tza3054a NXP Semiconductors, tza3054a Datasheet - Page 6

• Manufacturer Part Number: tza3054a
• Description: 100 Mbits/s To 3.2 Gbits/s A-rate Tm Limiting Amplifier
• Manufacturer: NXP Semiconductors

Philips Semiconductors
8. Functional description
9397 750 13466
Objective data sheet
8.1 RF input
8.2 Logarithmic level detect
The TZA3054A is a highly sensitive limiting amplifier with an input voltage range from
2.5 mV to 1200 mV (p-p) Single-Ended (SE). It is assumed that the inputs, requiring
AC-coupling, carry a complementary signal with the specified peak-to-peak value (true
differential excitation).
The TZA3054A includes a DC offset cancellation loop with a very low bandwidth of
approximately 1 kHz. The TZA3054A can support transmission standards allowing
extremely long sequences of consecutive identical bits by disabling the DC offset
cancellation, but at the expense of reduced sensitivity. The DC offset cancellation can be
disabled with I
burst mode applications.
As part of the ACE functionality, the TZA3054A has an automatic bandwidth adjustment
loop to achieve optimum performance over temperature at all bit rates. This means that
the input bandwidth is reduced automatically at lower bit rates. Wide band noise of the
optical front-end (photo detector and transimpedance amplifier) is thus reduced for lower
bit rates.
The automatic bandwidth adjustment of the input stage can be overruled by manual
settings via the I
burst-mode signals; see
The signal strength at the input is measured with a Logarithmic Level Detector (LLD) and
presented at pin LLD. The LLD reading has a sensitivity (S
V
retrieved from the I
V
Fig 4. RF input configuration.
i(p-p)(SE)
LLD
=
V
LLD
range of 1 mV to 1200 mV, which is available as a voltage on pin LLD, or can be
=
2
C-bus bit OFFSET in I
V
2
LLD(10 mV)
C-bus. This may be needed in the event of non-randomized or
2
C-bus register 0Ah in binary form.
Rev. 01 — 12 August 2004
Section
+
S
LLD
IN
INQ
8.6.
TZA3054A
20LOG
50
50
100 Mbit/s to 3.2 Gbit/s A-rate
2
C-bus register LIMCNF (12H). This also allows for
V
-----------------------
10 pF
10 mV
IN p
–
1.6 V
p
die pad (21)
1 V
, (expressed in mV).
LLD
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
) of typically 17 mV/dB for a
001aab366
1 V
TZA3054A
limiting amplifier
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