Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsInterface ICsInterface IC - transceivers RS485, RS562 4/4 SOIC 24

LTC1321/LTC1322/LTC1335

RS232/EIA562/RS485

Transceivers

The LTC1321/LTC1322/LTC1335 are low power CMOS

bidirectional transceivers, each featuring two

reconfigurable

interface ports. Each can be configured as two RS485

differential ports, as two single-ended ports, or as one

RS485 differential port and one single-ended port. The

LTC1321/LTC1322 can provide RS232 or EIA562 compat-

ible single-ended outputs; the LTC1335 provides EIA562

compatible outputs and additionally includes an output

enable pin, allowing the receiver logic level outputs to be

three-stated.

The RS232/EIA562 transceivers operate to 120kbaud and

are in full compliance with EIA/TIA-562 specification. The

RS485 transceivers operate to 10Mbaud and are in full

compliance with RS485 and RS422 specifications. All

interface drivers feature short-circuit and thermal shut-

down protection. An enable pin allows RS485 driver

outputs to be forced into high impedance which is main-

tained 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

connects the driver outputs back to the receiver inputs for

diagnostic self-test.

The LTC1321/LTC1322 can support RS232 voltage levels

when 6.5V ≤ V

≤ 10V and –6.5V ≥ V

≥ –10V. The

LTC1335 supports receiver output enable but not RS232

levels. A shutdown mode reduces the I

supply current

to 15µA.

ESCRIPTIO

APPLICATIONS

■

Low Power RS485/RS422/EIA562/RS232 Interface

■

Cable Repeater

■

Level Translator

■

LTC1321: 2-EIA562/RS232 Transceivers/2-RS485

Transceivers

■

LTC1322: 4-EIA562/RS232 Transceivers/2-RS485

Transceivers

■

LTC1335: 4-EIA562 Transceivers/2-RS485

Transceivers with OE

■

LTC1321/LTC1322 Have the Same Pinout as

SP301/SP302

■

LTC1335 Features Receiver Three-State Outputs

■

Low Supply Current: 1mA Typical

■

15µA Supply Current in Shutdown

■

120kBaud in EIA/TIA-562 or RS232 Mode

■

10MBaud in RS485/RS422 Mode

■

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

■

I/O Lines Can Withstand ±25V

■

Withstands Repeated 10kV ESD Pulses

ITY

CC2

CC1

120Ω

LTC1322

1321/22/35 TA01

RX OUT

RS485 INTERFACE

DR ENABLE

DR IN

EE1

–5V

LTC1322

RX OUT

DR ENABLE

DR IN

EE2



–5V

120Ω

4000-FT 24-GAUGE TWISTED PAIR

DR IN

RX OUT

DR IN

EIA562 INTERFACE

DR IN

RX OUT

DR IN

Summary of content (20 pages)

