LTC1320 AppleTalk© Transceiver U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ Single Chip Provides Complete LocalTalk©/AppleTalk© Port Low Power: ICC = 1.2mA Typ Shutdown Pin Reduces ICC to 30µA Typ Drivers Maintain High Impedance in Three-State or with Power Off 30ns Driver Propagation Delay Typ 5ns Driver Skew Typ Thermal Shutdown Protection Drivers are Short-Circuit Protected The LTC1320 is an RS422/RS562 line transceiver designed to operate on LocalTalk networks. It provides one differential RS422 driver, one single-ended RS562 driver, two single-ended RS562 receivers, and one differential RS422 receiver. The LTC1320 draws only 1.2mA quiescent current when active and 30µA in shutdown, making it ideal for use in battery-powered devices and other systems where power consumption is a primary concern. The LTC1320 drivers are specified to drive ±2V into 100Ω. Additionally, the driver outputs three-state when disabled, during shutdown, or when the power is off; they maintain high impedance even with output common-mode voltages beyond the power supply rails. Both the driver outputs and receiver inputs are protected against ESD damage to beyond 5kV. UO APPLICATI ■ ■ ■ S LocalTalk Peripherals Notebook/Palmtop Computers Battery-Powered Systems The LTC1320 is available in the 18-pin SOL package. AppleTalk and LocalTalk are registered trademarks of Apple Computer, Inc. UO TYPICAL APPLICATI Output Waveforms Typical LocalTalk Connection 5V 18 DATA IN TX ENABLE 3 RX ENABLE SHUTDOWN 22Ω 16 22Ω 100pF 22Ω 1 5 DATA OUT 17 22Ω DATA IN 5V/DIV 120Ω 2V/DIV 100pF LTC1320 #1 1k 8 4 9 LocalTalk TRANSFORMER 14 –5V 11 22Ω 22Ω 10 22Ω 100pF 22Ω 1k SIGNALS ON LINE 2V/DIV LTC1320 • TA01 100pF 5V/DIV DATA OUT (REMOTE RECEIVER) 50ns/DIV 1 LTC1320 U U RATI GS W W W W AXI U U ABSOLUTE PACKAGE/ORDER I FOR ATIO Supply Voltage (VDD) ................................................ 7V Supply Voltage (VSS) .............................................. – 7V Input Voltage (Logic Inputs) ......... – 0.3V to VDD + 0.3V Input Voltage (Receiver Inputs) ............................ ±15V Driver Output Voltage (Forced) ............................. ±15V Output Short-Circuit Duration ......................... Indefinite Operating Temperature Range ................... 0°C ot 70°C Storage Temperature Range ................ – 65°c to 150°C Lead Temperature (Soldering, 10 sec)................ 300°C TOP VIEW TXD 1 18 VDD TXI 2 17 TXD – TXDEN 3 16 TXD + SD 4 15 TXO RXEN 5 14 VSS RXO 6 13 RXI RXO 7 12 RXI RXDO 8 11 RXD – GND 9 10 RXD+ ORDER PART NUMBER LTC1320CS S PACKAGE 18-LEAD PLASTIC SOL LTC1320 • PO01 TJMAX = 150°C, θJA = 100°C/W Consult factory for Industrial and Military grade parts. DC ELECTRICAL CHARACTERISTICS VS = ±5V ±5%, TA = 0°C to 70°C (Notes 2, 3) SYMBOL PARAMETER CONDITIONS VOD Differential Driver Output Voltage No Load RL = 100Ω (Figure 1) Change in Magnitude of Driver Differential Output