General description

The TZA3026 is a transimpedance amplifier with Automatic Gain Control (AGC), designed
to be used in STM4/OC12 fiber optic links. It amplifies the current generated by a photo
detector (PIN diode or avalanche photodiode) and converts it to a differential output
voltage. It offers a current mirror of average photo current for RSSI monitoring to be used
in SFF8472 compliant modules.

The low noise characteristics makes it suitable for STM4/OC12 applications, but also for
FTTx applications.

Features

Low equivalent input noise current, typically 67 nA (RMS)

Wide dynamic range, typically 0.85

A to 1.5 mA (p-p)

Differential transimpedance of 14 k

(typical)

Bandwidth from DC to 650 MHz (typical)

Differential outputs

On-chip AGC with possibility of external control

Single supply voltage 3.3 V, range 2.9 V to 3.6 V

Bias voltage for PIN diode

Current output of average photo current for RSSI monitoring

Identical ports available on both sides of die for easy bond layout and RF polarity
selection

Applications

Digital fiber optic receiver modules in telecommunications transmission systems, in
high speed data networks or in FTTx systems

Ordering information

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

Rev. 01 -- 2 May 2005

Product data sheet

Table 1:

Ordering information

Type number

Package

Name

Description

Version

TZA3026U

bare die, dimensions approximately
0.82 mm

1.3 mm

9397 750 14763

Product data sheet

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Philips Semiconductors

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

Pinning information

6.1 Pinning

6.2 Pin description

Fig 2.

Pad configuration

001aac618

IDREF_MON

AGC

OUTQ

OUT

GND

IDREF_MON

AGC

DREF

IPHOTO

DREF

OUT

OUTQ

GND

TZA3026

Table 2:

Bonding pad description

Bonding pad locations with respect to the center of the die (see

Figure 10

), X and Y are in

Symbol

Pad X

Type

Description

DREF

493.6

140

output

bias voltage output for PIN diode; connect cathode of PIN diode to
pad 1 or pad 3

IPHOTO

493.6

input

current input; anode of PIN diode should be connected to this pad

DREF

493.6

140

output

bias voltage output for PIN diode; connect cathode of PIN diode to
pad 1 or pad 3

353.6

278.6

supply

supply voltage; connect supply voltage to pad 4 or pad 17

IDREF_MON

213.6

278.6

output

current output for RSSI measurements; connect a resistor to pad 5
or pad 16 and ground

AGC

73.6

278.6

input

AGC voltage; use pad 6 or pad 15

OUTQ

66.4

278.6

output

data output; complement of pad OUT; use pad 7 or pad 13

OUT

206.4

278.6

output

data output; use pad 8 or pad 14

[1]

GND

346.4

278.6

ground

ground; connect together pads 9, 10, 11 and pad 12 as many as
possible

GND

486.4

278.6

ground

ground; connect together pads 9, 10, 11 and pad 12 as many as
possible

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Philips Semiconductors

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

[1]

These pads go HIGH when current flows into pad IPHOTO.

Functional description

The TZA3026 is a TransImpedance Amplifier (TIA) intended for use in fiber optic receivers
for signal recovery in STM4/OC12 or FTTx applications. It amplifies the current generated
by a photo detector (PIN diode or avalanche photodiode) and converts it to a differential
output voltage.

The most important characteristics of the TZA3026 are high receiver sensitivity, wide
dynamic range and large bandwidth. Excellent receiver sensitivity is achieved by
minimizing transimpedance amplifier noise.

The TZA3026 has a wide dynamic range to handle the signal current generated by the
PIN diode which can vary from 0.85

A to 1.5 mA (p-p). This is implemented by an AGC

loop which reduces the preamplifier feedback resistance so that the amplifier remains
linear over the whole input range. The AGC loop hold capacitor is integrated on-chip, so
an external capacitor is not required.

The bandwidth of TZA3026 is optimized for STM4/OC12 application. It works from DC
onward due to the absence of offset control loops. Therefore the amount of Consecutive
Identical Digits (CID) will not effect the output waveform. A differential amplifier converts
the output of the preamplifier to a differential voltage.