PAGE 1
LTC1321/LTC1322/LTC1335 RS232/EIA562/RS485 Transceivers U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ LTC1321: 2-EIA562/RS232 Transceivers/2-RS485 Transceivers LTC1322: 4-EIA562/RS232 Transceivers/2-RS485 Transceivers LTC1335: 4-EIA562 Transceivers/2-RS485 Transceivers with OE LTC1321/LTC1322 Have the Same Pinout as SP301/SP302 LTC1335 Features Receiver Three-State Outputs Low Supply Current: 1mA Typical 15µA Supply Current in Shutdown 120kBaud in EIA/TIA-562 or RS232 Mode 10MBaud in RS485/RS4
PAGE 2
LTC1321/LTC1322/LTC1335 W W W AXI U U ABSOLUTE RATI GS Output Voltage Drivers ................................................. – 25V to 25V Receivers ............................... – 0.3V to (VCC + 0.3V) Output Short-Circuit Duration ......................... Indefinite Operating Temperature Range LTC1321C/LTC1322C/LTC1335C ......... 0°C to 70°C LTC1321I/LTC1322I/LTC1335I ......... – 40°C to 85°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)..........
PAGE 3
LTC1321/LTC1322/LTC1335 DC ELECTRICAL CHARACTERISTICS VCC = VDD (LTC1321/LTC1322) = 5V ±5%, VEE = – 5V ±5% (Notes 2, 3) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS RS485 Driver (SEL1 = SEL2 = HIGH) VOD1 Differential Driver Output Voltage (Unloaded) IO = 0 ● VOD2 Differential Driver Output Voltage (With Load) Figure 1, R = 50Ω (RS422) Figure 1, R = 27Ω (RS485) ● ● 5 V 5 5 V V ∆VOD Change in Magnitude of Driver Differential Output Voltage for Complementary Output States Figure 1, R = 2
PAGE 4
LTC1321/LTC1322/LTC1335 DC ELECTRICAL CHARACTERISTICS VCC = VDD (LTC1321/LTC1322) = 5V ±5%, VEE = – 5V ±5% (Notes 2, 3) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Supply Currents ICC VCC Supply Current No Load (SEL1 = SEL2 = HIGH) Shutdown, ON/OFF = 0V ● ● 1000 15 2000 50 µA µA IDD VDD Supply Current (LTC1321/LTC1322) No Load (SEL1 = SEL2 = LOW) Shutdown, ON/OFF = 0V ● ● 300 0.
PAGE 5
LTC1321/LTC1322/LTC1335 U W TYPICAL PERFORMANCE CHARACTERISTICS RS485 Driver Differential Output Voltage vs Temperature RS485 Driver Differential Output Current vs Output Voltage 15 70 2.4 2.3 2.2 2.1 2.0 1.9 1.8 1.7 TA = 25°C 60 12 50 TIME (µs) RL = 54Ω 2.
PAGE 6
LTC1321/LTC1322/LTC1335 U W TYPICAL PERFORMANCE CHARACTERISTICS 5.0 0.5 20 IOUT = 3mA IOUT = 3mA 4.9 18 0.4 4.7 4.6 4.5 4.4 4.3 16 14 0.3 TIME (ns) OUTPUT VOLTAGE (V) 4.8 OUTPUT VOLTAGE (V) RS485 Receiver tPLH – tPHL vs Temperature Receiver Output Low Voltage vs Temperature Receiver Output High Voltage vs Temperature 0.2 2 4.
PAGE 7
LTC1321/LTC1322/LTC1335 U U U PI FU CTIO S LTC1321 LTC1322/LTC1335 VDD (Pin 1): Positive Supply Input for EIA/TIA-562 Drivers. B1: (Pin 2): Receiver Input. A1 (Pin 3): Receiver Input. Z1 (Pin 4): Driver Output. Y1 (Pin 5): Driver Output. SEL1 (Pin 6): Interface Mode Select Input. SEL2 (Pin 7): Interface Mode Select Input. Y2 (Pin 8): Driver Output. Z2 (Pin 9): Driver Output. A2 (Pin 10): Receiver Input. B2 (Pin 11): Receiver Input. GND (Pin 12): Ground. VEE (Pin 13): Negative Supply.
