Datasheet VSC7927X, VSC7927KFRL, VSC7927KFL, VSC7927KF Datasheet (VITESSE)

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7927

SONET/SDH 2.5Gb/s Laser Diode Driver

Features

• Rise Times of Less Than 100ps

• High Speed Operation
(Up to 2.5 Gb/s NRZ Data)

• Differential or Single-Ended Inputs

• Single Supply

• ECL-Compatible Clock and Data Inputs

• Direct Access to Modulation and Bias FETs

• Data Density Monito rs

• On-Chip Reclocking Register

• On-Chip Mux for Clocked or Non-clocked Appli­cations

• On-Chip 50

Ω Input Termination: Clock and Data

General Description

The VSC7927 is a single 5V supply, 2.5 Gb/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 density outputs are provided to allow the user to adjust the laser bias
in high unbalanced data applications. Clock and data inputs are differentially terminated to 50

Ω.

Applications

• SDH/SONET @ 622Mb/s, 1.244Gb/s, 2.488Gb/s

• Full Speed Fibre Channel (1.062Gb/s)

VSC7927 Block Diagram

DIN

DINTERM*

NDIN

CLK

CLKTERM*

NCLK

*Terminated to Off-chip Capacitor

**On Die Components

50 Ω

50 Ω

50 Ω

50 Ω

**

**

**

**

DQ

M
U
X

SEL

VIP

VIB

DCC

MK

NMK

MIP

I

MOD

MIB

IOUT

NIOUT

IBIAS

I

BIAS

G52201-0, Rev 3.0 Page 1
04/05/01

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

Table 1: Signal Pin Reference

Signal Type Level # Pins Description

DIN, NDIN In ECL 2 Data Input and Data Reference, On-chip 50Ω Termination
MK, NMK Out ECL 2 Data Density Differential Outputs
NIOUT Out

IOUT Out — 1 Laser Modulation Current Output (to Laser Cathode)
VSS Pwr Pwr 2 Negative Voltage Rail
GND Pwr Pwr 5 Positive Voltage Rail
VIP In DC 1 Modulation Gate Node
MIP In DC 1 Modulatio n Sou r ce Node
VIB I n DC 1 Bias Gate Node
MIB In DC 1 Bias Source Node
IBIAS Out DC 1 Laser Bias Output (To Laser Cathode)
CLK, NCLK In ECL 2 Clock Input and Clock Reference, On-chip 50Ω Termination
DINTERM In DC 1 Data Reference
CLKTERM In DC 1 Clock Reference
DCC In DC 1 Duty Cycle Control, Leave Floating
SEL In DC 1 Clk/Non-clk Data Select
T otal Pin s

—— 24

— 1 Laser Modulation Current Output (Complementary)

VSC7927

Table 2: Mux Select Logic Table

SEL Mode Select

V

SS

GND Non-clocked Data In

N/C Non-clocked Data In

Clocked Data In

Table 3: Absolute Maximum Ratings

Symbol Rating Limit

V

SS

T

J

T

STG

Negative Power Supply Voltage VCC to -6.0V
Maximum Junction Temperature -55°C to + 125°C
Storage Temperature -65°C to +150°C

Table 4: Recommended Operating Conditions

Symbol Parameter Min Typ Max Units Conditions

GND Positive Voltage Rail — 0 — V
VSS Negative Voltage Rail -5.5 -5.2 -4.9 V
T

Cl

T

J

NOTES: (1) Lower limit of specification is ambient temperature and upper limit is case temperature. (2) See section “Calculation of the

Operational Temperature
Junction Temperature ——125 °C

Maximum Case Temperature” for detailed maximum temperature calculations.

(1)

-40 — 85

(2)

°C Power dissipation = 1.3W

Page 2 G52201-0, Rev 3.0

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Internet: www.vitesse.com

04/05/01/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7927

SONET/SDH 2.5Gb/s Laser Diode Driver

Table 5: High Speed Inputs and ECL Outputs

Symbol Parameter Min Typ Max Units Conditions

V

IN

V

CM

V

OH

V

OL

V

IN

Single-ended Input Voltage Swing 300 — 1500 mVp-p V
Differential Input Common Mode Range -2.3 — -1.3 V VSS = -5.2V
ECL Output High Vol tag e -1200 ——mV 50Ω to -2.0V
ECL Output Low Voltage ——-1600 mV 50Ω to -2.0V
On-Chip Terminations 35 — 65 Ω

CM

Table 6: Power Diss ipat ion

Symbol Parameter Min Typ Max Units Conditions

= -5.5V, I

V

I

P

VSS

D

Power Supply Current (VSS) ——120 mA

Total Power Dissipation ——700 mW

SS

0mA, MK/NMK open circuit
V

= -5.5V, I

SS

0mA, R

LOAD

MK/NMK terminated 50Ω to -2V

T able 7: Laser Driver DC Electrical Specifications

Symbol Parameter Min Typ Max Units Conditions

I

BIAS

I

MOD

V

V

V

IB

IP

OCM

Programmable Laser Bias Current 2 — 100 mA —
Programmable Modulation Current 2 — 100 mA

