PEF2256EV22NP Lantiq, PEF2256EV22NP Datasheet - Page 386

• Manufacturer Part Number: PEF2256EV22NP
• Manufacturer: Lantiq

Specifications of PEF2256EV22NP

• Number Of Transceivers: 1
• Screening Level: Industrial
• Mounting: Surface Mount
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Lead Free Status / RoHS Status: Supplier Unconfirmed

Transmit Pulse-Mask Registers (Read/Write)
Value after reset: 7B
XPM0
XPM1
XPM2
The transmit pulse shape which is defined in ANSI T1.102 is output on pins XL1 and XL2.
The level of the pulse shape can be programmed by registers XPM(2:0) to create a
custom waveform. In order to get an optimized pulse shape for the external transformers
each pulse shape is internally divided into four sub pulse shapes. In each sub pulse
shape a programmed 5 bit value defines the level of the analog voltage on pins XL1/2.
Together four 5 bit values have to be programmed to form one complete transmit pulse
shape.The four 5 bit values are sent in the following sequence:
Changing the LSB of each subpulse in registers XPM(2:0) changes the amplitude of the
differential voltage on XL1/2 by approximately 90 mV.
The XPM values in the following table are based on simulations. They are valid for the
following external circuitry: transformer ratio 1:2.4, cable PULB 22AWG (100 ), serial
resistors 2 . Adjustment of these coefficients can be necessary for other external
conditions.
Table 70
Range in
m
0 to 40
40 to 81
81 to 122
122 to 162 399 to 533 FC
162 to 200 533 to 655 3F
1)
Data Sheet
Register values of V1.2 may also be used. For optimum results V2.1 values must be applied.
XP12
XP30
7
0
Range in
ft.
0 to 133
133 to 266 B6
266 to 399 D9
Pulse Shaper Programming (T1/J1)
XP04 to 00:
XP14 to 10:
XP24 to 20:
XP34 to 30:
XP11
XP24
XLT
H
, 03
XPM0
95
H
, 40
DAXLT
XP10
XP23
H
hexadecimal
First pulse shape level
Second pulse shape level
Third pulse shape level
Fourth pulse shape level
XPM1
16
9E
26
36
CB
XP04
XP22
386
XPM2
01
01
01
01
01
XP03
XP21
XP34
1)
XP04-
XP00
21
22
25
28
31
XP02
XP20
XP33
XP14-
XP10
20
21
22
23
28
XP01
XP14
XP32
decimal
Rev. 1.1, 2005-06-13
T1/J1 Registers
PEF 2256 H/E
XP24-
XP20
5
7
9
13
18
XP00
XP13
XP31
0
FALC
XP34-
XP30
2
3
2
2
3
(26)
(27)
(28)
®
56