PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 251

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

Note 72: The three 22 nF capacitors can be replaced by one 33 nF capacitor in the
To improve transmission performance the following recommendations should be
considered in circuit design:
• All capacitors of the hybrid should be MKT. Ceramic capacitors are not recommended
• Do not cross hybrid or XTAL with clock lines
• Analog lines between transformer and chip should be symmetric and close together
• Hybrid layout should be symmetric
• If possible there should be a ground plane underneath the IEC-Q
• Blocking of VDD according to recommendation and as close as possible to device
• Tolerances
Semiconductor Group
so that noise is inducted symmetrically
(see also "Power Supply Blocking Recommendation", page 249).
Resistors: 1%
6.8 nF:
22 nF:
middle. However, the solution with the three capacitors can absorb
longitudinal disturbances in a better way.
5%
5%
251
Application Hints
Data Sheet 01.99
PEB 2091
PEF 2091