DESCRIPTIO. LTC1323 Single 5V AppleTalk Transceiver

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1 LTC Single V AppleTalk Transceiver FEATRES Single Chip Provides Complete LocalTalk /AppleTalk Port Operates From a Single V Supply ESD Protection to ±0kV on Receiver Inputs and Driver Outputs Low Power: I CC =.ma Typ Shutdown Pin Reduces I CC to 0.µA Typ Receiver Keep-Alive Function: I CC = 6µA Typ Differential Driver Drives Either Differential AppleTalk or Single-Ended EIA6 Loads Drivers Maintain High Impedance in Three-State or with Power Off Thermal Shutdown Protection Drivers are Short-Circuit Protected APPLICATI O S LocalTalk Peripherals Notebook/Palmtop Computers Battery-Powered Systems, LTC and LT are registered trademarks of Linear Technology Corporation. AppleTalk and LocalTalk are registered trademarks of Apple Computer, Inc. DESCRIPTIO The LTC is a multi-protocol line transceiver designed to operate on AppleTalk or EIA6-compatible singleended networks while operating from a single V supply. There are two versions of the LTC available: a 6-pin version designed to connect to an AppleTalk network, and a -pin version which also includes the additional single-ended drivers and receivers necessary to create an Apple-compatible serial port. An on-board charge pump generates a V supply which can be used to power external devices. Additionally, the -pin LTC features a micropower keep-alive mode during which one of the single-ended receivers is kept active to monitor external wake-up signals. The LTC draws only.ma quiescent current when active, 6µA in receiver keepalive mode, and 0.µA in shutdown, making it ideal for use in battery-powered systems. The differential driver can drive either differential AppleTalk loads or conventional single-ended loads. The driver outputs three-state when disabled, during shutdown, in receiver keep-alive mode, or when the power is off. The driver outputs will 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 ±0kV. TYPICAL APPLICATI O LTC 0.µF CHARGE PMP CPEN TXD TXDEN 6 SHDN EN O O 0 DO 0 6 V D D µf 0.µF µf = Ω TO 0Ω Ω TO 0Ω 00pF 6 LTC TA0

2 LTC ABSOLTE AXI RATI GS W W W Supply Voltage ( )... V Input Voltage Logic Inputs... 0.V to 0.V Receiver Inputs... ±V Driver Output Voltage (Forced)... ±V Driver Short-Circuit Duration... Indefinite Operating Temperature Range... 0 C to 0 C Storage Temperature Range... 6 C to 0 C Lead Temperature (Soldering, 0 sec) C PACKAGE/ORDER I FOR W ATIO C TOP VIEW ORDER PART NMBER ORDER PART NMBER C CPEN TXD TXDEN 6 SHDN EN O O 0 DO NC NC GND C C NC NC D D PGND LTCCG C C TXD TXDEN SHDN EN 6 DO GND TOP VIEW S PACKAGE 6-LEAD PLASTIC SO T JMAX = C, θ JA = C/W 6 C C 0 D D LTCCS G PACKAGE -LEAD PLASTIC SSOP T JMAX = 0 C, θ JA = 6 C/W C TOP VIEW ORDER PART NMBER C CPEN C C LTCCSW TXD 0 TXDEN 6 SHDN EN O 6 O 0 D DO D GND PGND SW PACKAGE -LEAD PLASTIC SO WIDE T JMAX = C, θ JA = C/W Consult factory for Industrial and Military grade parts.

3 LTC ELECTRICAL CHARACTERISTICS = V ±0%, T A = 0 C to 0 C (Notes, ) SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS Supplies I CC Normal Operation Supply Current No Load, SHDN =, CPEN =, TXDEN =,. ma EN = Receiver Keep-Alive Supply Current No Load, SHDN =, CPEN =, TXDEN =, 6 00 µa EN = Shutdown Supply Current No Load, SHDN =, CPEN = X, TXDEN = X, 0. 0 µa EN = Negative Supply Output Voltage I LOAD 0mA (Note ),.. V = V, R L = 00Ω (Figure ), =, R = k (Figure ) f OSC Charge Pump Oscillator Frequency 00 khz Differential Driver V OD Differential Output Voltage No Load ± V R L = 00Ω (Figure ) ± V OD Change in Magnitude of Differential R L = 00Ω (Figure ) 0. V Output Voltage Differential Driver V OC Differential Common-Mode R L = 00Ω V Output Voltage V OS Single-Ended Output Voltage No Load ±.0 V R L = k to GND ±. V V CMR Common-Mode Range SHDN = or CPEN = or Power Off ±0 V I SS Short-Circuit Current V V O V 0 00 ma I OZ Three-State Output Current SHDN = or CPEN = or Power Off, ± ±00 µa V O Single-Ended Driver (Note ) V OS Single-Ended Output Voltage No Load ±. V R L = k to GND ±. V V CMR Common-Mode Range SHDN = or CPEN = or TXDEN = ±0 V or Power Off I SS Short-Circuit Current V V O V 0 00 ma I OZ Three-State Output Current SHDN = or CPEN = or TXDEN = ± ±00 µa or Power Off, V O Receivers R IN Input Resistance V V IN V kω Differential Receiver Threshold Voltage V V CM V mv Differential Receiver Input Hysteresis V V CM V 0 mv Single-Ended Input, Low Voltage (Note ) 0. V Single-Ended Input, High Voltage (Note ) V Output High Voltage I O = ma. V Output Low Voltage I O = ma 0. V I SS Output Short-Circuit Current V V O V ma I OZ Output Three-State Current V V O V, EN = ± ±00 µa

