82P2288BB8 IDT, Integrated Device Technology Inc, 82P2288BB8 Datasheet - Page 24

• Manufacturer Part Number: 82P2288BB8
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of 82P2288BB8

• Screening Level: Industrial
• Mounting: Surface Mount
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Lead Free Status / RoHS Status: Not Compliant

3.2
impedance matching circuit or external impedance matching circuit.
circuit is enabled. 100 Ω, 110 Ω, 75 Ω or 120 Ω internal impedance
matching circuit can be selected by the R_TERM[1:0] bits.
3.2.1
Intrusive Monitoring per T1.102 can be performed between two devices.
The monitored link of one device is in normal operation, and the moni-
toring link of the other device taps the monitored one through a high
impedance bridging circuit. Refer to
and
RRINGn of the monitoring link is dramatically attenuated. To compen-
sate this bridge resistive attenuation, Monitor Gain can be used to boost
Table 3: Impedance Matching Value For The Receiver
Functional Description
IDT82P2288
The receiver impedance matching can be realized by using internal
When the R_TERM[2] bit is ‘0’, the internal impedance matching
In both T1/J1 and E1 short haul applications, the Protected Non-
After the high resistance bridging circuit, the signal arriving at RTIPn/
Figure 5&Figure 6
RECEIVER IMPEDANCE MATCHING
LINE MONITOR
Cable Configuration
120 Ω (E1)
100 Ω (T1)
110 Ω (J1)
75 Ω (E1)
(COAX).
R
X
T
Line
X
Line
Note: 1. Common decoupling capacitor
A
B
2. Cp 0-560 (pF)
3. D1 - D8, Motorola - MBR0540T1;
•
•
2:1
1:1
Figure 3&Figure 4
•
•
Cp
R_TERM[2:0]
R
Figure 2. Receive / Transmit Line Circuit
R
0 0 0
0 0 1
0 1 0
0 1 1
•
•
R
R
T
T
D6
D5
VDDAR
Internal Termination
(Twisted Pair)
·
VDDAX
VDDAR
VDDAX
D2
D1
D8
D7
D4
D3
·
·
·
International Rectifier - 11DQ04 or 10BQ060
RTIP
RRING
TTIP
TRING
24
OCTAL T1/E1/J1 LONG HAUL / SHORT HAUL TRANSCEIVER
circuit is disabled, and different external resistors should be used to
realize different impedance matching.
cable for one link. Table 3 lists the recommended matching resistor
values for the receiver.
the signal by 22 dB, as selected by the MG[1:0] bits (b1~0, T1/J1-
02AH,...). For normal operation, the Monitor Gain should be set to 0 dB,
i.e., the Monitor Gain of the monitored link should be 0 dB.
Partially Internal Impedance Matching mode. Here the external r or
internal IM is used for voltage division, not for impedance matching. That
is, the r (IM) and the R make up of a resistance bridge. The resistive
attenuation of this bridge is 20lg(r/(2R+r)) dB for Twisted Pair or 20lg(r/
(R+r)) dB for COAX. The value of resistive attenuation should be consis-
tent with the setting of Monitor Gain (22 dB).
120 Ω
R
When the R_TERM[2] bit is ‘1’, the internal impedance matching
Figure 2 shows the appropriate components to connect with the
The monitoring link can be configured to any of the External or
R
VDDAR
VDDAX
GNDA
GNDA
0.1µF
0.1µF
R_TERM[2:0]
•
•
1 X X
External Termination
68µF
68µF
3.3 V
1
3.3 V
1
March 04, 2009
120 Ω
100 Ω
110 Ω
75 Ω
R
R