7.1 PIN diode connections

The performance of an optical receiver is largely determined by the combined effect of the
transimpedance amplifier and the PIN diode. In particular, the method used to connect the
PIN diode to the input (pad IPHOTO) and the layout around the input pad strongly
influences the main parameters of a transimpedance amplifier, such as sensitivity,
bandwidth, and PSRR.

Sensitivity is most affected by the value of the total capacitance at the input pad.
Therefore, to obtain the highest possible sensitivity the total capacitance should be as low
as possible.

GND

486.4

278.6

ground

ground; connect together pads 9, 10, 11 and pad 12 as many as
possible

GND

346.4

278.6

ground

ground; connect together pads 9, 10, 11 and pad 12 as many as
possible

OUTQ

206.4

278.6

output

data output; complement of pad OUT; use pad 7 or pad 13

OUT

66.4

278.6

output

data output; use pad 8 or pad 14

[1]

AGC

73.6

278.6

input

AGC voltage; use pad 6 or pad 15

IDREF_MON

213.6

278.6

output

current output for RSSI measurements; connect a resistor to pad 5
or pad 16 and ground

353.6

278.6

supply

supply voltage; connect supply voltage to pad 4 or pad 17

Table 2:

Bonding pad description

...continued

Bonding pad locations with respect to the center of the die (see

Figure 10

), X and Y are in

Symbol

Pad X

Type

Description

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Philips Semiconductors

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

The parasitic capacitance can be minimized through:

1. Reducing the capacitance of the PIN diode. This is achieved by proper choice of PIN

diode and typically a high reverse voltage.

2. Reducing the parasitics around the input pad. This is achieved by placing the PIN

diode as close as possible to the TIA.

The PIN diode can be biased with a positive or a negative voltage.

Figure 3

shows the PIN

diode biased positively, using the on-chip bias pad DREF. The voltage at DREF is derived
from V

by a low-pass filter comprising internal resistor R

DREF

and external capacitor C2

which decouples any supply voltage noise. The value of external capacitor C2 affects the
value of PSRR and should have a minimum value of 470 pF. Increasing this value
improves the value of PSRR. The current through R

DREF

is measured and sourced at pad

IDREF_MON, see

Section 7.3

If the biasing for the PIN diode is done external to the IC, pad DREF can be left
unconnected. If a negative bias voltage is used, the configuration shown in

Figure 4

can

be used. In this configuration, the direction of the signal current is reversed to that shown
in

Figure 3

. It is essential that in these applications, the PIN diode bias voltage is filtered to

achieve the best sensitivity.

For maximum freedom on bonding location, 2 outputs are available for DREF (pads 1
and 3). These are internally connected. Both outputs can be used if necessary. If only one
is used, the other can be left open.

Fig 3.

The PIN diode connected between
the input and pad DREF

Fig 4.

The PIN diode connected between
the input and a negative supply
voltage

001aac619

RDREF

300

C2
470 pF

DREF

IPHOTO

4 or 17

1 or 3

TZA3026

001aac620

RDREF

300

DREF

negative

bias voltage

IPHOTO

4 or 17

1 or 3

TZA3026

9397 750 14763

Product data sheet

Rev. 01 -- 2 May 2005

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Philips Semiconductors

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

7.2 Automatic gain control

The TZA3026 transimpedance amplifier can handle input currents from 0.85

A to 1.5 mA

which is equivalent to a dynamic range of 65 dB (electrical equivalent with 32.5 dB
optical). At low input currents, the transimpedance must be high to obtain enough output
voltage, and the noise should be low enough to guarantee a minimum bit error rate. At
high input currents however, the transimpedance should be low to prevent excessive
distortion at the output stage. To achieve the dynamic range, the gain of the amplifier
depends on the level of the input signal. This is achieved in the TZA3026 by an AGC loop.

The AGC loop comprises a peak detector and a gain control circuit. The peak detector
detects the amplitude of the signal and stores it on a hold capacitor. The hold capacitor
voltage is compared to a threshold voltage. The AGC is only active when the input signal
level is larger than the threshold level and is inactive when the input signal is smaller than
the threshold level.

When the AGC is inactive, the transimpedance is at its maximum. When the AGC is
active, the feedback resistor value of the transimpedance amplifier is reduced, reducing its
transimpedance, to keep the output voltage constant.

Figure 5

shows the transimpedance

as function of the input current.

