LTC1320

LTC1320 AppleTalk© Transceiver U Output Waveforms 5V/DIV 2V/DIV 1k 11 22Ω 10 22Ω 9 14 –5V 22Ω 100pF 22Ω LTC1320 • TA01 FEATURES s s s s DESCRIPTIO s s s s 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. The LTC1320 is available in the 18-pin SOL package. APPLICATI s s s LocalTalk Peripherals Notebook/Palmtop Computers Battery-Powered Systems AppleTalk and LocalTalk are registered trademarks of Apple Computer, Inc. TYPICAL APPLICATI Typical LocalTalk Connection 5V 18 1 3 5 RX ENABLE DATA OUT SHUTDOWN 8 4 LTC1320 #1 16 22Ω 17 22Ω 22Ω 100pF 22Ω 100pF 1k SIGNALS ON LINE LocalTalk TRANSFORMER DATA IN 120Ω DATA IN TX ENABLE UO UO S 2V/DIV 100pF DATA OUT (REMOTE RECEIVER) 50ns/DIV 5V/DIV 1 LTC1320 ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO TOP VIEW TXD TXI TXDEN SD RXEN RXO RXO RXDO GND 1 2 3 4 5 6 7 8 9 18 VDD 17 TXD – 16 TXD + 15 TXO 14 VSS 13 RXI 12 RXI 11 RXD – 10 RXD+ 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 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 SYMBOL VOD PARAMETER Differential Driver Output Voltage Change in Magnitude of Driver Differential Output Voltage VOC Driver Common-Mode Output Voltage Output Common-Mode Range Single-Ended Driver Output Voltage Input High Voltage Input Low Voltage Input Current Three-State Output Current Driver Short-Circuit Current Receiver Input Resistance VOH VOL Receiver Output High Voltage Receiver Output Low Voltage Receiver Output Short-Circuit Current Receiver Output Three-State Current Differential Receiver Threshold Voltage Differential Receiver Input Hysteresis Single-Ended Receiver Input Low Voltage Single-Ended Receiver Input High Voltage IDD ISS Supply Current Supply Current VS = ± 5V ± 5%, TA = 0°C to 70°C (Notes 2, 3) MIN q q CONDITIONS No Load RL = 100Ω (Figure 1) RL = 100Ω (Figure 1) RL = 100Ω (Figure 1) SD = 5V or Power Off No Load RL = 400Ω All Logic Input Pins All Logic Input Pins All Logic Input Pins SD = 5V or Power Off, – 10V < VO < 10V – 5V < VO < 5V – 7V < VIN < 7V IO = – 4mA IO = 4mA 0V < VO < 5V 0V < VO < 5V – 7V < VCM < 7V – 7V < VCM < 7V q q q q q q q q q q q q q q q q TYP MAX UNITS V V 8.0 2.0 0.2 3 ± 10 ± 4.0 ± 3.4 2.0 0.8 ±1 ±2 35 12 3.5 0.4 7 ±2 – 200 70 0.8 2 1.2 30 2 3.0 350 350 85 ± 100 200 350 ± 20 ± 100 500 No Load, SD = 0V No Load, SD = 5V No Load, SD = 5V q q q 2 U V V V V V V V µA µA mA kΩ V V mA µA mV mV V V mA µA µA W U U WW W LTC1320 SWITCHI G CHARACTERISTICS SYMBOL tPLH, HL tSKEW tr, f tENH, L tH, Ldis tPLH, HL tr, f tPLH, HL tENH, L tH, Ldis PARAMETER Differential Driver Propagation Delay Differential Driver Output to Output Differential Driver Rise/Fall Time Driver Enable to Output Active Driver Output Active to Disable Single-Ended Driver Propagation Delay Single-Ended Driver Rise/Fall Time Receiver Propagation Delay Receiver Enable to Output Active Receiver Output Active to Disable The q 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. TYPICAL