MICREL SY88913 Datasheet

1.25Gbps HIGH-SPEED
LIMITING POST AMPLIFIER

SY88913

FEATURES

■ Up to 1.25Gbps operation

■ Low noise

■ Chatter-Free /LOS Generation

■ PECL /LOS Output

■ TTL /EN Input

■ Differential PECL inputs for data

■ /EN input is TTL with internal 27K pull up

■ Single power supply

■ Designed for use with SY88902 and SY88904

■ Available in a tiny 10-pin (3mm) MSOP

PIN CONFIGURATION

LOS

1/EN

D

IN

2

/D

IN

V

REF

LVL

MSOP

3

K10-1

4
5

10 V

9
8
7
6

CC

D

OUT

/D

OUT

/LOS
GND

DESCRIPTION

The SY88913 limiting post amplifier with its high gain
and wide bandwidth is ideal for use as a post amplifier in
fiber-optic receivers with data rates up to 1.25Gbps.
Signals as small as 5mVp-p can be amplified to drive
devices with PECL inputs. The SY88913 generates a
chatter-free PECL Loss of Signal (/LOS).

The SY88913 incorporates a programmble level detect
function to identify when the input signal has been lost.
This information can be fed back to the /EN input of the
device to maintain stability under loss of signal conditions.
Using LOSLVL pin the sensitivity of the level detect can
be adjusted. The LOSLVL voltage can be set by
connecting a resistor divider between VCC and VREF,
Figure 2. Figure 3 shows the relationship between input
level sensitivity and the voltage set on LOSLVL. Figure 4
shows the relationship between input level sensitivity and
resistor divider ratio.

APPLICATIONS

■ 1.25Gbps Gigabit Ethernet

■ 531Mbps and 1062Mbps Fibre Channel

■ 622Mbps SONET

■ Gigabit Interface Converter

BLOCK DIAGRAM

GND

LOS

V

D

D

REF

V

LVL

IN

IN

CC

Limiting
Amplifier

1

ECL
Buffer

Level
Detect

Enable

D

OUT

D

OUT

EN

LOS

Rev.: E Amendment: /1
Issue Date: July 2000

Micrel

SY88913

PIN NAMES

Pin Type Function

DIN Data Input Data Input
/DIN Data Input Inverting Data Input
LOS LVL Input Loss of Signal Level Set
/EN TTL Input Output Enable (active Low)
/LOS PECL Output Loss of Signal Indicator

(active Low)
GND Ground Ground
DOUT PECL Output Data Output
/DOUT PECL Output Inverting Data Output
VCC Power Supply Positive Power Supply
V

REF Output Reference Voltage Output

for LOS Level Set (see Fig. 2)

ABSOLUTE MAXIMUM RATINGS

Symbol Rating Value Unit

VCC Power Supply Voltage 0 to +7.0 V
DIN, /DIN Input Voltage 0 to VCC V
DOUT, /DOUT , /LOS Output Voltage (with 50Ω load) VCC –2.5, VCC +0.3 V
TA Operating Temperature Range –40 to +85 °C

store Storage Temperature Range –55 to +125 °C

T

NOTE:

1. Permanent device damage may occur if ABSOLUTE MAXIMUM RATINGS are exceeded. This is a stress rating only and functional operation is not implied
at conditions other than those detailed in the operational sections of this data sheet. Exposure to ABSOLUTE MAXIMUM RATlNG conditions for extended
periods may affect device reliability.

(1)

GENERAL DESCRIPTION

General

The SY88913 is an integrated limiting amplifier intended
for high-frequency fiber-optic applications. The circuit
connects to typical transimpedance amplifiers found within
a fiber-optics link. The linear signal output from a
transimpedance amplifier can contain significant amounts
of noise, and may vary in amplitude over time. The SY88913
limiting amplifier quantizes the signal and outputs a voltage­limited waveform.

The TTL /EN pin allows the user to disable the signal
without removing the input signal.