4 LTC ELECTRICAL CHARACTERISTICS = V ±0%, T A = 0 C to 0 C (Notes and ) SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS Logic Inputs V IH Input High Voltage All Logic Input Pins.0 V V IL Input Low Voltage All Logic Input Pins 0. V I C Input Current All Logic Input Pins ±.0 ±0 µa Switching Characteristics t PLH, t PHL Differential Driver Propagation Delay R L = 00Ω, C L = 00pF (Figures, ) 0 0 ns Differential Driver Propagation Delay R L = k, C L = 00pF (Figures, ) 0 0 ns with Single-Ended Load Single-Ended Driver Propagation Delay R L = k, C L = 00pF, (Figures, 0) (Note ) 0 0 ns Differential Receiver Propagation Delay C L = pf (Figures, ) 0 60 ns Single-Ended Receiver C L = pf (Figures 6, ) (Note ) 0 60 ns Propagation Delay Inverting Receiver Propagation Delay C L = pf (Figures 6, ) (Note ) ns in Keep-Alive Mode, SHDN =, CPEN = t SKEW Differential Driver Output to Output R L = 00Ω, C L = 00pF (Figures, ) 0 0 ns t r, t f Differential Driver Rise/Fall Time R L = 00Ω, C L = 00pF (Figures, ) 0 0 ns Differential Driver Rise/Fall Time R L = k, C L = 00pF (Figures, ) 0 0 ns with Single-Ended Load Single-Ended Driver Rise/Fall Time R L = k, C L = 00pF (Figures, 0) (Note ) 0 ns t HDIS, t LDIS Differential Driver Output Active C L = pf (Figures, ) 0 0 ns to Disable Any Receiver Output Active to Disable C L = pf (Figures, ) 0 00 ns t ENH, t ENL Differential Driver C L = pf (Figures, ) 0 0 ns Enable to Output Active Any Receiver, Enable to Output Active C L = pf (Figures, ) 0 00 ns R Supply Rise Time from Shutdown C = C = 0.µF, C VEE = µf 0. ms or Receiver Keep-Alive The denotes specifications which apply over the full operating temperature range. Note : Absolute maximum ratings are those values beyond which the life of a device may be impaired. Note : 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 : All typicals are given at = V, T A = C. Note : I LOAD is an external current being sunk into the pin. Note : These specifications apply to the -pin SO Wide package only.

5 LTC TYPICAL PERFORMANCE CHARACTERISTICS W CHARGE PMP OTPT VOLTAGE (V) Charge Pump Output Voltage vs Load Current T A = C V S = V R L(DIFF) = 00Ω R L(SE) = k TO GND V = V 0 0 LOAD CRRENT (ma) 0 DIFFERENTIAL DRIVER OTPT (V) 0 0 Differential Driver Swing vs Load Resistance T A = C V S = V k k k k 0k LOAD RESISTANCE (Ω) SINGLE-ENDED DRIVER OTPT (V) 0 0 Single-Ended Driver Swing vs Load Resistance T A = C V S = V k k k k 0k LOAD RESISTANCE (Ω) LTC TPC0 LTC TPC0 LTC TPC0 SPPLY CRRENT (ma) Supply Current vs Temperature V S = V NO LOAD 0 0 TEMPERATRE ( C) 00 LTC TPC0 DIFFERENTIAL DRIVER OTPT (V) Differential Driver Swing vs Temperature 0 0 V S = V R L = 00Ω TEMPERATRE ( C) LTC TPC0 SINGLE-ENDED DRIVER OTPT (V) 0 0 Single-Ended Driver Swing vs Temperature V S = V R L = k TO GND TEMPERATRE ( C) LTC TPC06

