oq2541bhp NXP Semiconductors, oq2541bhp Datasheet - Page 7

• Manufacturer Part Number: oq2541bhp
• Description: Oq2541bhp; Oq2541bu Sdh/sonet Data And Clock Recovery Unit Stm1/4/16 Oc3/12/48 Ge
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Power supply and power control loop
The OQ2541B contains an on-board voltage regulator.
An external power transistor is needed to deliver the
supply to this circuit. The required external circuit is
straightforward, and can be built using a few components.
A suitable circuit with a power supply of 4.5 V is illustrated
in Fig.6. Do not omit the 2
100 nF decoupling capacitor.
A different configuration could be used, as long as the
power supply rejection ratio is greater than 60 dB for all
frequencies. The inductor is an RF choke with an
impedance greater than 50
2 MHz. Any transistor with a
sufficient current sink capability can be used.
The OQ2541B can also be used with a power supply of
power control circuit is to change the emitter resistor R1
(see Table 1).
Table 1 Value of resistor R1
2000 Sep 18
5.0 or 5.2 V. The only adaptation to be made to the
SDH/SONET data and clock recovery unit
STM1/4/16 OC3/12/48 GE
CREF
DIN,
V EE
POWER SUPPLY
Fig.4 RF data and clock input circuit.
4.5 V
5.0 V
5.2 V
50
resistor in series with the
at frequencies higher than
of approximately 100 and
RESISTOR R1
10.0
6.8
8.2
MGL669
50
DINQ,
CREFQ
7
Output amplitude reference
The voltage swing at the CML compatible output stages
(pins DOUT, DOUTQ, COUT, COUTQ, DLOOP,
DLOOPQ, CLOOP and CLOOPQ) can be controlled by
adjusting the voltage on pin AREF (see Fig.7). An internal
voltage divider of 500
ground and V
In most applications, the outputs will be DC coupled to a
50
a 200 mV (p-p) single-ended swing across this load. The
voltage on pin AREF is half the single-ended peak-to-peak
value of the output signal ( 100 mV). No adjustments are
necessary with DC coupling.
If the outputs are AC coupled, the voltage on pin AREF is
half the single-ended peak-to-peak value of the output
signal multiplied by a factor
where R
impedance of the OQ2541B (100 ).
The resulting output amplitude with the same voltage on
pin AREF is thus different for DC and AC coupled loads.
handbook, halfpage
load. The output level regulation circuit will maintain
L
Fig.5 RF data and clock output circuit.
is the external load and R
EE
100
OQ2541BHP; OQ2541BU
initially fixes this level.
V EE
and 16 k connected between
R
------------------- -
L
R
+
100
V AREF
L
R
o
DOUTQ, COUTQ
o
DOUT, COUT
Product specification
is the output
MGL670