GS4911B/GS4910B HD/SD/Graphics Clock and Timing Generator with GENLOCK
Key Features Description
The GS4911B is a highly flexible, digitally controlled clock 
Video Clock Synthesis
synthesis circuit and timing generator with genlock capability. It 
 Generates any video or graphics clock up to 165MHz
can be used to generate video and audio clocks and timing signals, 
 Pre-programmed for 8 video and 13 graphics clocks
and allows multiple devices to be genlocked to an input reference.
 Accuracy of free-running clock frequency limited only by 
The GS4910B includes all the features of the GS4911B, but does 
crystal reference
not offer audio clocks or AFS pulse generation.
 One differential and two single-ended video/graphics clock 
outputs
The GS4911B/GS4910B will recognize input reference signals 
 Each clock may be individually delayed for skew control
conforming to 36 different video standards and 16 different 
 Video output clock may be directly connected to Gennums 
graphic formats, and will genlock the output timing information to 
serializers for a SMPTE-compliant HD-SDI output
the incoming reference. The GS4911B/GS4910B supports 
cross-locking, allowing the output to be genlocked to an incoming 
Audio Clock Synthesis (GS4911B only)
reference that is different from the output video standard 
 Three audio clock outputs
selected.
 Generates any audio clock up to 512*96kHz
The user may select to output one of 8 different video sample 
 Pre-programmed for 7 audio clocks
clock rates or 13 different graphic display clock rates, or may 
program any clock frequency between 13.5MHz and 165MHz. 
Timing Generation
The chosen clock frequency can be further divided using internal 
 Generates up to 8 timing signals at a time
dividers, and is available on two video clock outputs and one 
 Choose from 9 pre-programmed timing signals: H and V sync 
LVDS video clock output pair. The video clocks are frequency and 
and blanking, F Sync, F Digital, AFS (GS4911B only), Display 
phased-locked to the horizontal timing reference, and can be 
Enable, 10FID, and up to 4 user-defined timing signals
individually delayed with respect to the timing outputs for clock 
 Pre-programmed to generate timing for 35 different video 
skew control.
formats and 13 different graphic display formats
Eight user-selectable timing outputs are provided that can 
Genlock Capability
automatically produce the following timing signals for 35 
 Clocks may be free-running or genlocked to an input 
different video formats and 13 different graphics formats: HSync, 
reference with a variable offset step size of 100-200ps 
Hblanking, VSync, Vblanking, F sync, F digital, AFS (GS4911B 
(depending on exact clock frequency)
only), DE, and 10FID. These timing outputs may be locked to the 
 Variable timing offset step size of 100-200ps up to one frame
input reference signal for genlock timing and may be phase 
 Output may be cross-locked to a different input reference
adjusted via internal registers.
 Freeze operation on loss of reference
In addition, the GS4911B provides three audio sample clock 
 Optional crash or drift lock on application of reference
outputs that can produce audio clocks up to 512fs with fs ranging 
 Automatic input format detection
from 9.7kHz to 96kHz. Audio to video phasing is accomplished by 
an external 10FID input reference, a 10FID signal specified via 
General Features
internal registers, or a user-programmed audio frame sequence.
 Reduces design complexity and saves board space - 9mm x 
9mm package plus crystal reference replaces multiple 
The GS4911B/GS4910B is Pb-free, and the encapsulation 
VCXOs, PLLs and timing generators
compound does not contain halogenated flame retardant (RoHS 
 Pb-free and RoHS Compliant
Compliant).
 Low power operation typically 300mW
 1.8V core and 1.8V or 3.3V I/O power supplies
 64-PIN QFN package
Applications
 Video cameras; Digital audio and/or video recording/play 
back devices; Digital audio and/or video processing devices; 
Computer/video displays; DVD/MPEG devices; Digital Set 
top boxes; Video projectors; High definition video systems; 
Multi-media PC applications
GS4911B/GS4910B HD/SD/Graphics Clock and Timing 1 of 119
www.gennum.com
Generator with GENLOCK
Data Sheet
36655 - 5 June 2009user[4:1]
27MHz
  Input Reference TIMING_OUT_8
AFS
Rate Identification
10FID TIMING_OUT_7
REF_LOST
    and Control
ref_rate
DE
TIMING_OUT_6
F digital
Flywheel and Video
TIMING_OUT_5
Crosspoint
F sync
  Timing Generator
TIMING_OUT_4
V blanking
TIMING_OUT_3
V sync
TIMING_OUT_2
H blanking
Clock Synthesis
TIMING_OUT_1
H sync
    and Control
PCLK1
Clock
Video Clock
PCLK2
pclk 3x Video Clock 
Phase
     Divide
  Delay Adjust
PCLK3
Adjust
PCLK3
ACLK1
aclk_512
Audio Clock
ACLK2
aclk_384     Divide
ACLK3
HSYNC
VSYNC
FSYNC
10FID
Application Programming Interace
GS4911B Functional Block Diagram
GS4911B/GS4910B HD/SD/Graphics Clock and Timing 2 of 119
Generator with GENLOCK
Data Sheet
36655 - 5 June 2009
JTAG/HOST
SCLK_TCLK
SDIN_TDI
SDOUT_TDO
CS_TMS
X1
X2
ASR_SEL[2:0]
VID_STD[5:0]
GENLOCK
LOCK_LOST