Voltage RL = 100Ω (Figure 1) Driver Common-Mode Output Voltage RL = 100Ω (Figure 1) Output Common-Mode Range SD = 5V or Power Off ● Single-Ended Driver Output Voltage No Load RL = 400Ω ● ● ±4.0 ±3.4 V V Input High Voltage All Logic Input Pins ● 2.0 V Input Low Voltage All Logic Input Pins ● Input Current All Logic Input Pins ● Three-State Output Current SD = 5V or Power Off, – 10V < VO < 10V ● Driver Short-Circuit Current – 5V < VO < 5V ● 35 Receiver Input Resistance – 7V < VIN < 7V ● 12 3.5 VOC MIN ● ● 8.0 2.0 Receiver Output High Voltage IO = – 4mA ● Receiver Output Low Voltage IO = 4mA ● Receiver Output Short-Circuit Current 0V < VO < 5V ● Receiver Output Three-State Current 0V < VO < 5V ● Differential Receiver Threshold Voltage – 7V < VCM < 7V ● Differential Receiver Input Hysteresis – 7V < VCM < 7V V V ±10 V 0.8 V ±1 ±20 µA ±2 ±100 µA 350 500 mA kΩ V 7 ±2 – 200 0.4 V 85 mA ±100 µA 200 mV 70 ● ● UNITS V V 3 VOL Single-Ended Receiver Input High Voltage MAX 0.2 VOH Single-Ended Receiver Input Low Voltage TYP mV 0.8 V 2 V IDD Supply Current No Load, SD = 0V No Load, SD = 5V ● ● 1.2 30 3.0 350 mA µA ISS Supply Current No Load, SD = 5V ● 2 350 µA 2 LTC1320 U SWITCHI G CHARACTERISTICS VS = ±5V ±5%, TA = 0°C to 70°C (Notes 2, 3) SYMBOL PARAMETER CONDITIONS TYP MAX UNITS tPLH, HL Differential Driver Propagation Delay RL = 100Ω, CL = 100pF (Figures 2, 8) ● 40 120 ns tSKEW Differential Driver Output to Output RL = 100Ω, CL = 100pF (Figures 2, 8) ● 10 50 ns tr, f Differential Driver Rise/Fall Time RL = 100Ω, CL = 100pF (Figures 2, 8) ● 15 80 ns tENH, L Driver Enable to Output Active CL = 100pF (Figures 3, 4, 10) ● 50 150 ns tH, Ldis Driver Output Active to Disable CL = 15pF (Figures 3, 4, 10) ● 50 150 ns tPLH, HL Single-Ended Driver Propagation Delay RL = 450Ω, CL = 100pF (Figures 5, 11) ● 40 120 ns tr, f Single-Ended Driver Rise/Fall Time RL = 450Ω, CL = 100pF (Figures 5, 12) ● 15 80 ns tPLH, HL Receiver Propagation Delay CL = 15pF (Figures 13, 14) ● 60 160 ns tENH, L Receiver Enable to Output Active CL = 100pF (Figures 6, 7, 15) ● 30 100 ns tH, Ldis Receiver Output Active to Disable CL = 15pF (Figures 6, 7, 15) ● 30 100 ns The ● denotes specifications which apply over the full operating temperature range. Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. MIN Note 2: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to ground unless otherwise specified. Note 3: All typicals are given at VS = ±5V, TA = 25°C. U W TYPICAL PERFOR A CE CHARACTERISTICS Differential Output Swing vs Load Current Output Swing vs Load Current 5 OUTPUT HIGH 3 2 1 0 –1 –2 –3 OUTPUT LOW 8 SUPPLY CURRENT (mA) DIFFERENTIAL OUTPUT SWING (V) 4 OUTPUT SWING (V) Supply Current vs Temperature 1.2 10 6 4 0 20 60 80 40 OUTPUT CURRENT (mA) 100 IDD 1.0 0.004 2 ISS 0.002 –4 –5 1.1 0 0 20 60 80 40 OUTPUT CURRENT (mA) LTC1320 • G01 100 LTC1320 • G02 0 0 10 50 20 30 40 TEMPERATURE (°C) 60 70 LTC1320 • G03 