VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7923
Features
• Rise Times Less Than 100ps • High Speed Operation (Up to 2.4Gb/s NRZ Data) • Single-Ended or Differential Input Operation • Single Power Supply • Direct Access to Modulation and Bias FETs • Data Density Monitors
SONET/SDH 2.5Gb/s Laser Diode Driver
Applications
• SONET/SDH at 622Mb/s, 1.244Gb/s, 2.488Gb/s, 3.125Gb/s • Full-Speed Fibre Channel (1.062Gb/s)
General Description
The VSC7923 is a single 5V supply, 2.4 Gb/s laser diode driver with direct access to the laser modulation and bias FET’s. Laser bias and modulation currents are set by external components allowing precision monitoring and setting of the current levels. Data inputs accept ECL levels. Data density outputs are provided to allow the user to adjust the laser bias in high unbalanced data applications.
VSC7923 Block Diagram
IOUT NIOUT
MK NMK
DIN VREF IMOD VIP IBIAS
VIB MIP MIB
G52203-0, Rev 3.0 05/11/01
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
Page 1
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
SONET/SDH 2.5Gb/s Laser Diode Driver
Table 1: Signal Pin Reference Signal
DIN MK, NMK NIOUT IOUT VSS GND VIP MIP VIB MIB VREF Total Pins
VSC7923
Type
In Out Out Out Pwr Pwr In In In In In
Level
ECL ECL
# Pins
1 2 1 1 Data Input
Description
Data Density Differential Outputs Laser Modulation Current Output (Complementary) Laser Modulation Current Output (To Laser Cathode)) Negative Voltage Rail Positive Voltage Rail Modulation Gate Node Modulation Source Node Bias Gate Node Bias Source Node Data Input Reference
Pwr Pwr DC DC DC DC DC
5 9 1 1 1 1 1 24
Table 2: Absolute Maximum Ratings Symbol
VSS TJ TSTG
Rating
Negative Power Supply Voltage Maximum Junction Temperature Storage Temperature
Limit
VCC to -6.0V -55°C to + 125°C -65°C to +150°C
Table 3: Recommended Operating Conditions Symbol
GND VSS TCl TJ
Parameter
Positive Voltage Rail Negative Voltage Rail Operational Temperature(1) Junction Temperature
Min —
-5.5 -40
Typ
0 -5.2
Max —
-4.9 85(2) 125
Units
V V °C °C
Conditions
—
— —
Power dissipation = 1.25W
NOTES: (1) Lower limit of specification is ambient temperature and upper limit is case temperature. (2) See section “Calculation of the Maximum Case Temperature” for detailed maximum temperature calculations.
Table 4: ECL Input and Outputs Symbol
VIN VOH VOL
Parameter
Input Voltage Swing ECL Output High Voltage ECL Output Low Voltage
Min
300 -1200
Typ — — —
Max
800
Units
mV mV mV
Conditions
Peak-to-peak, VREF = -2.0V 50Ω to -2.0V 50Ω to -2.0V
—
-1600
—
Page 2
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G52203-0, Rev 3.0 05/11/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7923
Table 5: Power Dissipation Symbol
IVSS PD PDMAX
SONET/SDH 2.5Gb/s Laser Diode Driver
Parameter
Power Supply Current (VSS) Total Power Dissipation Maximum Power Dissipation
Min — — —
Typ — — —
Max
220 1210 1815
Units
mA mW mW
Conditions
VSS = -5.5V, IMOD = IBIAS = 0mA VSS = -5.5V, IMOD = IBIAS = 0mA, RLOAD = 25Ω to GND VSS = -5.5V, IMOD = 60mA, IBIAS = 50mA, IOUT = 0V
Table 6: Laser Driver DC Electrical Specifications Symbol
IBIAS IMOD VIB VIP VOCM
Parameter
Programmable Laser Bias Current Programmable Modulation Current Laser Bias Control Voltage Laser Modulation Control Voltage Output Voltage Compliance
Min
2 2 — — GND 2.2V
Typ
— — — — —
Max
50 60 VSS + 2.1 VSS + 2.1 —
Units
mA mA V V V —
Conditions —
IBIAS = 50mA IMOD= 60mA VSS = -5.2V
Table 7: Laser Driver AC Electrical Specifications Symbol
tR, tF
Parameter
Output Rise and Fall Times
Min —
Typ —
Max
100
Units
ps
Conditions
25Ω load, 20%-80%, 15mA < IMOD < 60mA, IBIAS = 20mA
Table 8: Package Thermal Specifications Symbol
θJCC θJCMG
Parameter
Thermal Resistance from Junction-to-Case Thermal Resistance from Junction-to-Case
Min — —
Typ
25 32
Max — —
Units
°C/W °C/W
Conditions
Ceramic Package Metal Glass Package
G52203-0, Rev 3.0 05/11/01
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
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VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
SONET/SDH 2.5Gb/s Laser Diode Driver
VSC7923