V

+

Laser Bias Control Voltage ——

Laser Modulation Control Voltage ——

Output Voltage Compliance —

GND -

3V

SS

2.1

V

+

SS

2.1

— VV

—

VI

VI

BIAS

MOD

SS

= 50mA

= 60mA

= -5.2V

= -2.0V

= I

MOD

BIAS

= I

MOD

= 25Ω to GND,

BIAS

=

=

T able 8: Laser Driver AC Electrical Specifications

Symbol Parameter Min Typ Max Units Conditions

25Ω load, 20%-80%,

tR, t

t

SU

t

H

F

Output Rise and Fall Times ——100 ps

Data to Clock Setup Time — 50 90 ps
Hold Time 20 50 — ps

20mA < I

= 60mA

I

BIAS

—
—

MOD

< 60mA,

Table 9: Package Thermal Specifications

Symbol Parameter Min Typ Max Units Conditions

θ

JCC

G52201-0, Rev 3.0 Page 3
04/05/01

Thermal Resistance from Junction-to-Case — 25 — °C/W Ceramic Package

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

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Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

VSC7927

Calculation of the Maximum Case Temperature

The VSC7927 is designed to operate with a maximum junction temperature of 125°C. The rise from the
case to junction is determined by the power dissip ation of the dev ice. The power dissipation is determine d by
the V

current plus the operating I

SS

MOD

and I

BIAS

currents.

The power of the chip is determined by the following formula:

P

= (-VSS * ISS) + ((V

D

IOUT – VSS

) * I

MOD

For example with:

V

SS

I

MOD

I

BIAS

V

IBIAS

V

IOUT

P

D

P

D

=-5.2V
=40mA
=20mA
=-2.0V
=-2.0V

= (-5.2 * 150mA) + ((5.2 - 2.0) * 40mA) + ((5.2-- 2.0) * 20mA)

= 780mW + 128mW + 64mW = 972mW

) + ((V

IBIAS – VSS

) * I

BIAS

)

θ

The thermal rise from junction-to-case is

* PD. For the ceramic package, θ

JC

mal rise is:

25°C/W * 972W = 24.3°C

The maximum case temperature is:

125°C – 24.3°C = 100.7°C

The absolute maximum power dissipation of the device is at:

V

I

MOD

I

BIAS

V

IBIAS

V

IOUT

P

D

P

D

SS

=-5.5V
=60mA
=50mA
=0V
=0V

= (5.5 * 150mA) + (5.5 * 60mA) + (5.5mA * 50mA)

= 1.43W

This will net a maximum junction to case thermal rise of: 1.43W * 25°C/W = 35.8°C

This situation will allow maximum case temperature of: 35.8°C – 58°C = 89.2°C

= 25°C/W. Thus the ther-

JCP

Page 4 G52201-0, Rev 3.0

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04/05/01/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7927

DIN

(CLK)

DINTERM

(CLKTERM)

NDIN

(NCLK)

SONET/SDH 2.5Gb/s Laser Diode Driver

Figure 1: On-chip Data and Clock Input Configuration

GND GND

X

50

*

4.0K

*

X

*

50

6.4K

*

X

*On-chip
Components

DINTERM to -2.0V for Differential ECL Inputs

Figure 2: Single-Ended Operation

DATA BUFFER
(CLOCK BUFFER)

VSSVSS

DA T A

SOURCE

CLOCK

SOURCE

0.1µf

0.1µf

GND

GND

0.1µf

0.1µf

0.1µf

0.1µf

7927

DIN
DINTERM
NDIN

GND

CLK
CLKTERM
NCLK

GND

G52201-0, Rev 3.0 Page 5
04/05/01

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Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

Figure 3: Single-Ended AC-Coupled

SOURCE

0.1µf

GND

Figure 4: Differential AC-Coupled

0.1µf

SOURCE

0.1µf

0.1µf

DINTERM

(CLKTERM)

NDIN

(NCLK)

0.1µf

GND

DIN

(CLK)

X

X
X

DIN

(CLK)

X

DINTERM

(CLKTERM)

X

VSC7927

GND

50

50

50

4.0K

-2.0V

6.4K

VSS

GND

4.0K

-2.0V

SOURCE

0.1µf

NDIN

(NCLK)

X

GND

Figure 5: Differential DC-Coupled

DIN

(CLK)

X

DINTERM

(CLKTERM)

X

NDIN

(NCLK)

X

-2.0V

50

50

50

6.4K

VSS

GND

4.0K

-2.0V

6.4K

VSS

Page 6 G52201-0, Rev 3.0

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04/05/01/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7927

SONET/SDH 2.5Gb/s Laser Diode Driver

Figure 6: Control Signals VIP and VIB

I (MIB)

30 mA

VIB

VSS + 1.5 Volts (Typical)

