Linear公司的LTC4313是熱插拔兩線雙向總線緩沖器,噪音容限高達0.3VCC,支持電壓1.5V, 1.8V, 2.5V, 3.3V 和5V,在插入時, SDA和SCL線能預(yù)充電到1V以最小化對總線的干擾.器件和I2C,I2C快速模式和SMBus兼容, ±4kV人體模式ESD保護,主要用在容性緩沖器/總線擴展器,板熱插拔,包括ATCA的通信系統(tǒng),電平轉(zhuǎn)換,PMBus和服務(wù)器.本文介紹了LTC4313主要特性,方框圖,以及多種應(yīng)用電路.
The LTC4313 is a hot swappable 2-wire bus buffer that provides bidirectional buffering while maintaining a low offset voltage and high noise margin up to 0.3 • VCC. The high noise margin allows the LTC4313 to be interoperable with devices that drive a high VOL (>0.4V) and allows multiple LTC4313s to be cascaded. The LTC4313-1 and LTC4313-2 support level translation between 3.3V and 5V busses. In addition to these voltages, the LTC4313-3 also supports level translation to 1.5V, 1.8V and 2.5V.
During insertion, the SDA and SCL lines are pre-charged to 1V to minimize bus disturbances. Connection is established between the input and output after ENABLE is asserted high and a stop bit or bus idle condition has been detected on the SDA and SCL pins. If both data and clock are not simultaneously high at least once in 45ms, the input is disconnected from the output. Up to 16 clock pulses are subsequently generated to free the stuck bus. Rise time accelerators (RTAs) provide pull-up currents on SDA and SCL rising edges to meet rise time specifications in heavily loaded systems. The RTAs are configured as slew limited switches in the LTC4313-1 and 2.5mA current sources in the LTC4313-2. The LTC4313-3 does not have RTAs.
LTC4313主要特性:
Bidirectional Buffer Increases Fanout
High Noise Margin with VIL = 0.3•VCC
Compatible with Non-Compliant I2C Devices That Drive a High VOL
Strong (LTC4313-1) and 2.5mA (LTC4313-2) Rise Time Accelerator Current
Level Shift 1.5V, 1.8V, 2.5V, 3.3V and 5V Busses
Prevents SDA and SCL Corruption During Live Board Insertion and Removal from Backplane
Stuck Bus Disconnect and Recovery
Compatible with I2C, I2C Fast Mode and SMBus
±4kV Human Body Model ESD Ruggedness
High Impedance SDA, SCL Pins When Unpowered
8-Lead MSOP and 8-Lead (3mm × 3mm) DFN Packages
LTC4313應(yīng)用:
Capacitance Buffers/Bus Extender
Live Board Insertion
Telecommunications Systems Including ATCA
Level Translation
PMBus
Servers
圖1. LTC4313方框圖
圖2. LTC4313典型應(yīng)用電路圖
圖3. LTC4313帶連接器的I2C熱插拔應(yīng)用電路圖
圖4.采用LTC4313-3從3.3V到1.8V的電平轉(zhuǎn)移電路圖
圖5.LTC4313在總線ATCA中應(yīng)用電路(僅顯示一路時鐘)
圖6.LTC4313-2在放射狀地連接(6x4列)通信系統(tǒng)的應(yīng)用
圖7.LTC4313-1和其它LTC緩沖器級聯(lián)的應(yīng)用電路
圖8.LTC4313和非兼容I2C器件的通信
圖9.LTC4313在轉(zhuǎn)發(fā)器中的應(yīng)用
詳情請見:
http://cds.linear.com/docs/Datasheet/4313123f.pdf
