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参数资料
| 型号： | LTC1531CSW |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 运动控制电子 |
| 英文描述： | Self-Powered Isolated Comparator |
| 中文描述： | COMPARATOR, PDSO28 |
| 封装： | 0.300 INCH, PLASTIC, SOP-28 |
| 文件页数： | 6/16页 |
| 文件大小： | 266K |
| 代理商： | LTC1531CSW |
6
LTC1531
APPLICATIO
S I
FOR
ATIO
U
The LTC1531 is an isolated self-powered dual differential
comparator. It contains a switched-capacitor comparator
that is self-powered through a capacitive isolation barrier.
The capacitive isolation barrier provides 2500V
RMS
of
isolation. The isolated comparator cycles between storing
power and performing sampled comparisons. During the
power delivery cycle, the nonisolated powered side deliv-
ers power through the internal isolation capacitors and
rectifier onto an external storage capacitor. Periodically
the isolated comparator makes a comparison if sufficient
voltage has been stored on the external supply capacitor.
See Timing and Block Diagrams.
During a comparison, the isolated side uses the energy
stored on the external capacitor to deliver a regulated 2.5V
power source for 108
μ
s followed by a sampled compari-
son. The result is transmitted back to the nonisolated
powered side and latched as the logic level DATA output.
A comparison will occur during the listen cycle if sufficient
voltage (3.3V) has been stored on the isolated external
capacitor. New DATA is latched only if a comparison was
actually done. A zero-crossing trigger pulse output for
firing a triac, ZCDATA, is available to trigger a triac when
the latched DATA output is high. A VALID data output pulse
is provided after each power-listen cycle in which a com-
parison was done to indicate that DATA has been updated.
The VALID output can be used to clock external circuitry
when a new comparator DATA value occurs.
W
U
U
POWER-LISTEN CYCLE
Self-Powering Through the Isolation Barrier
The LTC1531 comparator powered side toggles between
delivering power to the isolated side and listening for a
comparison result (see Timing Diagram). During the power
cycle, AC power is delivered through the isolation capaci-
tors, formed in the lead frame, to the isolated side. During
the listen cycle, the powered side receives pulses from the
isolated side and determines if a valid comparison
occurred.
The isolated side of the LTC1531 requires an external
capacitor connected to V
PW
whose value must be large
enough to sustain less than a 300mV drop for 108
μ
s with
the internal + external V
REG
load current. Power is deliv-
ered to this external capacitor through the internal isola-
tion capacitors and rectifiers during the power cycle.
When this voltage reaches approximately 3.3V, the com-
pare circuitry is enabled and a comparison will occur
during the next listen cycle. With V
CC
= 5V, this capacitive
coupled isolated power source can be modeled as an
equivalent 5.3V to 6.5V source with a 100k
source
impedance. The V
PW
pin will tend to self-regulate at 3.3V
with a ripple determined by the discharge current supplied
during the 108
μ
s V
REG
output pulse and the external
capacitor value. The value of the capacitor affects the initial
start-up time and the ripple voltage on V
PW
, but it does not
influence the sample rate of the comparator. This is
because the sample rate is determined by the rate of power
delivered through the isolation barrier and the rate it is
consumed in the internal plus external isolated circuits.
Any excessive external DC loading on V
PW
may prevent the
capacitor voltage from reaching the required 3.3V enable
voltage. Up to 20
μ
A of continuous loading on V
PW
can be
tolerated based on the 100k, 5.3V model of the power
source (see Typical Applications for examples). The qui-
escent current of the isolated side is approximately 2
μ
A
to 3
μ
A.
SAMPLE RATE
The comparator sample rate depends on the charging rate
through the isolated capacitors and the external + internal
load current . The power-listen cycles at 700Hz to 900Hz,
however, a comparison will only occur when V
PW
exceeds
the 3.3V enable voltage. Typical sample rate for light
loading is 200Hz to 300Hz. The actual sampling is not
uniform, but occurs during the listen period of the power
cycle and when V
PW
≥
3.3V. Typical sample rates for
various supply and load conditions are plotted in Figure 3.
