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參數(shù)資料
| 型號： | CPC7695BCTR |
| 廠商： | CLARE INC |
| 元件分類： | 通信及網(wǎng)絡(luò) |
| 中文描述： | SPECIALTY TELECOM CIRCUIT, PDSO28 |
| 封裝： | SOIC-28 |
| 文件頁數(shù)： | 11/23頁 |
| 文件大小： | 677K |
| 代理商： | CPC7695BCTR |
CPC7695
R00D
PRELIMINARY
19
As an input, the TSD pin can be utilized to place the
CPC7695 into the “All-Off” state by simply pulling the
input low via an open-collector type buffer. Using a
standard output with an active logic high drive
capability will sink the pull-up current resulting in
unnecessary power consumption.
Use of a standard output buffer with an active high
drive capability will not disable the thermal shutdown
mechanism. The ability to enter thermal shutdown
during a fault condition is independent of the
connection at the TSD input.
The CPC7695’s internal pull up has a nominal value of
16
μA.
2.6 Ringing Switch Zero-Cross Current Turn Off
After the application of a logic input to turn SW4 off,
the ringing switch is designed to delay the change in
state until the next zero-crossing. Once on, the switch
requires a zero-current cross to turn off, and therefore
should not be used to switch a pure DC signal. The
switch will remain in the on state no matter the logic
input until the next zero crossing. These switching
characteristics will reduce and possibly eliminate
overall system impulse noise normally associated with
ringing switches. See Clare application note AN-144,
more information. The attributes of ringing switch SW4
may make it possible to eliminate the need for a
zero-cross switching scheme. A minimum impedance
of 300
Ω in series with the ringing generator is
recommended.
2.7 Power Supplies
Both a +5 V supply and battery voltage are connected
to the CPC7695. Switch state control is powered
exclusively by the +5 V supply. As a result, the
CPC7695 exhibits extremely low power consumption
during active and idle states.
Although battery power is not used for switch control, it
is required to supply trigger current for the integrated
internal protection circuitry SCR during fault
conditions. This integrated SCR is designed to
activate whenever the voltage at TBAT or RBAT drops 2
to 4 V below the applied voltage on the VBAT pin.
Because the battery supply at this pin is required to
source trigger current during negative overvoltage
fault conditions at tip and ring, it is important that the
net supplying this current be a low impedance path for
high speed transients such as lightning. This will
permit trigger currents to flow enabling the SCR to
activate and thereby prevent a fault induced negative
overvoltage event at the TBAT or RBAT nodes.
2.8 Battery Voltage Monitor
The CPC7695 also uses the VBAT pin to monitor
battery voltage. If the system battery voltage is lost,
the CPC7695 immediately enters the all-off state. It
remains in this state until the system battery voltage is
restored. The device also enters the all-off state if the
battery voltage rises more positive than about –10 V
and remains in the all-off state until the battery voltage
drops below –15 V. This battery monitor feature draws
a small current from the battery (less than 1
μA
typical) and will add slightly to the device’s overall
power dissipation.
This monitor function performs properly if the
CPC7695 and SLIC share a common battery supply
origin. Otherwise, if battery is lost to the CPC7695 but
not to the SLIC, the VBAT pin will be internally biased
by the potential applied to the TBAT or RBAT pins via
the internal protection circuitry SCR trigger current
path.
2.9 Protection
2.9.1 Diode Bridge/SCR
The CPC7695 uses a combination of current limited
break switches, a diode bridge/SCR clamping circuit,
and a thermal shutdown mechanism to protect the
SLIC device or other associated circuitry from damage
during line transient events such as lightning. During a
positive transient condition, the fault current is
conducted through the diode bridge to ground via
FGND. Voltage is clamped to a diode drop above
ground. During a negative transient of 2 to 4 V more
negative than the voltage source at VBAT, the SCR
conducts and faults are shunted to FGND via the SCR
or the diode bridge.
In order for the SCR to crowbar or foldback, the SCR’s
on-voltage (see “Protection Circuitry Electrical
Specifications” on page 13) must be less than the
applied voltage at the VBAT pin. If the VBAT voltage is
less negative than the SCR on-voltage, or if the VBAT
supply is unable to source the trigger current, the SCR
will not crowbar.
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| CPC7695ZA | 功能描述:IC LINE CARD ACCESS SW 20-SOIC RoHS:是 類別:集成電路 (IC) >> 接口 - 電信 系列:* 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS 產(chǎn)品變化通告:Product Discontinuation 06/Feb/2012 標準包裝:750 系列:* |
| CPC7695ZATR | 功能描述:IC LINE CARD ACCESS SW 20-SOIC RoHS:是 類別:集成電路 (IC) >> 接口 - 電信 系列:* 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS 產(chǎn)品變化通告:Product Discontinuation 06/Feb/2012 標準包裝:750 系列:* |
| CPC7695ZB | 功能描述:IC LINE CARD ACCESS SW 20-SOIC RoHS:是 類別:集成電路 (IC) >> 接口 - 電信 系列:* 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS 產(chǎn)品變化通告:Product Discontinuation 06/Feb/2012 標準包裝:750 系列:* |
| CPC7695ZBTR | 功能描述:IC LINE CARD ACCESS SW 20-SOIC RoHS:是 類別:集成電路 (IC) >> 接口 - 電信 系列:* 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS 產(chǎn)品變化通告:Product Discontinuation 06/Feb/2012 標準包裝:750 系列:* |
| CPC7695ZC | 功能描述:IC LINE CARD ACCESS SW 20-SOIC RoHS:是 類別:集成電路 (IC) >> 接口 - 電信 系列:* 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS 產(chǎn)品變化通告:Product Discontinuation 06/Feb/2012 標準包裝:750 系列:* |
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