U U U PI FU CTIO S TXD (Pin 1): RS422 Differential Driver Input (TTL Compatible). TXI (Pin 2): RS562 Single-Ended Driver Input (TTL compatible. TXDEN (Pin 3): RS422 Differential Driver Output Enable (TTL Compatible). A high level on this pin forces the RS422 driver into three-state; a low level enables the driver. This input does not affect the RS562 single-ended driver. SD (Pin 4): Shutdown Input (TTL Compatible). When this pin is high, the chip is shut down: all driver outputs threestate and the supply current drops to 30µA. A low on this pin allows normal operation. 3 LTC1320 U U U PI FU CTIO S RXEN (Pin 5): Receiver Enable (TTL Compatible). A high level on this pin disables the receivers and three-states the logic outputs; a low level allows normal operation. To prevent erratic behavior at the receiver outputs during shutdown, RXEN should be pulled high along with SD. RXO (Pin 6): Inverting RS562 Single-Ended Receiver Output. RXI (Pin 12): Noninverting RS562 Receiver Input. This input controls the RXO output; it has no effect on the RXO output. RXI (Pin 13): Inverting RS562 Receiver Input. This input controls the RXO output; it has no effect on the RXO output. RXO (Pin 7): Noninverting RS562 Single-Ended Receiver Output. VSS (Pin 14): Negative Supply. – 4.75 ≥ VSS ≥ – 5.25V. The voltage on this pin must never exceed ground on power up or power-down. RXDO (Pin 8): RS422 Differential Receiver Output. TXO (Pin 15): RS562 Single-Ended Driver Output. GND (Pin 9): Ground Pin. TXD+ (Pin 16): RS422 Differential Driver Noninverting Output. RXD+ (Pin 10): RS422 Differential Receiver Noninverting Input. When this pin is ≥ 200mV above RXD –, RXDO will be high; when this pin is ≥ 200mV below RXD –, RXDO will be low. TXD – (Pin 17): RS422 Differential Driver Inverting Output. VDD (Pin 18): Positive Supply. 4.75V ≤ VDD ≤ 5.25V. RXD – (Pin 11): RS422 Differential Receiver Inverting Input. TEST CIRCUITS TXD+ RL/2 VOD TXD+ + RL/2 VOC – – TXD LTC1320 • F01 VSS LTC1320 • TCF02 OUTPUT UNDER TEST 500Ω RL CL LTC1320 • F03 Figure 3 TXO TXI 500Ω CL Figure 2 Figure 1 CL VDD OUTPUT UNDER TEST CL2 TXD OUTPUT UNDER TEST 500Ω CL1 RL TXD VDD OUTPUT UNDER TEST CL 500Ω CL VSS Figure 4 4 LTC1320 • F04 Figure 5 LTC1320 • F07 LTC1320 • F06 LTC1320 • F05 Figure 6 Figure 7 LTC1320 U W SWITCHI G WAVEFOR S 3V TXD 0V f = 1MHz: tr < 10ns: tf < 10ns 1.5V 3V TXI 0V 1.5V tPLH tPHL VOH TXO VOL TXD – TXD + f = 1MHz: tr < 10ns: tf < 10ns 1.5V 1.5V tPHL tPLH 0V 0V LTC1320 • F11 VO 1/2 VO tSKEW Figure 11 1/2 VO tSKEW LTC1320 • F08 Figure 8 VOH VOL VO –VO 90% tr 90% 10% tr 90% VDIFF = V(TXD+) – V(TXD–) 10% 90% 10% tf LTC1320 • F12 10% tf Figure 12 LTC1320 • F09 Figure 9 3V RXI 0V 3V TXDEN 0V 5V TXD+, TXD – VOL VOH TXD+, TXD – –5V 1.5V f = 1MHz: tr ≤ 10ns: tf ≤ 10ns 0V VOH RXO VOL tLdis OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH tHdis 1.5V f = 1MHz: tr < 10ns: tf < 10ns 1.5V tPLH 0.5V 0V tPLH 