Fiber Optic “Light to Logic”
Receiver with Clock Recovery
Preliminary Technical Data
RGR2622
Features
• Light to Logic 20-Pin DIP
Receiver Offers ECL
Compatibility
• Sensitivity:
–31 dBm
• Phase-Locked Loop (PLL)
Timing Recovery Circuit
• Meets All SONET Jitter
Requirements
(CCITT G.958)
• Single +5 V Supply,
Typically <1.00 W
• SONET/SDH Compliant
Applications
• Telecommunication
Networks
• SONET OC12 and SDH
STM4 Compatible
• Local and Metropolitan Area
Networks
• ATM Single Mode Public
Network
• Military Communications
and Control Systems
• Digital Cable TV Networks
Description
The RGR2622 receiver provides
optical signal conversion and
processing. It converts 1200 nm
to 1600 nm wavelength lightwave
information into an electrical
signal at data rates of 622 Mb/s.
Each receiver contains an InGaAs
PIN photodiode, a high sensitivity, wide dynamic range transimpedance amplifier, capacitively
coupled to a PLL based clock
recovery circuit. The clock and
data outputs are retimed
complementary PECL.
A complementary CMOS
compatible low light alarm is also
provided.
Preliminary Product Disclaimer
This preliminary data sheet is provided to assist you in the evaluation of engineering samples of the product which is under development.
Until Hewlett-Packard releases this product for general sales, HP reserves the right to alter prices, specifications, features, capabilities,
function, manufacturing release dates, and even general availability of the product at any time.
406
(5/97)
Connection Diagram
Top View
FIBER PIGTAIL
GND
GND
GND
CLOCK
CLOCK
GND
DATA
GND
DATA
PD BIAS
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
Pin Descriptions
Pins 1, 2, 3, 6, 8, 13, 15, 16,
GND:
These pins should be connected
to the circuit ground.
Pins 4, 5, CLOCK, CLOCK:
These pins provide
complementary PECL CLOCK
and CLOCK outputs.
Pins 7, 9, DATA, DATA:
These pins provide complementary PECL DATA and DATA
outputs.
The RGR2622 DATA output is
noninverting, an optical pulse
causes the DATA output to go to
NC
NC
NC
NC
GND
GND
ALARM
GND
ALARM
+5 V
the PECL logic high state (+4 V
nominal).
Pin 10, PD Bias:
This pin must be connected to
any voltage from 0 V (GND) to
–5 V. This provides the photodiode bias. The current drawn is
directly proportional to the
average received photocurrent.
I = Responsivity x Mean Power.
The Responsivity will be between
0.8 A/W and 1.0 A/W.
Pin 11, +5 V:
This pin should be connected to
+5 V supply. The network shown
below should be placed as close
as possible to pin 11.
Pins 12, 14, ALARM, ALARM:
These pins provide complementary ALARM and ALARM outputs.
This is the low light alarm.
ALARM goes to a logic low
(CMOS compatible) state when
the optical power drops below
the threshold level (insufficient
optical power).
The optical power must increase
to a higher level than the level
where the alarm went low before
ALARM will return to a logic
high. This difference is the alarm
hysteresis.
Pins 17, 18, 19, 20 NC:
These pins are not connected.
PIN 11
1 µH
100 nF 100 nF10 µF
+5 V
407
Functional Description
Design
The receiver contains an InGaAsP
photodetector, transimpedance
amplifier and interface amplifier
circuit, including a clock recovery
and data retiming function. It is
designed with a multimode fiber
pigtail to allow maximum
flexibility in connector options.
The interface amplifier is ac
coupled to the preamplifier
circuit.
Terminating the Outputs
The data outputs of the RGR2622
are PECL compatible. Care
should be taken to match termination impedances to the interconnect to minimize reflection
effects. In order to balance the
drive currents drawn from the
RGR2622 all serial data outputs
(DATA and DATA, CLOCK and
CLOCK) should be terminated
identically, even if only one
output is used.
This will lower the power supply
noise generated by the RGR2622
and improve performance at low
optical input power levels.
Power Supplies
The RGR2622 will operate to
specifications with a single +5 V
power supply (Pin 10 grounded).
The –5 V pin bias is provided to
maintain functional compatibility
with second sources.
