Philips tza3034 DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

TZA3034

SDH/SONET STM1/OC3 postamplifier

Product speciﬁcation Supersedes data of 1999 Mar 16 File under Integrated Circuits, IC19

1999 Nov 03

Philips Semiconductors Product speciﬁcation

SDH/SONET STM1/OC3 postampliﬁer TZA3034

FEATURES

• PincompatiblewiththeNE/SA5224andNE/SA5225but with extended power supply range and less external component count

• Wideband operation from 1.0 kHz to 150 MHz typical

• Applicable in 155 Mbits/s SDH/SONET receivers

• Single supply voltage from 3.0 to 5.5 V

• Positive Emitter Coupled Logic (PECL) compatible data

outputs

• Programmable input signal level detection which can be adjusted using a single external resistor

• On-chip DC offset compensation without external capacitor.

ORDERING INFORMATION

TYPE

NUMBER

TZA3034T SO16 plastic small outline package; 16 leads; body width 3.9 mm SOT109-1 TZA3034TT TSSOP16 plastic thin shrink small outline package; 16 leads; body width 4.4 mm SOT403-1 TZA3034U − bare die in wafﬂe pack carriers; die dimensions 1.55 × 1.55 mm −

NAME DESCRIPTION VERSION

APPLICATIONS

• Digital fibre optic receiver in short, medium and long haul optical telecommunications transmission systems or in high speed data networks

• Wideband RF gain block.

GENERAL DESCRIPTION

The TZA3034 is a high gain limiting amplifier that is designed to process signals from fibre optic preamplifiers like the TZA3033. It is pin compatible with the NE/SA5224 and NE/SA5225 but with extended power supply range, and needs less external components. Capable of operating at 155 Mbits/s, the chip has input signal level detection with a user-programmable threshold. The data and level detection status outputs are differential outputs for optimum noise margin and ease of use.

PACKAGE

1999 Nov 03 2

Philips Semiconductors Product speciﬁcation

SDH/SONET STM1/OC3 postampliﬁer TZA3034

BLOCK DIAGRAM

ref

TEST

2 (2, 10, 15, 21, 26)

4 (7) 5 (8)

16 (30)

15 (29)

AGND V

A1 A2 A3

1 kΩ

(3, 4, 6, 9) 3

BAND GAP

REFERENCE

(1, 14) 1

SUB

DC-OFFSET

COMPENSATION

RECTIFIER

CCA

handbook, full pagewidth

DIN

DINQ

RSET

The numbers in brackets refer to the pad numbers of the bare die version.

Fig.1 Block diagram.

(11, 12) 6

25 kΩ

(19, 20, 22, 25)11(27, 28)

(13) 7

DGND V

TZA3034

CCD

(24) 13 (23) 12

(16) 8

(18) 10

(17) 9

DOUT DOUTQ

JAM

ST STQ

MGR281

handbook, halfpage

SUB

TEST

AGND

DIN

DINQ

CCA

JAM

1 2 3 4

TZA3034T

5 6 7 8

MGR282

16 15 14 13 12 11 10

RSET V

ref

CCD

DOUT DOUTQ DGND ST STQ

Fig.2 Pin configuration of TZA3034T.

1999 Nov 03 3

handbook, halfpage

Fig.3 Pin configuration of TZA3034TT.

SUB

TEST

AGND

DIN

DINQ

CCA

JAM

1 2 3 4

TZA3034TT

5 6 7 8

MBK997

16 15 14 13 12 11 10

RSET V

ref

CCD

DOUT DOUTQ DGND ST STQ

Philips Semiconductors Product speciﬁcation

SDH/SONET STM1/OC3 postampliﬁer TZA3034

PINNING

SYMBOL

TZA3034T

TZA3034TT

PAD

TZA3034U

TYPE

(1)

DESCRIPTION

SUB 1 1, 14 S substrate pin; must be at the same potential as pin AGND TEST 2 2, 10, 15,

− for test purpose only; to be left open in the application

21, 26 AGND 3 3, 4, 6, 9 S analog ground; must be at the same potential as pin DGND DIN 4 7 I differential input; complementary to pin DINQ; DC bias level is set

internally at approximately 2.1 V

DINQ 5 8 I differential input; complementary to pin DIN; DC bias level is set

internally at approximately 2.1 V

CCA

6 11, 12 S analog supply voltage; must be at the same potential as pin V

CCD

CF 7 13 A input for connection of capacitor to set time constant of leveldetector

input ﬁlter (optional); the capacitor should be connected between V

and pin CF

CCA

JAM 8 16 I PECL-compatible input; controls the output buffers,

pins DOUTand DOUTQ; when a LOW signal is applied, the output bufferswill follow the input signal; when a HIGH signal is applied, the output buffers will latch into LOW and HIGH states respectively; when not connected, pin JAM is actively pulled LOW

STQ 9 17 O PECL-compatible status output of the input signal level detector;

when the input signal is below the user-programmed threshold level, this output is HIGH; complementary to pin ST

