7:5] Function
Description in
Table 4-12: Host Register
Map
Converted to Data Sheet. Updated
Power numbers in
Table 2-1: DC
Electrical Characteristics.
Added
Table
4-5: Suggested LOS Threshold Settings.
Updates to Section
4.15 Host Interface.
4
158127
–
May 2012
3
158063
–
May 2012
2
153705
–
March 2010
1
152592
–
September
2009
July 2009
0
152329
–
Converted document to Preliminary
Data Sheet.
Added
Figure 4-2: De-emphasis
Waveform.
Removed ‘Proprietary & Confidential”
from document.
D
152240
–
July 2009
C
152042
–
June 2009
GS2985 Multi-Rate SDI Reclocker with Equalization &
De-emphasis
Data Sheet
36663 - 5
July 2012
2 of 45
Proprietary & Confidential
Version
B
A
ECR
151967
151318
PCN
–
–
Date
May 2009
April 2009
Changes and/or Modifications
Added Section
4.15 Host Interface.
New document.
GS2985 Multi-Rate SDI Reclocker with Equalization &
De-emphasis
Data Sheet
36663 - 5
July 2012
3 of 45
Proprietary & Confidential
Contents
Features.................................................................................................................................................................1
Applications.........................................................................................................................................................1
Description...........................................................................................................................................................1
Revision History .................................................................................................................................................2
1. Pin Out...............................................................................................................................................................5
1.1 Pin Assignment ..................................................................................................................................5
1.2 Pin Descriptions ................................................................................................................................6
2. Electrical Characteristics ............................................................................................................................9
2.1 Absolute Maximum Ratings ..........................................................................................................9
2.2 DC Electrical Characteristics ........................................................................................................9
2.3 AC Electrical Characteristics ..................................................................................................... 10
3. Input/Output Circuits ............................................................................................................................... 13
4. Detailed Description.................................................................................................................................. 18
4.1 Serial Data Input ............................................................................................................................ 18
4.2 Modes of Operation ...................................................................................................................... 18
4.3 Input Trace Equalization ............................................................................................................. 18
4.4 4:1 Input Mux .................................................................................................................................. 19
4.5 Crystal Buffer .................................................................................................................................. 20
4.6 LOS (Loss Of Signal) Detection .................................................................................................. 20
4.7 Serial Digital Reclocker ............................................................................................................... 21
4.8 Lock Detection ................................................................................................................................ 21
4.8.1 Lock Detect and Asynchronous Lock ......................................................................... 22
4.9 Serial Data Output ......................................................................................................................... 22
4.9.1 Output Signal Interface Levels...................................................................................... 22
4.9.2 Adjustable Output Swing................................................................................................ 22
4.9.3 Output De-emphasis ........................................................................................................ 22
4.10 Automatic and Manual Data Rate Selection ...................................................................... 23
4.11 SD/HD Indication ........................................................................................................................ 24
4.12 Bypass Mode ................................................................................................................................. 25
4.13 DVB-ASI ......................................................................................................................................... 25
4.14 Output Mute and Data/Clock Output Selection ............................................................... 25
4.15 Host Interface ............................................................................................................................... 26
4.15.1 Introduction ...................................................................................................................... 26
4.15.2 Legacy Mode & Start-up................................................................................................ 26
4.15.3 Host Interface Mode & Start-up.................................................................................. 26
4.15.4 Clock & Data Timing....................................................................................................... 27
4.15.5 Single Device Operation ............................................................................................... 27
4.15.6 Write Operation - Single Device ................................................................................ 28
4.15.7 Read Operation - Single Device ................................................................................. 28
4.15.8 Daisy Chain Operation.................................................................................................. 31
4.15.9 Read & Write Operation - Daisy Chained Devices............................................... 32
4.15.10 Writing to all Devices .................................................................................................. 32
GS2985 Multi-Rate SDI Reclocker with Equalization &
De-emphasis
Data Sheet
36663 - 5
July 2012
4 of 45
Proprietary & Confidential
4.15.11 Writing to a Single Device in the Chain ................................................................ 33
4.15.12 Reading from all Devices ........................................................................................... 33
4.15.13 Reading from a Single Device in the Chain.......................................................... 34
4.15.14 Host Register Map......................................................................................................... 35
4.16 Device Power-up ......................................................................................................................... 39
4.17 Standby ........................................................................................................................................... 39
5. Typical Application Circuit ..................................................................................................................... 40
6. Package and Ordering Information...................................................................................................... 41
6.1 Package Dimensions ..................................................................................................................... 41
6.2 Recommended PCB Footprint ................................................................................................... 42
6.3 Packaging Data ............................................................................................................................... 42
6.4 Marking Diagram ........................................................................................................................... 43
6.5 Solder Reflow Profile .................................................................................................................... 43
6.6 Ordering Information ................................................................................................................... 44
GS2985 Multi-Rate SDI Reclocker with Equalization &
De-emphasis
Data Sheet
36663 - 5
July 2012
5 of 45
Proprietary & Confidential
京公网安备 11010802033920号
EEWORLD
