BL3085B

BL3085B High ESD-Protected, Fail-Safe, Slew-Rate-Limited RS-485 Transceivers General Description The BL3085B is a half-duplex RS-485 transceiver with ±18kV IEC 61000-4-2 contact discharge protection. The BL3085B contains one driver and one receiver. The device features fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted. This means that the receiver output will be logic high even if all transmitters on a terminated bus are disabled. The BL3085B features reduced slew-rate driver that minimizes EMI and reduces reflections caused by improperly terminated cables, allowing error-free data transmission up to 250kbps. The BL3085B has a 1/8 unit load receiver input impedance that allows up to 256 transceivers on the bus. Configuration Functional Block of BL3085B Applications





RS-485 Communications Level Translators Transceivers for EMI-Sensitive Applications Industrial Control Local Area Networks Energy Meter Networks Lighting Systems Page- 1 - www.belling.com.cn V1.2 BL3085B Pin Function Description Pin Number Name 1 RO Receiver Output. 2 /RE Receiver Output Enable. /RE is low to enable the Receiver; /RE is high to disable the Receiver. 3 DE Driver Output Enable: DE is high to enable the Driver; DE is low to disable the Driver. 4 DI Driver Input 5 GND 6 A Non-inverting Receiver Input and Non-inverting Driver Output. 7 B Inverting Receiver Input and Inverting Driver Output. 8 VCC Function Ground. Power Supply. Function Table Receiving Transmitting Inputs Inputs Outputs /RE DE DI B A X 1 1 0 1 X 1 0 1 0 0 0 X High-Z High-Z 1 0 X Page2 Shutdown Outputs /RE DE A-B RO 0 X ≥-0.05V 1 0 X ≤-0.2V 0 0 X Open/shorted 1 1 1 X High-Z 1 0 X Shutdown www.belling.com.cn V1.2 BL3085B Absolute Maximum Ratings Parameter Symbol Rating Units VCC +7 V /RE, DE -0.3 to VCC+0.3 V DI -0.3 to VCC+0.3 V Transmitter Output Voltage A, B -8 to +13 V Receiver Input Voltage A, B -8 to +13 V Receiver Output Voltage RO -0.3 to VCC+0.3 V -40 to +85 ℃ Power Supply Control Input Voltage Transmitter Input Voltage Operating Temperature DC Electrical Characteristics （VCC=+5V±5℅,TA=-40℃～+85℃，Typical Values are VCC=+5V and TA＝25℃） （Note 1） Parameter Power Supply Symbol Conditions Vcc MIN 4.5 TYP MAX UNITS 5.5 V Driver Differential Driver Output(no load) VOD1 Figure 1 Differential Output VOD2 Figure 1，R=27Ω ∆VOD Figure 1，R=27Ω 0.2 V VOC Figure 1，R=27Ω 3 V Change in Magnitude of Common-Mode Voltage（Note 2） ∆VOC Figure 1，R=27Ω 0.2 V Input High Voltage VIH1 DE,DI,/RE Input Low Voltage VIL1 DE,DI,/RE Driver Change in Magnitude of Differential Output Voltage （Note 2） Driver Common-mode Output Voltage Page3 www.belling.com.cn 5 1.5 V V 2.0 V 0.8 V V1.2 BL3085B DI Input Hysteresis VHYS Input Current(A and B) Driver Short-Circuit Output Current IIN4 100 DE=GND VCC=GND 5.25V or VIN=12V 125 VIN=-7V -75 -7V≦VOUT≦VCC IOSD mV µA -100 0V≦VOUT≦12V 100 mA Receiver Receiver Differential Threshold Voltage Receiver Hysteresis VTH -7V≦VCM≦12V -200 Input -125 -50 40 mV mV Receiver Output High