To reduce sensitivity to offsets and output loads, the AGC detector senses the output just
before the output buffer.

Figure 6

shows the AGC voltage as function of the input current.

Fig 5.

Transimpedance as function of the input
current

Fig 6.

AGC voltage as function of the input current

001aac621

(

transimpedance

)

001aac622

AGC

(V)

(

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Product data sheet

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Philips Semiconductors

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

For applications where the transimpedance is controlled by the TIA it is advised to leave
the AGC pads unconnected to achieve fast attack and decay times.

The AGC function can be overruled by applying a voltage to pad AGC. In this
configuration, connecting pad AGC to ground gives maximum transimpedance and
connecting it to V

gives minimum transimpedance. This is depicted in

Figure 7

. The

AGC voltage should be derived from the V

for proper functioning.

For maximum freedom on bonding location, 2 pads are available for AGC (pads 6 and 15).
These pads are internally connected. Both pads can be used if necessary.

7.3 Monitoring RSSI via IDREF_MON

To facilitate RSSI monitoring in modules (e.g. SFF8472 compliant SFP modules), a
current output is provided. This output gives a current which is 20 % of the average DREF
current through the 300

bias resistor. By connecting a resistor to the IDREF_MON

output, a voltage proportional with the average input power can be obtained.

The RSSI monitoring is implemented by measuring the voltage over the 300

bias

resistor. This method is preferred over simple current mirror because at small photo
currents the voltage drop over the resistor is very small. This gives a higher bias voltage
yielding better performance of the photodiode.

For maximum freedom on bonding location, 2 pads are available for IDREF_MON (pads 5
and 16). These pads are internally connected. Both pads can be used if necessary. If only
one is used, the other can be left open.

Fig 7.

Transimpedance as function of the AGC voltage

001aac623

AGC

(V)

0.3V

0.9V

0.7V

0.5V

transimpedance

)

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Product data sheet

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Philips Semiconductors

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

Limiting values

Characteristics

Table 3:

Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134).

Symbol Parameter

Conditions

Min

Max

Unit

supply voltage

0.5

+3.8

pad DC voltage

pad

IPHOTO

0.5

+2.0

OUT, OUTQ

0.5

+ 0.5

AGC, IDREF_MON

0.5

+ 0.5

DREF

0.5

+ 0.5

pad DC current

pad

IPHOTO

4.0

+4.0

OUT, OUTQ

+10

AGC, IDREF_MON

0.2

+0.2

DREF

4.0

+4.0

tot

total power dissipation

300

amb

ambient temperature

+85

junction temperature

150

stg

storage temperature

+150

Table 4:

Characteristics

Typical values at T

= 25

C and V

= 3.3 V; minimum and maximum values are valid over the entire ambient temperature

range and supply voltage range; all voltages are measured with respect to ground; unless otherwise specified.

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

supply voltage

2.9

3.3

3.6

supply current

AC-coupled; R

L(dif)

= 100

;

excluding I

DREF

and I

IDREF_MON

tot

total power dissipation

junction temperature

+125

amb

ambient temperature

+25

+85

small-signal
transresistance of the
receiver

measured differentially;
AC-coupled, R

L(dif)

= 100

9.5

-3dB(h)

high frequency

3 dB point C

= 0.7 pF; V

= 3.3 V

440

650

MHz

n(tot)(rms)

total integrated RMS noise
current over bandwidth

referenced to input;
C

= 0.7 pF;

= 450 MHz

third-order Bessel filter

[1]

Automatic gain control loop: pad AGC

att

attack time

AGC pad unconnected

decay

decay time

AGC pad unconnected

O(data)(p-p)

data output voltage
(peak-to-peak value)

referenced to output;
measured differentially

125

9397 750 14763

Product data sheet

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Philips Semiconductors

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

[1]

Guaranteed by design.

[2]

The input current range is determined by the allowed Pulse Width Distortion (PWD), which is <5 % over the whole input current range.

The PWD is defined as:

, where T is the clock period.

