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LTC1334ISW

LTC1334ISW

  • 厂商:

    LINER

  • 封装:

  • 描述:

    LTC1334ISW - Single 5V RS232/RS485 Multiprotocol Transceiver - Linear Technology

  • 数据手册
  • 价格&库存
LTC1334ISW 数据手册
LTC1334 Single 5V RS232/RS485 Multiprotocol Transceiver FEATURES s s s s s s s s s DESCRIPTIO s s Four RS232 Transceivers or Two RS485 Transceivers on One Chip Operates from a Single 5V Supply Withstands Repeated ± 10kV ESD Pulses Uses Small Charge Pump Capacitors: 0.1µF Low Supply Current: 8mA Typical 10µA Supply Current in Shutdown Self-Testing Capability in Loopback Mode Power-Up/Down Glitch-Free Outputs Driver Maintains High Impedance in Three-State, Shutdown or with Power Off Thermal Shutdown Protection Receiver Inputs Can Withstand ± 25V The LTC ®1334 is a low power CMOS bidirectional transceiver featuring two reconfigurable interface ports. It can be configured as two RS485 differential ports, as two dual RS232 single-ended ports or as one RS485 differential port and one dual RS232 single-ended port. An onboard charge pump requires four 0.1µF capacitors to generate boosted positive and negative supplies, allowing the RS232 drivers to meet the RS232 ± 5V output swing requirement with only a single 5V supply. A shutdown mode reduces the ICC supply current to 10µA. The RS232 transceivers are in full compliance with RS232 specifications. The RS485 transceivers are in full compliance with RS485 and RS422 specifications. All interface drivers feature short-circuit and thermal shutdown protection. An enable pin allows RS485 driver outputs to be forced into high impedance, which is maintained even when the outputs are forced beyond supply rails or power is off. Both driver outputs and receiver inputs feature ±10kV ESD protection. A loopback mode allows the driver outputs to be connected back to the receiver inputs for diagnostic self-test. , LTC and LT are registered trademarks of Linear Technology Corporation. APPLICATIO S s s s s Low Power RS485/RS422/RS232/EIA562 Interface Software-Selectable Multiprotocol Interface Port Cable Repeaters Level Translators TYPICAL APPLICATIO 2 3 LTC1334 VCC1 5V RX OUT DR ENABLE DR IN 5V 5V DR IN DR IN RX OUT RX OUT 26 24 23 22 21 20 19 18 17 16 15 1 28 27 4 5 120Ω 6 7 8 9 11 10 13 12 14 5V 0V RS485 INTERFACE 120Ω 13 12 11 10 5V 9 8 4 5 6 7 14 4000-FT 24-GAUGE TWISTED PAIR RS232 INTERFACE 0V ALL CAPACITORS: 0.1µF MONOLITHIC CERAMIC TYPE LTC1334 • TA01 U 27 28 1 LTC1334 2 3 26 17 18 19 21 20 24 25 22 23 15 VCC2 5V RX OUT DR ENABLE DR IN 5V 5V RX OUT RX OUT DR IN DR IN U U 1 LTC1334 ABSOLUTE (Note 1) AXI U RATI GS PACKAGE/ORDER I FOR ATIO TOP VIEW C1+ 1 28 C2+ 27 C2 – 26 VCC 25 RB1 24 RA1 23 DZ1/DE1 22 DY1 21 LB 20 ON/OFF 19 DY2 18 DZ2/DE2 17 RA2 16 RB2 15 VEE C1– 2 VDD 3 A1 4 B1 5 Y1 6 Z1 7 SEL1 8 SEL2 9 Z2 10 Y2 11 B2 12 A2 13 GND 14 Supply Voltage (VCC) ............................................. 6.5V Input Voltage Drivers ................................... – 0.3V to (VCC + 0.3V) Receivers ............................................. – 25V to 25V ON/OFF, LB, SEL1, SEL2 ........ – 0.3V to (VCC + 0.3V) Output Voltage Drivers ................................................. – 18V to 18V Receivers ............................... – 0.3V to (VCC + 0.3V) Short-Circuit Duration Output ........................................................ Indefinite VDD, VEE, C1+, C1–, C2+, C2 – .......................... 30 sec Operating Temperature Range Commercial ........................................... 0°C to 70°C Industrial ............................................ – 40°C to 85°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................ 300°C ORDER PART NUMBER LTC1334CG LTC1334CNW LTC1334CSW LTC1334IG LTC1334ISW G PACKAGE NW PACKAGE 28-LEAD PLASTIC SSOP 28-LEAD PDIP WIDE SW PACKAGE 28-LEAD PLASTIC SO WIDE TJMAX = 125°C, θJA = 90°C/W (G) TJMAX = 125°C, θJA = 56°C/W (NW) TJMAX = 125°C, θJA = 85°C/W (SW) Consult factory for Military grade parts. DC ELECTRICAL CHARACTERISTICS SYMBOL VOD1 VOD2 ∆VOD VOC ∆VOC IOSD IOZD VO IOSD VIH VIL IIN PARAMETER Differential Driver Output Voltage (Unloaded) Differential Driver Output Voltage (With Load) Change in Magnitude of Driver Differential Output Voltage for Complementary Output States Driver Common Mode Output Voltage Change in Magnitude of Driver Common Mode Output Voltage for Complementary Output States Driver Short-Circuit Current Three-State Output Current (Y, Z) Output Voltage Swing Output Short-Circuit Current Input High Voltage Input Low Voltage Input Current RS485 Driver (SEL1 = SEL2 = High) IO = 0 The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF (Notes 2, 3) CONDITIONS q q q q q q q q q MIN TYP MAX 6 UNITS V V V V V V mA mA µA V V Figure 1, R = 50Ω (RS422) Figure 1, R = 27Ω (RS485) Figure 1, R = 27Ω or R = 50Ω Figure 1, R = 27Ω or R = 50Ω Figure 1, R = 27Ω or R = 50Ω – 7V ≤ VO ≤ 12V, VO = High – 7V ≤ VO ≤ 12V, VO = Low (Note 4) – 7V ≤ VO ≤ 12V Figure 4, RL = 3k, Positive Figure 4, RL = 3k, Negative V O = 0V D, DE, ON/OFF, SEL1, SEL2, LB D, DE, ON/OFF, SEL1, SEL2, LB D, SEL1, SEL2 DE, ON/OFF, LB 2.0 1.5 6 6 0.2 3 0.2 35 10 ±5 5 –5 6.5 – 6.5 250 250 ± 500 RS232 Driver (SEL1 = SEL2 = Low) q q q ± 60 2 0.8 –4 ± 10 – 15 Driver Inputs and Control Inputs q q q q 2 U mA V V µA µA W U U WW W LTC1334 DC ELECTRICAL CHARACTERISTICS SYMBOL VTH ∆VTH IIN RIN VTH ∆VTH RIN VOH VOL IOSR IOZR ROB VDD VEE PARAMETER Differential Input Threshold Voltage Input Hysteresis Input Current (A, B) Input Resistance Receiver Input Threshold Voltage Receiver Input Hysteresis Receiver Input Resistance Receiver Output High Voltage Receiver Output Low Voltage Short-Circuit Current Three-State Output Current Inactive “B” Output Pull-Up Resistance (Note 5) VDD Output Voltage VEE Output Voltage RS485 Receiver (SEL1 = SEL2 = High) The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF (Notes 2, 3) CONDITIONS – 7V ≤ VCM ≤ 12V, LTC1334C –7V ≤ VCM ≤ 7V, LTC1334I VCM = 0V VIN = – 7V VIN = 12V – 7V ≤ VIN ≤ 12V Input Low Threshold Input High Threshold VIN = ± 10V IO = – 3mA, VIN = 0V, SEL1 = SEL2 = Low IO = 3mA, VIN = 3V, SEL1 = SEL2 = Low 0V ≤ VO ≤ VCC ON/OFF = Low ON/OFF = High, SEL1 = SEL2 = High No Load, ON/OFF = High IDD = – 10mA, ON/OFF = High No Load, ON/OFF = High IEE = 10mA, ON/OFF = High No Load, SEL1 = SEL2 = High No Load Shutdown, ON/OFF = 0V q q q q q q q q q q q MIN – 0.2 –0.3 TYP MAX 0.2 0.3 UNITS V V mV mA mA kΩ V V V kΩ V 70 – 0.8 1.0 12 0.8 2.4 0.6 3 3.5 7 50 8.5 7.6 – 7.7 – 6.9 8 10 25 100 5 4.6 0.2 0.4 85 ± 10 7 24 RS232 Receiver (SEL1 = SEL2 = Low) q q Receiver Output V mA µA kΩ V V V V mA µA Power Supply Generator Power Supply ICC VCC Supply Current AC ELECTRICAL CHARACTERISTICS SYMBOL SR tT tPLH tPHL tPLH tPHL t PLH t PHL tSKEW tr, tf PARAMETER Slew Rate Transition Time Driver Input to Output Driver Input to Output Receiver Input to Output Receiver Input to Output Driver Input to Output Driver Input to Output Driver Output to Output Driver Rise and Fall Time RS232 Mode (SEL1 = SEL2 = Low) The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF (Notes 2, 3) CONDITIONS Figure 4, RL = 3k, CL = 15pF Figure 4, RL = 3k, CL = 1000pF Figure 4, RL = 3k, CL = 2500pF