HFD3020-500/BBA - HONEYWELL

HFD3020

TTL Output Receiver

OUTLINE DIMENSIONS in inches (mm)DESCRIPTION

The HFD3020 is a sensitive differentiating optical

receiver designed for use in short distance, 850 nm fiber

optic systems. The receiver uses a hybrid construction

consisting of a PIN photodiode, bipolar integrated

receiver circuit with internal voltage regulation and

external bypass capacitor. The TTL output allows the

HFD3020 to be interfaced directly with standard TTL

circuits. It is supplied in a Honeywell plastic package, and

can be mounted in several fiber optic connectors.

Companion optical transmitters are available.

APPLICATION

Digital HFD3020 fiber optic receivers convert the optical

signal in a point to point data communications fiber optic

link to a TTL output. The receiver is designed to be

mounted in a fiber optic connector that aligns the optical

axis of the component to the axis of the optical fiber. Its

PIN photodiode is mechanically centered within the

TO-18 package.

Electrical isolation is important in obtaining the maximum

performance of this high sensitivity receiver. A 0.1 µF

ceramic capacitor must be connected between pin #1

and pin #4. This minimizes external noise on the power

leads. Shielding can reduce coupled noise and allow the

maximum sensitivity to be obtained. This can include the

use of ground planes in the PCB, shielding around the

device, and shielding around the leads. The specified

maximum operating temperature of 100¡C allows the

HFD3020 to be designed into a broad variety of

applications.

FEATURES

Converts fiber optic input signals to TTL digital

outputs

•

Typical sensitivity 500 nW peak (-33 dBm)

•

Single 5 V supply requirement

•

Edge detection circuitry gives 20 dB minimum

dynamic range, low Pulse Width Distortion

•

Operates up to 10 Mbps NRZ

•

Plastic cap with TO-18 header

•

Available in metal package (HFD3000)

•

(12.7)

.165 (4.19)

.176 (4.47)

.500 MIN

.229 (5.82)

CRUSH RING

WINDOW

.047 (1.19) DIA.

.220(5.59)

.210(5.33)

.081 (2.06)

FIBER203.DIM

FIBER105.TIF

Pinout

1. Capacitor

2. VÙÙ

3. Output (TTL)

4. Case (ground)

Honeywell reserves the right to make

changes in order to improve design and

supply the best products possible.

262 h

HFD3020

TTL Output Receiver

APPLICATION

(

continued

)

Honeywell also offers companion transmitters designed

to operate in conjunction with the HFD3020.

OPERATION

Optical power (photons) from the fiber strikes the

photodiode and is converted to electrical current. This

current is then converted into a voltage in the

transimpedance preamplifier. The postamplifier is a

voltage gain stage with excellent temperature tracking.

The edge detection circuit includes an operational

amplifier configured as a differentiator, whose output is

proportional to the rate of change of the optical signal. A

latch retains the most recent edge transition and an

inverting buffer drives the TTL output. For example, a

light On to light Off transition of the input produces a

TTL high output logic level.

Bandwidth has been limited to minimize noise problems.

Reduced pulse width distortion (PWD) is a by-product of

the bandwidth limitation. The output of the differentiator

has a fixed settling time, assuring good PWD in most

applications. Another effect of fixed settling time is the

increase of PWD with increased optical power. Very

high input optical power may overdrive the differentiator,

causing high PWD due to the settling time. The

accompanying curves illustrate how PWD increases with

increased optical power, increased temperature, and

decreased duty cycle.

PWD manifests itself as an increase in the width of the

TTL low portion of an output waveform, with the TTL

high portion decreasing by a like amount. The amount of

PWD that a given system can tolerate without an error

due to a missing bit of information, is dependant upon

system considerations. The output of the HFD3020 will

typically connect to the input of some form of a Serial

Interface Adaptor IC. The specifications for that IC

govern the amount of PWD that can be tolerated in that

system.

The edge detection circuit monitors the output of the

differentiator, and triggers when its output exceeds

preset levels. These levels are established to be

sufficiently above the worst case RMS noise level to

allow excellent bit error rate and are low enough to give

high sensitivities which permit operation over long link

lengths. This circuitry recognizes the polarity of the

change of the optical signal, setting the latch to a "1"

when the optical input decreases.

Note: the final output stage inverts the polarity. When

initially powered up, the output state is set to a "1". After

setting of the device occurs, incoming edge transitions

are recognized and logic switching occurs.

