PSF21150 INFINEON [Infineon Technologies AG], PSF21150 Datasheet - Page 62

• Manufacturer Part Number: PSF21150
• Description: IPAC-X ISDN PC ADAPTER CIRCUIT
• Manufacturer: INFINEON [Infineon Technologies AG]

PSB 21150
PSF 21150
Description of Functional Blocks
3.3.6
Receiver Characteristics
The receiver consists of a differential input stage, a peak detector and a set of
comparators. Additional noise immunity is achieved by digital oversampling after the
comparators. A simplified equivalent circuit of the receiver is shown in
Figure
30.
100 kOhm
Figure 30
Equivalent Internal Circuit of the Receiver Stage
The input stage works together with external 10 k
resistors to match the input voltage
to the internal thresholds. The data detection threshold Vref is continiously adapted
between a maximal (Vrefmax) and a minimal (Vrefmin) reference level related to the line
level. The peak detector requires maximum 2 s to reach the peak value while storing
the peak level for at least 250 s (RC > 1 ms).
The additional level detector for power up/down control works with a fixed thresholds
VrefLD. The level detector monitors the line input signals to detect whether an INFO is
present. When closing an analog loop it is therefore possible to indicate an incoming
signal during activated loop.
Data Sheet
62
2000-07-21