Figures 4, 9, RL = 3k, CL = 15pF Figures 4, 9, RL = 3k, CL = 15pF Figures 5, 10 Figures 5, 10 Figures 2, 6, RL = 54Ω, CL = 100pF Figures 2, 6, RL = 54Ω, CL = 100pF Figures 2, 6, RL = 54Ω, CL = 100pF Figures 2, 6, RL = 54Ω, CL = 100pF q q q q q q q MIN TYP MAX 30 UNITS V/µs V/µs µs µs µs µs µs ns ns ns ns 4 0.22 1.9 0.6 0.6 0.3 0.4 20 20 3 40 40 5 15 3.1 4 4 6 6 70 70 15 40 RS485 Mode (SEL1 = SEL2 = High) q q q q 3 LTC1334 AC ELECTRICAL CHARACTERISTICS SYMBOL tZL tZH tLZ tHZ t PLH t PHL tSKEW PARAMETER Driver Enable to Output Low Driver Enable to Output High Driver Disable from Low Driver Disable from High Receiver Input to Output Receiver Input to Output Differential Receiver Skew, tPLH – tPHL RS485 Mode (SEL1 = SEL2 = High) The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF (Notes 2, 3) CONDITIONS Figures 3, 7, CL = 100pF, S1 Closed Figures 3, 7, CL = 100pF, S2 Closed Figures 3, 7, CL = 15pF, S1 Closed Figures 3, 7, CL = 15pF, S2 Closed Figures 2, 8, RL = 54Ω, CL = 100pF Figures 2, 8, RL = 54Ω, CL = 100pF Figures 2, 8, RL = 54Ω, CL = 100pF q q q q q q MIN TYP 50 50 50 60 MAX 90 90 90 90 140 140 UNITS ns ns ns ns ns ns ns 20 20 60 70 10 Note 1: Absolute Maximum Ratings are those values beyond which the safety of the device cannot be guaranteed. Note 2: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless otherwise specified. Note 3: All typicals are given at VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF and TA = 25°C. Note 4: Short-circuit current for RS485 driver output low state folds back above VCC. Peak current occurs around VO = 3V. Note 5: The “B” RS232 receiver output is disabled in RS485 mode (SEL1 = SEL2 = high). The unused output driver goes into a high impedance mode and has a resistor to VCC. See Applications Information section for more details. TYPICAL PERFORMANCE CHARACTERISTICS Receiver Output High Voltage vs Temperature 5.0 4.9 4.8 IOUT = 3mA VCC = 5V OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 4.7 4.6 4.5 4.4 4.3 4.2 4.1 4.0 –50 –25 50 0 75 25 TEMPERATURE (°C) 100 125 TIME (ns) 4 UW LTC1334 • TPC01 Receiver Output Low Voltage vs Temperature 0.5 IOUT = 3mA VCC = 5V 0.4 20 18 16 14 0.3 12 10 8 6 0.1 4 2 0 –50 –25 50 0 75 25 TEMPERATURE (°C) 100 125 RS485 Receiver Skew tPLH – tPHL vs Temperature VCC = 5V 0.2 0 –50 –25 50 0 75 25 TEMPERATURE (°C) 100 125 LTC1334 • TPC02 LTC1334 • TPC03 LTC1334 TYPICAL PERFORMANCE CHARACTERISTICS Receiver Output Current vs Output High Voltage 20 18 16 OUTPUT CURRENT (mA) INPUT THRESHOLD VOLTAGE (V) TA = 25°C VCC = 5V OUTPUT CURRENT (mA) 14 12 10 8 6 4 2 0 2.0 2.5 3.5 4.0 3.0 OUTPUT VOLTAGE (V) 4.5 5.0 Charge Pump Output Voltage vs Temperature 10 8 6 OUTPUT VOLTAGE (V) VDD (–10mA LOAD) SUPPLY CURRENT (mA) 4 2 0 –2 –4 –6 –8 –10 –50 –25 VCC = 5V SUPPLY CURRENT (mA) VDD (NO LOAD) VEE (10mA LOAD) VEE (NO LOAD) 50 0 75 25 TEMPERATURE (°C) 100 125 RS485 Driver Differential Output Voltage vs Temperature 2.6 DIFFERENTIAL OUTPUT CURRENT (mA) DIFFERENTIAL OUTPUT VOLTAGE (V) 2.5 2.4 2.3 2.2 2.1 2.0 1.9 1.8 1.7 RL = 54Ω VCC = 5V 40 30 20 TIME (µs) 1.6 –50 –25 50 0 75 25 TEMPERATURE (°C) UW LTC1334 • TPC04 Receiver Output Current vs Output Low Voltage 40 35 30 25 20 15 10 5 0 0 0.5 1.0 1.5 2.0 OUTPUT VOLTAGE (V) 2.5 3.0 TA = 25°C VCC = 5V 2.0 RS232 Receiver Input Threshold Voltage vs Temperature VCC = 5V 1.8 1.6 1.4 1.2 1.0 0.8 –50 –25 INPUT HIGH INPUT LOW 50 25 75 0 TEMPERATURE (°C) 100 125 LTC1334 • TPC05 LTC1334 • TPC06 Supply Current vs Temperature (RS485) 25 VCC = 5V NO LOAD SEL 1 = SEL 2 = HIGH 10 9 8 7 6 5 4 3 2 1 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 