ST 10 18 O PECL-compatible status output of the input signal level detector;

when the input signal is below the user-programmed threshold level, this output is LOW; complementary to pin STQ

DGND 11 19, 20, 22,

S digital ground; must be at the same potential as pin AGND

DOUTQ 12 23 O PECL-compatible differential output; this pin will be forced into a

HIGH condition when pin JAM is HIGH; complementary to pin DOUT

DOUT 13 24 O PECL-compatible differential output; this pin will be forced into a

LOW condition when pin JAM is HIGH; complementary to

pin DOUTQ V V

CCD ref

14 27, 28 S digital supply voltage; must be at the same potential as V

CCA

15 29 O band gap reference voltage; typical value is 1.2 V; internal series

resistor of 1 kΩ RSET 16 30 A input signal level detector threshold setting; nominal DC voltage is

− 1.5 V;threshold level is set by connecting an external resistor

CCA

between V

and pin RSET or by forcing a current into pin RSET;

CCA

default value for this resistor is 180 kΩ which corresponds with

approximately 4 mV (p-p) differential input signal n.c. − 5, 31, 32 − not connected

Note

1. Pin type abbreviations: O = Output, I = Input, S = power Supply and A = Analog function.

1999 Nov 03 4

Philips Semiconductors Product speciﬁcation

SDH/SONET STM1/OC3 postampliﬁer TZA3034

FUNCTIONAL DESCRIPTION

The TZA3034 accepts up to 155 Mbits/s SDH/SONET data streams, with amplitudes from2 mV up to 1.5 V (p-p) single-ended. The input signal will be amplified andlimited to differential PECL output levels (see Fig.1).

The input buffer A1 presents an impedance of approximately 4.5 kΩ to the data stream on the inputs pin DIN and pin DINQ. The input can be used both single-ended and differential, but differential operation is preferred for better performance.

Because of the high gain of the postamplifier, a very small offset voltage would shift the decision level in such a way that the input sensitivity decreases drastically. Therefore a DC offset compensation circuit is implemented in the TZA3034, which keeps the input of buffer A3 at its toggle point in the absence of any input signal.

An input signal level detection is implemented to check if the input signal is above the user-programmed level. The outcome of this test is available at the PECL outputs, pins ST and STQ. This flag can also be used to prevent the PECL outputs pins DOUT and DOUTQ from reacting to noise in the absence of a valid input signal, by connecting pin STQ to pin JAM. This guarantees that data willonly be transmitted when the input signal-to-noise ratio is sufficient for low bit error rate system operation.

PECL logic

The logic level symbol definitions for PECL are shown in Fig.4.

Input biasing

The inputs, pins DIN and DINQ, are DC biased at approximately 2.1 V by an internal reference generator (see Fig.5). The TZA3034 can be DC coupled, but AC coupling is preferred. In case of DC coupling, the driving source must operate within the allowable input signal range (1.3 V to V

). Also a DC offset voltage of

CCA

more than a few millivolts should be avoided, since the internal DC offset compensation circuit has a limited correction range.

If AC coupling is used to remove any DC compatibility requirement, the coupling capacitors must be large enough to pass the lowest input frequency of interest. For example, 1 nF coupling capacitors react with the internal 4.5 kΩ input bias resistors to yield a lower −3dB frequency of 35 kHz. This then sets a limit on the maximum number of consecutive pulses that can be sensed accurately at the system data rate. Capacitor tolerance and resistor variation must be included for an accurate calculation.

DC-offset compensation

A control loop connected between the inputs of buffer A3 andamplifier A1 (see Fig.1) will keep theinputof buffer A3 at its toggle point in the absence of any input signal. Because of the active offset compensation which is integrated in the TZA3034, no external capacitor is required. The loop time constant determines the lower cut-off frequency of the amplifier chain, which is set at approximately 850 Hz.

Input signal level detection

The TZA3034 allows for user-programmable input signal leveldetectionand can automatically disable the switching of the PECL outputs if the input signal is below a set threshold. This prevents the outputs from reacting to noise in the absence of avalid input signal, and insures that data will only be transmitted when the signal-to-noise ratio of the input signal is sufficient for low bit-error-rate system operation.ComplementaryPECLflags(pins ST and STQ) indicate whether the input signal is above or below the programmed threshold level.

The input signal is amplified and rectified before being compared to a programmable threshold reference. A filter isincluded to prevent noise spikes from triggeringthe level detector. This filter has a nominal 1 µs time constant and additional filtering can be achieved by using an external capacitor between V

and pin CF (the internal driving

CCA

impedance nominally is 25 kΩ). The resultant signal is then compared to a threshold current through pin RSET. This current can be set by connecting an external resistor between V

and pin RSET, or by forcing a current into

CCA

pin RSET (see Fig.6).

1999 Nov 03 5

Philips Semiconductors Product speciﬁcation

SDH/SONET STM1/OC3 postampliﬁer TZA3034

The relationship between the threshold current and the detected input voltage is approximately:

RSET

0.0018 V

–()A[]×=

DINVDINQ

(1)

In the formulas (1) and (3), the voltage on pin DIN and pin DINQ is measured as peak-to-peak value.