Calculation of the Maximum Case Temperature
The VSC7923 is designed to operate with a maximum junction temperature of 125°C. The rise from the case to junction is determined by the power dissipation of the device. The power dissipation is determined by the VSS current plus the operating IMOD and IBIAS currents. The power of the chip is determined by the following formula: PD=(-VSS * ISS) + ((VIOUT – VSS) * IMOD) + ((VIBIAS – VSS) * IBIAS) For example with: VSS IMOD IBIAS VIBIAS VIOUT = = = = = -5.2V 40mA 20mA -2.0V -2.0V
PD = 5.2 * 220mA) + ((5.2 - 2.0) * 40mA) + ((5.2-- 2.0) * 20mA) PD = 1144mW + 128mW + 64mW = 1.336W The thermal rise from junction to case is θJC * PD. For the metal glass package, θJC = 32 °C/W. Thus the thermal rise is: 32°C/W * 1.336W = 42.7°C The maximum case temperature is: 125°C – 42.7°C = 82.3°C The absolute maximum power dissipation of the device is at: VSS IMOD IBIAS VIBIAS VIOUT PD PD = = = = = -5.5V 60mA 50mA 0V 0V
= (5.5 * 220mA) + (5.5 * 60mA) + (5.5mA * 50mA) = 1.815W
This will net a maximum junction to case thermal rise of: 1.815W * 32°C/W = 58°C This situation will allow maximum case temperature of: 125°C – 58°C = 67°C
Page 4
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G52203-0, Rev 3.0 05/11/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7923
Input Termination Schemes
SONET/SDH 2.5Gb/s Laser Diode Driver
Figure 1: Input Structure
OV (GND)
1400 DIN X VREF X 4300
1400 + 4300 • Nominal VREF = -1.3V • 1400, 4300 Ohm Resistor on die, nominal values
-5.2V (VSS)
Figure 2: Single Ended AC Coupled
GND 0.1µF SOURCE
GND
DIN
50 Ohms
GND
X
50Ω VREF
+
X
0.1µF GND VSS
-
-2V
Figure 3: Differential AC Coupled
GND 0.1µF SOURCE 50Ω -2V 0.1µF DIN
X
GND GND
+
X
GND GND
VSS
50Ω -2V
VREF
G52203-0, Rev 3.0 05/11/01
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
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VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
SONET/SDH 2.5Gb/s Laser Diode Driver
Figure 4: Differential DC Coupled
VSC7923
GND DIN
X
SOURCE
GND GND
50Ω
+
X
GND GND
VSS
50Ω -2V
-2V
VREF
Figure 5: Single Ended AC Coupled with Offset Adjust
GND .01µF SOURCE
GND GND
DIN
X
50Ω
GND
+
VREF
-
X
GND
GND
.01µF VSS
2000 4300 VSS
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G52203-0, Rev 3.0 05/11/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7923
I (MIB) 50 mA
SONET/SDH 2.5Gb/s Laser Diode Driver
Figure 6: Control Signals VIP and VIB
VIB 1.5V (Typical) 2.1V (Maximum) Typical Bias Current v.s. Bias Voltage I (MIP)
60 mA
VIP 1.5V (Typical) 2.1V (Maximum) Typical Modulation Current v.s. Modulation Voltage
Figure 7: Simplified Output Structure
NIOUT
IOUT
X
X
IP
X
IMOD
OUTPUT DIFF PAIR IBIAS
X VIB
X
MIP
X
MIB
G52203-0, Rev 3.0 05/11/01
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
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VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
SONET/SDH 2.5Gb/s Laser Diode Driver
Figure 8: Pad Assignments for VSC7923 Die
1720µm 1620µm 50µm 50µm
VSC7923
50µm
120
120µm 150µm
PAD 34 PAD 33 PAD 32 PAD 31 PAD 30 PAD 29 PAD 28 PAD 27 PAD 26 VREF VSS VSS VSS VSS VIP MIP MIP MIB PAD 1 DIN PAD 2 VSS PAD 3 DIN PAD 4 GND PAD 5 GND PAD 6 GND PAD 7 VSS PAD 8 VSS N/C PAD 9 PAD 25 VIB PAD 24 GND0 PAD 23 OUT PAD 22 OUT PAD 21 GND0 PAD 20 NOUT PAD 19 VSS PAD 18 VSS N/C GND GND GND GND GND NMARK MARK PAD 10 PAD 11 PAD 12 PAD 13 PAD 14 PAD 15 PAD 16 PAD 17
30µm
1620µm
1720µm
50µm
NOTES: 1) Die size = 1620µm x 1620µm 2) Actual die size = 1720µm x 1720µm (after die are cut up) 3) Pad size = 120µm x 120µm 4) Pad pitch = 150µm 5) Space betwen pads = 30µm
Page 8
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
G52203-0, Rev 3.0 05/11/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7923
SONET/SDH 2.5Gb/s Laser Diode Driver
Pin Diagram for 24 Pin Metal-Glass Package
VREF VSS VSS VIP MIP MIB
24 23 22 21 20 19 VSS DIN GND GND GND VSS 1 2 3 4 5 6 7 18 17 16 15 14 13 VIB GND IOUT GND NIOUT VSS
Top View
(LID)
8
9 10 11 12
N/C GND
Note:
Package bottom plate is connected to GND within the package. Package lid is electrically unconnected.
