LE79R241DJC Zarlink, LE79R241DJC Datasheet - Page 4

• Manufacturer Part Number: LE79R241DJC
• Description: SLIC 1-CH 63dB 70mA 5V 32-Pin PLCC Tube
• Manufacturer: Zarlink

Specifications of LE79R241DJC

• Package: 32PLCC
• Number Of Channels Per Chip: 1
• Polarity Reversal: Yes
• Longitudinal Balanced: 63 dB
• Loop Current: 70(Min) mA
• Minimum Operating Supply Voltage: 4.75 V
• Typical Operating Supply Voltage: 5 V
• Typical Supply Current: 7.5 mA

The VE790 series ISLAC devices perform the codec and filter functions associated with the four-wire section of the subscriber
line circuitry in a digital switch. These functions involve converting an analog voice signal into digital PCM samples and converting
digital PCM samples back into an analog signal. During conversion, digital filters are used to band-limit the voice signals.
The user-programmable filters set the receive and transmit gain, perform the transhybrid balancing function, permit adjustment
of the two-wire termination impedance and provide frequency attenuation adjustment (equalization) of the receive and transmit
paths. Adaptive transhybrid balancing is also included. All programmable digital filter coefficients can be calculated using
WinSLAC software. The PCM codes can be either 16-bit linear two’s-complement or 8-bit companded A-law or µ-law.
Besides the codec functions, the 790 series voice chip set provides all the sensing, feedback, and clocking necessary to
completely control Le79R241 ISLIC device functions with programmable parameters. System-level parameters under
programmable control include active loop current limits, feed resistance, and feed mode voltages.
The VE790 series ISLAC devices supply complete mode control to the Le79R241 ISLIC device using the control bus (P1-P3)
and tri-level load signal (LD
The 790 series voice chip set provides extensive loop supervision capability including off-hook, ring-trip and ground-key
detection. Detection thresholds for these functions are programmable. A programmable debounce timer is available that
eliminates false detection due to contact bounce.
For subscriber line diagnostics, AC and DC line conditions can be monitored using built-in test tools. Measured parameters can
be compared to programmed threshold levels to set a pass/fail bit. The user can choose to send the actual measurement data
directly to a higher level processor by way of the PCM voice channel. Both longitudinal and metallic resistance and capacitance
can be measured, which allows leakage resistance, line capacitance, and telephones to be identified.
*Note:
i = channel number
•
•
–
–
–
A low-level voltage proportional to the voice signal (VOUT
A voltage that controls longitudinal offset for test purposes (VLB
TMN
TMP
TMS
HPA
HPB
VBH
RYE
VBL
AD
BD
SA
SB
R2
R3
R1
DC loop current
Internal ringing signal
12 or 16 kHz metering signal
i
).
Management
Thermal
Control
Driver 1
Drivers
Relay
Relay
Two-Wire
Interface
Control
Relay
Switch Driver
Figure 1. Block Diagram
Zarlink Semiconductor Inc.
Input Decoder and
Control Registers
Meas.
Fault
4
Longitudinal
Control
Transmission
Conditioning
Gain/Level
Attenuator
i
)
Signal
Signal
Shift
i
)
RSN
VTX
VLB
VSAB
VREF
IMT
ILG
CREF
P1
P2
P3
LD