2

Micrel

SY88913

DC ELECTRICAL CHARACTERISTICS

VCC = +5V ±10%, RLOAD = 50Ω to VCC-2V, TA = –40°C to +85°C

T

A = –40°CTA = 0°CTA = +25°CTA = +85°C

Symbol Parameter Min. Max. Min. Max. Min. Typ. Max. Min. Max. Unit

(4)

(1)

— 35 — 35 — 21 35 — 35 mA

(5)

–0.3

—20
— 100

GND +2.0 VCC -1.0 GND +2.0 VCC -1.0 GND +2.0 —VCC -1.0 GND +2.0 VCC -1.0

VCC-1085 VCC-880 VCC-1025 VCC-880 VCC-1025 VCC-955 VCC-880 VCC-1025 VCC-880

VCC-1830 VCC–1555 VCC-1810 VCC–1620 VCC-1810 VCC–1705 VCC–1620 VCC-1810 VCC–1620

VCC-2.625 VCC–2.325 VCC-2.625 VCC–2.325 VCC-2.625 VCC–2.475 VCC–2.325 VCC-2.625 VCC–2.325

— –0.3

(2)

(3)

(5)

— –0.3

—20
— 100

(2)

(3)

(5)

——20
— — 100

— — –0.3

(2)

(3)

(5)

—20
— 100

2.0 — 2.0 — 2.0 — — 2.0 — V
— 0.8 — 0.8 — — 0.8 — 0.8 V

4. IREF must be limited to be within –0.8mA (source) and 0.5mA (sink).

5. VIN = 0.5V

—mA

(2)

(3)

ICC
IIL

IH

I

Power Supply Current
/EN Input LOW Current
/EN Input HIGH Current

VCMR Common Mode Range
Voffset Differential Output Offset — ±100 — ±100 — — ±100 — ±100 mV
LOSLVL LOSLVL Level VREF VCC VREF VCC VREF —VCC VREF VCC V

OH DOUT and /DOUT

V

HIGH Output

OL DOUT and /DOUT

V

LOW Output
VREF Reference Supply
VIH

IL

V

NOTES:

1. No Output Load.

2. VIN = 2.7V

3. VIN = VCC

/EN Input HIGH Voltage

/EN Input LOW Voltage

µA

V

mV

mV

V

AC ELECTRICAL CHARACTERISTICS

VCC = +5V ±10%, RLOAD = 50Ω to VCC - 2V, TA = –40°C to +85°C

TA = –40°CTA = 0°CTA = +25°CTA = +85°C

Symbol Parameter Min. Max. Min. Max. Min. Typ. Max. Min. Max. Unit Conditions

PSRR Power Supply

Rejection Ratio 55MHz

VID Input Voltage Range 5 1800 5 1800 5 — 1800 5 1800 mVp-p

r, tf Output Rise/Fall Time — 350 — 350 — 200 350 — 350 ps VID > 100mVp-p

t

OD Differential Output — — — — — 600 — — — mV VID = 15mVp-p

V

Voltage Swing

OFFL /LOS Release Time

t

Minimum Input

OFFH /LOS Release Time

t

Maximum Input
tONL /LOS Assert Time
VSR /LOS Sensitivity Range 5 50 5 50 5 — 50 5 50 mVp-p
HYS /LOS Hysteresis 2 8 2 8 2 4.6 8 2 8 dB

NOTES:

1. Input referred noise = RMS output noise/low frequency gain.

2. Input is 622MHz square wave.

(1)

(2)

(3)

(3)

(4)

— — — — — 35 — — — dB Input referred,

—————trin,tfin ——— VID < 100mVp-p

—————200———mVVID = 5mVp-p
— 0.5 — 0.5 — 0.1 0.5 — 0.5 µs

— 0.5 — 0.5 — 0.1 0.5 — 0.5 µs

— 0.5 — 0.5 — 0.2 0.5 — 0.5 µs

3. Input is a 200MHz square wave, tr < 300ps, 8mVp-p.

4. Input is a 200MHz square wave, tr < 300ps, 1.8Vp-p.

3