1.5V 3V RXI 0V 0.5V tENH 1.5V tPHL 1.5V tENL f = 1MHz: tr < 10ns: tf < 10ns 1.5V LTC1320 • F10 VOH RXO VOL 1.5V tPHL 1.5V 1.5V LTC1320 • F13 Figure 10 2.5V (RXD–) – (RXD+) –2.5V Figure 13 f = 1MHz: tr < 10ns: tf < 10ns 0V tPHL VOH RXDO VOL 0V tPLH 1.5V 1.5V LTC1320 • F14 Figure 14 3V RXEN 0V 5V RXO, RXO, RXDO VOL VOH RXO, RXO, RXDO 0V 1.5V f = 1MHz: tr ≤ 10ns: tf ≤ 10ns tENL 1.5V tLdis 1.5V OUTPUT NORMALLY LOW 0.5V OUTPUT NORMALLY HIGH 0.5V 1.5V tHdis tENH LTC1320 • F15 Figure 15 5 LTC1320 U W U UO APPLICATI S I FOR ATIO Thermal Shutdown Protection The LTC1320 includes a thermal shutdown circuit which protects the part against prolonged shorts at the driver outputs. If any driver output is shorted to another output or to the power supply, the current will be initially limited to 450mA max. The die temperature will rise to about 150°C, at which point the thermal shutdown circuit turns off the driver outputs. When the die cools to about 130°C, the outputs re-enable. If the shorted condition still exists, the part will heat again and the cycle will repeat. When the short is removed, the part will return to normal operation. This oscillation occurs at about 10Hz and prevents the part from being damaged by excessive power dissipation. Power Shutdown The power shutdown feature of the LTC1320 is designed primarily for battery-powered systems. When SD (pin 4) is forced high, the part enters shutdown mode. In shut- down, the supply current drops from 1.2mA to 30µA typ. The driver outputs are three-stated and the power to the receivers is removed. The receiver outputs are not automatically three-stated in shutdown, and can toggle erroneously due to feedthrough from the inputs. This can be prevented by pulling RXEN high along with SD; this will three-state the receiver outputs and prevent the generation of spurious data. Supply Bypassing The LTC1320 requires that both VDD and VSS are well bypassed; data errors can result from inadequate bypassing. Bypass capacitor values of 0.1µF to 1µF from VDD to ground and from VSS to ground are adequate. Lead lengths and trace lengths between the capacitors and the chip should be short to minimize lead inductance. UO TYPICAL APPLICATI S Single 5V Supply RS422 to RS562/RS562 to RS422 Converter 5V 5V 0.1µF 0.1µF 18 LOGIC I/O 5V 18 1 17 2 16 3 15 4 13 5 LTC1320 12 6 11 7 10 + RS422 IN – DRIVER I/O RS562 IN 7 RXO TXD+ 16 TXD – 17 TXDEN 3 RS562 OUT NC NC + – RS422 OUT SD 4 RXEN 5 9 14 GND 2 9 0.1µF + LTC1046 5 LT1054 4 * 3 100µF 1N5817 LTC1320 • TA03 *LTC1046 GIVES 300µA QUIESCENT CURRENT WHEN LTC1320 IS SHUT DOWN LT1054 PROVIDES HIGHER OUTPUT DRIVE 6 RXI 13 LTC1320 12 RXI 1 TXD 8 10µF RXO 6 8 RXDO 2µF + TXO 15 10 RXD + 2 TXI 8 + 11 RXD – VDD VSS 14 –5V 0.1µF LTC1320 • TA04 LTC1320 UO TYPICAL APPLICATI S Switched Negative Supply ≥ 25k ESD Protection 5V 5V 0.1µF 0.1µF 18 LOGIC I/O 1 TXD TXD – 17 2 TXI TXD + 16 3 TXDEN TXO 15 4 SD RXI 13 5 RXEN