Gennum GS1522 Hdtv serial digital serializer Datasheet

HD-LINX ™ GS1522
HDTV Serial Digital Serializer
PRELIMINARY DATA SHEET
DESCRIPTION
• SMPTE 292M compliant
The GS1522 is a monolithic bipolar integrated circuit
designed to serialize SMPTE 274M and SMPTE 260M bit
parallel digital signals.
• 20:1 parallel to serial conversion
• NRZ(I) encoder & SMPTE scrambler with selectable
bypass
• NRZ to NRZ(I) serial data conversion
This device performs the following functions:
•
Sync word mapping for 8-bit/10-bit operation.
•
Parallel to Serial conversion of Luma & Chroma data
•
Interleaving of Luma and Chroma data
•
Data Scrambling (using the X +X +1 algorithm)
•
Conversion of NRZ to NRZI serial data (using the (X+1)
algorithm)
•
Selectable DUAL or QUAD 75Ω Cable Driver outputs
•
Lock Detect Output
•
1.485Gb/s or 1.485/1.001Gb/s operation
• 1.485Gb/s and 1.485/1.001Gb/s operation
• lock detect output
• selectable DUAL or QUAD 75Ω cable driver outputs
• 8 bit or 10 bit input data support
9
4
• 20 bit wide inputs
• 3.3V and 5V CMOS/TTL compatible inputs
• single +5.0V power supply
APPLICATIONS
SMPTE 292M Serial Digital Interfaces for Video Cameras,
Camcorders, VTR's, Signal Generators, Portable Equipment, and NLE's.
ORDERING INFORMATION
PART NUMBER
PACKAGE
TEMPERATURE
GS1522-CQR
128 pin MQFP
0°C to 70°C
This device requires a single 5V supply and typically
consumes less than 1000mW of power while driving two
75Ω cables.
The GS1522 uses the GO1515 external VCO connected to
the internal PLL circuitry to achieve ultra low noise PLL
performance.
RESET BYPASS
SYNC_DETECT
_DISABLE
20
DATA_IN[19:0]
20
RSET0
SYNC DETECT
SDO0+
SMPTE
INPUT
LATCH
SCRAMBLER
O/P0
RESET
INTERLEAVER
BYPASS
PCLK_IN
SDO0-
PARALLEL
TO SERIAL
CONVERTER
SCLK
PLL
SDO1+
O/P1
NRZ TO NRZI
SDO1PLOAD
MUTE
GO1515
RSET1
SDO1_EN
PLL_LOCK
FUNCTIONAL BLOCK DIAGRAM
Revision Date: August 2000
Document No. 522 - 26 - 00
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: [email protected]
www.gennum.com
GS1522
FEATURES
ABSOLUTE MAXIMUM RATINGS
PARAMETER
VALUE
Supply Voltage (VS)
5.5V
Input Voltage Range (any input)
VEE – 0.5 < VIN < VCC+ 0.5
TBD
Power Dissipation (VCC = 5.25V)
TBD
Input ESD Voltage
TBD
Die Temperature
GS1522
DC Input Current (any input)
125°C
0°C ≤ TA ≤ 70°C
Operating Temperature Range
-40°C ≤ TS ≤ 150°C
Storage Temperature Range
Lead Temperature (soldering 10 seconds)
260°C
AC ELECTRICAL CHARACTERISTICS
VCC = 5V, VEE = 0V, TA = 0°C to 70°C unless otherwise specified.
PARAMETER
CONDITIONS
SYMBOL
MIN
TYP
MAX
UNITS
BRSDO
-
1.485
-
Gb/s
Serial data bit rate
SMPTE 292M
Digital Serial Data
Outputs
Differential outputs
VSDO
750
800
850
mV p-p
Rise/Fall times, 20-80%
tr, tf
-
150
270
ps
-
0
7
%
15
17
-
dB
Overshoot
Output Return Loss @
1.485GHz
ORL
Lock Time
Worst case
tLOCK
Typical Loop Bandwidth
≤ 0.1dB peaking,
1.485Gb/s
Intrinsic Jitter
Pseudo-random
NOTES
1.485/1.001Gb/s also
With 52.3Ω 1% RSET
Resistor
As per SMPTE292M
(5MHz to clock
frequency), using
Gennum Evaluation
Board, recommended
layout and components.
-
200
250
ms
-
0.200
1.5
MHz
tIJR
-
-
100
ps p-p
tIJP
-
-
100
ps p-p
tIJR
-
-
100
ps p-p
tIJP
-
-
100
ps p-p
PRBS (223-1)
(200kHz LBW)
Pathological
23
PRBS (2 -1)
(200kHz LBW)
Pseudo-random
(1.5 MHz LBW)
Pathological
(1.5 MHz LBW)
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AC ELECTRICAL CHARACTERISTICS - PARALLEL TO SERIAL STAGE
VDD = 5V, TA = 0°C to 70°C unless otherwise specified.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
VIL
-
-
0.8
V
For compatibility with TTL
voltage levels
VIH
2.0
-
-
V
For compatibility with TTL
voltage levels
Input Capacitance
CIN
-
1
2
pF
Output Voltage Levels
VOL
-
-
0.4
V
For compatibility with TTL
voltage levels
VOH
2.4
-
-
V
For compatibility with TTL
voltage levels
PCLK_IN
-
74.25
-
MHz
Input Clock Pulse Width
Low
tPWL
5
-
-
ns
Input Clock Pulse Width
High
tPWH
5
-
-
ns
Input Clock Rise/Fall time
tr, tf
-
500
1000
ps
Input Clock Rise/Fall time
Matching
trfm
-
200
-
ps
Input Setup Time
tSU
1.0
-
-
ns
Input Hold Time
tIH
0
-
-
ns
Input Voltage Levels
Parallel Input Clock
Frequency
NOTES
74.25/1.001MHz also
20% to 80%
DC ELECTRICAL CHARACTERISTICS
VCC = 5V, VEE = 0V, TA = 0°C to 70°C unless otherwise specified.
