ST490ABDR

ST490AB Low power high speed RS-485/RS-422 transceiver Features ■ Low supply current: 5 mA max ■ -7 V to 12 V common mode input voltage range ■ 70 mV typical input hysteresis ■ Designed for 25 Mbps operation ■ Operate from a single 5 V supply ■ ±4 kV ESD protection ■ Current limiting and thermal shutdown for driver overload protection DIP-8 SO-8 Description The ST490A is a low power transceiver for RS485 and RS-422 communications. The device contains one driver and one receiver in full duplex configuration. The ST490A draws 5 mA (typ.) of supply current when unloaded or fully loaded with disabled drivers. It operates from a single 5 V supply. Driver is short-circuit current limited and is protected against excessive power dissipation by thermal shutdown circuitry that place the driver outputs into a high-impedance state. The receiver input has a fail-safe feature that guarantees a logic high output if both inputs are open circuit. Table 1. Device summary Order code Temperature range Package Packaging ST490ABN -40 to 85 °C DIP-8 50 parts per tube / 40 tube per box ST490ABDR -40 to 85 °C SO-8 (tape and reel) 2500 parts per reel February 2008 Rev 5 1/17 www.st.com 17 Contents ST490AB Contents 1 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Truth tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 Test circuit and typical characteristics 6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2/17 ......................... 8 ST490AB Pin configuration 1 Pin configuration Figure 1. Pin connections Table 2. Pin description Pin n° Symbol Name and function 1 VCC Supply voltage 2 RO Receiver output 3 DI Driver input 4 GND 5 Y Non-inverting driver output 6 Z Inverting driver output 7 B Inverting receiver input 8 A Non-inverting receiver input Ground 3/17 Truth tables ST490AB 2 Truth tables Table 3. Truth table (driver) Inputs DI Y Z L L H H H L Note: X = Don’t care; Z = High impedance Table 4. Truth table (receiver) Note: 4/17 Outputs Differential inputs Outputs A-B RO ≥ -0.2V H between -0.2V to 0.2V ? ≤-0.2V L OPEN H X = Don’t care; Z = High impedance ST490AB Maximum ratings 3 Maximum ratings Table 5. Absolute maximum ratings Symbol Parameter VCC Supply voltage VDI Driver input voltage Value Unit 7 V -0.5 to 7 V VY, VZ Driver output voltage -7.5 to 12.5 V VA, VB Receiver input voltage -7.5 to 12.5 V -0.3 to (VCC + 0.3) V 3.5 kV VRO Receiver output voltage ESD Human body model Note: Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. 5/17 Electrical characteristics ST490AB 4 Electrical characteristics Table 6. Electrical characteristics (VCC = 4.5 V to 5.5 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred to TA = 25 °C) Symbol ISUPPLY Parameter Min. No load supply current Typ. Max. Unit 2 5 mA CIN Input capacitance 1.8 pF CYZ Driver output capacitance 1.2 pF Output capacitance 2.3 pF COUT Table 7. Transmitter electrical characteristics (VCC = 4.5 V to 5.5 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred to TA = 25 °C) Symbol Parameter VOD1 Differential drive output (no load) VOD2 Differential drive output (with load) RL= 54Ω (RS-422) (Figure 1) 1.5 2.6 VOD3 Differential drive output (with load) RL= 100Ω (RS-422) (Figure 1) 2 3 ΔVOD Change in magnitude of driver differential output voltage for complementary output states RL= 54Ω or 100Ω (Figure 1) VOC Driver common mode output voltage RL= 54Ω (Figure 1) ΔVOC Change in magnitude of driver common mode output voltage RL= 54Ω (Figure 1) IOFF Power off output current VCC = 0V, VO=-7V to 12V IOSD Driver short circuit output current VO=-7V to 12V 6/17 VIL Input logic threshold low VIH Input logic threshold high Test conditions Min. Typ. 0 1 0 ± 35 2 Max. Unit VCC V 5 V V 0.2 V 3 V 0.2 V ± 100 µA ± 250 mA 0.8 V V ST490AB Table 8. Symbol Electrical characteristics Receiver electrical characteristics (VCC = 4.5 V to 5.5 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred to TA = 25 °C) Parameter Test conditions Min. IIN1 Logic input current IIN2 Input current (A, B) VTH Receiver differential threshold voltage VCM = -7V to 12V ΔVTH Receiver input hysteresis VCM = 0V VOH Receiver output high voltage IOUT = -8mA, VID = 200mV VOL Receiver output low voltage IOUT = 8mA, VID = -200mV RRIN Receiver input resistance VCM = -7V to 12V 12 IOSR Receiver short-circuit current VO = 0V to VCC 7 Table 9. Symbol Other input=0V VCC= 0 or 5.25V Typ. Max. Unit ± 2.0 μA VIN=12V 0.5 1 mA VIN=-7V -0.35 -0.8 mA 0.2 V -0.2 3.5 70 mV 4.7 V 0.2 0.4 24 V kΩ 95 mA Driver switching characteristics (VCC = 4.5 V to 5.5 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred to TA = 25 °C) Parameter Test conditions Min. Typ. 25 50 Max. Unit DR Maximum data rate Jitter