6 LTC PI F CTIO S LTCCS LTCCSW LTCCG C C CHARGE PMP 6 C C C CHARGE PMP C C C CHARGE PMP C TXD C CPEN C CPEN 6 C TXDEN TXD TXD NC SHDN 0 NC EN 6 TXDEN 6 TXDEN 6 DO 0 D SHDN SHDN GND D EN O 6 EN O D 0 0 DO GND D PGND DO NC NC GND D 6 D PGND C : C Positive Input. Connect a 0.µF capacitor between C and C. C : C Negative Input. Connect a 0.µF capacitor between C and C. CPEN: TTL Level Charge Pump Enable Input. With CPEN held low, the charge pump is enabled and the chip operates normally. When CPEN is pulled high, the charge pump is disabled as well as both drivers, the noninverting single-ended receiver, and the differential receiver. The inverting single-ended receiver () is kept alive to monitor the control line and I CC drops to 6µA. To turn off the receiver and drop I CC to 0.µA, pull the SHDN pin high. TXD: Differential Driver Input (TTL compatible). : Single-Ended Driver Input (TTL compatible). TXDEN: Differential Driver Output Enable (TTL compatible). A high level on this pin forces the differential driver into three-state; a low level enables the driver. This input does not affect the single-ended driver. SHDN: Shutdown Input (TTL compatible). When this pin is high, the chip is shut down. All driver and receiver outputs are three-state, the charge pump turns off, and the supply current drops to 0.µA. A low level on this pin allows normal operation. 6 EN: 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. O: Inverting Single-Ended Receiver Output. Remains active in the receiver keep-alive mode. O: Noninverting Single-Ended Receiver Output. DO: Differential Receiver Output. GND: Signal Ground. Connect to PGND with -pin package. PGND: Power ground is connected internally to the charge pump and differential driver. Connect to the GND pin. D : Differential Receiver Noninverting Input. When this pin is 00mV above D, DO will be high; when this pin is 00mV below D, DO will be low. D : Differential Receiver Inverting Input. : Noninverting Receiver Input. This input controls the O output. : Inverting Receiver Input. This input controls the O output. In receiver keep-alive mode (CPEN high, SHDN low), this receiver can be used to monitor a wake-up control signal.

7 PI F CTIO S : Single-Ended Driver Output. : Differential Driver Noninverting Output. : Differential Driver Inverting Output. : Negative Supply Charge Pump Output. Requires a µf bypass capacitor to ground. If an external load is connected to the pin, the bypass capacitor value should be increased to.µf. LTC C : C Negative Input. Connect a 0.µF capacitor between C and C. C : C Positive Input. Connect a 0.µF capacitor between C and C. : Positive Supply Input..V.V. Requires a µf bypass capacitor to ground. TEST CIRCITS R V C OD D L D DO R L V R OC C D L pf R L C L LTC F0 LTC F0 Figure Figure Figure R L C L LTC F0 OTPT 00Ω S O O C L S C L R L C L C L LTC F0 LTC F0 Figure Figure Figure 6 LTC F06 SWITCHI G WAVEFOR S W TXD V t PLH f = MHz: t r 0ns: t f 0ns t PHL V O V O 0% 0% t r 0% V DIFF = V( ) V( ) / V O 0% t f 0% 0% V O t SKEW t SKEW LTC F0 Figure. Differential Driver

8 LTC SWITCHI G WAVEFOR S W V TXDEN f = MHz: t r 0ns: t f 0ns V, t ZL.V OTPT NORMALLY LOW tlz 0.V, t ZH t OTPT NORMALLY HIGH HZ.V Figure. Differential Driver Enable and Disable 0.V LTC F0 V TXD t PHL f = MHz: t r 0ns: t f 0ns t PLH 0% t r 0% 0% Figure. Differential Driver With Single-Ended Load t f 0% LTC F0 V f = MHz: t r 0ns: t f 0ns t PHL t PLH 0% 0% 0% 0% LTC F0 t r Figure 0. Single-Ended Driver t r (D ) (D ) V OD f = MHz: t r 0ns: t f 0ns V OD t PLH t PHL DO Figure. Differential Receiver LTC F

