AN681 datasheet, PDF - EEWORLD Datasheet

Datasheet> All Categories > AN681

Preview

AN681: DescriptionUSING THE Si87XX FAMILY OF DIGITAL ISOLATORS; File Size216KB，10 Pages; ManufacturerSILABS; Websitehttp://www.silabs.com

Download Datasheet View All

AN681 Overview

USING THE Si87XX FAMILY OF DIGITAL ISOLATORS

Preview

Download Datasheet

View All

AN681

SING T H E

Si87

AMILY O F

IGITA L

S O L A T O R S

1. Introduction

Optocouplers provide both galvanic signal isolation and output level shifting in a single package but are notorious

for their long propagation times, poor common-mode transient immunity (CMTI), and performance degradation with

temperature and device age. Modern isolation devices fabricated in CMOS process technology offer higher

performance and reliability with none of the downside issues of optocouplers. The Silicon Labs Si87xx family of

digital isolators can directly replace optocouplers while providing substantial gains in performance and reliability.

This application note describes how to correctly apply the Si87xx. (For more information about Silicon Labs CMOS

isolation technology and comparisons with optocouplers, please see Silicon Labs’ white paper “CMOS

Digital

Isolators Supersede Optocouplers in Industrial Applications”.

For more information on the Si87xx isolator family,

see the Si87xx product data sheet. Both publications are available for download at

www.silabs.com/isolation.)

2. Device Overview

Optocoupler

ANODE

CATHODE

Shield

Optical Receiver

VDD

GND

Figure 1. Optocoupler Block Diagram

The optocoupler of Figure 1 consists of an input side LED with a transparent shield (to reduce capacitive coupling

for higher CMTI), an optical receiver, and an open-collector output. The LED emits light when sufficient current

flows from anode to cathode. Emitted light passing through the transparent shield strikes the receiver’s photo

diode, initiating bias current flow from VDD and causing the open-collector output to go low. Absence of current

through the input side LED causes the open-collector output to remain high.

As shown in Figure 2, anode-cathode voltage VF provides Si87xx input-side bias voltage. The diode emulator

circuit provides two functions: First, it mimics the input behavior of an optocoupler LED to ensure compatibility with

external drive circuits, and, second, it enables the transmitter when forward diode current (IF) is at or above its

threshold level. When enabled, the transmitter sends a continuous carrier to the receiver, which forces the output

(VO) low when sufficient in-band receiver carrier energy is detected. Conversely, the receiver drives VO high when

IF is below its minimum threshold level.

Rev. 0.3 8/12

AN681

Recommended Resources

Single line control indicator light circuit b

Excellent performance touch dimmer circuit

Precision threshold detector circuit diagram

motorcycle anti-theft alarm

Lithium battery charger circuit

Computer motherboard circuit diagram 815 5_13

Choosing the Right Power Controller for USB Type-C and QC 3.0: With the popularity of electronic products such as computers, mobile phones, and digital cameras, more and more electronic devices are interconnected to transmit data and quickly charge, which makes U...; qwqwqw2088 Analogue and Mixed Signal

Just started using WinCE: I came into contact with WinCE yesterday. Now my concept of it is Windows CE. I don’t know anything else. I am uploading a book. I don’t know how good it is, but it is very clear. It is available for ...; hades2011 Embedded System

Tiva TM4C123GXL MCU software simulation IIC problem: It is necessary to use TM4C to read data through IIC. The hardware is not easy to transplant, so I wrote a software to simulate IIC. SDA and SCL are both externally pulled up by resistors. At the begi...; spuer_liu TI Technology Forum

Classification of power amplifiers: Power amplifiers are divided into the following four types according to their working status: (1) Class A working state The collector current of the transistor is always flowing during the entire work...; fish001 Analogue and Mixed Signal

The MSP430 LanuchPad on TI's official website is only $4.3. Who wants to organize a group purchase?: The MSP430 LanuchPad on TI's official website is only $4.3, a very exquisite little thing. Who wants to organize a group purchase?...; elulis Microcontroller MCU

Beaglebone black and MPU-6050 three-axis acceleration connection problem: I use beaglebone black to connect to MPU-6050 three-axis acceleration module (VCC3.3, GND, SDA, SCL). I use i2cdetect -y -r 1 on beaglebone black, but it doesn't find the three-axis acceleration modul...; hzm000000 DSP and ARM Processors

Shortcut: E0 E1 E2 E3 E4 E5 E6 E7 E8 E9 EA EB EC ED EE EF EG EH EI EJ EK EL EM EN EO EP EQ ER ES ET EU EV EW EX EY EZ F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 FA FB FC FD FE FF FG FH FI FJ FK FL FM FN FO FP FQ FR FS FT FU FV FW FX FY FZ G0 G1 G2 G3 G4 G5 G6 G7 G8 G9 GA GB GC GD GE GF GG GH GI GJ GK GL GM GN GO GP GQ GR GS GT GU GV GW GX GZ H0 H1 H2 H3 H4 H5 H6 H7 H8 HA HB HC HD HE HF HG HH HI HJ HK HL HM HN HO HP HQ HR HS HT HU HV HW HX HY HZ I1 I2 I3 I4 I5 I6 I7 IA IB IC ID IE IF IG IH II IK IL IM IN IO IP IQ IR IS IT IU IV IW IX J0 J1 J2 J6 J7 JA JB JC JD JE JF JG JH JJ JK JL JM JN JP JQ JR JS JT JV JW JX JZ K0 K1 K2 K3 K4 K5 K6 K7 K8 K9 KA KB KC KD KE KF KG KH KI KJ KK KL KM KN KO KP KQ KR KS KT KU KV KW KX KY KZ

Popular Components