P2781 ETAL, P2781 Datasheet - Page 3

• Manufacturer Part Number: P2781
• Description: Line Matching Transformer
• Manufacturer: ETAL

Specifications of P2781

• Current Rating: 100µA
• Transformer Mounting: PC Board
• Length/height, External: 7mm
• Pitch Spacing: 2.54mm
• External Width: 9mm
• External Depth: 12.7mm
• Transformer Type: Line Matching
• Insertion Loss: 2dB
• Mounting Type: SMD
• Rohs Compliant: Yes
• Primary Impedance: 600ohm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The circuit of Fig. 6 gives good TX and RX
flatness (±0.3dBm 200Hz - 4kHz).
alternative arrangement, using existing PCB
sites, is shown in Fig. 7. Note, however, that TX
flatness will be degraded with the topology.
Frequency response driven by terminal
equipment (voltage scource with 430
resistance) measured across 600
600
±0.2dB 200Hz to 4kHz
ETALDOC 240/9
dB
Frequency Response
Fig 3
Recommended Circuit
Fig 6
PERFORMANCE
-0.4
* If return loss >16dB, 300Hz - 4kHz is acceptable, blocking
-0.1
-0.2
-0.3
Recommended Circuit
Fig 2
capacitor may be relaxed to 4.7 F
100Hz
600
0
LINE
MATCH
200
6.8 F
300
20%
500
+ _
6.8nF
*
5%
Frequency
1kHz
+50%
_
20%
2
6.8nF
+ _
3
5%
4 5
is within
series
+ 2%
430
_
10
An
Page 3 of 5
Note:
To obtain harmonic distortion power in dBm, add
fundamental power in dBm to third harmonic in
dBc e.g. at -10dBm power in line at 450Hz, third
harmonic power is -10 + (-74) = -84dBm typical.
dB
Return Loss
Third Harmonic Distortion vs. Signal Level
Fig 4
Fig 5
Recommended Circuit
Fig 7
-14
-18
-22
-26
-30
-60
-65
-70
-75
-80
100Hz
-15
Fundamental
450Hz
200
300
Fundamental Power (dBm)
500
-10
Frequency
Worst Case
1kHz
Typical
2
-5
P2781
January 2001
3
Typical
4 5
10
0