le9502 Zarlink Semiconductor, le9502 Datasheet - Page 10

• Manufacturer Part Number: le9502
• Description: Ringing Subscriber Line Interface Circuit
• Manufacturer: Zarlink Semiconductor

Thermal Overload
When the die temperature around the power amplifier of a Le9502 RSLIC device channel reaches approximately 160° C, the F
pins are pulled Low and V
except for the logic interface block. The SLIC channel goes into a state similar to Disconnect, making the line current zero. When
the temperature drops below 145° C, the SLIC channel returns to its previous state. It is important to recognize that even while
a channel experiences thermal overload, the state of the device can be modified.
Reference Current Generator
To set the hook switch threshold for both channels, an external resistor (R
please refer to
Moreover, internally this block generates I
Control Logic
Each channel of the Le9502 RSLIC device has three input pins from a codec device (CHS, C2, and C1). The inputs set the
operational state of each channel. There are five operational SLIC device states (See Table 1): Low Power Standby, Disconnect,
Normal Active, Reverse Polarity, and Ringing
.
Note:
* See CHS Specifications on
** Standby state with switcher turned off.
Table 1. SLIC Device Operating States
Low *
Float
Float
Float
Float
CHS
Pull
Line Card Parts List
C2
0
0
1
1
0
page
REG
C1
0
1
0
1
0
will collapse. At the same time, all the blocks controlling that channel of the device are shut off,
17.
Low Power Standby
Reverse Polarity
Normal Active
Ringing
Disconnect**
Operating State
on page
RAMP
21.
which is used to help set the frequency of operation desired for the switcher.
Zarlink Semiconductor Inc.
Voice Transmission Disabled. Loop current capability is reduced.
Similar to normal active, but DC polarity is reversed so that the Ring lead is
more positive than the Tip. Supports on hook transmission.
SLIC device fully operational. Supports on hook transmission.
Ringing state with V
maintains minimum headroom for the sourcing and sinking amplifiers in order
to maximize power efficiency.
SLIC device is shut down. Mainly used if a line fault is detected or to shut down
a line.
10
SET
AB
) from ISET to AGND pins is used. For R
set to K
R
•(V
Description
RINGP
– V
RINGM
). The switching supply
SET
value,
i