- 您现在的位置：买卖IC网 > PDF目录180046 > LUCL9219GAR-DT Low-Cost Line Interface with Reverse Battery and Dual Current Limit PDF资料下载
参数资料
| 型号： | LUCL9219GAR-DT |
| 英文描述： | Low-Cost Line Interface with Reverse Battery and Dual Current Limit |
| 中文描述： | 低成本线接口，具有反向电池和双电流限制 |
| 文件页数： | 16/30页 |
| 文件大小： | 397K |
| 代理商： | LUCL9219GAR-DT |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页当前第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页
Agere Systems Inc.
23
Data Sheet
November 2001
with Reverse Battery and Dual Current Limit
L9219A/G Low-Cost Line Interface
Applications (continued)
ac Design (continued)
Receive Interface (continued)
With a third-generation codec, the line card designer
has different concerns. To design the ac interface, the
designer must first decide upon all termination imped-
ance, hybrid balances, and transmission level points
(TLP) requirements that the line card must meet. In the
transmit direction, the only concern is that the SLIC
does not provide a signal that is too hot and overloads
the codec input. Thus, for the highest TLP that is being
designed to, given the SLIC gain, the designer, as a
function of voice band frequency, must ensure that the
codec is not overloaded. With a given TLP and a given
SLIC gain, if the signal will cause a codec overload, the
designer must insert some sort of loss, typically a resis-
tor divider, between the SLIC output and codec input.
In the receive direction, the issue is to optimize S/N.
Again, the designer must consider all the considered
TLPs. The idea is, for all desired TLPs, to run the
codec at or as close as possible to its maximum output
signal, to optimize the S/N. Remember noise floor is
constant, so the hotter the signal from the codec, the
better the S/N. The problem is, if the codec is feeding a
high-gain SLIC, either an external resistor divider is
needed to knock the gain down to meet the TLP
requirements, or the codec is not operating near maxi-
mum signal levels, thus compromising the S/N.
It appears the solution is to have a SLIC with a low
gain, especially in the receive direction. This will allow
the codec to operate near its maximum output signal
(to optimize S/N), without an external resistor divider
(to minimize cost).
Note also that some third-generation codecs require
the designer to provide an inherent resistive termina-
tion via external networks. The codec will then provide
gain shaping, as a function of frequency to meet the
return loss requirements. Further stability issues may
add external components or excessive ground plane
requirements to the design.
To meet the unique requirements of both types of
codecs, the L9219 offers two receive gain choices.
These receive gains are mask-programmable at the
factory and are offered as two different code variations.
For interface with a first-generation codec, the L9219A
is offered with a receive gain of 7.86. For interface with
a third-generation codec, the L9219G is offered with a
receive gain of 2. In either case, the transconductance
in the transmit direction, or the transmit gain, is 403
.
Example 1: Real Termination (First-Generation Codec)
ac equivalent circuits for real termination using a T7504 codec is shown in Figure 23.
Figure 16. ac Equivalent Circuit
RP
ZT
+
–
RP
VT/R
IT/R
VS
ZT/R
+
–
RING
AV = –1
AV = 1
VITR
–
+
–
CURRENT
SENSE
TIP
+
–
RT1
RRCV
RHB1
RT2
RCVN
RCVP
RX
VGSX
VFXIN
VFR
1/4 T7504 CODEC
RG
2.4 V
–0.403 V/mA
AV =
L9219 SLIC
VFXIP
3.93
12-3581 (F).c
相关PDF资料 |
PDF描述 |
|---|---|
| LUPXA255A0C200 | 32-BIT, 200 MHz, MICROPROCESSOR, PBGA256 |
| LUPXA255A0C300 | 32-BIT, 300 MHz, MICROPROCESSOR, PBGA256 |
| LV100 | Voltage Transducer LV 100 |
| LV200-AW | Voltage Transducer LV 200-AW/2 |
| LV25-1000 | Voltage Transducer LV 25-1000 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LUCL9310AP-D | 制造商:AGERE 制造商全称:AGERE 功能描述:Line Interface and Line Access Circuit Full-Feature SLIC,Ringing Relay,and Test Access Device |
| LUCL9310AP-DT | 制造商:AGERE 制造商全称:AGERE 功能描述:Line Interface and Line Access Circuit Full-Feature SLIC,Ringing Relay,and Test Access Device |
| LUCL9310GP-D | 制造商:AGERE 制造商全称:AGERE 功能描述:Line Interface and Line Access Circuit Full-Feature SLIC,Ringing Relay,and Test Access Device |
| LUCL9310GP-DT | 制造商:AGERE 制造商全称:AGERE 功能描述:Line Interface and Line Access Circuit Full-Feature SLIC,Ringing Relay,and Test Access Device |
| LUCL9311AP-D | 制造商:AGERE 制造商全称:AGERE 功能描述:Line Interface and Line Access Circuit Full-Feature SLIC with High Longitudinal Balance, Ringing Relay,and GR-909 Test Access |
发布紧急采购，3分钟左右您将得到回复。