PARAMETER
CONDITIONS
SYMBOL
MIN
TYP
MAX
UNITS
NOTES
Positive Supply Voltage
Operating Range
VCC
4.75
5.00
5.25
V
Power (system power)
VCC = 5.00V, T=25°C
PD
-
950
-
mW
(Driving two 75Ω outputs)
VCC = 5.00V, T=25°C
PD
-
1170
-
mW
(Driving four 75Ω outputs)
VCC = 5.25V, T=70°C
-
-
300
mA
(Driving four 75Ω outputs)
VCC = 5.00V, T=25°C
-
234
-
mA
(Driving four 75Ω outputs)
SDO1 disabled
-
-
240
mA
(Driving two 75Ω outputs)
-
190
-
mA
(Driving two 75Ω outputs)
Supply Current
VCC = 5.25V, 70°C
SDO1 disabled
VCC = 5.0V, 25°C
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GS1522
SYMBOL
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
OSC_VEE
A0
NC
NC
NC
VEE2
RSET0
VCC2
NC
SDO0
SDO_NC
SDO0
NC
NC
NC
SDO1
SDO_NC
SDO1
NC
VCC2
RSET1
NC
NC
NC
NC
NC
PIN CONNECTIONS
GS1522
NC
65
38
NC
NC
66
37
NC
NC
67
36
NC
NC
68
35
NC
NC
69
34
NC
NC
70
33
NC
NC
71
32
NC
NC
72
31
SDO1_EN
NC
73
30
VEE2
VCO
74
29
VEE2
VCO
75
28
VEE2
PD_VEE
76
27
VEE2
PDSUB_VEE
77
26
VEE2
IJI
78
25
VCC2
PD_VCC
79
24
VCC2
NC
80
23
VCC2
NC
81
22
VCC2
LFS
82
21
VCC2
NC
83
20
NC
LFS
84
19
NC
PLCAP
85
18
VEE2
DM
86
17
RESET
PLCAP
87
16
BYPASS
DFT_VEE
88
15
PLL_LOCK
LFA_VEE
89
14
NC
LFA
90
13
XDIV20
LBCONT
91
12
NC
LFA_VCC
92
11
NC
NC
93
10
BUF_VEE
VCC3
94
9
NC
VEE3
95
8
NC
SYNC_DETECT_DISABLE
96
7
NC
NC
97
6
NC
NC
98
5
NC
NC
99
4
NC
NC
100
3
NC
NC
101
2
PCLK_IN
NC
102
1
VEE3
DATA_IN[19]
DATA_IN[18]
DATA_IN[17]
DATA_IN[16]
DATA_IN[15]
NC
NC
DATA_IN[14]
DATA_IN[13]
DATA_IN[12]
DATA_IN[11]
DATA_IN[10]
DATA_IN[9]
NC
NC
DATA_IN[8]
DATA_IN[7]
NC
NC
DATA_IN[6]
DATA_IN[5]
DATA_IN[4]
DATA_IN[3]
DATA_IN[2]
DATA_IN[1]
DATA_IN[0]
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
GS1522
TOP
VIEW
NOTE: No Heat Sink Required
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PIN DESCRIPTIONS
NUMBER
1, 95
2
LEVEL
TYPE
DESCRIPTION
VEE3
Power
Input
Negative Supply. Most negative power supply connection, for
input stage.
PCLK_IN
TTL
Input
Parallel Data Clock. 74.25 or 74.25/1.001MHz
NC
No Connect. These pins are not used internally. These pins
should be floating.
10
BUF_VEE
Power
TEST
Negative Supply/Test Pin. Most negative power supply
connection. For buffer for oscillator/divider for test purposes only.
Leave floating for normal operation.
13
XDIV20
TTL
TEST
Test Pin. Test block output. Leave floating for normal operation.
15
PLL_LOCK
TTL
Output
Status Signal Output. Indicates when the GS1522 is phase locked
to the incoming PCLK_IN clock signal. LOGIC HIGH indicates
PLL is in Lock. LOGIC LOW indicates PLL is out of Lock.
16
BYPASS
TTL
Input
Control Signal Input. Used to bypass the scrambling function if
data is already scrambled by GS1501 or if non-SMPTE encoded
data stream such as 8b/10b is to be transmitted. When BYPASS is
LOW, the SMPTE scrambler and NRZ(I) encoder are enabled.
When BYPASS is HIGH, the SMPTE scrambler and NRZ(I) encoder
are bypassed.
17
RESET
TTL
Input
Control Signal Input. Used to reset the SMPTE scrambler. For
logic HIGH; Resets the SMPTE scrambler and NRZ(I) encoder.
For logic LOW: normal SMPTE scrambler and NRZ(I) encoder
operation.
18, 26, 27, 28,
29, 30, 59
VEE2
Power
Input
Negative Supply. Most negative power supply connection. For
Cable Driver outputs and all other digital circuitry excluding input
stage and PLL stage.
21, 22, 23, 24,
25, 45, 57
VCC2
Power
Input
Positive Supply. Most positive power supply connection. For
Cable Driver outputs and all other digital circuitry excluding input
stage and PLL stage.
31
SDO1_EN
Power
Input
Control Signal Input. Used to enable or disable the second serial
data output stage. This signal must be tied to GND to enable this
stage. Do not connect to a logic low.
44
RSET1
Input
Control Signal Input. External resistor is used to set the data
output amplitude for SDO1 and SDO1. Use a ±1% resistor.
47, 49
SDO1+, SDO1-
Analog
Output
Serial Data Output Signal. Current mode serial data output #1.
Use 75Ω ±1% pull up resistors to VCC2.
48, 54
SDO_NC
53, 55
SDO0+, SDO0-
No Connect. Not used internally. This pin must be left floating.
Analog
Output
Serial Data Output Signal. Current mode serial data output #0.
Use 75Ω ± 1% pull up resistors to VCC2.
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GS1522
3, 4, 5, 6, 7, 8,
9, 11, 12, 14,
19, 20, 32, 33,
34, 35, 36, 37,
38, 39, 40, 41,
42, 43,46, 50,
51, 52, 56, 60,
61, 62, 65, 66,
67, 68, 69, 70,
71, 72, 73, 80,
81, 83, 93, 97,
98, 99, 100,
101, 102, 108,
109, 116, 117,
120, 121
SYMBOL
PIN DESCRIPTIONS (Continued)
NUMBER
LEVEL
TYPE
DESCRIPTION
58
RSET0
Analog
Input
Control Signal Input. External resistor is used to set the data
output amplitude for SDO0 and SDO0. Use a ±1% resistor.