PAGE 8
LTC1321/LTC1322/LTC1335 U U FU CTIO TABLES LTC1321 LTC1322 RS485 Driver Mode RS485 Driver Mode ON/OFF INPUTS SEL DE D LINE CONDITION OUTPUTS Y Z ON/OFF INPUTS SEL DE D LINE CONDITION OUTPUTS Y Z 1 1 1 0 No Fault 0 1 1 1 1 0 No Fault 0 1 1 1 1 1 No Fault 1 0 1 1 1 1 No Fault 1 0 1 1 1 X Fault Z Z 1 1 1 X Fault Z Z 1 1 0 X X Z Z 1 1 0 X X Z Z 0 1 X X X Z Z 0 1 X X X Z Z RS485 Receiver Mode RS485 Receiver Mode ON/OFF INPUTS
PAGE 9
LTC1321/LTC1322/LTC1335 U U FU CTIO TABLES LTC1335 EIA562 Driver Mode RS485 Driver Mode ON/OFF INPUTS SEL DE D LINE CONDITION OUTPUTS Y Z ON/OFF INPUTS SEL D LINE CONDITION OUTPUT Y, Z 1 1 1 0 No Fault 0 1 1 0 0 No Fault 1 1 1 1 1 No Fault 1 0 1 0 1 No Fault 0 1 1 1 X Fault Z Z 1 0 X Fault Z 1 1 0 X X Z Z 0 0 X X Z 0 1 X X X Z Z RS485 Receiver Mode EIA562 Receiver Mode INPUTS INPUTS ON/OFF SEL OE A–B OUTPUT R ON/OFF SEL OE A OR B
PAGE 10
LTC1321/LTC1322/LTC1335 W BLOCK DIAGRA SM LTC1321 Interface Configuration With Loopback VDD Y1 SEL1 PORT 1 = EIA562 MODE PORT 2 = EIA562 MODE 1 24 22 5 6 20 19 VCC VDD RA1 Z1 Y2 7 8 18 17 15 GND 12 13 22 4 21 DY1 LB Y1 *SEL1 SEL2 PORT 1 = RS485 MODE PORT 2 = EIA562 MODE 1 24 ON DY2 SEL2 Y2 20 6 19 7 18 8 17 15 RA2 VEE 5 GND 12 13 VCC VDD PORT 1 = EIA562 MODE PORT 2 = RS485 MODE 1 24 22 RA1 DE1 DY1 LB ON Y1 SEL1 *SEL2 Y2 20 6 19 7 8 18 17 16 DY2 Z2 RA2 VEE 5 GND
PAGE 11
LTC1321/LTC1322/LTC1335 W BLOCK DIAGRA SM LTC1322/LTC1335 Interface Configuration With Loopback PORT 1 = EIA562 MODE PORT 2 = EIA562 MODE 24 1 * *VDD /OE PORT 1 = RS485 MODE PORT 2 = EIA562 MODE VCC 1 *VDD /OE 24 * 23 23 22 Z1 Y1 SEL1 4 21 5 6 20 19 7 SEL2 18 17 9 16 Y2 Z2 15 GND Z1 21 LB 14 13 12 ON DY2 Y2 DZ2 Z2 20 5 6 Y1 **SEL1 19 7 SEL2 8 22 4 DZ1 DY1 8 18 17 9 16 15 RA2 RB2 VEE *VDD /OE GND 14 13 12 VCC *VDD /OE PORT 1 = RS485 MODE PORT 2 = RS485 MODE
PAGE 12
LTC1321/LTC1322/LTC1335 U W SWITCHI G WAVEFOR S 3V f = 1MHz: tr ≤ 10ns: tf ≤ 10ns 1.5V D 1.5V 0V tPLH tPHL VO 90% Y–Z VDIFF = V(Y) – V(Z) 50% 10% –VO 90% 50% 10% 1/2 VO tr tf Z VO Y tSKEW tSKEW 1321/22/35 F07 Figure 7. RS485 Driver Propagation Delays 3V 1.5V DE f = 1MHz: tr ≤ 10ns: tf ≤ 10ns 1.5V 0V tZL tLZ 5V Y OR Z 2.3V OUTPUT NORMALLY LOW VOL tZH OUTPUT NORMALLY HIGH VOH 0.5V tHZ 0.5V 2.3V Y OR Z 0V 1321/22/35 F08 Figure 8.
PAGE 13
LTC1321/LTC1322/LTC1335 U W SWITCHI G WAVEFOR S V IH 1.7V 1.3V A OR B VIL tPHL tPLH VOH 2.4V R 1321/22/35 F11 0.8V VOL Figure 11. EIA/TIA-562 Receiver Propagation Delays 3V 1.5V OE 0V f = 1MHz: tr ≤ 10ns: tf ≤ 10ns tZL 1.5V tLZ 5V R 1.5V OUTPUT NORMALLY LOW VOL tZH OUTPUT NORMALLY HIGH VOH 0.5V tHZ 0.5V 1.5V R 0V 1321/22/35 F12 Figure 12.
PAGE 14
