ATA01504资料

ATA01504

AGC Transimpedance Amplifier

SONET OC-3

FEATURES

······

Single +5 Volt SupplyTO Package CompatibleAutomatic Gain Control-38 dBM Sensitivity0 dBm Overload175 MHz Bandwidth

PRELIMINARY DATA SHEET-Rev 1

APPLICATIONS

···

SONET OC-3/SDH STM-1 (155 Mb/s) ReceiverFDDI, Ethernet Fiber LANLow Noise RF Amplifier

D1CPRODUCT DESCRIPTION

The ANADIGICS ATA01504 is a 5V low noisetransimpedance amplifier with AGC designed to beused in OC-3/STM-1 fiber optic links. The device isused in conjunction with a photodetector (PIN diodeor avalanche photodiode) to convert an optical signal

into an output voltage. The ATA01504 offers abandwidth of 175MHz, a dynamic range of 38dB andan alternate pad layout as compared to the ATA01501.It is manufactured in a GaAs MESFET process andis available in bare die form.

VDDAGC19K+70K4.5 pF+ 0.8VOUT

GNDCAGC

IINGNDor

neg.supply- 45 VGAUS PATENT5442321,5602510,5047728Photodector cathode must be connected to IIN for proper AGC operationFigure 1: Equivalent Circuit

08/2001

元器件交易网www.cecb2b.com

ATA01504

Figure 2: Bonding Pad Layout

Table 1: Pad Description

PADVDDIINVOUTCAGCDescriptionVDDTIAInputCurrentTIAOutputVoltageExternalAGCCapacitorCommentPositivesupplyforinputgainstageConnectdetectorcathodeforproperoperationRequiresexternalDCblock70K*(CAGC*4.5pF)=AGCTimeConstantELECTRICAL CHARACTERISTICS

Table 2: Absolute Maximum Ratings

VDDIINTATS7.0V5mAOperatingTemp.-40oCto125oCStorageTemp.-65oCto150oCStresses in excess of the absolute ratings may causepermanent damage. Functional operation is not impliedunder these conditions. Exposure to absolute ratingsfor extended periods of time may adversely affectreliability.

2

PRELIMINARY DATA SHEET - Rev 1

08/2001

元器件交易网www.cecb2b.com

ATA01504

Table 3: Electrical Specifications (1)

(TA = 25°C, VDD =+5.0V + 10%, CDIODE + CSTRAY = 0.5 pF, Det. cathode to IIN)

PARAMETERTransresistance(RL=¥,IDC<500nA)Transresistance(RL=50W)(1)Bandwidth-3dBInputResistance(2)OutputResistanceSupplyCurrentInputOffsetVoltageOutputOffsetVoltageAGCThreshold(IIN)(3)OpticalOverload(4)MIN5.5150301.515-3TYP17817550050301.61.830014161-38MAX10UNITKWKWMHzW60451.9WmAVoltsVoltsmAdBmInputNoiseCurrent(5)AGCTimeConstant(6)OffsetVoltageDriftOpticalSensitivity(7)OperatingVoltageRangeOperatingTemperatureRange+4.5-4020nAmsecmV/ºCdBm+6.085VoltsºC+5.0Notes:1. f = 50MHz

2. Measured with Iin below AGC Threshold. During AGC, input impedance will decrease proportionally to Iin.

3. Defined as the Iin where Transresistance has decreased by 50%.4. See note on 󰀮Indirect Measurement of Optical Overload.󰀱5. See note on 󰀮Measurement of Input Referred Noise Current.󰀱6. CAGC = 220 pF

7. Parameter is guaranteed (not tested) by design and characterization data @155 Mb/s, assuming dectector responsivity of 0.9.

PRELIMINARY DATA SHEET - Rev 1

08/2001

3

元器件交易网www.cecb2b.com

ATA01504

APPLICATION INFORMATION

V

CAGC

Figure 3: ATA 01504D1C Typical Bonding Diagram

Power supplies and general layout considerationsThe ATA01504D1C may be operated from a positivesupply as low as +4.5 V and as high as +6.0 V. Below+4.5 V, bandwidth, overload and sensitivity willdegrade, while at +6.0 V, bandwidth, overload andsensitivity. Use of surface mount (preferably MIM typecapacitors), low inductance power supply bypasscapacitors (>=56pF) are essential for good highfrequency and low noise performance. The powersupply bypass capacitors should be mounted on orconnected to a good low inductance ground plane.General layout considerations

Since the gain stages of the transimpedanceamplifier have an open loop bandwidth in excess of1.0 GHz, it is essential to maintain good highfrequency layout practices. To prevent oscillations, alow inductance RF ground plane should be madeavailable for power supply bypassing. Traces thatcan be made short should be made short, and theutmost care should be taken to maintain very lowcapacitance at the photodiode TIA interface (IIN), asexcess capacitance at this node will cause adegradation in bandwidth and sensitivity (seeBandwidth vs. CT curves).4

210Bandwith (MHz)2001901801701601500 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

B(3dB) A ≈/ 2 π Rf (Cin +Ct)VDD = 5.5 VVDD = 5.0 VVDD = 4.5 VCT(pF)

Figure 4: Bandwidth vs. CT

Note: All performance curves are typical @ TA =25 °C

unless otherwise noted.

PRELIMINARY DATA SHEET - Rev 1

08/2001

元器件交易网www.cecb2b.com

ATA01504

IIN connection

(refer to the equivalent circuit diagram) Bonding thedetector cathode to IIN (and thus drawing current fromthe ATA01504) improves the dynamic range. Althoughthe detector may be used in the reverse direction forinput currents not exceeding 25 mA, the specificationsfor optical overload will not be met.