9 LTC SWITCHI G WAVEFOR S W V IH, f = MHz: t r 0ns: t f 0ns V IL t PHL 0.V t PLH.V V IH V Figure. Single-Ended Receiver LTC F V EN f = MHz: t r 0ns: t f 0ns V t ZL t LZ O, O, DO.V OTPT NORMALLY LOW 0.V t ZH OTPT NORMALLY HIGH t HZ 0.V O, O, DO.V LTC F Figure. Receiver Enable and Disable W APPLICATIO S I FOR ATIO Functional Description The serial port on the back of an Apple-compatible computer or peripheral is a fairly versatile multi-protocol connector. It must be able to connect to a wide bandwidth LAN (an AppleTalk/LocalTalk network), which requires a high speed differential transceiver to meet the AppleTalk specification, and it must also be able to connect directly to a printer or modem through a short RS style link. The LTC is designed to provide all the functions necessary to implement such a port on a single chip. Two versions of the LTC are available: a 6-pin SO version which provides the minimum solution for interfacing to an AppleTalk network in a smaller package, and a larger -pin SO Wide version which additionally includes all the handshaking lines required to implement a complete AppleTalk/ modem/printer serial port. All LTCs run from a single V power supply while providing true single-ended compatibility, and include a 0.µA low power shutdown mode to improve lifetime in battery-powered devices. The - pin SO Wide version also includes a receiver keep-alive mode for monitoring external signals while drawing 6µA typically. The LTC includes an RS-compatible differential driver/receiver pair for data transmission, with the driver specified to drive V into the 00Ω primary of a typical LocalTalk interface transformer/rfi interference network. Either output of the differential RS driver can also act as an single-ended driver, allowing the LTC to communicate over a standard serial connection. The -pin SO Wide LTC also includes an extra single ended only driver and two extra RS-compatible single-ended receivers for handshaking lines. All versions include an onboard charge pump to provide a regulated V supply required for the single-ended drivers. The charge pump can also provide up to 0mA of external load current to power other circuitry.

10 LTC W APPLICATIO S I FOR ATIO Driving Differential AppleTalk or Single-Ended Loads The differential driver is able to drive either an AppleTalk load or a single-ended load such as a printer or modem. With a differential AppleTalk load, and will typically swing between.v and.v (Figure a). With a single-ended k load such as a printer, either or will meet the single-ended voltage swing requirement of ±.V (Figure b). An automatic switching circuit prevents the differential driver from overloading the charge pump if the outputs are shorted to ground while driving single-ended signals. This allows the second single-ended driver to continue to operate normally when the first is shorted, and allows external circuitry attached to the charge pump output to continue to operate even if there are faults at the driver outputs. µf = V LTC.µF EXTERNAL CHIP GND.V.V I VEE 0mA Figure Thermal Shutdown Protection I VEE LTC F The LTC includes a thermal shutdown circuit which protects against prolonged shorts at the driver outputs. If a driver output is shorted to another output or to the power supply, the current will be initially limited to a maximum of 00mA. When the die temperature rises above 0 C, the thermal shutdown circuit disables the driver outputs. When the die cools to about 0 C, the outputs are reenabled. If the short still exists, the part will heat again and the cycle will repeat. This oscillation occurs at about 0Hz and prevents the part from being damaged by excessive power dissipation. When the short is removed, the part will return to normal operation. C Power Shutdown The power shutdown feature of the LTC is designed for battery-powered systems. When SHDN is forced high the part enters shutdown mode. In shutdown the supply current typically drops from.ma to 0.µA, the charge pump turns off, and the driver and receiver outputs are three-stated. Receiver Keep-Alive Mode (-Pin SO Wide Only) The -pin SO Wide version of the LTC also features a power saving receiver keep-alive mode. When CPEN is pulled high the charge pump is turned off and the outputs of both drivers, the noninverting single-ended receiver and the differential receiver are forced into three-state. The inverting single-ended receiver () is kept alive with I CC dropping to 6µA and the receiver delay time increasing to a maximum of 00ns. The receiver can then be used to monitor a wake-up control signal. Charge Pump Capacitors and Supply Bypassing The LTC requires two external 0.µF capacitors for the charge pump to operate: one from C to C and one from C to C. These capacitors should be low ESR types and should be mounted as close as possible to the LTC. Monolithic ceramic capacitors work well in this application. Do not use capacitors greater than µf at the charge pump pins or internal peak currents can rise to destructive levels. The LTC also requires that both and be well bypassed to ensure proper charge pump operation and prevent data errors. A µf capacitor from to ground is adequate. A µf capacitor is required from to ground and should be increased to.µf if an external load is connected to the pin. Ceramic or tantalum capacitors are adequate for power supply bypassing; aluminum electrolytic capacitors should only be used if their ESR is low enough for proper charge pump operation. Inadequate bypass or charge pump capacitors will cause the charge pump output to go out of regulation prematurely, degrading the output swing at the SINGLE- ENDED driver outputs. 0

