CS5460A
lution, because these resistors will dissipate what
can be a significant amount of power, and they will
cause an undesirable voltage drop which decreas-
es the voltage level presented to the VA+ and VD+
supply pins.
3.15 Improving RFI Immunity
During EMC acceptance testing of a power meter-
ing assembly, the performance of the CS5460A’s
A/D converters can be adversely affected by exter-
nal radio frequency interference (RFI). Such exter-
nal RFI can be coupled into the copper traces
and/or wires on the PCB. If RFI is coupled into any
of the traces which tie into the CS5460A’s
Vin+/Vin- or Iin+/Iin- input pins, then errors may be
present in the CS5460A’s power/energy registra-
tion results.
When such degradation in performance is detect-
addition to or as an alternative to these capacitors,
addition of inductors L1 - L4 can sometimes help to
suppress any incoming RFI. Note that the addition-
al components just discussed can sometimes actu-
ally degrade the CS5460A’s immunity to RFI. The
exact configuration that works best can vary signif-
icantly, according to the exact PCB layout/orienta-
tion. Finally, note that inside the CS5460A, the
Vin+, Vin-, Iin+, and Iin- pins have all been buffered
with ~10 pF of internal capacitance (to VA-) in at-
tempt to improve the device’s immunity to external
RFI.
3.16 PCB Layout
For optimal performance, the CS5460A should be
placed entirely over an analog ground plane with
both the VA- and DGND pins of the device con-
nected to the analog plane.
ed, the CS5460A’s immunity to RF disturbance
Note:
Refer to the CDB5460A Evaluation Board for
may be improved by configuring the ‘+’ and ‘-’ in-
puts of the voltage/current channel inputs such that
they are more symmetrical. This is illustrated in
Figure 20 with the addition of resistors R3 and R4,
as well as capacitors C5 and C6. Note that the in-
put circuitry placed in front of the voltage/current
channel inputs in Figure 20 represents a sin-
gle-ended input configurations (for both channels).
Therefore, these extra resistors and components
may not necessarily be needed to achieve the sim-
ple basic anti-aliasing filtering on the inputs. How-
ever, the addition of these extra components can
create more symmetry across the ‘+’ and ‘-’ inputs
of the voltage/current input channels, which can of-
ten help to reduce the CS5460A’s susceptibility to
RFI. The value of C5 should be the same as C3,
(and so the designer may have to re-calculate the
desired value of C3, since the addition of C5 will
change the overall differential-/common-mode fre-
quency responses of the input filter.) A similar ar-
gument can be made for the addition of C6 (to
match C8) on the current channel’s input filter. Fi-
nally, addition of capacitors C4 and C7 can also
sometimes help to improve CS5460A’s perfor-
mance in the presence of RFI. All of these input ca-
pacitors (C3 - C8) should be placed in very close
proximity to the ‘+’ and ‘-’ pins of the voltage/cur-
rent input pins in order to maximize their ability to
protect the input pins from high-frequency RFI. In
38
suggested layout details, as well as
Applications Note 18 for more detailed layout
guidelines. Before layout, please call for our
Free Schematic Review Service.
4. SERIAL PORT OVERVIEW
The CS5460A's serial port incorporates a state
machine with transmit/receive buffers. The state
machine interprets 8 bit command words on the
rising edge of SCLK. Upon decoding of the com-
mand word, the state machine performs the re-
quested command or prepares for a data transfer
of the addressed register. Request for a read re-
quires an internal register transfer to the transmit
buffer, while a write waits until the completion of
24 SCLKs before performing a transfer. The inter-
nal registers are used to control the ADC's func-
tions. All registers are 24-bits in length. Figure 21,
in section 5, summarizes the internal registers
available.
The CS5460A is initialized and fully operational in
its active state upon power-on. After a power-on,
the device will wait to receive a valid command (the
first 8-bits clocked into the serial port). Upon re-
ceiving and decoding a valid command word, the
state machine instructs the converter to either per-
form a system operation, or transfer data to or from
an internal register.
DS487F5
相关PDF资料
CDB5461AU BOARD EVAL & SOFTWARE CS5461A
CDB5466U BOARD EVAL & SOFTWARE CS5466 ADC
CDB5467U BOARD EVAL FOR CS5467 ADC
CDB5560-2 DEV BOARD FOR CS5560 W/SE INPUT
CDB5571-2 DEV BOARD FOR CS5571 W/SE INPUT
CDB8422 BOARD EVAL FOR CS8422 RCVR
CDB8952T BOARD EVAL FOR CS8952
CDCE906-706PERFEVM EVAL MOD PERFORMANCE CDCE906/706
相关代理商/技术参数
CDB5460AU-Z 制造商:Cirrus Logic 功能描述:PB-FREEEVAL BOARD FOR CS5460 - Bulk
CDB5461 制造商:Cirrus Logic 功能描述:EVAL BD FOR CS5461 - Bulk
CDB5461A 功能描述:EVAL BOARD FOR CS5461 RoHS:否 类别:编程器,开发系统 >> 过时/停产零件编号 系列:- 标准包装:1 系列:- 类型:MCU 适用于相关产品:Freescale MC68HC908LJ/LK(80-QFP ZIF 插口) 所含物品:面板、缆线、软件、数据表和用户手册 其它名称:520-1035
CDB5461AU 功能描述:数据转换 IC 开发工具 Eval Bd Sngl-Phase Pow/Energy RoHS:否 制造商:Texas Instruments 产品:Demonstration Kits 类型:ADC 工具用于评估:ADS130E08 接口类型:SPI 工作电源电压:- 6 V to + 6 V
CDB5461AU-Z 制造商:Cirrus Logic 功能描述:PB-FREEEVAL BOARD FOR CS5461 WITH USB - Bulk
CDB5462 制造商:Cirrus Logic 功能描述:EVAL BOARD FOR CS5462 - Bulk
CDB5463U 功能描述:数据转换 IC 开发工具 Eval Bd Sngl-Phase Pow/Energy RoHS:否 制造商:Texas Instruments 产品:Demonstration Kits 类型:ADC 工具用于评估:ADS130E08 接口类型:SPI 工作电源电压:- 6 V to + 6 V
CDB5463U-Z 功能描述:EVAL BOARD USB FOR CS5463 RoHS:是 类别:编程器,开发系统 >> 评估板 - 模数转换器 (ADC) 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- ADC 的数量:1 位数:12 采样率(每秒):94.4k 数据接口:USB 输入范围:±VREF/2 在以下条件下的电源(标准):- 工作温度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板,软件