63
A0
TTL
TEST
Test Signal. Used for manufacturing test purposes only. This pin
must be tied low for normal operation.
64
OSC_VEE
Power
Input
Negative Supply. Ground for ring oscillator. This pin must be
floating for normal operation.
74
VCO
Analog
Input
Control Signal Input. Input pin is AC coupled to ground using a
50Ω transmission line.
75
VCO
Analog
Input
Control Signal Input. Voltage controlled oscillator input. This pin is
connected to the output pin of the GO1515 VCO. This pin must be
connected to the GO1515 VCO output pin via a 50Ω transmission
line.
76
PD_VEE
Power
Input
Negative Supply. Most negative power supply connection. For
phase detector stage.
77
PDSUB_VEE
Power
Input
Guard Ring. Ground guard ring connection to isolate phase
detector in PLL stage.
78
IJI
Analog
Output
79
PD_VCC
Power
Input
Positive Supply. Most positive power supply connection. For
phase detector stage.
82, 84
LFS, LFS
Analog
Input
Loop Filter Connections.
85, 87
PLCAP, PLCAP
Analog
Input
Control Signal Input. Phase lock detect time constant capacitor.
Status Signal Output. Indicates the amount of excessive jitter on
the incoming SDI and SDI input.
86
DM
88
DFT_VEE
Power
Input
Most Negative Power Supply Connection . Enables the jitter
demodulator functionality. This pin should be connected to
ground. If left floating, the DM function is disabled resulting in a
current saving of 340µA.
89
LFA_VEE
Power
Input
Negative Supply. Most negative power supply connection. For
loop filter stage.
90
LFA
Analog
Output
91
LBCONT
Analog
Input
Control Signal Input. Used to provide electronic control of Loop
Bandwidth.
92
LFA_VCC
Power
Input
Positive Supply. Most positive power supply connection. For loop
filter stage.
94
VCC3
Power
Input
Positive Supply. Most positive power supply connection. For input
stage.
96
SYNC_DETECT_DISABLE
TTL
Input
Control Signal Input. Used to disable the sync detection function.
Logic HIGH disables sync detection. Logic LOW: 000-003 is
mapped into 000 and 3FC-3FF is mapped into 3FF for 8-bit
operation.
DATA_IN[19:0]
TTL
Input
Input Data Bus. The device receives a 20 bits data stream running
at 74.25 or 74.25/1.001 MHz from the GS1501 HDTV Formatter or
GS1511 HDTV Formatter. Input data can be in SMPTE292M
scrambled or unscrambled format. DATA_IN[19] is the MSB (pin
103). DATA_IN[0] is the LSB (pin 128).
103, 104, 105,
106, 107, 110,
111, 112, 113,
114, 115, 118,
119, 122, 123,
124, 125, 126,
127, 128
Test Signal. Used for manufacturing test only. This pin must be
left floating in normal operation.
Control Signal Output. Control voltage for GO1515 VCO.
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GS1522
SYMBOL
INPUT/OUTPUT CIRCUITS
PD_VCC
LFA_VCC
5k
5k
500
GS1522
LFA
10k
10k
40
31p
40
5mA
100µA
PD_VEE
50
LFA_VEE
VCO
VCO
Fig. 4 LFA Circuit
Fig. 1 VCO/VCO Input Circuit
LFA_VCC
PD_VCC
25k
10k
10k
DM
LFS
400µA
85µA
LFA_VEE
DFT_VEE
Fig. 5 LFS Output Circuit
Fig. 2 DM Output Circuit
LFA_VCC
PD_VCC
20k
10k
10k
PLCAP
5k
PLCAP
LFS
100µA
100µA
100µA
PD_VEE
100µA
100µA
LFA_VEE
Fig. 3 PLCAP/PLCAP Output Circuit
Fig. 6 LFS Input Circuit
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VCC3
2k
BIAS
PD_VCC
10k
GS1522
10k
D0 - D19,
SYNC_DETECT_DISABLE
PLL_LOCK
PD_VEE
VEE3
All on-chip resistors have ±20% tolerance at room temperature.
Fig. 7 PLL_LOCK Output Circuit
Fig. 10 Data Input and SYNC_DETECT_DISABLE Circuit
VCC
1k
PD_VCC
10k
BIAS
IJI
PCLK_IN
5k
5k
VCC
30k A
VEE
PD_VEE
Fig. 8 IJI Output Circuit
Fig. 11 PCLK_IN Circuit
VCC
20k
SDO
SDO
BIAS
RESET
10k
+
CD_VEE
VEE
RSET
Fig. 9 SDO/SDO Output Circuit
Fig. 12 RESET Circuit
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VCC
5k
5k
BIAS
GS1522
BYPASS
10k
VEE
Fig. 13 BYPASS Circuit
DETAILED DESCRIPTION
ones respectively. This allows the system to be compatible
with 8-bit and 10-bit data. For non-SMPTE standard parallel
data, a logic input Sync Detect Disable pin (96) is available
to disable this feature.
The GS1522 HDTV Serializer is a bipolar integrated circuit
used to convert parallel data into serial format according to
the SMPTE 292M standard. The device encodes both 8-bit
and 10-bit TTL compatible parallel signals producing a
serial data rate of 1.485Gb/s. The device operates from a
single 5V supply and is available in a 128 pin MQFP
package.
4. SCRAMBLER
The scrambler is a linear feedback shift register used to
pseudo-randomize the incoming data according to the fixed
The functional blocks within the device include the input
latches, interleaver, sync detector, parallel to serial
converter, SMPTE scrambler, NRZ to NRZ(I) converter, two
internal cable drivers, PLL for 20x parallel clock
multiplication and lock detect circuitry.
9
4
polynomial (X +X +1). This minimizes the DC component in
the output serial stream. The NRZ to NRZ(I) converter uses
another polynomial (X + 1) to convert a long sequence of
ones to a series of transitions, minimizing polarity effects.
These functions can be disabled by setting the BYPASS pin
(16) high.
