le79231 Zarlink Semiconductor, le79231 Datasheet - Page 15

• Manufacturer Part Number: le79231
• Description: Intelligent Subscriber Line Interface Circuit
• Manufacturer: Zarlink Semiconductor

Current-Limit Behavior
Thermal Shutdown Fault Indications
Note:
1.
2.
3.
4.
5.
6.
OPERATING MODES
The Le79231 ISLIC device receives multiplexed control data on the P1, P2 and P3 pins. The LD pin then controls the loading of
P1, P2, and P3 values into the proper bits in the Le79231 ISLIC device control register. When the LD pin is less than 0.3 V below
V
bits in the Le79231 ISLIC device control register. When the LD pin is more than 0.3 V above V
ISLIC device control data C1, C2, and C3, which are latched into the last three bits of the Le79231 ISLIC device control register.
Connecting the LD pin to VREF locks the contents of the Le79231 ISLIC device control register.
The operating mode of the Le79231 ISLIC device is determined by the C1, C2, and C3 bits in the control register of the Le79231
ISLIC device. Table 1 defines the Le79231 ISLIC device operating modes set by these signals.
Under normal operating conditions, the Le79231 ISLIC device does not have active relays. The Le79231 ISLIC device to VE790
series ISLAC device interface is designed to allow continuous real-time control of the relay drivers to avoid incorrect data loads
to the relay bit latches of the Le79231 ISLIC device.
To perform external ringing, the VE790 series ISLAC device is set to external ringing mode (RMODE = 1), enables the ring relay,
and puts the Le79231 ISLIC device in the Standby mode.
REF
These tests are performed with the following load impedances:
Frequency < 12 kHz – Longitudinal impedance = 500 Ω; metallic impedance = 300 Ω
Frequency > 12 kHz – Longitudinal impedance = 90 Ω; metallic impedance = 135 Ω
Not tested or partially tested in production. This parameter is guaranteed by characterization or correlation to other tests.
This parameter is tested at 1 kHz in production. Performance at other frequencies is guaranteed by characterization.
When the Le79231 ISLIC device and VE790 series ISLAC device are in the anti-sat operating region, this parameter is degraded. The exact
degradation depends on system design.
–55 dBm gain tracking level not tested in production. This parameter is guaranteed by characterization and correlation to other tests.
This spec is valid from 0 V to VBL or –50 V, whichever is lower in magnitude.
(< (V
Table 1. Operating Modes
Disconnect
Tip Open
Standby
No Fault
Thermal Shutdown
REF
C3
0
0
0
0
SLIC Mode
– 0.3 V)), P1–P3 must contain data for relay control bits RD1, RD2 and RD3. These are latched into the first three
C2
0
0
1
1
C1
0
1
0
1
Applied fault between ground and T/R
VBH applied to Tip or Ring
Ring Short to GND
Short Tip-to-VBH
Short Ring-to-GND
Standby (See note 1)
Tip Open (See note 1)
On-Hook Transmission,
Fixed Longitudinal
Voltage
Disconnect
Operating Mode
Fault
Condition
High Battery
(BATH) and BGND
High Battery
(BATH) and BGND
High Battery
(BATH) and BGND
Low Battery
selection at VBL
Zarlink Semiconductor Inc.
Battery Voltage
Selection
15
(High ohmic feed): Loop supervision
active, A and B amplifiers shut down
Tip Open: AD at High-Impedance,
Channel A power amplifier shut down
Fixed longitudinal voltage of –28 V
AD and BD at High-Impedance,
Channel A and B power amplifiers shut
down
IMT operates normally (V
KG, IMT above 2.8 V; ILG operates normally
Min
20
24
26
Operating Mode
VBH/200 kΩ
Typ
35
38
35
1
REF
Indication
, P1–P3 must contain Le79231
REF
±1 V)
Max
100
46
47
44
RMGPi & RMGLi
A and B Amplifier
Connection to
Unit
mA
µA
A
Resistors
Output
Open
Open
Note
6