le9531cmqc Zarlink Semiconductor, le9531cmqc Datasheet - Page 6

• Manufacturer Part Number: le9531cmqc
• Description: Ringing Subscriber Line Interface Circuit
• Manufacturer: Zarlink Semiconductor

Le9531
Data Sheet
In the Ringing state a power ring signal is provided to the tip/ring pair. During the Ringing state, a user-supplied,
low-voltage ring signal is differentially input to the device’s RINGP and RINGN inputs. These signals are amplified
to produce the power ring signal at Tip-Ring. This signal may be a sine wave or filtered square wave to produce a
sine wave or trapezoidal output. A DC offset may also be applied. The Ring Trip detector is active during the
Ringing state.
Both the ring trip and loop closure supervision functions are included. The loop closure has a fixed on-hook to off-
hook threshold in the active and scan
states.
In either case, there is a hysteresis. The ring trip detector requires
only a single-pole filter at the input, minimizing external components. The ring trip threshold at a given battery
voltage is fixed.
In the ground start state, the tip drive amplifier is turned off. The device presents a high impedance (>100 k) to PT
and a current-limited battery (V
) to PR. V
is clamped to less than 56.5 V in this state at PR. The NSTAT loop
BAT
BAT
current detector is used for ring ground detection. In the ground start state, since the loop current is common mode,
the loop closure threshold is reduced in half, thus maintaining loop supervision at specified levels.
Upon reaching the thermal shutdown temperature, the device will enter an all off state. Upon cooling, the device will
re-enter the state it was in prior to thermal shutdown. Hysteresis is built in to prevent oscillation.
SLIC operation state is controlled via a parallel unlatched control scheme.
The Le9531 device uses a voltage feed and current sense architecture; thus, the transmit gain is a trans-
impedance. The trans-impedance is set via a single external resistor, and is designed for optimal performance with
a trans-impedance at 205 V/A. This interface is single-ended. The interface at the receive can be differential, with a
gain of 8.
There is a 1.5-V internal reference voltage. This reference voltage is output at the V
The VITR output is also
REF.
referenced to V
The RCVP/RCVN pins are floating inputs.
REF.
A test load switch and an integrated diode bridge is included to support integrated test algorithms.
The Exposed Pad is to be connected to a ground plane on the printed circuit board for thermal conduction. Also,
with the 48-pin eTQFP package the internal analog grounds and battery grounds are connected to the exposed
pad. The ground plane to which the exposed pad connects has to be good for both analog signal ground and
battery ground.
The package of the device is a small 28-pin QFN (4mm x 5mm). It is also available in 48-pin eTQFP (7mm x 7mm)
with the same pin outs as Le9530 on channel 2.
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Zarlink Semiconductor Inc.