Philips tza3044 DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

TZA3044; TZA3044B

SDH/SONET STM4/OC12 and

1.25 Gbits/s Gigabit Ethernet
postamplifiers

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

1999 Nov 03

Philips Semiconductors Product specification

SDH/SONET STM4/OC12 and

1.25 Gbits/s Gigabit Ethernet postamplifiers

FEATURES

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

• Wideband operation from 1.0 kHz to 1.25 GHz typical

• Applicable in 622 Mbits/s SDH/SONET receivers and

1.25 Gbits/s Gigabit Ethernet receivers

• Single supply voltage from 3.0 to 5.5 V

• Positive Emitter Coupled Logic (PECL) compatible data

outputs

• Positive Emitter Coupled Logic (PECL) compatible
status outputs (TTL compatible status outputs for the
TZA3044B)

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

• On-chip DC offset compensation without external
capacitor.

APPLICATIONS

• Digital fibre optic receiver for SDH/SONET STM4/OC12
and Gigabit Ethernet applications

• Wideband RF gain block.

GENERAL DESCRIPTION

The TZA3044 is a high gain limiting amplifier that is
designed to process signals from fibre optic preamplifiers
like the TZA3043 and TZA3023. 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 up to 1.25 Gbits/s, the chip has input
signalleveldetectionwithauser-programmablethreshold.
The data and level detection status outputs are differential
outputs for optimum noise margin and ease of use.
The TZA3044B has the same functionality as the
TZA3044, but with TTL compatible status outputs
(pins ST and STQ), and TTL compatible JAM input.

TZA3044; TZA3044B

ORDERING INFORMATION

TYPE

NUMBER

TZA3044T SO16 plastic small outline package; 16 leads; body width 3.9 mm SOT109-1
TZA3044TT TSSOP16 plastic thin shrink small outline package; 16 leads; body width 4.4 mm SOT403-1
TZA3044U − bare die in waffle pack carriers; die dimensions 1.55 × 1.55 mm −
TZA3044BT SO16 plastic small outline package; 16 leads; body width 3.9 mm SOT109-1
TZA3044BTT TSSOP16 plastic thin shrink small outline package; 16 leads; body width 4.4 mm SOT403-1
TZA3044BU − bare die in waffle pack carriers; die dimensions 1.55 × 1.55 mm −

NAME DESCRIPTION VERSION

PACKAGE

1999 Nov 03 2

Philips Semiconductors Product specification

SDH/SONET STM4/OC12 and

1.25 Gbits/s Gigabit Ethernet postamplifiers

BLOCK DIAGRAM

ref

TEST

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

4 (7)
5 (8)

16 (30)

15 (29)

(3, 4, 6, 9)
3

DC-OFFSET

COMPENSATION

A1 A2 A3

25 kΩ

(11, 12)
6

1 kΩ

RECTIFIER

BAND GAP

REFERENCE

(1, 14)
1

handbook, full pagewidth

DIN

DINQ

RSET

V

A4

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

(13)
7

TZA3044; TZA3044B

TZA3044

(24) 13
(23) 12

(16) 8

(18) 10

(17) 9

14

DOUT
DOUTQ

JAM

ST
STQ

AGND V

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

SUB

CCA

Fig.1 Block diagram.

handbook, halfpage

SUB

TEST

AGND

DIN

DINQ

V

CCA

CF

JAM

1
2
3
4

TZA3044T

TZA3044BT

5
6
7
8

MGR241

16
15
14
13
12
11
10

9

RSET
V

ref

V

CCD

DOUT
DOUTQ
DGND
ST
STQ

CF

DGND V

handbook, halfpage

SUB

TEST

AGND

DIN

DINQ

V

CCA

CF

JAM

CCD

1
2
3
4

TZA3044TT

TZA3044BTT

5
6
7
8

MGR240

MBK998

16
15
14
13
12
11
10

9

RSET
V

ref

V

CCD

DOUT
DOUTQ
DGND
ST
STQ

Fig.2 Pin configuration of TZA3044T and

TZA3044BT.

1999 Nov 03 3

Fig.3 Pin configuration of TZA3044TT and

TZA3044BTT.

Philips Semiconductors Product specification

SDH/SONET STM4/OC12 and

TZA3044; TZA3044B

1.25 Gbits/s Gigabit Ethernet postamplifiers

PINNING

PIN

SYMBOL

TZA3044T

TZA3044TT

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

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

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

V

CCA

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

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

JAM 8 16 I PECL-compatible input (TTL compatible for the TZA3044B);

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

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

DGND 11 19, 20, 22,

DOUTQ 12 23 O PECL-compatible differential output; forced into a HIGH condition

DOUT 13 24 O PECL-compatible differential output; forced into a LOW condition

V
V

CCD
ref

14 27, 28 S digital supply voltage; must be at the same potential as V
15 29 O band gap reference voltage; typical value is 1.2 V; internal series

RSET 16 30 A input signal level detector programming; nominal DC voltage is

n.c. − 5, 31, 32 − not connected

PAD

TZA3044U

21, 26

25

(1)

TYPE

DESCRIPTION

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

internally at approximately 2.1 V

internally at approximately 2.1 V

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

and pin CF

CCA

controls the output buffers pins DOUTand DOUTQ; when a LOW
signal is applied, the outputs will 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

(TTL compatible for the TZA3044B); when the input signal is below
the user-programmed threshold level, this output is HIGH;
complementary to pin ST