LTC1320 RXI 12 6 RXO RXD – 11 7 RXO RXD + 10 1 TXD TXD – 17 * TXD + 16 2 TXI DRIVER I/O DATA INPUT/OUTPUT 8 RXDO 9 18 VDD TXO 15 4 SD RXI 13 LTC1320 5 RXEN 14 0.1µF 3 TXDEN 1N5817* * * RXI 12 6 RXO RXD – 11 7 RXO RXD + 10 * * * 8 RXDO –5V GND LTC1320 • TA05 VSS 9 *SCHOTTKY DIODE PREVENTS VSS FROM EXCEEDING GND ON POWER-UP OR POWER-DOWN TO OUTSIDE WORLD PROTECTED AGAINST ESD DAMAGE TO ±25kV * 14 LTC1320 • TA06 0.1µF –5V *GENERAL SEMICONDUCTOR ICTE-22C OR EQUIVALENT U PACKAGE DESCRIPTIO 0.447 – 0.463 (11.354 – 11.760) 18 17 16 15 14 13 12 11 10 S Package 18-Lead Plastic SOL 0.394 – 0.419 (10.007 – 10.643) SEE NOTE 1 0.291 – 0.299 (7.391 – 7.595) 0.005 (0.127) RAD MIN 2 3 4 5 6 7 8 0.093 – 0.104 (2.362 – 2.642) 0.010 – 0.029 × 45° (0.254 – 0.737) 9 0.037 – 0.045 (0.940 – 1.143) 0° – 8° TYP 0.009 – 0.013 (0.229 – 0.330) SEE NOTE 0.016 – 0.050 (0.406 – 1.270) 0.050 (1.270) TYP 0.004 – 0.012 (0.102 – 0.305) 0.014 – 0.019 (0.356 – 0.482) TYP NOTE: 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. 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 circuits as described herein will not infringe on existing patent rights. SOL18 0392 7 LTC1320 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 CENTRAL REGION Linear Technology Corporation Chesapeake Square 229 Mitchell Court, Suite A-25 Addison, IL 60101 Phone: (708) 620-6910 FAX: (708) 620-6977 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. Suite 206 Woodland Hills, CA 91364 Phone: (818) 703-0835 FAX: (818) 703-0517 NORTHWEST REGION Linear Technology Corporation 782 Sycamore Dr. Milpitas, CA 95035 Phone: (408) 428-2050 FAX: (408) 432-6331 International Sales Offices FRANCE Linear Technology S.A.R.L. Immeuble "Le Quartz" 58 Chemin de la Justice 92290 Chatenay Mallabry France Phone: 33-1-46316161 FAX: 33-1-46314613 KOREA Linear Technology Korea Branch Namsong Building, #505 Itaewon-Dong 260-199 Yongsan-Ku, Seoul Korea Phone: 82-2-792-1617 FAX: 82-2-792-1619 TAIWAN Linear Technology Corporation Rm. 801, No. 46, Sec. 2 Chung Shan N. Rd. Taipei, Taiwan, R.O.C. Phone: 886-2-521-7575 FAX: 886-2-562-2285 GERMANY Linear Techonolgy GMBH Untere Hauptstr. 9 D-8057 Eching Germany Phone: 49-89-319741-0 FAX: 49-89-3194821 SINGAPORE Linear Technology Pte. Ltd. 101 Boon Keng Road #02-15 Kallang Ind. Estates Singapore 1233 Phone: 65-293-5322 FAX: 65-292-0398 UNITED KINGDOM Linear Technology (UK) Ltd. The Coliseum, Riverside Way Camberley, Surrey GU15 3YL United Kingdom Phone: 44-276-677676 FAX: 44-276-64851 JAPAN Linear Technology KK 5F YZ Building 4-4-12 Iidabashi Chiyoda-Ku Tokyo, 102 Japan Phone: 81-3-3237-7891 FAX: 81-3-3237-8010 World Headquarters Linear Technology Corporation 1630 McCarthy Blvd. Milpitas, CA 95035-7487 Phone: (408) 432-1900 FAX: (408) 434-0507 10/92 8 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 ● FAX: (408) 434-0507 ● TELEX: 499-3977 LT/GP 1192 10K REV 0 LINEAR TECHNOLOGY CORPORATION 1992