PERFOR A CE CHARACTERISTICS Output Swing vs Load Current 5 OUTPUT HIGH 10 3 DIFFERENTIAL OUTPUT SWING (V) 4 SUPPLY CURRENT (mA) OUTPUT SWING (V) 2 1 0 –1 –2 –3 –4 –5 0 20 60 80 40 OUTPUT CURRENT (mA) 100 OUTPUT LOW 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. UW U U VS = ± 5V ± 5%, TA = 0°C to 70°C (Notes 2, 3) MIN q q q q q q q q q q CONDITIONS RL = 100Ω, CL = 100pF (Figures 2, 8) RL = 100Ω, CL = 100pF (Figures 2, 8) RL = 100Ω, CL = 100pF (Figures 2, 8) CL = 100pF (Figures 3, 4, 10) CL = 15pF (Figures 3, 4, 10) RL = 450Ω, CL = 100pF (Figures 5, 11) RL = 450Ω, CL = 100pF (Figures 5, 12) CL = 15pF (Figures 13, 14) CL = 100pF (Figures 6, 7, 15) CL = 15pF (Figures 6, 7, 15) TYP 40 10 15 50 50 40 15 60 30 30 MAX 120 50 80 150 150 120 80 160 100 100 UNITS ns ns ns ns ns ns ns ns ns ns 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. Differential Output Swing vs Load Current 1.2 Supply Current vs Temperature 8 1.1 IDD 6 1.0 4 0.004 0.002 ISS 0 10 50 20 30 40 TEMPERATURE (°C) 60 70 2 0 0 20 60 80 40 OUTPUT CURRENT (mA) 100 0 LTC1320 • G01 LTC1320 • G02 LTC1320 • G03 U U 3 LTC1320 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. RXO (Pin 7): Noninverting RS562 Single-Ended Receiver Output. RXDO (Pin 8): RS422 Differential Receiver Output. GND (Pin 9): Ground Pin. 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. RXD – (Pin 11): RS422 Differential Receiver Inverting Input. 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. 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. TXO (Pin 15): RS562 Single-Ended Driver Output. TXD+ (Pin 16): RS422 Differential Driver Noninverting Output. TXD – (Pin 17): RS422 Differential Driver Inverting Output. VDD (Pin 18): Positive Supply. 4.75V ≤ VDD ≤ 5.25V. TEST CIRCUITS TXD+ RL/2 VOD RL/2 TXD LTC1320 • F01 Figure 1 OUTPUT UNDER TEST CL 500Ω VSS LTC1320 • F04 Figure 4 4 U U U TXD+ + VOC TXD RL CL1 CL2 TXD – LTC1320 • TCF02 500Ω OUTPUT UNDER TEST CL VSS LTC1320 • F03 VDD – Figure 2 Figure 3 TXI RL TXO 500Ω OUTPUT UNDER TEST CL LTC1320 • F05 LTC1320 • F06 OUTPUT UNDER TEST VDD CL CL 500Ω LTC1320 • F07 Figure 5 Figure 6 Figure 7 LTC1320 SWITCHI G WAVEFOR S 3V TXD 0V 1.5V f = 1MHz: tr < 10ns: tf < 10ns tPLH TXD – TXD + VO 1/2 VO tSKEW tSKEW 1/2 VO LTC1320 • F08 Figure 8 VOH VOL VO –VO 10% tr 90% VDIFF = V(TXD+) – V(TXD–) tf 90% 10% LTC1320 • F09 Figure 9 3V RXI 0V 1.5V f = 1MHz: tr < 10ns: tf < 10ns tPHL VOH RXO VOL 1.5V 1.5V tPLH 1.5V 3V TXDEN 0V 5V TXD+, TXD – VOL VOH TXD+, TXD – –5V 1.5V f = 1MHz: tr ≤ 10ns: tf ≤ 10ns tENL 0V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH 0V tENH Figure 10 2.5V (RXD–) – (RXD+) –2.5V VOH RXDO VOL 3V RXEN 0V 5V RXO, RXO, RXDO VOL VOH RXO, RXO, RXDO 0V W U 1.5V tPHL 3V TXI 0V VOH TXO VOL 1.5V f = 1MHz: tr < 10ns: tf < 10ns 1.5V tPLH 0V LTC1320 • F11 tPHL 0V Figure 11 90% 10% tr 90% 10% tf LTC1320 • F12 Figure 12 1.5V tLdis 0.5V 3V RXI 0V VOH RXO