Bias voltage: pad DREF

DREF

resistance between pad
DREF and pad V

tested at DC level;
T

amb

= 25

250

300

350

RDREF

temperature coefficient
R

DREF

0.33

Input: pad IPHOTO

PD(p-p)

input current (peak-to-peak
value)

[2]

1500 -

+1500

bias

input bias voltage

700

850

1000

Monitor: pad IDREF_MON

MON

monitor voltage

[1]

0.4 V

MON

monitor current ratio

ratio I

DREF_MON

/ I

DREF

19.5

20.5

MON(offset)

monitor offset current

amb

= 25

MON(offset)

temperature coefficient
monitor offset current

nA/

Data outputs: pads OUT and OUTQ

o(cm)

common mode output
voltage

AC-coupled; R

L(dif)

= 100

1.2 -

o(dif)(p-p)

differential load output
voltage (peak-to-peak
value)

AC-coupled; R

L(dif)

= 100

= 0.84

A (p-p)

= 100

A (p-p)

125

= 1500

A (p-p)

250

500

O(dif)

differential output
resistance

tested at DC level

100

rise time

20 % to 80 %;
I

= 100

A(p-p)

300

fall time

80 % to 20 %;
I

= 100

A (p-p)

300

Table 4:

Characteristics

...continued

Typical values at T

= 25

C and V

= 3.3 V; minimum and maximum values are valid over the entire ambient temperature

range and supply voltage range; all voltages are measured with respect to ground; unless otherwise specified.

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

PWD

pulse width

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

0.5

(

)

100

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9397 750 14763

oninklijk

e Philips Electronics N.V

. 2005. All r

ights reser

ed.

Pr
oduct data sheet

Re
v

.
01 -- 2 Ma

y 2005

11 of 15

Philips Semiconductor

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

11.

est inf

ormation

Total impedance of the test circuit (Z

) is calculated by the equation Z

= s

(R + Z

)

2, where s

is the insertion loss of ports 1 and 2.

Typical values: R = 330

, Z

= 75

Fig 9.

Test circuit

001aac626

330

8.2

PORT2

= 50

PORT1

DC-IN

DATA

CLOCK

GND

OUT

OUTQ

IPHOTO

NETWORK ANALYZER

TZA3026

PATTERN

GENERATOR

S-PARAMETER TEST SET

22 nF

9, 10, 11, 12

4 or 17

8 or 14

7 or 13

TRIGGER

INPUT

SAMPLING OSCILLOSCOPE

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SDH/SONET STM4/OC12 transimpedance amplifier

12. Bare die information

13. Package outline

Not applicable.

Origin is center of die.

Fig 10. Bonding pad locations

Table 5:

Physical characteristics of the bare die

Parameter

Value

Glass passivation

0.3

m PSG (PhosphoSilicate Glass) on top of 0.8

m silicon nitride

Bonding pad
dimension

minimum dimension of exposed metallization is 90

(pad size = 100

100

m) except pads 2 and 3 which have exposed

metallization of 80

m (pad size = 90

Metallization

2.8

m AlCu

Thickness

380

m nominal

Die dimension

820

1300

m (

)

Backing

silicon; electrically connected to GND potential through substrate contacts

Attach temperature

<440

C; recommended die attach is glue

Attach time

<15 s

(0,0)

001aac627

Philips Semiconductors

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

9397 750 14763

Product data sheet

Rev. 01 -- 2 May 2005

14 of 15

16. Data sheet status

[1]

Please consult the most recently issued data sheet before initiating or completing a design.

[2]

The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at
URL http://www.semiconductors.philips.com.

[3]

For data sheets describing multiple type numbers, the highest-level product status determines the data sheet status.

17. Definitions

Short-form specification -- The data in a short-form specification is
extracted from a full data sheet with the same type number and title. For
detailed information see the relevant data sheet or data handbook.

Limiting values definition -- Limiting values given are in accordance with
the Absolute Maximum Rating System (IEC 60134). Stress above one or
more of the limiting values may cause permanent damage to the device.
These are stress ratings only and operation of the device at these or at any
other conditions above those given in the Characteristics sections of the
specification is not implied. Exposure to limiting values for extended periods
may affect device reliability.

Application information -- Applications that are described herein for any
of these products are for illustrative purposes only. Philips Semiconductors
make no representation or warranty that such applications will be suitable for
the specified use without further testing or modification.