11 LTC W APPLICATIO S I FOR ATIO Driving an External Load from An external load may be connected between ground and the pin as shown in Figure. The LTC pin will sink up to a maximum of 0mA while maintaining the pin voltage between.v and.v. If an external load is connected, the bypass capacitor should be increased to.µf. Both LTC and the external chip should have separate bypass capacitors but can share the capacitor. EMI Filter Most LocalTalk applications use an electromagnetic interference (EMI) filter consisting of a resistor-capacitor T network between each driver and receiver and the connector. nfortunately, the resistors significantly attenuate the drivers output signals before they reach the cable. Because µf = V LTC.µF EXTERNAL CHIP GND.V.V I VEE 0mA I VEE C LTC F the LTC uses a single supply differential driver, the resistor values should be reduced to Ω to 0Ω to guarantee adequate voltage swing on the cable (Figure 6a). In most applications, removing the resistors completely does not cause an increase in EMI as long as a shielded connector and cable are used (Figure 6b). With the resistors removed the only DC load is the primary resistance of the LocalTalk transformer. This will increase the DC standby current when the driver outputs are active, but does not adversely affect the drivers because they can handle a direct indefinite short circuits without damage. Transformer primary resistance should be above Ω to keep the LTC operating normally and prevent it from entering thermal shutdown. For maximum swing and EMI immunity, a ferrite bead and capacitor T network can be used (Figure 6c). Ω TO 0Ω Ω TO 0Ω 00pF 00pF Figure 6. EMI Filters FERRITE BEAD (a) (b) (c) FERRITE BEAD 00pF LTC F6 Figure TYPICAL APPLICATIONS N Typical LocalTalk Connection V µf 0.µF DATA IN TX ENABLE SHDN ENABLE DATA OT 6 6 CHARGE PMP LTCCS TX 0 0.µF 00pF 00pF 00pF µf LocalTalk TRANSFORMER LTC TA0 0Ω 00pF 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.

12 LTC PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. G Package -Lead Plastic SSOP (0.0) (LTC DWG # ) ** (.0.) (..) * (0.0 0.) (0. 0.) (0. 0.) 0.06 (0.6) BSC *DIMENSIONS DO NOT INCLDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.mm) PER SIDE ** DIMENSIONS DO NOT INCLDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.00" (0.mm) PER SIDE (0. 0.) (0.0 0.) (.6.0) G SSOP 06 S Package 6-Lead Plastic Small Outline (Narrow 0.0) (LTC DWG # ) * ( ) (0.0 0.) (0. 0.0) 0 TYP (.6.) (0.0 0.) (0. 0.) *DIMENSION DOES NOT INCLDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.mm) PER SIDE ** DIMENSION DOES NOT INCLDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.00" (0.mm) PER SIDE 0.00 (.0) TYP (. 6.) ** (.0.) S6 06 SW Package -Lead Plastic Small Outline (Wide 0.00) (LTC DWG # ) 0. 0.** (..) (0. 0.) (.6.6) (0.0.) * (.0.600) TYP (0. 0.0) NOTE (0.06.0) 0.00 (.0) TYP (0.6 0.) NOTE:. PIN IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANFACTRING OPTIONS THE PART MAY BE SPPLIED WITH OR WITHOT ANY OF THE OPTIONS. *DIMENSION DOES NOT INCLDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.mm) PER SIDE ** DIMENSION DOES NOT INCLDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.00" (0.mm) PER SIDE NOTE ( ) ( ) S (WIDE) 06 LT/GP 0K PRINTED IN SA Linear Technology Corporation 60 McCarthy Blvd., Milpitas, CA 0- (0) -00 FAX: (0) -00 TELEX: - LINEAR TECHNOLOGY CORPORATION

FEATURES TYPICAL APPLICATIO. LTC1382 5V Low Power RS232 Transceiver with Shutdown DESCRIPTIO APPLICATIO S

FEATURES TYPICAL APPLICATIO. LTC1382 5V Low Power RS232 Transceiver with Shutdown DESCRIPTIO APPLICATIO S FEATRES Operates from a Single V Supply Low Supply Current: I CC = µa I CC =.µa in Shutdown Mode ESD Protection Over ±1kV ses Small Capacitors:.1µF Operates to 1kBaud Output Overvoltage Does Not Force