VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7924
Features
• Rise Times Less Than 100ps • High-Speed Operation (Up to 2.5Gb/s NRZ Data) • Single-Ended Operation • Single Power Supply • Direct Access to Modulation and Bias FETs • Data Density Monitors • 24-Pin Ceramic Package
SONET/SDH 2.5Gb/s Laser Diode Driver
Applications
• SONET/SDH at 622Mb/s, 1.244Gb/s, and 2.488Gb/s • Full-Speed Fibre Channel (1.062Gb/s)
General Description
The VSC7924 is a single 5V supply, 2.5Gb/s laser diode driver with direct access to the laser modulation and bias FETs. 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.
VSC7924 Block Diagram
IOUT NIOUT
MK NMK DIN VREF IMOD VIP *TERM VIB MIP MIB IBIAS
*Terminated to Off-chip Capacitor
G52156-0, Rev 3.0 05/01/01
© 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 TERM Total Pins
VSC7924
Description
Data Input 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 Data Input Reference
Type
In Out Out Out Pwr Pwr In In In In In In
Level
ECL ECL
# Pins
1 2 1 1
Pwr Pwr DC DC DC DC DC DC
5 8 1 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: ECL Input and Outputs Symbol
VIN VOH VOL
Parameter
Input Voltage Swing ECL Output High Voltage ECL Output Low Voltage
Min
300 -1200 -2000
Typ
Max
800 -700 -1600
Units
mV mV mV
Conditions
Peak-to-peak, VREF = -1.3V 50Ω to -2.0V 50Ω to -2.0V
Table 4: 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 “Calculation of the Maximum Case Temperature” section for detailed maximum temperature calculations.
Page 2
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
G52156-0, Rev 3.0 05/01/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7924
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 1120 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
Typ
Max
50 60 VSS + 2.1 VSS + 2.1
Units
mA mA V V V
Conditions
IBIAS = 50mA IMOD= 60mA VSS = -5.2V
GND -2.2V
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
Parameter
Thermal Resistance from junction-to-case
Min
Typ
25
Max
Units
°C/W
Conditions
Ceramic Package
G52156-0, Rev 3.0 05/01/01
© 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
VSC7924
Calculation of the Maximum Case Temperature
The VSC7924 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 (-5.2 * 220mA) + ((5.2 - 2.0) * 40mA) + ((5.2-- 2.0) * 20mA) 1144mW + 128mW + 64mW = 1.336W
PD = PD =
The thermal rise from junction to case is θJC * PD. For the ceramic package, θJC = 25°C/W. Thus the thermal rise is: 25°C/W * 1.336W = 33.4°C The maximum case temperature is: 125°C – 33.4°C = 91.6°C The absolute maximum power dissipation of the device is at: VSS IMOD IBIAS VIBIAS VIOUT = = = = = -5.5V 60mA 50mA 0V 0V (5.5 * 220mA) + (5.5 * 60mA) + (5.5mA * 50mA) PD = 1.815W
PD =
This will net a maximum junction to case thermal rise of: 1.815W * 25°C/W = 45.4°C This situation will allow maximum case temperature of: 125°C – 45.4°C = 79.6°C
Page 4
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
G52156-0, Rev 3.0 05/01/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7924
Input Termination Schemes
SONET/SDH 2.5Gb/s Laser Diode Driver
Figure 1: Input Structure
OV (GND)
1.4kΩ 1400 1.4kΩ 1400
DIN X VREF X TERM X 12pF 3Ω
+ 4.3kΩ 4300 4.3kΩ 4300
• Nominal VREF = -1.3V • 1400, 4300 Ohm Resistor on die, nominal values
Nominal VREF = 1.3V 1.4kΩ, 4.3kΩ resistor on die, nominal values
