L9214A/G
Low-Cost Ringing SLIC
Preliminary Data Sheet
October 2001
Scan
State Definitions (continued)
■ Except for loop closure, all circuits (including ring trip
and common-mode detector) are powered down.
Reverse Active (Fast Polarity Reversal)
Off-hook
■ On-hook transmission is disabled.
■ Pin PT is positive with respect to PR, and VBAT1 is
applied to tip/ring.
■ Pin PR is positive with respect to PT.
■ VBAT2 is applied to tip/ring drive amplifiers via the soft
battery switch for the majority of loop lengths. This
may also be derived from VBAT1 through a power
control resistor.
■ The tip to ring on-hook differential voltage will be
between –42.5 V and –56.5 V with a –65 V primary
battery.
■ Loop closure and common-mode detect are active.
■ Ring trip detector is turned off to conserve power.
Disconnect
■ Overhead is set to nominal 4.0 V for undistorted
transmission of 0 dBm into 600 Ω and may be
increased automatically for larger signal levels.
■ The tip/ring amplifiers and all supervision are turned
off.
■ The SLIC goes into a high-impedance state.
■ NSTAT is forced high (on-hook).
On-hook
■ Pin PR is positive with respect to PT.
Ring
■ VBAT1 is applied to tip/ring drive amplifiers. The tip to
ring on-hook differential voltage will be between
–42.5 V and –56.5 V with a primary battery of –65 V.
■ Ringing controlled digitally or by a PWM input signal
■ Power ring signal is applied to tip and ring.
■ Software-selectable slew rate, fast or slow.
■ Loop closure and common-mode detect are active.
■ Ring trip detector is turned off to conserve power.
■ On-hook transmission is enabled.
■ Ring trip supervision and common-mode current
supervision are active; loop closure is inactive.
■ Overhead is set to nominal 17.0 V for undistorted
transmission of 0 dBm into 600 Ω.
■ Overhead voltage is reduced to typically 2.5 V and
current limit set at IPROG is disabled.
■ Current is limited by saturation current of the amplifi-
ers themselves, typically 72 mA peak at 125 °C.
Reverse Active (Slow Polarity Reversal)
Off-hook
Thermal Shutdown
■ Same as the reverse active (fast polarity reversal)
state, but with slower polarity reversal.
■ Not controlled via truth table inputs.
■ This mode is caused by excessive heating of the
device, such as may be encountered in an extended
power-cross situation.
On-hook
■ Same as the reverse active (fast polarity reversal)
state, but with slower polarity reversal.
Agere Systems Inc.
13
AGERE [ AGERE SYSTEMS ]