1. INPUT LATCHES
The 20-bit input latch accepts either 3.3V or 5V CMOS/TTL
inputs. The input data is buffered and then latched on the
rising edge of the PCLK_IN pin (2). The output of the latch
is a differential signal for increased noise immunity. Further
noise isolation is provided by the use of separate power
supplies.
5. UNIQUE SLEW PHASE LOCK LOOP (S-PLL)
A unique feature of the GS1522 is the innovative slew phase
lock loop (S-PLL). When a step phase change is applied to
the PLL, the output phase gains constant rate of change
with respect to time. This behavior is termed slew. Figure 14
shows an example of input and output phase variation over
time for slew and linear (conventional) PLLs. Since the
slewing is a non-linear behavior, the small signal analysis
cannot be done in the same way as it is done for the
standard PLL. However, it is still possible to plot input jitter
transfer characteristics at a constant input jitter modulation.
2. INTERLEAVER
The interleaver takes the 20-bit wide parallel data (Y and C)
and reduces it internally to a 10-bit wide word by alternating
the Y and C data words according to SMPTE 292M, section
6.1.
Slew PLLs offer several advantages such as excellent noise
immunity. Because of the infinite bandwidth for an infinitely
small input jitter modulation (or jitter introduced by VCO),
the loop corrects for that immediately thus the small signal
noise of the VCO is cancelled. The GS1522 uses a very
clean, external VCO called the GO1515 (refer to the
GO1515 Data Sheet for details). In addition, the bi-level
digital phase detector provides constant loop bandwidth
that is predominantly independent of the data transition
density. The loop bandwidth of a conventional tri-stable
3. SYNC DETECTOR
The sync detector looks for the reserved words 000-003
and 3FC-3FF in 10-bit hexadecimal, or 00-03 and FC-FF in
8-bit hexadecimal used in the TRS-ID sync word. When
there is an occurrence of all zeros or all ones in the eight
higher order bits, the lower two bits are forced to zeros or
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charge pump drops with reducing data transitions. During
pathological signals, the data transition density reduces
from 0.5 to 0.05, but the slew PLL’s performance does not
change significantly.
PHASE (UI)
INPUT
OUTPUT
0.0
SLEW PLL RESPONSE
Fig. 15 Phase Lock Loop Frequency Synthesis
7. LOCK LOGIC
8. PHASE DETECTOR
0.2
PHASE (UI)
GO1515
VCO
DIVIDE-BY-20
Logic is used to produce the PLL_LOCK (15) signal which
is based on the LFS signal and phase lock signal. When
there is not any data input, the integrator will charge and
eventually saturate at either end. By sensing the saturation
of the integrator, it is determined that no data is present. If
either data is not present or phase lock is low, the lock
signal is made low. Logic signals are used to acquire the
frequency by sweeping the integrator. Injecting a current
into the summing node of the integrator achieves the
sweep. The sweep is disabled once phase lock is asserted.
The direction of the sweep is also changed once LFS
saturates at either end.
0.2
0.1
PHASE
DETECTOR
PCLK_IN
INPUT
0.1
OUTPUT
0.0
LINEAR (CONVENTIONAL) PLL RESPONSE
Fig. 14 PLL Characteristics
6. PHASE LOCK LOOP FREQUENCY SYNTHESIS
The GS1522 requires the HDTV parallel clock (74.25 or
74.25/1.001 MHz) to synthesize a serial clock which is 20
times the parallel clock frequency (1.485MHz) using a
phase locked loop (PLL). This serial clock is then used to
strobe the output serial data. Figure 15 illustrates this
operation. The VCO is normally free-running at a frequency
close to the serial data rate. A divide-by-20 circuit converts
the free running serial clock frequency to approximately that
of the parallel clock. Within the phase detector, the dividedby-20 serial clock is then compared to the reference
parallel clock from the PCLK_IN pin (2). Based on the
leading or lagging alignment of the divided clock to the
input reference clock, the serial data output is synchronized
to the incoming parallel clock. The following sections
describe the functional blocks in greater detail.
The phase detector portion of the slew PLL used in the
GS1522 is a bi-level digital phase detector. It indicates
whether the data transition occurred before or after with
respect to the falling edge of the internal clock. When the
phase detector is locked, the data transition edges are
aligned to the falling edge of the clock. The input data is
then sampled by the rising edge of the clock, as shown in
Figure 16. In this manner, the allowed input jitter is 1UI p-p
in an ideal situation. However, due to setup and hold time,
the GS1522 typically achieves 0.8UI p-p input jitter
tolerance without causing any errors in this block. When the
signal is locked to the internal clock, the control output from
the phase detector is refreshed at the transition of each
rising edge of the data input. During this time, the phase of
the clock drifts in one direction.
PHASE ALIGNMENT
EDGE
RE-TIMING
EDGE
IN-PHASE CLOCK
0.8UI
INPUT CLOCK
WITH JITTER
OUTPUT DATA
Fig. 16 Phase Detector Characteristics
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GS1522
Because most of the PLL circuitry is digital, it is very robust
like other digital systems which are generally more robust
than their analog counterparts. Additionally, signals like DM
(86), which represents the internal functionality, can be
generated without adding additional artifacts. Thus, system
debugging is also possible with these features. The
complete slew PLL is made up of several blocks including
the phase detector, the charge pump and an external
Voltage Controlled Oscillator (VCO).
GS1522 PLL
During pathological signals, the amount of jitter that the
phase detector will add can be calculated. By choosing the
proper loop bandwidth, the amount of phase detector
induced jitter can also be limited. Typically, for a 1.41MHz
loop bandwidth at 0.2UI input jitter modulation, the phase
detector induced jitter is about 0.015UIp-p. This is not very
significant, even for the pathological signals.
connect LBCONT through a pull-up resistor (RPULL-UP). For
low loop bandwidth, leave LBCONT floating. The formula
below shows the change in the loop bandwidth using
RPULL-UP.
9. CHARGE PUMP
where LBWNOMINAL is the loop bandwidth when LBCONT is
left floating.
Because of the integrator, ΙF changes very slowly, whereas
ΙP could change at the positive edge of the data transition
as often as a clock period. In the locked position, the
average voltage at LFA (VLFA_VCC – 500(ΙP/2+ΙF) is such that
VCO generates frequency ƒ, equal to the data rate clock
frequency. Since ΙP is changing all the time between 0A and
100µA, there will be two levels generated at the LFA output.