125 Supply Current vs Temperature (RS232) VCC = 5V NO LOAD SEL 1 = SEL 2 = HIGH 20 15 10 5 0 –50 –25 50 0 75 25 TEMPERATURE (°C) 100 125 LTC1334 • TPC07 LTC1334 • TPC08 LTC1334 • TPC09 RS485 Driver Differential Output Current vs Output Voltage 70 60 50 9 15 RS485 Driver Skew vs Temperature VCC = 5V 12 TA = 25°C VCC = 5V 6 3 10 0 0 3 4 DIFFERENTIAL OUTPUT VOLTAGE (V) 1 2 5 0 –50 –25 100 125 50 0 75 25 TEMPERATURE (°C) 100 125 LTC1334 • TPC10 LTC1334 • TPC11 LTC1334 • TPC12 5 LTC1334 TYPICAL PERFORMANCE CHARACTERISTICS RS485 Driver Output High Voltage vs Output Current –80 –70 OUTPUT CURRENT (mA) 120 OUTPUT SHORT-CIRCUIT CURRENT (mA) –60 –50 –40 –30 –20 –10 0 0 OUTPUT CURRENT (mA) 1 3 OUTPUT VOLTAGE (V) 2 RS232 Driver Output Voltage vs Temperature 10 30 OUTPUT SHORT-CIRCUIT CURRENT (mA) 8 6 OUTPUT HIGH 25 20 15 10 5 OUTPUT LEAKAGE CURRENT (µA) OUTPUT VOLTAGE (V) 4 2 0 –2 –4 –6 –8 –10 –50 –25 50 0 75 25 TEMPERATURE (°C) 100 125 OUTPUT LOW VCC = 5V RL = 3k PIN FUNCTIONS C1+ (Pin 1): Commutating Capacitor C1 Positive Terminal. Requires 0.1µF external capacitor between Pins 1 and 2. C1– (Pin 2): Commutating Capacitor C1 Negative Terminal. VDD (Pin 3): Positive Supply Output for RS232 Drivers. Requires an external 0.1µF capacitor to ground. A1 (Pin 4): Receiver Input. B1 (Pin 5): Receiver Input. Y1 (Pin 6): Driver Output. Z1 (Pin 7): Driver Output. SEL1 (Pin 8): Interface Mode Select Input. SEL2 (Pin 9): Interface Mode Select Input. Z2 (Pin 10): Driver Output. Y2 (Pin 11): Driver Output. B2 (Pin 12): Receiver Input. A2 (Pin 13): Receiver Input. GND (Pin 14): Ground. VEE (Pin 15): Negative Supply Output. Requires an external 0.1µF capacitor to ground. 6 UW TA = 25°C VCC = 5V 4 5 LTC1334 • TPC13 LTC1334 • TPC16 RS485 Driver Output Low Voltage vs Output Current TA = 25°C VCC = 5V 160 RS485 Driver Output Short-Circuit Current vs Temperature VCC = 5V 140 120 100 80 60 40 –50 –25 100 80 60 40 20 0 SINK (VOUT = 5V) SOURCE (VOUT = 0V) 0 1 2 3 4 OUTPUT VOLTAGE (V) 5 50 25 75 0 TEMPERATURE (°C) 100 125 LTC1334 • TPC14 LTC1334 • TPC15 RS232 Driver Short-Circuit Current vs Temperature 500 VOUT = 0V VCC = 5V SOURCE 450 400 350 300 250 200 150 100 50 0 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 125 Driver Output Leakage Current (Disable/Shutdown) vs Temperature VCC = 5V SINK 0 –50 –25 50 0 75 25 TEMPERATURE (°C) 100 125 LTC1334 • TPC17 LTC1334 • TPC18 U U U LTC1334 PI FU CTIO S RB2 (Pin 16): Receiver Output. RA2 (Pin 17): Receiver Output. DZ2/DE2 (Pin 18): RS232 Driver Input in RS232 Mode. RS485 Driver Enable with internal pull-up in RS485 mode. DY2 (Pin 19): Driver Input. ON/OFF (Pin 20): A high logic input enables the transceivers. A low puts the device into shutdown mode and reduces ICC to 10µA. This pin has an internal pull-up. LB (Pin 21): Loopback Control Input. A low logic level enables internal loopback connections. This pin has an internal pull-up. DY1 (Pin 22): Driver Input. DZ1/DE1 (Pin 23): RS232 Driver Input in RS232 Mode. RS485 Driver Enable with internal pull-up in RS485 mode. RA1 (Pin 24): Receiver Output. RB1 (Pin 25): Receiver Output. VCC (Pin 26): Positive Supply; 4.75V ≤ VCC ≤ 5.25V C2 – (Pin 27): Commutating Capacitor C2 Negative Terminal. Requires 0.1µF external capacitor between Pins 27 and 28. C2 + (Pin 28): Commutating Capacitor C2 Positive Terminal. C1+ C1– VDD A1 B1 Y1 Z1 SEL1 SEL2 Z2 Y2 B2 A2 GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 C2 + C2 – VCC RB1 RA1 DZ1/DE1 DY1 LB ON/OFF DY2 DZ2/DE2 RA2 RB2 VEE FU CTIO TABLES RS485 Driver Mode ON/OFF 1 1 1 1 0 INPUTS SEL DE 1 1 1 1 1 1 1 1 0 X D 0 1 X X