LTC1321/LTC1322/LTC1335 U W U UO APPLICATI S I FOR ATIO 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. LTC1321/LTC1322 ONLY VCC 5V 24 0.1µF RX OUT EIA562 and RS485 output levels are supported when LTC1321/LTC1322/LTC1335 are powered from ±5V supplies.
PAGE 15
LTC1321/LTC1322/LTC1335 W U U UO APPLICATI S I FOR ATIO 1k OE RFI TXD TXI TXDEN RXEN RXO RXO RXDO 1k 18 1 5V 17 TXD – 2 RFI RFI 4 5 14 RFI 1k 5V 6 13 7 12 8 – 11 RXD + RFI 10 RXD RFI 9 LTC1320 24 2 23 22 3 21 4 120Ω 120Ω 16 TXD + 15 3 RFI 1 RFI SEL1, 5V 1k 22Ω 22Ω SEL2, 5V RFI = 20 5 6 7 19 LTC1335 18 8 17 9 16 100pF 10 5V RA1 DE1 DY1 5V 5V 15 11 14 12 13 –5V 1321/22/35 F15 Figure 15.
PAGE 16
LTC1321/LTC1322/LTC1335 UO TYPICAL APPLICATI S and receivers for half duplex multi-point data transmission. The wires must be terminated at both ends with resistors equal to the wire’s characteristic impedance, generally 120Ω. An optional shield around the twisted pair helps to reduce unwanted noise and should be connected to ground at one end. A typical EIA562/RS232 interface application is shown in Figure 17 with LTC1322. A typical EIA562 interface application with LTC1335 is shown in Figure 18.
PAGE 17
LTC1321/LTC1322/LTC1335 UO TYPICAL APPLICATI S A typical RS422 connection shown in Figure 20 allows one driver and ten receivers on a twisted pair of wires terminated with a 100Ω resistor at one end. The ground shield is optional. A typical twisted pair line repeater is shown in Figure 21. As data transmission rate drops with increased cable length, repeater can be inserted to improve transmission rate or to transmit beyond 4000 feet limit.
PAGE 18
LTC1321/LTC1322/LTC1335 UO TYPICAL APPLICATI S The LTC1322/LTC1335 can be used to translate EIA562 to RS422 interface level or vice versa as shown in Figure 22. One port is configured as EIA562 transceiver and the other as RS485 transceiver. The LTC1322 can also support RS232 to RS422 level translation if VDD is between 6.5V and 10V, and VEE is between – 6.5V and – 10V.
PAGE 19
LTC1321/LTC1322/LTC1335 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. N Package 24-Lead Plastic DIP 1.265 (32.131) 24 23 22 21 20 19 18 17 16 15 14 13 1 2 3 4 5 6 7 8 9 10 11 12 0.260 ± 0.010 (6.604 ± 0.254) 0.300 – 0.325 (7.620 – 8.255) 0.045 – 0.065 (1.143 – 1.651) 0.130 ± 0.005 (3.302 ± 0.127) 0.015 (0.381) MIN 0.009 – 0.015 (0.229 – 0.381) ( 0.125 (3.175) MIN +0.025 0.325 –0.015 +0.635 8.255 –0.381 0.065 (1.651) TYP ) 0.050 – 0.
PAGE 20
LTC1321/LTC1322/LTC1335 U.S. Area Sales Offices NORTHEAST REGION Linear Technology Corporation One Oxford Valley 2300 E. Lincoln Hwy.,Suite 306 Langhorne, PA 19047 Phone: (215) 757-8578 FAX: (215) 757-5631 SOUTHEAST REGION Linear Technology Corporation 17060 Dallas Parkway Suite 208 Dallas, TX 75248 Phone: (214) 733-3071 FAX: (214) 380-5138 SOUTHWEST REGION Linear Technology Corporation 22141 Ventura Blvd.