VOUT Connection

The output pad should be connected via a couplingcapacitor to the next stage of the receiver channel(filter or decision circuits), as the output buffers arenot designed to drive a DC coupled 50 ohm load(this would require an output bias current ofapproximately 36 mA to maintain a quiescent 1.8Volts across the output load). If VOUT is connected to ahigh input impedance decision circuit (>500 ohms),then a coupling capacitor may not be required,although caution should be exercised since DCoffsets of the photo detector/TIA combination maycause clipping of subsequent gain or decisioncircuits.

1087

IIIN50654321

Transimpedance (K Ohm)9

Output Collapseheavy AGCVDD = 5.5 VVDD = 4.5 VVDD =5.5 VLinear RegionRfIINVOUT-2.1 - 1.6 -1.1 - 0.6 - 0.1

IIN (mA DC)

Figure 5: Transimpedance vs. IIN

VDD = 4.5 V- 4

- 3

- 2

- 1

3.43.23.02.92.72.52.42.22.01.91.71.51.41.21.00.80.70.50.30.20.0

Bandwidth vs IINVDD=5.5 V1.5BANDWIDTH (GHz)1.31.10.90.7IIN (mA DC)

Figure 7: VOUT vs. IIN

VDD=4.5 VIIN15010.5.3 5000.1- 2.1 - 1.6 - 1.1 - 0.6 - 0.1

IIN (mA DC)

Figure 6: Bandwidth vs. IIN

Sensitivity and Bandwidth

In order to guarantee sensitivity and bandwidthperformance, the TIA is subjected to acomprehensive series of tests at the die sort level(100% testing at 25 oC) to verify the DC parametricperformance and the high frequency performance(i.e. adequate |S21|) of the amplifier. Acceptably high|S21| of the internal gain stages will ensure lowamplifier input capacitance and hence low inputreferred noise current. Transimpedance sensitivityand bandwidth are then guaranteed by design andcorrelation with RF and DC die sort test results.

PRELIMINARY DATA SHEET - Rev 1

08/2001

VOUT(Volts)5

元器件交易网www.cecb2b.com

ATA01504

Indirect Measurement of Optical Overload

Optical overload can be defined as the maximumoptical power above which the BER (bit error rate)increases beyond 1 error in 1010 bits. TheATA01504D1C is 100% tested at die sort by a DCmeasurement which has excellent correlation withan PRBS optical overload measurement. Themeasurement consists of sinking a negative current(see VOUT Vs IIN figure) from the TIA and determiningthe point of output voltage collapse. Also the inputnode virtual ground during 󰁃heavy AGC󰁄 is checkedto verify that the linearity (i.e. pulse width distortion)of the amplifier has not been compromised.Measurement of Input Referred Noise CurrentThe 󰁃Input Noise Current󰁄 is directly related tosensitivity . It can be defined as the output noisevoltage (Vout), with no input signal, (including a 110MHz lowpass filter at the output of the TIA) divided bythe AC transresistance.

Phase response

At frequencies below the 3dB bandwidth of the device,the transimpedance phase response ischaracteristic of a single pole transfer function (asshown in the Phase Vs Frequency curve). The outputimpedance is essentially resistive up to 1000 MHz.

14pA/ HzRfCT10 6 2

Figure 9: Phase (IIN to VOUT)

50CT=1.0pFCT =0.5pF - 0.1 1 10 100 1000

Frequency (MHz)

Figure 8: Input Referred Noise Spectral DensityAGC Capacitor

It is important to select an external AGC capacitor ofhigh quality and appropriate size. The ATA01504D1Chas an on-chip 70 KW resistor with a shunt 4 pFcapacitor to ground. Without external capacitance thechip will provide an AGC time constant of 280 nS. Forthe best performance in a typical 155 MB/s SONETreceiver, a minimum AGC capacitor of 56pF isrecommended. This will provide the minimumamount of protection against pattern sensitivity andpulse width distortion on repetitive data sequencesduring high average optical power conditions.Conservative design practices should be followedwhen selecting an AGC capacitor, since unit to unitvariability of the internal time constant and variousdata conditions can lead to data errors if the chosenvalue is too small.6

PRELIMINARY DATA SHEET - Rev 1

08/2001

元器件交易网www.cecb2b.com

ATA01504

NOTES

PRELIMINARY DATA SHEET - Rev 1

08/2001

7

元器件交易网www.cecb2b.com

ATA01504

ORDERING INFORMATION

PARTNUMBERATA01504D1CPACKAGEOPTIOND1CPACKAGEDESCRIPTIONDieANADIGICS, Inc.

141 Mount Bethel Road

Warren, New Jersey 07059, U.S.ATel: +1 (908) 668-5000Fax: +1 (908) 668-5132http://www.anadigics.comMktg@anadigics.comIMPORTANT NOTICE

ANADIGICS, Inc. reserves the right to make changes to its products or to discontinue any product at any time withoutnotice. The product specifications contained in Advanced Product Information sheets and Preliminary Data Sheets aresubject to change prior to a product󰀥s formal introduction. Information in Data Sheets have been carefully checked and areassumed to be reliable; however, ANADIGICS assumes no responsibilities for inaccuracies. ANADIGICS strongly urgescustomers to verify that the information they are using is current before placing orders.

WARNING

ANADIGICS products are not intended for use in life support appliances, devices, or systems. Use of an ANADIGICSproduct in any such application without written consent is prohibited.

8PRELIMINARY DATA SHEET - Rev 108/2001