Continuous micropower loads will also decrease the sample
rate.
V
REG
Reference Output
The V
REG
reference output pulses on for approximately
108
μ
s at 2.5V. During the off time, V
REG
does not go high
impedance. The V
REG
output stage is shown in Figure 5.
Large capacitance should not be attached to V
REG
in order
to avoid power loss. Charging of the V
REG
output capaci-
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| LTC1531CSW#PBF | 功能描述:IC COMP ISOLATED SLF-PWRD 28SOIC RoHS:是 类别:集成电路 (IC) >> 线性 - 比较器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 类型:通用 元件数:1 输出类型:CMOS，推挽式，满摆幅，TTL 电压 - 电源，单路/双路(±):2.5 V ~ 5.5 V，±1.25 V ~ 2.75 V 电压 - 输入偏移（最小值）:5mV @ 5.5V 电流 - 输入偏压（最小值）:1pA @ 5.5V 电流 - 输出（标准）:- 电流 - 静态（最大值）:24µA CMRR, PSRR（标准）:80dB CMRR，80dB PSRR 传输延迟（最大）:450ns 磁滞:±3mV 工作温度:-40°C ~ 85°C 封装/外壳:6-WFBGA，CSPBGA 安装类型:表面贴装 包装:管件 其它名称:Q3554586 |
| LTC1531CSW#TR | 功能描述:IC COMP DIFF DUAL SELFPWR 28SOIC RoHS:否 类别:集成电路 (IC) >> 线性 - 比较器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 类型:通用 元件数:1 输出类型:CMOS，推挽式，满摆幅，TTL 电压 - 电源，单路/双路(±):2.5 V ~ 5.5 V，±1.25 V ~ 2.75 V 电压 - 输入偏移（最小值）:5mV @ 5.5V 电流 - 输入偏压（最小值）:1pA @ 5.5V 电流 - 输出（标准）:- 电流 - 静态（最大值）:24µA CMRR, PSRR（标准）:80dB CMRR，80dB PSRR 传输延迟（最大）:450ns 磁滞:±3mV 工作温度:-40°C ~ 85°C 封装/外壳:6-WFBGA，CSPBGA 安装类型:表面贴装 包装:管件 其它名称:Q3554586 |
| LTC1531CSW#TRPBF | 功能描述:IC COMP ISOLATED SLF-PWRD 28SOIC RoHS:是 类别:集成电路 (IC) >> 线性 - 比较器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 类型:通用 元件数:1 输出类型:CMOS，推挽式，满摆幅，TTL 电压 - 电源，单路/双路(±):2.5 V ~ 5.5 V，±1.25 V ~ 2.75 V 电压 - 输入偏移（最小值）:5mV @ 5.5V 电流 - 输入偏压（最小值）:1pA @ 5.5V 电流 - 输出（标准）:- 电流 - 静态（最大值）:24µA CMRR, PSRR（标准）:80dB CMRR，80dB PSRR 传输延迟（最大）:450ns 磁滞:±3mV 工作温度:-40°C ~ 85°C 封装/外壳:6-WFBGA，CSPBGA 安装类型:表面贴装 包装:管件 其它名称:Q3554586 |
| LTC1531IS8 | 制造商:Linear Technology 功能描述:Self-Powered Isolated Comparator |
| LTC1535CSW | 功能描述:IC LINE TRANSCEIVER 28-SOIC RoHS:否 类别:集成电路 (IC) >> 接口 - 驱动器，接收器，收发器 系列:- 标准包装:27 系列:- 类型:收发器 驱动器/接收器数:3/3 规程:RS232，RS485 电源电压:4.75 V ~ 5.25 V 安装类型:表面贴装 封装/外壳:28-SOIC（0.295"，7.50mm 宽） 供应商设备封装:28-SOIC 包装:管件 |
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