Because the HFD3020 reacts to transitions in the optical

signal rather than DC levels, it shows excellent stability

versus temperature and other operating conditions.

Also, the device is much less sensitive to the absolute

level of the optical signal than DC coupled receivers,

allowing for a large range of optical source powers

and/or link distances to be directly interfaced.

Honeywell reserves the right to make

changes in order to improve design and

supply the best products possible. h263

HFD3020

TTL Output Receiver

TYP

ELECTRO-OPTICAL CHARACTERISTICS(TÙ = 25¡C, VÙÙ = 5 VDC unless otherwise stated)

UNITS TEST CONDITIONS

MINPARAMETER SYMBOL MAX

æÎ = 850 nm into 100/140

mMinimum In

ut Sensitivit

PÛÜ

W0.5 1.0

tical fiber

f = 2.5 MHz

eak

)

Dut

cle = 50%

PÛÜ – 0.1

IÏ – 0.8 mAHi

h Level Lo

ic Out

ut Volta

eVÏÝ V2.4 3.3

PÛÜ — 1

IÏ – 0.8 mALow Level Lo

ic Out

ut Volta

eVÏÚ V0.4

PÛÜ = 1

VÞ = 0.4 to 2.4 VRise Time tß ns12

PÛÜ = 1

VÞ = 2.4 to 0.4 VFall Time t¸ ns3

PÛÜ — 1

VÙÙ = 5.0 VSu

Current IÙÙ mA15 20

PÛÜ = 1

eakPulse Width Distortion PWD %510

PÛÜ = 100

eak20 25

f = 2.5 MHz

Dut

cle = 50%

ABSOLUTE MAXIMUM RATINGS

(25¡C Free-Air Temperature unless otherwise noted)

-40 to +100¡CStorage temperature

-40 to +100¡COperating temperature

260¡C, 10 sLead solder temperature

150¡CJunction temperature

+6 VSupply voltage

Stresses greater than those listed under "Absolute Maximum

Ratings" may cause permanent damage to the device. This is a

stress rating only and functional operation of the device at these or

any other conditions above those indicated in the operational

section of this specification is not implied. Exposure to absolute

maximum rating conditions for extended periods of time may affect

reliability.

RECOMMENDED OPERATING CONDITIONS

Operating temperature -40 to +85¡C

Supply voltage +4.5 to +5.5 V

Optical input power 1 to 100 µW

Optical signal pulse width > 100 ns

Optical signal edges (10 to 90%) < 20 ns

Honeywell reserves the right to make

changes in order to improve design and

supply the best products possible.

264 h

HFD3020

TTL Output Receiver

Description Catalog Listing

ORDER GUIDE

HFD3020-002Standard screening, plastic cap

package

This package is also available in special interface receptacles for

interfacing to standard fiber optic cables.

The inherent design of this component causes

it to be sensitive to electrostatic discharge

(ESD). To prevent ESD-induced damage

and/or degradation to equipment, take normal

ESD precautions when handling this product.

FIBER INTERFACE

Honeywell detectors are designed to interface with

multimode fibers with sizes (core/cladding diameters)

ranging from 50/125 to 200/230 microns. Honeywell

performs final tests using 100/140 micron core fiber. The

fiber chosen by the end user will depend upon a number

of application issues (distance, link budget, cable

attenuation, splice attenuation, and safety margin). The

50/125 and 62.5/125 micron fibers have the advantages

of high bandwidth and low cost, making them ideal for

higher bandwidth installations. The use of 100/140 and

200/230 micron core fibers results in greater power being

coupled by the transmitter, making it easier to splice or

connect in bulkhead areas. Optical cables can be

purchased from a number of sources.

BLOCK DIAGRAM

FIBER030.SC

SWITCHING WAVEFORM

FIBER002.CI

Pulse Width Distortion vs TemperatureFig. 1

FIBER047.GRA

Pulse Width Distortion vs FrequencyFig. 2

FIBER048.G

Honeywell reserves the right to make

changes in order to improve design and

supply the best products possible. h265

HFD3020

TTL Output Receiver

Pulse Width Distortion vs Optical Input

Power

Fig. 3

FIBER049.GRA

Propagation Delay vs Optical Input PowerFig. 4

FIBER050.G

Supply Current vs TemperatureFig. 5

FIBER030.GRA

Spectral ResponsivityFig. 6

FIBER101.G

Honeywell reserves the right to make

changes in order to improve design and

supply the best products possible.

266 h