10. VCO
The GO1515 is an external hybrid VCO, which has a centre
frequency of 1.485GHz and is also guaranteed to provide
1.485/1.001GHz within the control voltage (3.1V – 4.65V) of
the GS1522 over process, power supply and temperature.
The GO1515 is a very clean frequency source and,
because of the internal high Q resonator, it is an order of
magnitude more immune to external noise as compared to
on-chip VCOs.
The VCO gain, Kƒ, is nominally 16MHz/V. The control
voltage around the average LFA voltage will be 500 x ΙP/2.
This will produce two frequencies off from the centre by
ƒ=Kƒ x 500 x ΙP/2.
11. LBCONT
The LBCONT pin (91) is used to adjust the loop bandwidth
by externally changing the internal charge pump current.
For maximum loop bandwidth, connect LBCONT to the
most positive power supply. For medium loop bandwidth,
12. LOOP BANDWIDTH OPTIMIZATION
Since the feed back loop has only digital circuits, the small
signal analysis does not apply to the system. The effective
loop bandwidth scales with the amount of input jitter
modulation index. The following table summarizes the
relationship between input jitter modulation index and
bandwidth when RCP1 and CCP3 are not used. See the
Typical Application Circuit artwork for the location of RCP1
and CCP3 .
TABLE 1: Relationship Between Input Jitter Modulation Index and
Bandwidth
INPUT JITTER
MODULATION
INDEX
BANDWIDTH
BW JITTER FACTOR
(jitter modulation x BW)
0.05
5.657MHz
282.9kHzUI
0.10
2.828MHz
282.9kHzUI
0.20
1.414MHz
282.9kHzUI
0.50
565.7kHz
282.9kHzUI
The product of the input jitter modulation (IJM) and the
bandwidth (BW) is a constant. In this case, it is 282.9kHzUI.
The loop bandwidth automatically reduces with increasing
input jitter, which helps in cleaning up the signal as much
as possible.
Using a series combination of RCP1 and CCP3 in parallel to
an on-chip resistor (as shown in the Typical Application
Circuit) can reduce the loop bandwidth of the GS1522. The
parallel combination of the resistor is directly proportional to
the bandwidth factor. For example, the on-chip 500Ω
resistor yields 282.9kHzUI. If a 50Ω resistor is connected in
parallel, the effective resistance will be (50:500) 45.45Ω.
This
resistance
yields
a
bandwidth
factor
of
[282.9 x (45.45/500)] = 25.72kHzUI. The capacitance CCP3
in series with the RCP1 should be chosen such that the RC
factor is 50µF. For example, RCP1=50Ω would require
CCP3=1µF.
The synchronous lock time increases with reduced
bandwidth. Nominal synchronous lock time is equal to
[ 0.25 × 2 /Bandwidth factor]. That is, the default
bandwidth factor (282.9kHzUI) would yield 1.25µs. For
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GENNUM CORPORATION
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GS1522
The charge pump in a slew PLL is different from the charge
pump in a linear PLL. There are two main functions of the
charge pump. One function is to hold the frequency
information of the input data. This information is held by
CCP1, which is connected between LFS (82) and LFS (84).
The other capacitor, CCP2 between LFS and LFA_VEE (89) is
used to remove common mode noise. Both CCP1 and CCP2
should have the same value. The second function of the
charge pump is to provide a binary control voltage to the
VCO depending upon the phase detector output. The
output pin, LFA (90) controls the VCO. Internally there is a
500Ω pull-up resistor, which is driven with a 100µA current
called ΙP. Another analog current ΙF, with 5mA maximum
drive proportional to the voltage across the CCP1 is applied
at the same node. The voltage at the LFA node is
VLFA_VCC - 500(ΙP+ΙF) at any time.
( 25kΩ + R PULL – UP )
LBW = LBW NOMINAL × -----------------------------------------------------( 5kΩ + R PULL – UP )
should be no less than 5.6µF. This would result in 340ms of
lock time. If necessary, extra margin can be built by
increasing these capacitors at the expense of a longer
asynchronous lock time.
The Kƒ of the VCO (GO1515) is specified with a minimum of
11MHz/V and maximum of 21MHz/V which is about ±32%
variation. The 500 x ΙP/2 will vary about ±10%. The resulting
bandwidth factor would approximately vary by ±45% when
no RCP1 and CCP3 are used. ΙP by itself may vary by 30% so
the variability for lower bandwidths will increase by an
additional ±30%.
Bandwidths lower than 129kHz at 0.2UI modulation have
not been characterized, but it is believed that the
bandwidth could be further lowered. Since a lower
bandwidth has less correction for noise, extra care should
be taken to minimize board noise. Figures 18 and 19 show
the two measured loop bandwidths at these two settings.
Table 2 summarizes the two bandwidth settings.
The CCP1 and CCP2 capacitors should be changed with
reduced bandwidths. Smaller CCP1 and CCP2 capacitors
would result in jitter peaking, lower stability, less probability
of locking but at the same time lowering the asynchronous
lock time. Therefore, there is a trade-off between
asynchronous lock time and jitter peaking/stability. These
capacitors should be as large as possible for the allowable
lock time and should be no smaller than the allowed value.
With the recommended values, jitter peaking of less than
0.1dB has been measured at the lower loop bandwidth as
shown in Figure 17. At higher loop bandwidths, it is difficult
to measure jitter peaking because of the limitation of the
measurement unit.
Fig. 18 Typical Jitter Transfer Curve at Setting A in Table 2
Fig. 17 Typical Jitter Peaking
However, because relatively larger CCP1 and CCP2
capacitors can be used, over-damping of the loop response
occurs. An accurate jitter peaking measurement of 0.1dB
for the GS1522 requires the modulation source to have a
constant amount of jitter modulation index (within 0.1dB or
1.2%) over the frequency range beyond the loop
bandwidth.