GND -5.2V (VSS)
Figure 2: Single-Ended AC Coupled
GND 0.1µF SOURCE 50Ω -2V GND DIN
X
TERM or VREF
+
X
0.1µF VSS
-
Figure 3: Single Ended AC Coupled with Offset Adjust
GND 0.1µf SOURCE 50Ω DIN
X
VREF
+
-
X
GND 3 VSS 2000 2kΩ
4.3kΩ 4300
X
TERM 0.1µf GND
Page 5
VSS
G52156-0, Rev 3.0 05/01/01
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
SONET/SDH 2.5Gb/s Laser Diode Driver
Figure 4: Control Signals VIP and VIB
I (MIB) 50 mA
VSC7924
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 5: Simplified Output Structure
NIOUT
IOUT
X
X
VIP
X
IMOD
OUTPUT DIFF PAIR IBIAS
X VIB
X
MIP
X
MIB
Page 6
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
G52156-0, Rev 3.0 05/01/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7924
1720 1620
SONET/SDH 2.5Gb/s Laser Diode Driver
Figure 6: Pad Assignments for VSC7924 Die
50
50
50
120 120 150
PAD 34 PAD 33 PAD 32 PAD 31 PAD 30 PAD 29 VREF VSS VSS VSS VSS VIP PAD 1 DIN PAD 2 VSS PAD 3 DIN PAD 4 GND PAD 5 GND PAD 6 GND PAD 7 VSS PAD 8 VSS TERM PAD 9 TERM PAD 10 GND PAD 11
PAD 28 PAD 27 PAD 26 MIP MIP MIB PAD 25 VIB PAD 24 GND0 PAD 23 OUT PAD 22 OUT PAD 21 GND0 PAD 20 NOUT PAD 19 VSS PAD 18 VSS
30
1620
1720
GND GND GND GND NMARK MARK PAD 12 PAD 13 PAD 14 PAD 15 PAD 16 PAD 17
Dimensions in micrometers.
50
1) 2) 3) 4) 5)
Die size = 1620µm x 1620µm Actual die size = 1720µm x 1720µm (after the die are cut up) Pad size = 120µm x 120µm Pad pitch = 150µm Space between pads = 30µm
G52156-0, Rev 3.0 05/01/01
© 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
VSC7924
Pin Diagram for 24-Pin Ceramic Package
VREF MIB 19 18 17 16 15 14 7 8 9 10 11 13 12 VSS VSS MIP 20 VIP 21
VSS DIN GND GND GND VSS
24 1 2 3 4 5 6
23
22
VIB GND IOUT GND NIOUT VSS
TERM
GND
GND
GND
NMK
Note:
Package bottom plate is connected to GND within the package. Package lid is electrically unconnected.
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
MK
G52156-0, Rev 3.0 05/01/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7924
SONET/SDH 2.5Gb/s Laser Diode Driver
Package Information - 24 Pin Ceramic Package (Formed Leads)
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
G52156-0, Rev 3.0 05/01/01
© 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 9
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
SONET/SDH 2.5Gb/s Laser Diode Driver
VSC7924
Package Information - 24 Pin Ceramic Package (Straight Leads)
Top View Key
A 24 23 22 21 20 19
mm
9.5 7.7 5.8 1.27 0.30 1.7 0.6 9.53 0.125 8.51
In
0.374 0.303 .230 0.050 0.012 0.067 0.024 0.375 0.005 0.335
A B C D E
E
INDEX
F
18 17 16 15 14 13
1 2 3 A 4 5 6
G H I J
7
8
9
10 11
D 12
Side View
B
I
G
F
C
H
C
NOTES: Drawing not to scale. Package #: 101-000-0 Issue #:1
Page 10
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
G52156-0, Rev 3.0 05/01/01
VITESSE
SEMICONDUCTOR CORPORATION
Preliminary Data Sheet
VSC7924
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.
VSC7924
Device Type VSC7924: 2.5Gb/s Laser Diode Driver
XX
Package Style KF: (Ceramic - Straight Leads) KFL: (Ceramic- Formed Leads)
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.
G52156-0, Rev 3.0 05/01/01
© 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
VSC7924
Page 12
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012 Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com Internet: www.vitesse.com
G52156-0, Rev 3.0 05/01/01