ST491ACD

ST491A STMICROELECTRONICS | Alldatasheet

Document overview

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Technical content

■ LOW SUPPLY CURRENT: 5mA MAX ■ DESIGNED FOR RS485 INTERFACE

APPLICATIONS

■ -7 TO 12 COMMON MODE INPUT VOLTAGE RANGE ■ 70mV TYPICAL INPUT HYSTERESIS ■ DESIGNED FOR 25Mbps OPERATION ■ OPERATE FROM SINGLE 5 SUPPLY ■ ±4kV ESD PROTECTION ■ CURRENT LIMITING AND THERMAL SHUTDOWN FOR DRIVER OVERLOAD PROTECTION

DESCRIPTION

The ST491A is a low power transceiver for RS-485 and RS-422 communications. The device contains one driver and one receiver in full duplex configuration. The ST491A draws 5mA (typ.) of supply current when unloaded and operates from a single 5V 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. ORDERING CODES Type Temperature Range Package Comments ST491ACN 0 to 70 °C DIP-14 25parts per tube / 40tube per box ST491ABN -40 to 85 °C DIP-14 25parts per tube / 40tube per box ST491ACD 0 to 70 °C SO-14 (Tube) 50parts per tube / 20tube per box ST491ABD -40 to 85 °C SO-14 (Tube) 50parts per tube / 20tube per box ST491ACDR 0 to 70 °C SO-14 (Tape & Reel) 2500 parts per reel ST491ABDR -40 to 85 °C SO-14 (Tape & Reel) 2500 parts per reel ST491A LOW POWER HIGH SPEED RS-485/RS-422 TRANSCEIVER DIP SOP

TRUTH TABLE (DRIVER) X= Don’t Care; Z=High Impedance TRUTH TABLE (RECEIVER) ?= Irrelevant; X= Don’t Care; Z=High Impedance PlN N° SYMBOL NAME AND FUNCTION

1 NC Not Connected

2 RO Receiver Output.

3 RE Receiver Output Enable

4 DE Driver Output Enable

5 DI Inverting Driver Input.

6 GND Ground

7 GND Ground

8 NC Not Connected

9 Y Non-inverting Driver Output

10 Z Inverting Driver Output

11 B Inverting Receiver Input

12 A Non-inverting Receiver Input

13 NC Not Connected

≥ -0.2V L H between -0.2V to 0.2V L ? ≤ -0.2V L L OPEN L H XH Z

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied.

ELECTRICAL CHARACTERISTICS

VCC =4 . 5 Vt o5 . 5 V ,TA = -40 to 85°C, unless otherwise specified. Typical values are referred to TA =2 5 ° C ) TRANSMITTER ELECTRICAL CHARACTERISTICS VCC = 4.5V to 5.5V, TA = -40 to 85°C, unless otherwise specified. Typical values are referred to Ta = 25°C) Symbol Parameter Value Unit VCC Supply Voltage 7V VDI Driver Input Voltage -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 VRO Receiver Output Voltage -0.3 to (V CC + 0.3) V ESD Human Body Model 3.5 KV Symbol Parameter Test Conditions Min. Typ. Max. Unit ISUPPLY No Load Supply Current 2 5 mA C IN Input Capacitance 1.8 pF C YZ Driver Output Capacitance 1.2 pF C OUT Output Capacitance 2.3 pF Symbol Parameter Test Conditions Min. Typ. Max. Unit VOD1 Differential Drive Output (No load) VCC V VOD2 Differential Drive Output (With Load) R L=5 4Ω (RS-422) (Figure 1) 1.5 2.6 5 V VOD3 Differential Drive Output (With Load) R L= 100Ω (RS-422) (Figure 1) 2 3 V ΔVOD Change in magnitude of Driver Differential Output Voltage for Complementary Output States (Note1) R L=5 4Ω or 100Ω (Figure 1) 0 0.2 V VOC Driver Common Mode Output Voltage R L=5 4Ω (Figure 1) 1 3 V ΔVOC Change in magnitude of Driver Common Mode Output Voltage (Note1) R L=5 4Ω (Figure 1) 0 0.2 V IOFF Power Off Output Current VCC =0 V V O =-7V to 12V ± 100 µA IOSD Driver Short Circuit Output Current VO =-7V to 12V ± 35 ± 250 mA VIL Input Logic Threshold Low 0.8 V VIH Input Logic Threshold High 2 V