X CONDITIONS No Fault No Fault Thermal Fault X X OUTPUTS Z Y 0 1 Z Z Z 1 0 Z Z Z RS485 Receiver Mode ON/OFF 1 1 1 0 INPUTS SEL 1 1 1 1 B–A < – 0.2V > 0.2V Inputs Open X OUTPUTS RA RB* 0 1 1 Z 1 1 1 Z *See Note 5 of Electrical Characteristics table. U U U U U RS232 Driver Mode ON/OFF 1 1 1 0 INPUTS SEL 0 0 0 0 D 0 1 X X CONDITIONS No Fault No Fault Thermal Fault X OUTPUTS Y, Z 1 0 Z Z RS232 Receiver Mode ON/OFF 1 1 1 0 INPUTS SEL 0 0 0 0 A, B 0 1 Inputs Open X OUTPUTS RA, RB 1 0 1 Z 7 LTC1334 BLOCK DIAGRA SM Interface Configuration with Loopback Disabled PORT 1 = RS232 MODE PORT 2 = RS232 MODE 1 28 C1 VDD A1 B1 Y1 Z1 SEL1 = 0V 2 3 4 5 6 7 8 21 20 19 18 17 16 15 27 26 25 24 23 22 VCC RB1 RA1 DZ1 DY1 LB ON DY2 DZ2 RA2 RB2 VEE 9 10 11 12 13 14 C2 C1 VDD A1 B1 Y1 Z1 SEL1 = 5V PORT 1 = RS485 MODE PORT 2 = RS232 MODE 1 28 2 3 4 5 6 7 8 21 20 19 18 17 16 15 27 26 25 24 23 22 VCC RB1 RA1 DE1 DY1 LB ON DY2 DZ2 RA2 RB2 VEE 9 10 11 12 13 14 C2 C1 VDD A1 B1 Y1 Z1 SEL1 = 0V PORT 1 = RS232 MODE PORT 2 = RS485 MODE 1 28 2 3 4 5 6 7 8 21 20 19 18 17 16 15 27 26 25 24 23 22 VCC RB1 RA1 DZ1 DY1 LB ON DY2 DE2 RA2 RB2 VEE 9 10 11 12 13 14 C2 C1 VDD A1 B1 Y1 Z1 SEL1 = 5V PORT 1 = RS485 MODE PORT 2 = RS485 MODE 1 28 2 3 4 5 6 7 8 21 20 19 18 17 16 15 27 26 25 24 23 22 VCC RB1 RA1 DE1 DY1 LB ON DY2 DE2 RA2 RB2 VEE C2 SEL2 = 0V Z2 Y2 B2 A2 GND 9 10 11 12 13 14 PORT 1 = RS232 MODE PORT 2 = RS232 MODE 1 28 C1 VDD 2 3 27 26 25 24 VCC RB1 RA1 DZ1 DY1 LB ON DY2 DZ2 RA2 RB2 VEE GND 14 9 10 11 Y1 Z1 SEL1 = 5V 6 7 8 Y1 Z1 SEL1 = 0V 6 7 8 23 22 21 20 SEL2 = 0V Z2 Y2 9 10 11 19 18 17 16 GND 14 15 8 W SEL2 = 0V Z2 Y2 B2 A2 GND SEL2 = 5V Z2 Y2 B2 A2 GND SEL2 = 5V Z2 Y2 B2 A2 GND LTC1334 • BD01 Interface Configuration with Loopback Enabled PORT 1 = RS485 MODE PORT 2 = RS232 MODE 1 28 C2 C1 VDD 2 3 27 26 25 24 23 22 21 20 19 18 17 16 15 VCC RB1 RA1 DE1 DY1 LB ON DY2 DZ2 RA2 RB2 VEE GND Y1 Z1 SEL1 = 0V C2 C1 VDD PORT 1 = RS232 MODE PORT 2 = RS485 MODE 1 28 2 3 27 26 25 24 6 7 8 21 20 19 18 17 16 14 15 23 22 VCC RB1 RA1 DZ1 DY1 LB ON DY2 DE2 RA2 RB2 VEE GND SEL2 = 5V Z2 Y2 Y1 Z1 SEL1 = 5V C2 C1 VDD PORT 1 = RS485 MODE PORT 2 = RS485 MODE 1 28 2 3 27 26 25 24 6 7 8 21 9 10 11 20 19 18 17 16 14 15 23 22 VCC RB1 RA1 DE1 DY1 LB ON DY2 DE2 RA2 RB2 VEE C2 SEL2 = 0V Z2 Y2 SEL2 = 5V Z2 Y2 9 10 11 LTC1334 • BD02 LTC1334 TEST CIRCUITS Z R VOD R Y LTC1334 • F01 LTC1334 • F02 LTC1334 • F03 VCC 3V D VOC SEL Z RL DE 3V Y CL A CL B 3V SEL R 15pF 500Ω DR OUT CL S2 S1 Figure 1. RS422/RS485 Driver Test Load Figure 2. RS485 Driver/Receiver Timing Test Circuit Figure 3. RS485 Driver Output Enable/Disable Timing Test Load 0V SEL D Y, Z D 0V SEL Y, Z VIN A, B 0V SEL R VOUT 15pF LTC1334 • F05 CL RL LTC1334 • F04 Figure 4. RS232 Driver Swing/Timing Test Circuit Figure 5. RS232 Receiver Timing Test Circuit SWITCHI G WAVEFOR S 3V D 0V tPLH VO Z–Y –VO 50% 10% 1.5V Y VO Z tSKEW tSKEW LTC1334 • F06 W U f = 1MHz: tr ≤ 10ns: tf ≤ 10ns 1.5V tPHL 90% VDIFF = V(Z) – V(Y) 90% 50% 10% tf tr 1/2 VO Figure 6. RS485 Driver Propagation Delays 9 LTC1334 SWITCHI G WAVEFOR S 3V DE 0V tZL 5V Y, Z VOL tZH VOH Z, Y 0V LTC1334 • F07 VOD2 B–A –VOD2 tPLH VOH R VOL 0V 3V D 0V tPHL VO Y, Z –VO 0V LTC1334 • F09 1.5V VIH A, B VIL tPHL VOH R VOL 0.8V tPLH 2.4V LTC1334 • F10 1.3V Figure 10. RS232 Receiver Propagation Delays 10 W 1.5V U f = 1MHz: tr ≤ 10ns: tf ≤ 10ns 1.5V tLZ 2.3V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH 2.3V tHZ 0.5V 0.5V Figure 7. RS485 Driver Enable and Disable Times f = 1MHz: tr ≤ 10ns: tf ≤ 10ns INPUT 0V tPHL 1.5V LTC1334 • F08 OUTPUT 1.5V Figure 8. RS485 Receiver Propagation Delays 1.5V tPLH 