Circuit Layout
The RGR2622 uses very high
bandwidth circuitry to achieve its
high level of performance. Care
must be taken to ensure stable
operation. The use of ground
planes and transmission line
interconnects is required. The use
of a standard evaluation board is
highly recommended for those
users who are not familiar with
these techniques.
Signal traces should conform to
ECL design rules to prevent
reflections and ringing from
degrading performance. Useful
guidelines are contained in ECL
manufacturer design manuals.
Manufacturing
The fiber pigtail on the device
requires normal fiber handling
considerations. Care should be
taken to avoid tight bends as well
as excessive tension on the fiber
pigtail.
The allowable temperature range
for the RGR2622 is limited by the
material used in the pigtail.
Exposure to temperatures over
+85°C is not recommended. Low
profile sockets or hand soldering
are recommended for this part.
TI
AMP
V
NEG
(-5 V OR GND)
Figure 1. Block Diagram.
MID
AMP
+5 V
0 V
VCC (+5 V)
LOW PASS FILTER
GND (0 V)
PLL
CLOCK AND
DATA RECOVERY
ALARM
ALARM
DATA
DATA
CLOCK
CLOCK
408
Performance Specifications Absolute Maximum Ratings
Absolute maximum limits mean that no catastrophic damage will occur if the product is subjected to these ratings for short periods, provided that
each limiting parameter is in isolation and all other parameters have values within the performance specification. It should not be assumed that
limiting values of more than one parameter can be applied to the product at the same time.
Parameter Symbol Minimum Maximum Units Note
Supply Voltage V
Supply Voltage V
CC
NEG
–0.5 +5.5 V 1
–10 +0.5 V 1
Environmental Parameters
Parameter Symbol Minimum Maximum Units Note
Operating Temperature - –40 +85 °C-
Storage Temperature - –40 +85 °C-
Humidity - - 85 %RH -
Electrical Parameters (–40°C to +85°C)
Parameter Symbol Minimum Maximum Units Note
Supply Voltage V
CC
VCC Supply Current - - 250 mA 4
DATA Output Level (high) - 3.8 4.15 V 2, 3
DATA Output Level (low) - 3.1 3.5 V 2, 3
ALARM Output Level (high) V off 4.5 5.0 V 3
ALARM Output Level (low) V on 0 0.5 V 3
Notes:
1. On an RGR2622 VCC of –0.5 V and V
2. Output terminated to (VCC -2) with 50 Ω load or equivalent.
3. Output voltages are for VCC = 5.0 V.
4. Outputs not loaded.
of +0.5 V may not be applied simultaneously.
NEG
4.75 5.25 V -
409
Optical Parameters (–40°C to +85°C)
Parameter Symbol Minimum Typical Maximum Units Note
Wavelength - 1200 - 1600 nm Receiver Sensitivity - - –33.5 –31 dBm 1
Maximum Input Power - –4 - - dBm Alarm ON - –40 - –30 dBm Hysteresis - 1 - 6 dB Alarm Response Time - - - 600 µSReliability Target - - - 2000 FIT -
Jitter Tolerance ITU G.958 Compliant
Jitter Transfer ITU G.958 Compliant
Jitter Generation ITU G.958 Compliant
Note:
1. At a BER of 1 x 10
-10
23-1
, 2
PRBS pattern NRZ data at the line rate with 10:1 extinction ratio. EOL.
Fiber Parameters
Fiber Pigtail Typical Units
Core Diameter 50 microns
Cladding Diameter 125 microns
Secondary Coating Diameter 900 microns
410
Drawing Dimensions
L
20 11
C
110
B A
J
H
K
DIM.
A
B
C
D
E
F
∅G
H
J
K
L
ALL DIMENSIONS IN MILLIMETERS
Ordering Information
RGR2622 - XX
Allowable part numbers
RGR2622
MIN. NOM.
32.9
–
16.0
–
2.6
–
–
2.7
–
–
400
–
–
–
–
–
2.54
0.46
–
–
10.16
–
Connector:
FP = FC/PC Polish
ST* = ST
SC = SC
DN = DN
MAX.
33.2
17.5
16.3
9.27
2.95
–
–
3.2
4.64
–
1220
D
F∅G
E
Handling Precautions
1. The RGR2622 can be damaged
by current surges or
overvoltage. Power supply
transient precautions should
be taken.
2. Normal handling precautions
for electrostatic sensitive
devices should be taken.
*ST is a registered trademark of AT&T.
411
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