Typical Bias Current v.s. Bias Voltage

I (MIP)

60 mA

VIP

VSS + 1.5 Volts (Typical)

VIP

X

Typical Modulation Current v.s. Modulation Voltage

Figure 7: Simplified Output Structure

NIOUT IOUT

XXX

I

MOD

OUTPUT
DIFF
PAIR

IBIAS

X

I

BIAS

X

MIP

MIB

X

VIB

G52201-0, Rev 3.0 Page 7
04/05/01

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VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

Figure 8: Pad Assignments for VSC7927 Die

50µm

PAD 34 PAD 33 PAD 32 PAD 31 PAD 30 PAD 29 PAD 28 PAD 27 PAD 26

120

DCC VSS VSS VSS VSS VIP MIP MIP MIB

120µm

150µm

30µm

PAD 1
N/C

PAD 2
NDIN

PAD 3
DIN

PAD 4
DINT

PAD 5
CLOCKT

PAD 6
CLOCK

1720µm

1620µm

PAD 25

VIB

PAD 24

GND

PAD 23

IOUT

PAD 22

IOUT

PAD 21

GND

PAD 20

GND

50µm

VSC7927

50µm

1620µm

1720µm

PAD 7
NCLOCK

PAD 8
N/C

SEL GND GND GND GND GND GND NMARK MARK

PAD 9 PAD 10 PAD 11 PAD 12 PAD 13 PAD 14 PAD 15 PAD 16 PAD 17

Die Size: 1620µm x 1620µm
Actual Die Size: 1720µmx1720µm (after the die are cut up)
Pad Size: 120µm x 120µm
Pad Pitch: 150µm
Space

Between Pads: 30µm

PAD 19

NIOUT

PAD 18

IBIAS

50µm

Page 8 G52201-0, Rev 3.0

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04/05/01/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7927

Pin Diagram for 24-Pin Ceramic Package

DCC

VSS

NDIN

DIN

DINTERM

CLKTERM

24 23 22 21 20 19

1

2

3

4

VSS

SONET/SDH 2.5Gb/s Laser Diode Driver

VIP

MIP

MIB

18

17

16

15

VIB

GND

IOUT

GND

CLK

NCLK

MK

14

13

MK

5

6

78910

SEL

GND

GND

Note: Package lid and bottom he at s pre ad e r are ele c tr ic ally

connected to GND within the package.

11 12

GND

NIOUT

IBIAS

G52201-0, Rev 3.0 Page 9
04/05/01

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VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

Package Information - 24 Pin Ceramic Package (Formed Leads)

Top View

A

24 23 22 21 20 19

INDEX

E

1

2

3

A

4

5

18

17

16

15

14

Key mm In

A 9.5 0.374
B 7.7 0.303
C 2.0 0.079
D1.27 0.050
E0.30 0.012

F 1.7 0.067
G 0.6 0.024
H11.5 0.453

I 0.125 0.005

J8.51 0.335

VSC7927

6

78910

D

11 12

13

Side View

B

F

I

G

J

H

NOTES:

Drawing not to scale.
Package #: 101-000-0 Issue #:1

C

Page 10 G52201-0, Rev 3.0

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04/05/01/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7927

SONET/SDH 2.5Gb/s Laser Diode Driver

Package Information - 24 Pin Ceramic Package (Straight Leads)

Top View

A

24 23 22 21 20 19

INDEX

E

1

2

3

A

4

5

18

17

16

15

14

Key mm In

A 9.5 0.374
B 7.7 0.303
C 5.8 .230
D1.27 0.050
E0.30 0.012

F 1.7 0.067
G 0.6 0.024
H9.53 0.375

I 0.125 0.005
J8.51 0.335

6

78910

D

11 12

13

Side View

B

I

C

HC

NOTES:

Drawing not to scale.

F

G

G52201-0, Rev 3.0 Page 11
04/05/01

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Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

Ordering Informatio n

The order number for this product is formed by a combination of the device number, and package style.

VSC7927

Device Type

VSC7927: 2.5Gb/s Laser Diode Driver

*Optional Reversed Formed Leads: Package leads have the same profile and dimensions,

but heat spreader is away from board. Please contact the factory for additional information.

VSC7927

XX

Package Style

KF: (Ceramic - Straight Leads)
KFL: (Ceramic- Formed Leads)
KFRL: (Ceramic - Reversed 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 con ce pt , development and/or testing phase. All information in this do cument, including descriptions of
features, functions, performan ce, technical specifications and availability, is subject to change wi th out notice at any ti me. Nothing contained in this
document shall be c ons trued as e xten ding an y w arran ty or pr omise , e xp ress or imp lied , th at a ny Vitesse produ ct wi ll b e av ail able as described or
will be suitable for or will accomp lis h any particular task.

Vitesse products are not intended for use in life support applia nc es, devices or systems. Use of a Vitesse product in such applications without writ­ten consent is prohibited.

Page 12 G52201-0, Rev 3.0

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04/05/01/01