Since the voltage on pin RSET is held constant at 1.5 V below V

RSET

, the current flowing into this pin will be:

CCA

1.5 A[]=

------------R

ADJ

(2)

Combining these two formulas results in a generalformula to calculate R

ADJ

--------------------------------------- -

for a given input signal level detection:

ADJ

830

–()

DINVDINQ

Ω[]=

(3)

Example: Detection should occur if the differential voltage of the input signals drops below 4 mV (p-p). In this case, a reference current of 0.0018 × 0.004 = 7.2 µA should flow into pin RSET. This can be set using a current source or simply by connecting a resistor of the appropriate value. The resistor must be connected between V

CCA

and

pin RSET. In this example the value would be:

ADJ

830

-------------- -

0.004

207.5 kΩ==

The hysteresis is fixed internally at 3 dB electrical. In the example of above, a differential level below 4 mV (p-p) of the input signal will drive pin ST to LOW, and an input signal level above 5.7 mV (p-p) will drive pin ST to HIGH.

Dissipation

Since the thermal resistance from junction to ambient

of the TSSOP package is higher than the thermal

th(j-a)

resistance of the SO package (see Chapter “Thermal characteristics”), the dissipation should be considered when using the TZA3034TT version.

The formula to calculate the worst case die temperature is:

ambRth j a–()

P×

max

(4)

where

= junction temperature

= ambient temperature

amb

= thermal resistance from junction to ambient

th(j-a)

= maximum power dissipation.

max

For the TZA3034T (SO package), the worst case die temperatureTj=85+115×0.3 = 119.5 °Cwhichis below the maximum operating temperature.

For the TZA3034TT (TSSOP package), the worst casedie temperature Tj=85+150×0.3 = 130 °C which is higher than the maximum operating temperature, and therefore strongly discouraged. It is recommended to lower the thermalresistancefromjunctiontoambient, e.g. by means of a dedicated board layout.

However, if the ambient temperature is limited to 75 °Cor the power supply is limited to 3.3 ±0.3 V, the junction temperature will stay below the maximum value without further precautions.

A function is provided to automatically disable the signal transmission when the chip senses that the input signal is below the programmed threshold level. This function can be put into operation by connecting pin JAM with pin STQ. When the input signal is below the programmed threshold level, the data outputs are then forced to a predetermined state (pin DOUT = LOW and pin DOUTQ = HIGH).

Response time of the input signal level detection circuit is determined by the time constant of the input capacitors, together with the filter time constant (1 µs internal plus the additional capacitor at pin CF). For SDH/SONET applications, couple capacitors of 1.5 nF are recommended, leading to a high-pass frequency of approximately 30 kHz and a maximum assert time of 30 µs.

1999 Nov 03 6

PECL output circuits

The output circuit of ST and STQ is given in Fig.7. The output circuit of DOUT and DOUTQ is given in Fig.8. Some PECL termination schemes are given in Fig.9.

Philips Semiconductors Product speciﬁcation

SDH/SONET STM1/OC3 postampliﬁer TZA3034

handbook, halfpage

(1)

(2)

(1) Output signal on pins DOUT or ST; complementary to output signal (2). (2) Output signal on pins DOUTQ or STQ; complementary to output signal (1)

Fig.4 Logic level symbol definitions for PECL outputs.

V V

MGS812

CC OH(max) OH(min)

OL(max) OL(min)

GND

DIN

4.5 kΩ

2.1 V

handbook, halfpage

Fig.5 Data input circuit DIN and DINQ.

1999 Nov 03 7

DINQ

4.5 kΩ

1 mA

MGR958

Philips Semiconductors Product speciﬁcation

SDH/SONET STM1/OC3 postampliﬁer TZA3034

RSET=VCCA

− 1.5 V.

handbook, halfpage

Fig.6 level detect input circuit RSET.

handbook, halfpage

LOW

RSET

CCA

HIGH

ADJ

RSET

TZA3034

MGS813

10 kΩ

Output STQ is complementary to output ST.

Fig.7 PECL output circuit ST and STQ.

handbook, halfpage

105 Ω 105 Ω

9 mA

Fig.8 PECL output circuit DOUT and DOUTQ.

1999 Nov 03 8

MGS814

DOUT DOUTQ

0.5 mA

MGR247

Philips Semiconductors Product speciﬁcation

SDH/SONET STM1/OC3 postampliﬁer TZA3034

handbook, full pagewidth

VCC − 2 V

R1 = 50 Ω R1 = 50 Ω

Zo = 50 Ω

VCC = 3.3 V

R1 = 127 Ω

Zo = 50 Ω

R2 = 82.5 Ω

GND

MGR248

R1 = 127 Ω

R2 = 82.5 Ω

MGR249

handbook, full pagewidth

Zo = 50 Ω

Fig.9 PECL output termination schemes.

1999 Nov 03 9

VCC = 5.0 V

R1 = 83.3 Ω

R2 = 125 Ω

GND

R1 = 83.3 Ω

R2 = 125 Ω

MGR250

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