Fig. 19 Typical Jitter Transfer Curve at Setting B in Table 2
It has been determined that for 282.9kHzUI, the minimum
value of the CCP1 and CCP2 capacitors should be no less
than 0.5µF. For added margin, 1µF capacitors are
recommended. The 1µF value gives a lock time of about
60ms in one attempt. For 25.72kHzUI, these capacitors
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GENNUM CORPORATION
522 - 26 - 00
GS1522
25.72kHzUI,
the
synchronous
lock
time
is
0.3535/25.72k=13.75µs. Since the CCP1, CCP2 and CCP3 are
also charged, it is measured to be about 11µs which is
slightly less than the calculated value of 13.75µs.
TABLE 2: Loop Bandwidth Setting Options
CCP3
CCP1
CCP2
BW
FACTOR
BW at 0.2 UI JITTER
MODULATION
INDEX
ASYNCHRONOUS
SYNCHRONOUS
A
Open
Open
1.0
1.0
282.9kHz
1.41MHz
60ms
1.25µs
B
50
1.0
5.6
5.6
25.72kHz
129kHz
340ms
11.0µs
13. PHASE LOCK
The phase lock circuit is used to determine the phase
locked condition. It is done by generating a quadrature
clock by delaying the in-phase clock (the clock whose
falling edge is aligned to the data transition) by 166ps
(0.25UI at 1.5GHz) with the tolerance of 0.05UI. When the
PLL is locked, the falling edge of the in-phase clock is
aligned with the data edges as shown in Figure 20. The
quadrature clock is in a logic high state in the vicinity of
input data transitions. The quadrature clock is sampled and
latched by positive edges of the data transitions. The
generated signal is low pass filtered with an RC network.
The R is an on-chip 6.67kΩ resistor and CPL is an internal
capacitor (31pF). The time constant is about 200ns.
PHASE ALIGNMENT
EDGE
RE-TIMING
EDGE
IN-PHASE CLOCK
14. INPUT JITTER INDICATOR (IJI)
This signal indicates the amount of excessive jitter (beyond
the quadrature clock window 0.5UI), which occurs beyond
the quadrature clock window (see Figure 19). All the input
data transitions occurring outside the quadrature clock
window, will be captured and filtered by the low pass filter
as mentioned in the Phase Lock section. The running time
average of the ratio of the transitions inside the quadrature
clock and outside the quadrature is available at the
PLCAP/PLCAP pins (87 and 85). A signal, IJI, which is the
buffered signal available at the PLCAP is provided so that
loading does not effect the filter circuit. The signal at IJI is
referenced with the power supply such that the factor
VIJI /V CC is a constant over process and power supply for a
given input jitter modulation. The IJI signal has 10kΩ output
impedance. Figure 21 shows the relationship of the IJI
signal with respect to the sine wave modulated input jitter.
TABLE 3: IJI Voltage as a Function of Sinusoidal Jitter
0.8UI
INPUT CLOCK
WITH JITTER
0.25UI
QUADERATURE
CLOCK
PLCAP SIGNAL
PLCAP SIGNAL
Fig. 20 PLL Circuit Principles
If the signal is not locked, the data transition phase could
be anywhere with respect to the internal clock or the
quadrature clock. In this case, the normalized filtered
sample of the quadrature clock will be 0.5. When VCO is
locked to the incoming data, data will only sample the
quadrature clock when it is logic high. The normalized
filtered sample quadrature clock will be 1.0. We chose a
threshold of 0.66 to generate the phase lock signal.
Because the threshold is lower than 1, it allows jitter to be
greater than 0.5UI before the phase lock circuit reads it as
“not phase locked”.
P-P SINE WAVE JITTER IN UI
IJI VOLTAGE
0.00
4.75
0.15
4.75
0.30
4.75
0.39
4.70
0.45
4.60
0.48
4.50
0.52
4.40
0.55
4.30
0.58
4.20
0.60
4.10
0.63
3.95
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GENNUM CORPORATION
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GS1522
RCP1
5.0
IJI SIGNAL (V)
4.8
4.6
4.4
4.2
GS1522
4.0
3.8
3.6
0.00
0.20
0.40
0.60
0.80
INPUT JITTER (UI)
Fig. 21 Input Jitter Indicator (Typical at TA = 25°C)
15. JITTER DEMODULATION (DM)
Fig. 22 Jitter Demodulation Signal
The differential jitter demodulation (DM) signal is available
at the DM pin (86). This signal is the phase correction signal
of the PLL loop, which is amplified and buffered. If the input
jitter is modulated, the PLL tracks the jitter if it is within loop
bandwidth. To track the input jitter, the VCO has to be
adjusted by the phase detector via the charge pump. Thus,
the signal which controls the VCO contains the information
of the input jitter modulation. The jitter demodulation signal
is only valid if the input jitter is less than 0.5UIp-p. The DM
signal has a 10kΩ output impedance, which could be low
pass filtered with appropriate capacitors to eliminate high
frequency noise. DFT_VEE (88) should be connected to
GND to activate the DM signal.
The DM signal can be used as a diagnostic tool. Assume
there is an HDTV SDI source, which contains excessive
noise during the horizontal blanking because of the
transient current flowing in the power supply. In order to
discover the source of the noise, one could probe around
the source board with a low frequency oscilloscope
(Bandwidth < 20MHz) that is triggered with an appropriately
filtered DM signal. The true cause of the modulation will be
synchronous and will appear as a stationary signal with
respect to the DM signal.
Figure 22 shows an example of such a situation. An HDTV
SDI signal is modulated with a modulation signal causing
about 0.2UI jitter in Figure 22 (Channel 1). The GS1522
receives this signal and locks to it. Figure 22 (Channel 2)
shows the DM signal. Notice the wave shape of the DM
signal, which is synchronous to the modulating signal. The
DM signal could also be used to compare the output jitter of
the HDTV signal source.
16. MUTE
The logic controls the mute block whenever the PLL_LOCK
(15) signal has a LOW logic state. Whenever the mute
signal is asserted, previous state of the output is latched.
17. CABLE DRIVER
The outputs of the GS1522 are a complimentary current
mode cable driver stages. The output swing and
impedance can be varied. Table 4 may be used to select
the RSET resistor for the desired output voltage level. Linear
interpolation can be used to determine the specific value of
the resistor for a given output swing at the load impedance.
For linear interpolation, either Figure 23 or the information in
Table 4 should be used. The admittance should be found
and then, by inverting the admittance, a resistor value for
the RSET can be found. The output can be used as dual
0.8V 75Ω cable drivers. It can also be used as a differential
transmission line driver. In this case, the pull-up resistor
should match the impedance of the transmission line
because the pull-up resistor acts as the source impedance.