RECEIVER ELECTRICAL CHARACTERISTICS VCC = 4.5V to 5.5V, TA = -40 to 85°C, unless otherwise specified. Typical values are referred to Ta = 25°C) DRIVER SWITCHING CHARACTERISTICS VCC =4 . 5 Vt o5 . 5 V ,TA = -40 to 85°C, unless otherwise specified. Typical values are referred to Ta = 25°C) RECEIVER SWITCHING CHARACTERISTICS VCC =4 . 5 Vt o5 . 5 V ,TA = -40 to 85°C, unless otherwise specified. Typical values are referred to Ta = 25°C) Symbol Parameter Test Conditions Min. Typ. Max. Unit IIN Input Current (A, B) other input=0V VCC = 0 or 5.25V VIN=12V 0.5 1 mA VIN=-7V -0.35 -0.8 mA V TH Receiver Differential Threshold Voltage VCM = -7V to 12V -0.2 0.2 V ΔV TH Receiver Input Hysteresis VCM =0 V 7 0 m V VOH Receiver Output High Voltage IOUT = -8mA, VID = 200mV 3.5 4.7 V V OL Receiver Output Low Voltage IOUT = 8mA, VID = -200mV 0.3 0.5 V R RIN Receiver Input Resistance VCM = -7V to 12V 12 24 K Ω Symbol Parameter Test Conditions Min. Typ. Max. Unit D R Maximum Data Rate Jitter <5% 25 50 Mbps tPLH tPHL Propagation Delay Input to Output R L=5 4Ω C L1=C L2=50pF, (Figure 1) 10 16 ns tSKEW Differential Output Delay Skew R L=5 4Ω C L1=C L2=50pF, (Figure 1) 1 3 ns tTLH tTHL Rise or Fall Differential Time R L=5 4Ω C L1=C L2=50pF, (Figure 1) 8 12 ns tPZL Output Enable Time C L= 50pF S1 Closed 14 25 ns tPZH Output Enable Time C L= 50pF S2 Closed 14 25 ns tPHZ Output Disable Time C L= 15pF S2 Closed 10 25 ns tPLZ Output Disable Time C L= 15pF S1 Closed 16 25 ns Symbol Parameter Test Conditions Min. Typ. Max. Unit tPLH tPHL Propagation Delay Input to Output C L = 15pF (Figures 2,4) 19 30 ns tSKD |tPLH -tPHL | Receiver Output Skew C L = 15pF (Figures 2,4) 1 3 ns tTLH tTHL Rise or Fall Time C L = 15pF (Figures 2,4) 6 ns tPZL Output Enable Time C RL = 15pF S1 Closed 6 12 ns tPZH Output Enable Time C RL = 15pF S2 Closed 7 12 ns tPHZ Output Disable Time C RL = 15pF S2 Closed 6 12 ns tPLZ Output Disable Time C RL = 15pF S1 Closed 6 12 ns

DIM. mm. inch a1 0.51 0.020 B 1.39 1.65 0.055 0.065 b 0.5 0.020 b1 0.25 0.010 D 20 0.787 E 8.5 0.335 e 2.54 0.100 e3 15.24 0.600 F 7.1 0.280 I 5.1 0.201 L 3.3 0.130 Z 1.27 2.54 0.050 0.100 Plastic DIP-14 MECHANICAL DATA P001A

DIM. mm. inch A 1.75 0.068 a1 0.1 0.2 0.003 0.007 a2 1.65 0.064 b 0.35 0.46 0.013 0.018 b1 0.19 0.25 0.007 0.010 C 0.5 0.019 c1 45˚ (typ.) D 8.55 8.75 0.336 0.344 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 7.62 0.300 F 3.8 4.0 0.149 0.157 G 4.6 5.3 0.181 0.208 L 0.5 1.27 0.019 0.050 M 0.68 0.026 S ˚ (max.) SO-14 MECHANICAL DATA PO13G

DIM. mm. inch A 330 12.992 C 12.8 13.2 0.504 0.519 D 20.2 0.795 N 60 2.362 T 22.4 0.882 Ao 6.4 6.6 0.252 0.260 Bo 9 9.2 0.354 0.362 Ko 2.1 2.3 0.082 0.090 Po 3.9 4.1 0.153 0.161 P 7.9 8.1 0.311 0.319 Tape & Reel SO-14 MECHANICAL DATA

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