0V Figure 9. RS232 Driver Propagation Delays 1.7V LTC1334 APPLICATI S I FOR ATIO Basic Theory of Operation The LTC1334 has two interface ports. Each port may be configured as a pair of single-ended RS232 transceivers or as a differential RS485 transceiver by forcing the port’s selection input to a low or high, respectively. The LTC1334 provides two RS232 drivers and two RS232 receivers or one RS485 driver and one RS485 receiver per port. All the interface drivers feature three-state outputs. Interface outputs are forced into high impedance when the driver is disabled, in the shutdown mode or with the power off. All the interface driver outputs are fault-protected by a current limiting and thermal shutdown circuit. The thermal shutdown circuit disables both the RS232 and RS485 driver outputs when the die temperature reaches 150°C. The thermal shutdown circuit reenables the drivers when the die temperature cools to 130°C. In RS485 mode, shutdown mode or with the power off, the input resistance of the receiver is 24k. The input resistance drops to 5k in RS232 mode. A logic low at the ON/OFF pin shuts down the device and forces all the outputs into a high impedance state. A logic high enables the device. An internal 4µA current source to VCC pulls the ON/OFF pin high if it is left open. C1 VDD 0.1µF RS485 I/O 120Ω 0.1µF 2 3 4 5 6 7 5V 8 9 ≥ ± 5V INTO 3kΩ LOAD RS232 DR OUT RS232 DR OUT RS232 RX IN RS232 RX IN Figure 11. RS232/RS485 Interfaces U In RS485 mode, an internal 4µA current source pulls the driver enable pin high if left open. The RS485 receiver has a 4µA current source at the noninverting input. If both the RS485 receiver inputs are open, the output goes to a high state. Both the current sources are disabled in the RS232 mode. The receiver output B is inactive in RS485 mode and has a 50k pull-up resistor to provide a known output state in this mode. A loopback mode enables internal connections from driver outputs to receiver inputs for self-test when the LB pin has a low logic state. The driver outputs are not isolated from the external loads. This allows transmitter verification under the loaded condition. An internal 4µA current source pulls the LB pin high if left open and disables the loopback configuration. RS232/RS485 Applications The LTC1334 can support both RS232 and RS485 levels with a single 5V supply as shown in Figure 11. Multiprotocol Applications The LTC1334 is well-suited for software controlled interface mode selection. Each port has a selection pin as shown in Figure 12. The single-ended transceivers support both RS232 and EIA562 levels. The differential transceivers support both RS485 and RS422. 28 LTC1334 27 26 24 23 22 21 20 19 18 17 16 15 RX OUT DR ENABLE DR IN 5V 5V DR IN DR IN RX OUT RX OUT VEE 0.1µF LTC1334 • F11 W U UO 1 0.1µF C2 VCC 5V 0.1µF 11 10 13 12 14 11 LTC1334 APPLICATI C1 S I FOR ATIO 1 LTC1334 28 27 0.1µF 26 2 3 0.1µF VDD 0.1µF INPUT A K1A 120Ω 0.1µF 25 RX OUT 4 PORT 1 INTERFACE 5V K1* TX2A-5V INPUT B OUTPUT A K1B 120Ω OUTPUT B 360k 5 6 24 RX OUT 22 8 DR IN SEL1 7 23 21 20 DR IN/ENABLE LB ON/OFF RX OUT FMMT619** 7.5k TERM1 16 13 INPUT A K2A 120Ω PORT 2 INTERFACE 5V K2* TX2A-5V INPUT B OUTPUT A K2B 120Ω OUTPUT B 360k FMMT619** 7.5k 12 11 17 RX OUT 19 9 DR IN SEL2 10 14 18 15 DR IN/ENABLE VEE LTC1334 • F12 0.1µF TERM2 *AROMAT CORP (800) 276-6289 **ZETEX (516) 543-7100 Figure 12. Multiprotocol Interface with Optional, Switchable Terminations 1/2 LTC1334 RX OUT DR ENABLE DR IN 5V 24 23 22 8 6 7 76 54 1/2 LTC1334 22 23 24 8 4 5 120Ω 120Ω Figure 14. Typical Connection for RS485 Interface 12 U C2 VCC 