VITESSE VSC7959W, VSC7959YD Datasheet

VITESSE

SEMICONDUCTOR CORPORATION

Advance Product Information

VSC7959

3.125Gb/s CML Limiting Amplifier with LOS Detect

Features Applications

• 3.3V or 5V Power Supply

• Typical Supply Current of 32mA

• Current-Mode Logic Outputs

• Optional Output Squelch

• Loss of Signal Detect

• Output Offset Correction

• Rise/Fall Times Faster than 100ps

• Packages: TSSOP-16, Bare Die

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

and 3.125Gb/s

• Full-Speed Fibre Channel (1.062Gb/s)

• Small Form Factor (SFF) Receivers

• ATM Optical Receivers

General Description

The VSC7959 is a single supply limiting amplifier with Loss of Signal (LOS) detect for SONET/SDH and
Fibre Channel applications up to 3.125Gb/s. The VSC7959 provides a constant output signal swing for a wide
range of input voltages a nd h as Current -Mode Logic ( CML) outp uts. Th e VSC796 1 pro vides the same funct ion­ality as the VSC7959 with positive emitter-coupled logic (PECL) outputs. Key features of the VSC7959 are its
RMS power detectors for programmable LOS detection, optional output squelch, adjustable output levels,
excellent jitter performance, and fast edge rates. The VSC7959 is available in die form or in a TSSOP-16 pack­age.

Block Diagram

VSC7959

TH

IN+

100

IN-

V

CC

8k

Ω

LOS

V

CC

8k

Ω

LOS

RMS Power

Detect and

Control

Ω

Lowpass Filter

Offset Correction

10pF

CZ1 CZ2

Output Control

SQUELCH

LEVEL

OUT+
OUT-

G52358-0, Rev 2.0 Page 1
02/09/01

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

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

Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Advance Product Information

3.125Gb/s CML Limiting Amplifier with LOS Detect

Electrical Characteristics

Table 1: DC Specifications

Symbol Parameter Min Typ Max Units Conditions

V

CC

I

CC

I

EE

I

CCSQ

I

EESQ

I

SQ

PSSR Power Supply Rejection Ratio 20 30 dB f < 2MHz

NOTE: (1) See Figure 5 for supply current measurement setup.

Table 2: DC Specifications

Power Supply Voltage 3.135 5.5 V

Power Supply Current

Power Supply Current

Power Supply Current when
Squelched

Power Supply Current when
Squelched

Squelch Input Current 0 400 µA

(1)

(1)

(1)

(1)

31 mA VCC = 3.3V
35 mA V
38 mA VCC = 3.3V
43 mΑ V
21 mA VCC = 3.3V
25 mA V
24 mA VCC = 3.3V
28 mA V

CC

CC

CC

CC

= 5V

= 5V

= 5V

= 5V

VSC7959

Symbol Parameter Min Typ Max Units Conditions

Data Rate 3.125 Gb/s

V

IN

J

D

J

R

t

R, tF

V

N

R

DIFF

f

L

V

SQ

V

CML

Z

O

NOTES: (1) Deterministic jitter measured peak-to-peak with K28.5 pattern. (2) Random jitter measured with minimum input.

Input V oltage Range 10 1200 mV Peak-to-peak
Deterministic Jitter 25 ps See Note 1
Random Jitter 8 ps See Note 2, RMS
Rise and Fall Times 55 100 ps 20% to 80%
Input Referred Noise 230 µV RMS, IN+ to IN­Differential Input Resistance 100 Ω IN+ to IN-

Low Frequency Cutof f
Output Signal When Squelched 20 mV Output AC-coupled

550 1200 mV Level = open, RL = 50Ω

CML Output Voltage

Output Resistance 100 Ω Single-ended

1100 1800 mV Level = GND, RL = 75Ω

2MHzC
2kHzC

20 mV Squelched

open

Z

= 0.1µF

Z

Page 2 G52358-0, Rev 2.0

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

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

Internet: www.vitesse.com

02/09/01

VITESSE

SEMICONDUCTOR CORPORATION

Advance Product Information

VSC7959

3.125Gb/s CML Limiting Amplifier with LOS Detect

Table 3: Loss of Signal Specifications

Symbol Parameter Min Typ Max Units Conditions

H
I

V

V

V
V

LOS

LOS

THA

THD

LOSH
LOSL

LOS Hystersis 3.1 3.3 5.5 dB H
LOS Assert/Deassert Time 0.22 0.25 0.28 µs

8.2 mV R

LOS Assert Threshold

LOS Deassert Threshold

LOS Output HIGH Volta ge 3.3 V I
LOS Output LOW Voltage 0.168 V I

12.8 19.8 21.8 mV R

57.2 mV R

11.4 mV R

26.2 29.0 31.6 mV R

75.2 mV R

= 20 log (V

LOS

= 2.5kΩ

TH

= 7kΩ

TH

= 20kΩ

TH

= 2.5kΩ

TH

= 7kΩ

TH

= 20kΩ

TH

= –30µA

LOS

= +1.2µA

LOS

Table 4: Loss of Signal Truth Table

SQUELCH LOS Output

High Low Off

Low High On

High Low On

Low Low On

THD/VTHA

)

Absolute Maximum Ratings

(1)

Power Supply Voltage (VCC).............................................................................................................-0.5V to +6V

Maximum Junction Temperature Range .........................................................................................................TBD

Storage Temperature Range (T

NOTE: (1) CAUTION: Stresses listed under “Absolute Maximum Ratings” may be applied to devices one at a time without caus-

ing permanent damage. Functionality at or above the values listed is not implied. Exposure to these values for extended
periods may affect device reliability.

).................................................................................................-55°C to +150°C

S

Recommended Operating Conditions

Positive Voltage Rail (VCC)..................................................................................................................3.3V or 5V

Junction Temperature Range (T
Ambient Temperature Range (T

G52358-0, Rev 2.0 Page 3
02/09/01

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

)................................................................................................-40°C to +100°C

J

).................................................................................................-40°C to +85°C

A

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

Internet: www.vitesse.com