VOL 1.5V f = 1MHz: tr < 10ns: tf < 10ns 1.5V tPHL 1.5V LTC1320 • F13 0.5V tHdis tPLH 1.5V LTC1320 • F10 Figure 13 0V f = 1MHz: tr < 10ns: tf < 10ns tPHL 1.5V 0V tPLH 1.5V LTC1320 • F14 Figure 14 f = 1MHz: tr ≤ 10ns: tf ≤ 10ns 1.5V 1.5V tLdis 0.5V tENL 1.5V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH 1.5V tENH tHdis 0.5V LTC1320 • F15 Figure 15 5 LTC1320 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- TYPICAL APPLICATI S RS422 to RS562/RS562 to RS422 Converter 5V 0.1µF 0.1µF 18 17 16 15 13 Single 5V Supply 5V 18 1 2 3 4 LOGIC I/O 5V 5 6 7 8 2µF 8 2 10µF LTC1046 5 LT1054 4 * 3 9 14 LTC1320 11 RXD – 10 RXD + 8 RXDO 2 TXI RS562 IN 12 RXI 7 RXO 1 TXD GND 9 12 11 10 DRIVER I/O + + *LTC1046 GIVES 300µA QUIESCENT CURRENT WHEN LTC1320 IS SHUT DOWN LT1054 PROVIDES HIGHER OUTPUT DRIVE 6 + 0.1µF 100µF 1N5817 LTC1320 • TA03 U 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. VDD TXO 15 RXO 6 RXI 13 LTC1320 TXD+ 16 TXD – 17 SD 4 RXEN 5 VSS 14 0.1µF LTC1320 • TA04 W UO U UO + RS422 IN – RS562 OUT NC NC TXDEN 3 + – RS422 OUT –5V LTC1320 TYPICAL APPLICATI 5V 0.1µF 18 1 TXD 2 TXI 3 TXDEN 4 SD LOGIC I/O 5 RXEN 6 RXO 7 RXO 8 RXDO 9 14 0.1µF LTC1320 TXD – 17 TXD + 16 TXO 15 RXI 13 RXI 12 RXD – 11 RXD + 10 4 SD DATA INPUT/OUTPUT 5 RXEN 6 RXO LTC1320 RXI 13 RXI 12 RXD – 11 RXD + 10 1 TXD 2 TXI 18 VDD Switched Negative Supply 5V DRIVER I/O 3 TXDEN TXO 15 –5V *SCHOTTKY DIODE PREVENTS VSS FROM EXCEEDING GND ON POWER-UP OR POWER-DOWN PACKAGE DESCRIPTIO S Package 18-Lead Plastic SOL 0.291 – 0.299 (7.391 – 7.595) 0.005 (0.127) RAD MIN 0.010 – 0.029 × 45° (0.254 – 0.737) 0.009 – 0.013 (0.229 – 0.330) SEE NOTE 0.016 – 0.050 (0.406 – 1.270) 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. U UO S ≥ 25k ESD Protection 0.1µF TXD – 17 TXD + 16 * * * * * * * VSS 14 0.1µF –5V LTC1320 • TA06 TO OUTSIDE WORLD PROTECTED AGAINST ESD DAMAGE TO ±25kV 1N5817* 7 RXO 8 RXDO LTC1320 • TA05 GND 9 *GENERAL SEMICONDUCTOR ICTE-22C OR EQUIVALENT 0.447 – 0.463 (11.354 – 11.760) 18 17 16 15 14 13 12 11 10 SEE NOTE 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 0.037 – 0.045 (0.940 – 1.143) 0° – 8° TYP 0.050 (1.270) TYP 0.004 – 0.012 (0.102 – 0.305) 0.014 – 0.019 (0.356 – 0.482) TYP 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 SOUTHEAST REGION Linear Technology Corporation 17060 Dallas Parkway Suite 208 Dallas, TX 75248 Phone: (214) 733-3071 FAX: (214) 380-5138 CENTRAL REGION Linear Technology Corporation Chesapeake Square 229 Mitchell Court, Suite A-25 Addison, IL 60101 Phone: (708) 620-6910 FAX: (708) 620-6977 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. 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The Coliseum, Riverside Way Camberley, Surrey GU15 3YL United Kingdom Phone: 44-276-677676 FAX: 44-276-64851 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 q FAX: (408) 434-0507 q TELEX: 499-3977 LT/GP 1192 10K REV 0 © LINEAR TECHNOLOGY CORPORATION 1992