5V W U UO Each receiver in the LTC1334 is designed to present one unit load (5kΩ nominal for RS232 and 12kΩ minimum for RS485) to the cable. Some RS485 and RS422 applications call for terminations, but these are only necessary at two nodes in the system and they must be disconnected when operating in the RS232 mode. A relay is the simplest, lowest cost method of switching terminations. In Figure 12 TERM1 and TERM2 select 120Ω terminations as needed. If terminations are needed in all RS485/RS422 applications, no extra control signals are required; simply connect TERM1 and TERM2 to SEL1 and SEL2. Typical Applications A typical RS232/EIA562 interface application is shown in Figure 13 with the LTC1334. A typical connection for a RS485 transceiver is shown in Figure 14. A twisted pair of wires connects up to 32 drivers and receivers for half duplex multipoint data transmission. The wires must be terminated at both ends with resistors equal to the wire’s characteristic impedance. An optional shield around the twisted pair helps to reduce unwanted noise and should be connected to ground at only one end. 1/2 LTC1334 DR IN DR IN RX OUT RX OUT 19 18 17 16 9 LTC1334 • F13 1/2 LTC1334 11 10 12 RS232/ EIA562 LINES 4 5 6 7 24 25 22 23 8 RX OUT RX OUT DR IN DR IN 13 INTERFACE Figure 13. Typical Connection for RS232/EIA562 Interface 1/2 LTC1334 13 17 12 18 11 10 19 9 RX OUT DR ENABLE DR IN 5V DR IN RX OUT DR ENABLE 5V LTC1334 F14 LTC1334 APPLICATI S I FOR ATIO A typical RS422 connection (Figure 15) allows one driver and ten receivers on a twisted pair of wires terminated with a 100Ω resistor at one end. A typical twisted-pair line repeater is shown in Figure 16. As data transmission rate drops with increased cable length, repeaters can be inserted to improve transmission rate or to transmit beyond the RS422 4000-foot limit. The LTC1334 can be used to translate RS232 to RS422 interface levels or vice versa as shown in Figure 17. One DR ENABLE DR IN 5V RX OUT 22 8 1/2 LTC1334 23 6 7 24 4 5 Figure 15. Typical Connection for RS422 Interface 17 22 5V RX IN RS232/EIA562 6 TX OUT 5 1/2 LTC1334 7 LTC1334 • F16 24 4 RX IN 100Ω 22 23 8 Figure 16. Typical Cable Repeater for RS422 Interface 5V 17 22 RX IN RS232/EIA562 DR OUT 11 13 23 8 6 RS422 7 LTC1334 4 100Ω 5 9 19 24 Figure 18. Typical Cable Extension for RS232/EIA562 Interface U port is configured as an RS232 transceiver and the other as an RS485 transceiver. Using two LTC1334s as level translators, the RS232/ EIA562 interface distance can be extended to 4000 feet with twisted-pair wires (Figure 18). AppleTalk®/LocalTalk® Applications Two AppleTalk applications are shown in Figure 19 and 20 with the LTC1323 and the LTC1334. AppleTalk and LocalTalk are registered trademarks of Apple Computer, Inc. W U UO 1/2 LTC1334 RX OUT 24 8 54 100Ω 12 5V 1/2 LTC1334 13 17 8 18 100Ω 11 10 LTC1334 • F15 RX OUT 5V DR ENABLE DR IN 19 5V 23 8 6 TX OUT 7 LTC1334 RS422 4 5 100Ω RX IN LTC1334 • F17 13 TX OUT 11 9 19 24 Figure 17. Typical RS232/EIA562 to RS422 Level Translator 24 19 4 100Ω 5 LTC1334 6 7 8 23 22 17 9 LTC1334 • F18 11 DR OUT RS232/EIA562 13 RX IN 5V 13 LTC1334 APPLICATI 1 0.33µF TXD TXDEN SHDN RXEN RXDO 2 3 4 5 6 7 8 CHARGE PUMP S I FOR ATIO 16 15 14 13 12 TXD – 11 TXD + 10 RXD – 9 RXD + EMI 1k EMI EMI EMI 5Ω TO 22Ω EMI = 5Ω TO 22Ω 1k 0.33µF 1µF 5V LTC1323CS-16 0.1µF 100pF Figure 19. AppleTalk/LocalTalk Implemented Using the LTC1323CS-16 and LTC1334 Transceivers 5Ω TO 22Ω LTC1323CS 1 0.33µF CPEN TXD TXI TXDEN SHDN RXEN RXO RXO RXDO 2 3 4 5 6 19 TXD + 7 18 TXO 8 9 10 11 15 RXD– 14 RXD+ 12 13 17 RXI 16 RXI EMI EMI