18. Disclaimers

Life support -- These products are not designed for use in life support
appliances, devices, or systems where malfunction of these products can
reasonably be expected to result in personal injury. Philips Semiconductors
customers using or selling these products for use in such applications do so
at their own risk and agree to fully indemnify Philips Semiconductors for any
damages resulting from such application.

Right to make changes -- Philips Semiconductors reserves the right to
make changes in the products - including circuits, standard cells, and/or
software - described or contained herein in order to improve design and/or
performance. When the product is in full production (status `Production'),
relevant changes will be communicated via a Customer Product/Process
Change Notification (CPCN). Philips Semiconductors assumes no
responsibility or liability for the use of any of these products, conveys no
license or title under any patent, copyright, or mask work right to these
products, and makes no representations or warranties that these products are
free from patent, copyright, or mask work right infringement, unless otherwise
specified.

Bare die -- All die are tested and are guaranteed to comply with all data
sheet limits up to the point of wafer sawing for a period of ninety (90) days
from the date of Philips' delivery. If there are data sheet limits not guaranteed,
these will be separately indicated in the data sheet. There are no post
packing tests performed on individual die or wafer. Philips Semiconductors
has no control of third party procedures in the sawing, handling, packing or
assembly of the die. Accordingly, Philips Semiconductors assumes no liability
for device functionality or performance of the die or systems after third party
sawing, handling, packing or assembly of the die. It is the responsibility of the
customer to test and qualify their application in which the die is used.

19. Trademarks

Notice -- All referenced brands, product names, service names and
trademarks are the property of their respective owners.

20. Contact information

For additional information, please visit: http://www.semiconductors.philips.com

For sales office addresses, send an email to: sales.addresses@www.semiconductors.philips.com

Level

Data sheet status

[1]

Product status

[2] [3]

Definition

Objective data

Development

This data sheet contains data from the objective specification for product development. Philips
Semiconductors reserves the right to change the specification in any manner without notice.

Preliminary data

Qualification

This data sheet contains data from the preliminary specification. Supplementary data will be published
at a later date. Philips Semiconductors reserves the right to change the specification without notice, in
order to improve the design and supply the best possible product.

III

Product data

Production

This data sheet contains data from the product specification. Philips Semiconductors reserves the
right to make changes at any time in order to improve the design, manufacturing and supply. Relevant
changes will be communicated via a Customer Product/Process Change Notification (CPCN).

All rights are reserved. Reproduction in whole or in part is prohibited without the prior
written consent of the copyright owner. The information presented in this document does
not form part of any quotation or contract, is believed to be accurate and reliable and may
be changed without notice. No liability will be accepted by the publisher for any
consequence of its use. Publication thereof does not convey nor imply any license under
patent- or other industrial or intellectual property rights.

Date of release: 2 May 2005

Document number: 9397 750 14763

Published in The Netherlands

Philips Semiconductors

TZA3026

SDH/SONET STM4/OC12 transimpedance amplifier

21. Contents

General description . . . . . . . . . . . . . . . . . . . . . . 1

Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Ordering information . . . . . . . . . . . . . . . . . . . . . 1

Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Pinning information . . . . . . . . . . . . . . . . . . . . . . 3

6.1

Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

6.2

Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 3

Functional description . . . . . . . . . . . . . . . . . . . 4

7.1

PIN diode connections . . . . . . . . . . . . . . . . . . . 4

7.2

Automatic gain control . . . . . . . . . . . . . . . . . . . 6

7.3

Monitoring RSSI via IDREF_MON . . . . . . . . . . 7

Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . . 8

Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Application information. . . . . . . . . . . . . . . . . . 10

Test information . . . . . . . . . . . . . . . . . . . . . . . . 11

Bare die information . . . . . . . . . . . . . . . . . . . . 12

Package outline . . . . . . . . . . . . . . . . . . . . . . . . 12

Handling information. . . . . . . . . . . . . . . . . . . . 13

14.1

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

14.2

Additional information . . . . . . . . . . . . . . . . . . . 13

Revision history . . . . . . . . . . . . . . . . . . . . . . . . 13

Data sheet status . . . . . . . . . . . . . . . . . . . . . . . 14

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Contact information . . . . . . . . . . . . . . . . . . . . 14

Document Outline

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: TZA3026U/F/Q/N1

Document Outline

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: TZA3026U/F/Q/N1