Voltage VOH IO=-4mA,VID=-50mV Receiver Output Low Voltage VOL IO=4mA,VID=-200mV 0.4 V Three-State Output Current at Receiver IOZR 0.4V≦VO≦2.4V ±1 µA Receiver Resistance RIN -7V≦VCM≦12V 96 IOSR 0V≦VRO≦VCC ±7 ICC No load ,/RE=DI= GND or VCC Input Receiver Output Short-Circuit Current VCC-1.5 V KΩ ±95 mA Supply Current Supply Current Supply Current Shutdown Mode in ISHDN DE=VCC 150 600 DE=GND 185 600 µA 10 µA DE=GND, /RE=VCC，DI=VCC or GND µA Note 1：All currents into the device are positive. All currents out of the device are negative. All voltages are referred to device ground unless otherwise noted. Note 2：△VOD and △VOC are the changes in VOD and VOC, respectively, when the DI input changes state. Switching Characteristics （VCC=+5V±5℅,TA=-40℃～+85℃，Typical values are at VCC=+5V，TA＝25℃） Parameter Driver Input to Output Page4 Symbol T DPLH T DPHL Conditions Figure 3 and 5，RDIFF=54Ω CL1=CL2=100pF www.belling.com.cn MIN TYP MAX 450 800 450 800 UNITS ns V1.2 BL3085B Driver Output |TDPLH – TDPHL| Skew Driver Rise or Fall Time T DSKEW Figure 3 and 5，RDIFF=54Ω CL1=CL2=100pF TDR, TDF Figure 3 and 5，RDIFF=54Ω CL1=CL2=100pF 150 100 ns 500 ns Maximum Data Rate F MAX Driver Enable to Output High T DZH Figure 4 and 6，CL=100pF S2 Closed 200 ns Driver Enable to Output Low T DZL Figure 4 and 6，CL=100pF S1 Closed 200 ns Driver Disable from Low Time T DLZ Figure 4 and 6，CL=15pF S1 Closed 300 ns Driver Disable from High Time T DHZ Figure 4 and 6，CL=15pF S2 Closed 300 ns T RPLH T RPHL Figure 7 and 9， ; rise and fall VID≦15ns time of 450 800 ns T RSKD Figure 7 and 9， ; rise and fall VID≦15ns time of 30 T RZL Figure 2 and 8，CL=100pF S1 Closed 20 50 ns T RZH Figure 2 and 8，CL=100pF S2 Closed 20 50 ns Receiver Disable Time from Low T RLZ Figure 2 and 8，CL=100pF S1 Closed 80 150 ns Receiver Disable Time from High T RHZ Figure 2 and 8，CL=100pF S2 Closed 80 150 ns Time to Shutdown T SHDN 50 300 ns Receiver Output |TRPLH – Differential Skew Input to TRPHL| Receiver Receiver Enable Output Low to Receiver Enable Output High to 250 kbps ns Driver Enable from Shutdown to Output High T DZH(SHDN) Figure 4 and 6，CL=15pF S2 Closed 200 ns Driver Enable from Shutdown to Output Low T DZL(SHDN) Figure 4 and 6，CL=15pF S1 Closed 200 ns Receiver Enable from Shutdown to Output High T RZH(SHDN) Figure 2 and 8，CL=100pF S2 Closed 300 ns Receiver Enable from Shutdown to Output Low T RZL(SHDN) Figure 2 and 8，CL=100pF S1 Closed 300 ns Page5 www.belling.com.cn V1.2 BL3085B Test Circuits and Timing Diagrams Figure 1：Driver DC Test Load Figure 2：Receiver Enable/Disable Timing Test Load Figure 3：Driver Timing Test Circuit Figure 4：Driver Enable/Disable Timing test Load Figure 5：Driver Propagation Delays Page6 Figure 6：Driver Enable and Disable Times www.belling.com.cn V1.2 BL3085B Figure 7：Receiver Propagation Delays Figure 8：Receiver Enable and Disable Times Figure 9：Receiver Propagation Delay Test Circuit Page7 www.belling.com.cn V1.2 BL3085B Package Information SOP8L Page8 www.belling.com.cn V1.2