CHARGE PUMP 24 23 22 21 20 TXD – EMI 0.33µF 1µF EMI = 5Ω TO 22Ω OR 100pF OR 100pF 5V 0.1µF 120Ω EMI EMI SEL2 EMI 120Ω EMI Figure 20. AppleTalk Direct Connect Using the LTC1323 DTE and the LTC1334 for DCE Transceivers 14 U 1 2 3 0.1µF 1k EMI EMI 120Ω 120Ω 1k EMI SEL1, 5V SEL2, 5V FERRITE BEAD OR OR 100pF 100pF FERRITE BEAD NC 7 8 9 10 EMI 4 5 6 LTC1334 28 27 26 25 24 23 22 21 20 19 18 17 16 15 0.1µF LTC1334 • F19 W U UO 0.1µF 5V NC RA1 DE1 DY1 5V 5V NC NC NC NC 11 NC 12 NC NC 13 14 FERRITE BEAD FERRITE BEAD 100pF 1 2 3 0.1µF EMI 120Ω EMI EMI 120Ω EMI SEL1 5V 7 8 9 10 11 12 13 14 5 6 23 22 21 20 19 18 17 16 15 0.1µF LTC1334 • F20 28 LTC1334 27 26 25 24 5V NC RA1 0.1µF 4 DE1 DY1 5V 5V DY2 DZ2 RA2 NC EMI EMI NC EMI LTC1334 PACKAGE DESCRIPTION 5.20 – 5.38** (0.205 – 0.212) 0.13 – 0.22 (0.005 – 0.009) 0.55 – 0.95 (0.022 – 0.037) NOTE: DIMENSIONS ARE IN MILLIMETERS *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.152mm (0.006") PER SIDE **DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.254mm (0.010") PER SIDE 0.505 – 0.560* (12.827 – 14.224) 0.600 – 0.625 (15.240 – 15.875) 0.009 – 0.015 (0.229 – 0.381) +0.035 0.625 –0.015 +0.889 –0.381 0.015 (0.381) MIN ( 15.87 ) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. U Dimensions in inches (millimeters) unless otherwise noted. G Package 28-Lead Plastic SSOP (0.209) (LTC DWG # 05-08-1640) 10.07 – 10.33* (0.397 – 0.407) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 7.65 – 7.90 (0.301 – 0.311) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1.73 – 1.99 (0.068 – 0.078) 0 ° – 8° 0.65 (0.0256) BSC 0.25 – 0.38 (0.010 – 0.015) 0.05 – 0.21 (0.002 – 0.008) G28 SSOP 1098 NW Package 28-Lead PDIP (Wide 0.600) (LTC DWG # 05-08-1520) 1.455* (36.957) MAX 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1 0.150 ± 0.005 (3.810 ± 0.127) 2 3 4 5 6 7 8 9 10 11 12 13 14 0.045 – 0.065 (1.143 – 1.651) 0.070 (1.778) TYP 0.125 (3.175) MIN 0.035 – 0.080 (0.889 – 2.032) 0.100 (2.54) BSC 0.018 ± 0.003 (0.457 ± 0.076) N28 1098 15 LTC1334 PACKAGE DESCRIPTION 0.291 – 0.299** (7.391 – 7.595) 0.010 – 0.029 × 45° (0.254 – 0.737) 0° – 8° TYP 0.009 – 0.013 (0.229 – 0.330) NOTE 1 0.016 – 0.050 (0.406 – 1.270) NOTE: 1. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS. THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE RELATED PARTS PART NUMBER LTC485 LT ® 1137A LTC1320 LTC1321/LTC1322/LTC1335 LTC1323 LTC1347 LTC1387 DESCRIPTION Low Power RS485 Interface Transceiver Low Power RS232 Transceiver AppleTalk Transceiver RS232/EIA562/RS485 Transceivers Single 5V AppleTalk Transceiver 5V Low Power RS232 Transceiver Single 5V RS232/RS485 Transceiver COMMENTS Single 5V Supply, Wide Common Mode Range ±15kV IEC-1000-4-2 ESD Protection, Three Drivers, Five Receivers AppleTalk/Local Talk Compliant Configurable, 10kV ESD Protection LocalTalk/AppleTalk Compliant 10kV ESD Three Drivers/Five Receivers, Five Receivers Alive in Shutdown Single Port, Configurable, 10kV ESD 16 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com U Dimensions in inches (millimeters) unless otherwise noted. SW Package 28-Lead Plastic Small Outline (Wide 0.300) (LTC DWG # 05-08-1690) 0.697 – 0.712* (17.70 – 18.08) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 NOTE 1 0.394 – 0.419 (10.007 – 10.643) 1 0.093 – 0.104 (2.362 – 2.642) 2 3 4 5 6 7 8 9 10 11 12 13 14 0.037 – 0.045 (0.940 – 1.143) 0.050 (1.270) BSC 0.014 – 0.019 (0.356 – 0.482) TYP 0.004 – 0.012 (0.102 – 0.305) S28 (WIDE) 1098 1334fa LT/TP 1099 2K REV A • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 1995
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