When it is used in this case, a higher value of RSET resistor
could be used in order to reduce the swing and to save
power. Other HD-LINX™ products can handle such low
input swings. It should be noted that the minimum RSET
resistor cannot be less than 50Ω for reliability reasons
because of higher current density.
14
GENNUM CORPORATION
522 - 26 - 00
0.8
0.6
75Ω
0.4
GS1522
SOURCE/END TERMINATED
OUTPUT SWING (V)
1.0
50Ω
0.2
0.0
0.00
0.01
0.02
0.03
1/RSET (Ω)
Fig. 23 Signal Swing for Various R SET Admittances
When the outputs are used to differentially drive some other
device such as the GS1508, it is recommended to use 50Ω
transmission lines with the smallest possible signal swing
while allowing 10% variation at the output swing to select
the right choice of the RSET resistor. To drive the GS1508,
the recommended RSET resistor is 150Ω. There is no need to
compensate for the return-loss in this situation. The
uncompensated waveform at the output is shown in Figure 24.
Fig. 24 Uncompensated Output Eye Waveform
Fig. 25 Compensated Output Eye Waveform
NOTE: Figures 24 and 25 show the waveforms on an
oscilloscope using a 75Ω to 50Ω pad.
TABLE 4: RSET Values for Various Output Load Conditions
OUTPUT CURRENT
TRANSMISSION LINE,
TERMINATED AT THE
END. (PULL-UP
RESISTOR AT THE
SOURCE = 75Ω)
TRANSMISSION LINE,
TERMINATED AT THE
END. (PULL-UP
RESISTOR AT THE
SOURCE = 50Ω)
0.0020
2.506mA
0.094V
0.063V
150.0Ω
0.0067
7.896mA
0.296V
0.197V
75.0Ω
0.0133
15.161mA
0.569V
0.379V
53.6Ω
0.0187
20.702mA
0.776V
0.517V
52.3Ω
0.0192
21.216mA
0.796V
0.530V
49.9Ω
0.0200
22.032mA
0.826V
-
RSET RESISTOR
ADMITTANCE (g) OF
THE RSET RESISTOR
(= 1/RSET RESISTOR)
500.0Ω
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GENNUM CORPORATION
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18. RETURN LOSS
Unless the artwork is an exact copy of the recommended
layout, every design should be verified for output return
loss. Changes in the layout should be tweaked until a return
loss of 25dB is attained while the GS1522 is not mounted
and L1 is shorted. Once the device is mounted, different
inductors should be used to match the parasitic
capacitance of the IC. When the right inductor is used,
maximum return loss between 5MHz to 800MHz is
achievable. Then the shunt capacitor between of 0.5pF to
1.5pF should be tried to increase the return loss between
800MHz and 1.5GHz. The larger inductor causes slower
rise/fall time. The larger shunt capacitor causes a kink in the
output waveform. Thus, the waveform must be verified to
meet SMPTE 292M specifications.
Since there are two levels at the output, depending upon
the output state (logic high or low), measurement should be
taken by latching the outputs in both states. Since the
actual output node voltages are different when a stream of
data passing as compared to the static situation created to
measure return loss, an interpolation is necessary. See the
GS1508 Preliminary Data Sheet for more information.
GS1522
In the application where the GS1522 directly drives a cable,
it is possible to achieve an output return loss (ORL) of about
17dB to 1.485GHz. Care should be taken with the PCB
layout. It is suggested to use the EB1522 as a reference
layout. The use of very small ‘0608’ surface mount
components and short distances between the components
will help in designing high frequency circuits. Openings in
the ground plane helps reduce PCB parasitic capacitance.
For best matching, a 12nH inductor in parallel with a 75Ω
resistor and a 1.5pF capacitor matches the 75Ω cable
impedance. The inductor and resistor cancel the parasitic
capacitance while the capacitor cancels the inductive effect
of the bond wire. In order to verify the performance of any
layout, a return loss measurement should be done by
shorting the inductor with a piece of wire, without the
GS1522 installed.
Fig. 26 Compensated Output Return Loss at Logic HIGH
Fig. 27 Compensated Output Return Loss at Logic LOW
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GENNUM CORPORATION
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D1_13
17
D1_12
D1_11
D1_10
D1_9
109 nc
110 DATA_IN[14]
111 DATA_IN[13]
112
DATA_IN[12]
113 DATA_IN[11]
114 DATA_IN[10]
115 DATA_IN[9]
nc 67
nc 66
nc 69
nc 68
nc 72
nc 71
nc 70
VCO 74
nc 73
VCO
78
PDSUB_VEE 77
PD_VEE 76
VCO 75
79
nc 65
C8
10n
60
59
RSET
R2
75
C7
R3
75
1p5
L1
12nH
R4
SDO_nc 54
SDO0 53
75
R5
nc 52
nc 51
75
L2
SET1
nc
nc
17 RESET
18
VEE2
19 nc
20
nc
21
VCC2
22
VCC2
23
VCC2
24
VCC2
25 V
CC2
26 V
EE2
27
VEE2
28 V
EE2
29 V
EE2
30 V
EE2
31 SDO1_EN
124
DATA_IN[4]
125 DATA_IN[3]
126
DATA_IN[2]
127 DATA_IN[1]
128 DATA_IN[0]
61
RSET0 58
VCC2 57 V 52.3
CC
56
nc
SDO0 55
118 DATA_IN[8]
119 DATA_IN[7]
120 nc
121
nc
122
DATA_IN[6]
123 DATA_IN[5]
1 V
EE3
2
D1_0
VEE2
JMP
14 nc
15 PLL_LOCK
16 BYPASS
D1_1
nc
VCC
62
nc 50
49
SDO1
48
SDO_nc
47
SDO1
46
nc
VCC2 45
44
R
12 nc
13 XDIV20
D1_2
nc
NOTE: R36 IS AN OPTIONAL 0Ω RESISTOR.
LEAVE FLOATING.
VCC
GS1522
nc
8 nc
9 nc
10 BUF_VEE
11 nc
D1_3
IJI
nc
NOTE: R35 IS AN OPTIONAL 1k RESISTOR.