(TTL compatible for the TZA3044B); when the input signal is below
the user-programmed threshold level, this output is LOW;
complementary to pin STQ

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

when pin JAM is HIGH; complementary to pin DOUT

when pin JAM is HIGH; complementary to pin DOUTQ

resistor of 1 kΩ

V

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

CCA

resistor between V

and pin RSET or by forcing a current into

CCA

pin RSET; default value for this resistor is 180 kΩ which
corresponds with approximately 4 mV (p-p) differential input signal

CCD

CCA

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 STM4/OC12 and

1.25 Gbits/s Gigabit Ethernet postamplifiers

FUNCTIONAL DESCRIPTION

The TZA3044 accepts up to 1.25 Gbits/s data streams,
with amplitudes from 2 mV (p-p) 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 DIN
and 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
TZA3044, 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 ST and STQ (TTL for the TZA3044B). This flag
can also be used to prevent the PECL outputs 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 will only 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.

TZA3044; TZA3044B

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 TZA3044, 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 TZA3044 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. Complementary PECL (TTL forthe TZA3044B)
flags (pins ST and STQ) indicate whether the input signal
is above or below the programmed threshold level.

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 TZA3044 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
than a few millivolts should be avoided, since the internal
DC offset compensation circuit has a limited correction
range.

1999 Nov 03 5

). Also a DC offset voltage of more

CCA

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
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
pin RSET (see Fig.6).

and pin RSET, or by forcing a current into

CCA

and pin CF (the internal driving

CCA

Philips Semiconductors Product specification

SDH/SONET STM4/OC12 and

1.25 Gbits/s Gigabit Ethernet postamplifiers

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

I

RSET

0.0018 V

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

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

I

RSET

, the current flowing into this pin will be:

CCA

1.5
A[]=

------------­R

ADJ

Combining these two formulas results in a generalformula
to calculate R

R

ADJ

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

for a given input signal level detection:

ADJ

830

V

–()

DINVDINQ

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
pin RSET. In this example the value would be:

R

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.

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

–()A[]×=

DINVDINQ

Ω[]=

CCA

(1)

(2)

(3)

and

TZA3044; TZA3044B

approximately 30 kHz and a maximum assert time of
30 µs.

Dissipation

Since the thermal resistance from junction to ambient
R

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 TZA3044TT version.

The formula to calculate the worst case die temperature is:

T

T

j

+=

ambRth j a–()

where

T

= junction temperature

j

T

= ambient temperature

amb

R

= thermal resistance from junction to ambient

th(j-a)

P

= maximum power dissipation.

max

For the TZA3044T (SO package), the worst case die
temperatureTj=85+115×0.3 = 119.5 °Cwhichis below
the maximum operating temperature.

For the TZA3044TT (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.

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.

P×

max

(4)

1999 Nov 03 6

Philips Semiconductors Product specification

SDH/SONET STM4/OC12 and

1.25 Gbits/s Gigabit Ethernet postamplifiers

handbook, halfpage

(1)

(2)

V
V

V
V

MGS812

V

CC
OH(max)
OH(min)

OL(max)
OL(min)

GND

TZA3044; TZA3044B

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

Fig.4 Logic level symbol definitions for PECL.

DIN

V

4.5 kΩ

CC

2.1 V

handbook, halfpage

DINQ

4.5 kΩ

1 mA

MGR958

Fig.5 Data input circuit DIN and DINQ.

1999 Nov 03 7

Philips Semiconductors Product specification

SDH/SONET STM4/OC12 and

1.25 Gbits/s Gigabit Ethernet postamplifiers

V

V

RSET

CC

V

CCA

R

ADJ

RSET

I

RSET

V

RSET=VCCA

handbook, full pagewidth

− 1.5 V

handbook, halfpage

Fig.6 Level detect input circuit RSET.

TZA3044

MGS815

TZA3044; TZA3044B

V

CC

V

LOW

Output STQ is complementary to output ST.

Fig.7 Output circuit ST and STQ for the TZA3044 (left) and TZA3044B (right).

handbook, halfpage

V

V

HIGH

CC

105 Ω 105 Ω

9 mA

10 kΩ

ST

0.5 mA

ST

MGS816

DOUT
DOUTQ

0.5 mA

Fig.8 PECL output circuit DOUT and DOUTQ.

1999 Nov 03 8

MGR247

Philips Semiconductors Product specification

SDH/SONET STM4/OC12 and

1.25 Gbits/s Gigabit Ethernet postamplifiers

handbook, full pagewidth

V

O

Zo = 50 Ω

V

OQ

VCC = 3.3 V

handbook, full pagewidth

V

I

V

IQ

TZA3044; TZA3044B

VCC − 2 V

R1 = 50 Ω R1 = 50 Ω

MGR248

handbook, full pagewidth

R1 = 127 Ω

V

V

I

V

IQ

V

I

V

IQ

O

Zo = 50 Ω

V

OQ

R2 = 82.5 Ω

GND

VCC = 5.0 V

R1 = 83.3 Ω

V

O

Zo = 50 Ω

V

OQ

R2 = 125 Ω

GND

R1 = 127 Ω

R2 = 82.5 Ω

MGR249

R1 = 83.3 Ω

R2 = 125 Ω

MGR250

Fig.9 PECL output termination schemes.

1999 Nov 03 9