Freescale Semiconductor, Inc.
MC145423
Errata
Universal Digital Loop Transceiver (UDLT-3)
Pin Selectable Master/Slave
Limited Distance Modem
This errata applies only to the following:
• Preproduction silicon marked “XCSAMPLE”.
• When setup to operate in UDLT1 mode triangle wave output.
Do to differences in device geometries and process, the LO1 and LO2 output impedance of the MC145423 is
higher during non-burst time than the MC145422 and MC145426 devices it replaces. To compensate for this
difference, the line interface requires a slight modification to optimize transmission performance.
The following partial schematic highlights these differences by placing the modifications inside dashed boxes.
These changes are:
• R19 changes from 110
Ω
to 75
Ω.
• R21 changes from 110
Ω
to 75
Ω.
• R23 is an added component with a value of 1400
Ω.
For all other device configurations, the original interface as found in the datasheet (page 25,
BASIC DIGITAL
TELSET)
can be used.
Freescale Semiconductor, Inc...
VDD
75
Ω
LO1
R19
D2
1400
Ω
R23
VDD
110
Ω
R22
1
µF
VDD
LI
VDD
VREF
NOTE: Battery feed limiting resistors;
value up to user discretion.
See Note
See Note
To
Battery
To
Twisted
Pair
D1
75
Ω
LO2
R21
D3
D4
For More Information On This Product,
Go to: www.freescale.com
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