LEAVE FLOATING.
7
D1_4
OSC_VEE 64
A0 63
JMP
5 nc
6 nc
D1_5
100n
10n
R36
3 nc
4 nc
D1_6
10µ
C6
R35
PCLK_IN
D1_7
L4
C15
10n
LOOP
FILTER
COMPONENTS
116 nc
117 nc
D1_8
C40
10µ
C14
1p5
VCC
43
42
41
nc
nc 40
nc 39
All resistors in ohms,
all capacitors in farads,
unless otherwise shown.
C21
OPTIONAL
RESET
BYPASS
522 - 26 - 00
0
10n
C16
470n
GS1522
R6
PCLK
PLL_LOCK
C12
VCC
J3
BNC_ANCHOR
C9
+
4µ7
C10
+
4µ7
J1
J2
BNC_ANCHOR
J4
12nH
C11
38 nc
D1_14
106 DATA_IN[16]
107 DATA_IN[15]
108 nc
1µ
36 nc
37 nc
D1_15
1µ
VCC
L3
C13
100n
34 nc
35 nc
D1_16
10n
VCC
VCC
C4
32 nc
33 nc
D1_17
103 DATA_IN[19]
104 DATA_IN[18]
105 DATA_IN[17]
CCP1
+
98
nc
nc 97
96
SYNC_DETECT_DISABLE
VEE3 95
VCC3 94
93
nc
92
LFA_VCC
91
LBCONT
LFA 90
D1_18
nc 100
nc 99
nc 102
nc 101
SYNC_DETECT_DISABLE
D1_19
CCP2
+
PD_VCC
100n
C5
10n
C1
LFS 82
81
nc
nc 80
C20
10µ
VCC
NOTE: L3 to L8 are 0Ω RESISTORS.
USE 12nH INDUCTORS IN
NOISY ENVIRONMENTS.
LBCONT
C17
100n
EE
L8
10µ
PLCAP 87
DM 86
C19
10µ
C48
LFA
C18
100n
VCC
VCC
L5
L7
C45
LFA_VEE 89
88
DFT_V
VCC
C47
10µ
IJI
C46
100n
VCC
L6
PLCAP 85
84
LFS
nc 83
VCC
LBCONT
GENNUM CORPORATION
TYPICAL APPLICATION CIRCUIT
SECOND PAIR OF
BNC SHOWN IS FOR
DUAL FOOTPRINT
OPTION ON INPUT
CONNECTORS
TYPICAL APPLICATION CIRCUIT (continued)
GO1515 VCO
POWER CONNECT
LFA
VCC
C37
C41
+
100n
VCC
10µ
C38
+
C44
RCP1
VCTR 1
GND
50
8
CCP3 +
1µ
GS1522 LOCK DETECT
7 nc
2
GND
6 GND
U2
GND GO1515
5 O/P
4
100n
GS1522
VCC 3
10µ
VCC
R22
R25
LOCK
VCO
GS1522 SYNC DETECT DISABLE
(10BIT/8BIT)
GS1522 SCRAMBLER BYPASS
VCC
Q1
LED1
22k
GS1522 RESET CIRCUIT
VCC
VCC
BYPASS
HDR1
HDR5
S1
SYNC_DETECT_DISABLE
150
RESET
1
2
3
4
R20
4k7
All resistors in ohms,
all capacitors in farads,
unless otherwise shown.
The figures above show the recommended application
circuit for the GS1522. The external VCO is the GO1515
and is specifically designed to be used with the GS1522.
Figures 28 through 31 show an example PC board layout of
Fig. 28 Top Layer of EB1522 PCB Layout
the GS1522 IC and the GO1515 VCO. This application
board layout does not reflect every detail of the typical
application circuit but is used as a general guide to the
location of the critical parts.
Fig. 29 Ground Layer of EB1522 PCB Layout
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GENNUM CORPORATION
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GS1522
Fig. 31 Bottom Layer of EB1522 PCB Layout
Fig. 30 Power Layer of EB1522 PCB Layout
APPLICATION INFORMATION
Please refer to the EBHDTX documentation for more
detailed application and circuit information for using the
GS1522 with the GS1501 and GS1511 Formatters.
19
GENNUM CORPORATION
522 - 26 - 00
PACKAGE DIMENSIONS
23.20 ±0.25
20.0 ±0.10
18.50 REF
GS1522
12 TYP
12.50 REF
0.75 MIN
17.20 ±0.25
0 -7
0.30 MAX RADIUS
14.0 ±0.10
0-7
0.13 MIN.
RADIUS
0.88 ±0.15
1.6
REF
3.00 MAX
0.50 BSC
2.80 ±0.25
128 pin MQFP
All dimensions are in millimetres.
0.27 ±0.08
REVISION NOTES:
Upgraded to Preliminary Data
Descriptions; Removed watermark.
CAUTION
ELECTROSTATIC
SENSITIVE DEVICES
DO NOT OPEN PACKAGES OR HANDLE
EXCEPT AT A STATIC-FREE WORKSTATION
Sheet;
Updated
Pin
For latest product information, visit www.gennum.com
DOCUMENT IDENTIFICATION
PRELIMINARY DATA SHEET
The product is in a preproduction phase and specifications
are subject to change without notice.
GENNUM CORPORATION
MAILING ADDRESS:
P.O. Box 489, Stn. A, Burlington, Ontario, Canada L7R 3Y3
Tel. +1 (905) 632-2996 Fax. +1 (905) 632-5946
SHIPPING ADDRESS:
970 Fraser Drive, Burlington, Ontario, Canada L7L 5P5
GENNUM JAPAN CORPORATION
C-101, Miyamae Village, 2-10-42 Miyamae, Suginami-ku
Tokyo 168-0081, Japan
Tel. +81 (03) 3334-7700 Fax. +81 (03) 3247-8839
GENNUM UK LIMITED
25 Long Garden Walk, Farnham, Surrey, England GU9 7HX
Tel. +44 (0)1252 747 000 Fax +44 (0)1252 726 523
Gennum Corporation assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement.
© Copyright May 2000 Gennum Corporation. All rights reserved. Printed in Canada.
20
522 - 26 - 00
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