G52203-0, Rev 3.0 05/11/01
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
GND GND MK MK
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VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
SONET/SDH 2.5Gb/s Laser Diode Driver
VSC7923
Package Information - 24 Pin Metal-Glass Package
Top View
Key
A B C D E F G H I
mm
7.11 6.10 1.02 0.76 0.30 2.08 1.02 9.52 0.13
In
0.280 0.240 0.040 0.030 0.012 0.082 0.040 0.375 0.005
(A) MAX
Pin 1 (D) TYP (E) ± .002
(LID)
Side View
Package Top (B) (I) (F) MAX (H) (C)
NOTES: Drawing not to scale. Package #: 101-291-8 Issue #:1 Lid #: 101-292-3 Issue #:1
Package Lid
(G)
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G52203-0, Rev 3.0 05/11/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7923
SONET/SDH 2.5Gb/s Laser Diode Driver
Pin Diagram for 24 Pin Ceramic Package
VREF
VSS DIN GND GND GND VSS
24 1 2 3 4 5 6 7
23
22
21
20
19 18 17 16 15 14
MIB
VSS
VSS
MIP
VIP
VIB GND IOUT GND NIOUT VSS
8
9
10
11
13 12
N/C
GND
GND
GND
NMK
Note:
Package bottom plate is connected to GND within the package. Package lid is electrically unconnected.
G52203-0, Rev 3.0 05/11/01
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
MK
Page 11
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
SONET/SDH 2.5Gb/s Laser Diode Driver
VSC7923
Package Information - 24 Pin Ceramic Package
Top View Key
A 24 23 22 21 20 19
mm
9.5 7.7 2.0 1.27 0.30 1.7 0.6 11.5 0.125 8.51
In
0.374 0.303 0.079 0.050 0.012 0.067 0.024 0.453 0.005 0.335
A B C D
INDEX E 1 2 3 A 4 5 6 15 14 13 17 16 18
E F G H I J
7
8
9
10 11
D 12
Side View
B
I J H C
G
F
NOTES: Drawing not to scale. Package #: 101-312-0 Issue #:1 L id #: 101-303-1 Issue #:1
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G52203-0, Rev 3.0 05/11/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7923
Ordering Information
SONET/SDH 2.5Gb/s Laser Diode Driver
The order number for this product is formed by a combination of the device number, and package style.
VSC7923
Device Type 2.5Gb/s Laser Diode Driver
XX
Package Style (24 pin) CA: Metal Glass Package—Straight Leads KF: Ceramic Package—Straight Leads KFL: Ceramic Package—Formed Leads X: Bare Die
Notice
Vitesse Semiconductor Corporation (“Vitesse”) provides this document for informational purposes only. This document contains pre-production information about Vitesse products in their concept, development and/or testing phase. All information in this document, including descriptions of features, functions, performance, technical specifications and availability, is subject to change without notice at any time. Nothing contained in this document shall be construed as extending any warranty or promise, express or implied, that any Vitesse product will be available as described or will be suitable for or will accomplish any particular task. Vitesse products are not intended for use in life support appliances, devices or systems. Use of a Vitesse product in such applications without written consent is prohibited.
G52203-0, Rev 3.0 05/11/01
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
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VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
SONET/SDH 2.5Gb/s Laser Diode Driver
VSC7923
Page 14
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
G52203-0, Rev 3.0 05/11/01