DESCRIPTIO. 3V RS562 or 5V/3V RS232 Transceiver with One Receiver Active in Shutdown

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FEATRES RS3 Compatible 3V Operation 3V Logic Interface ESD Protection Over ±kv 1kbaud Operation for R L = 3k, C L = pf kbaud Operation for R L = 3k, C L = pf One Low Power Receiver Remains Active

1 FEATRES RS3 Compatible 3V Operation 3V Logic Interface ESD Protection Over ±kv 1kbaud Operation for R L = 3k, C L = pf kbaud Operation for R L = 3k, C L = pf One Low Power Receiver Remains Active While in Shutdown µa Supply Current in Shutdown Low Power Driver Disable Mode ses Small Capacitors:.1µF,.µF CMOS Comparable Low Power: mw Easy PC Layout: Flowthrough Architecture Rugged Bipolar Design Outputs Assume a High Impedance State When Off or Powered Down APPLICATI O S Notebook Computers Palmtop Computers 3V RS or V/3V RS3 Transceiver with One Receiver Active in Shutdown DESCRIPTIO The LT 1331 is a 3-driver, -receiver RS3 transceiver designed for 3V and mixed 3V/V systems. Receivers operate from 3V logic supply V L, while the onboard charge pump and drivers operate from V or 3V supply V CC. The transceiver has two shutdown modes. One mode disables the drivers and the charge pump, the other shuts down all circuitry except for one low power receiver which can be used for ring detection. The V CC supply may be shut down while in ring detection mode. While shut down, the drivers and receivers assume high impedance output states. The is fully compliant with all EIA-RS3 specifications when. If V CC = 3V, output drive levels are compatible with all known interface circuits. Special bipolar construction techniques protect the drivers and receivers beyond the fault conditions stipulated for RS3. The RS3 I/O pins are resilient to multiple ±kv ESD strikes. An advanced driver output stage operates up to 1kbaud while driving heavy capacitive loads., LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATI O 3.3V Operation V.1µF.1µF DRIVER 1 OT RX1 IN DRIVER OT RX IN TO LINE RX3 IN RX IN DRIVER 3 OT RX IN (LOW-Q) ON/OFF 3.3V V L V.1µF.1µF DRIVER 1 IN RX1 OT DRIVER IN RX OT TO LOGIC RX3 OT RX OT DRIVER 3 IN RX OT (LOW-Q) RING DETECT IN GND DRIVER DISABLE µcontroller OR NC µprocessor SHTDOWN CONTROL OT RECEIVER OTPT C L = pf R DRIVER OTPT R L = 3k C L = pf INPT 1331 TA 1331 TA1 1

2 ABSOLTE AXI RATI GS W W W (Note 1) Supply Voltage (V CC )... V Supply Voltage (V L )... V V V V V Input Voltage Driver... V to V Receiver... 3V to 3V ON/OFF....3V to V CC.3V DRIVER DISABLE....3V to V CC.3V Output Voltage Driver... 3V to 3V Receiver....3V to V L.3V Short Circuit Duration V... 3 sec V... 3 sec Driver Output... Indefinite Receiver Output... Indefinite Operating Temperature Range... C to C Storage Temperature Range... C to 1 C Lead Temperature (Soldering, sec)... 3 C PACKAGE/ORDER I FOR V 1 V/3V V CC C1 3 C1 DRIVER 1 OT RX1 IN DRIVER OT RX IN RX3 IN 9 RX IN DRIVER 3 OT 11 RX IN (LOW-Q) 1 ON/OFF V V L G PACKAGE -LEAD SSOP TOP VIEW V C C DRIVER 1 IN RX1 OT 3 DRIVER IN RX OT 1 RX3 OT RX OT 19 DRIVER 3 IN RX OT 1 (LOW-Q) 1 GND 1 DRIVER DISABLE 1 NC NW PACKAGE -LEAD PDIP SW PACKAGE -LEAD PLASTIC SO T JMAX = 1 C, θ JA = 9 C/ W (G) T JMAX = 1 C, θ JA = C/ W (NW) T JMAX = 1 C, θ JA = C/ W (SW) W Consult factory for Industrial and Military grade parts. ATIO ORDER PART NMBER CG CNW CSW ELECTRICAL CHARA CTERISTICS (Note ) PARAMETER CONDITIONS MIN TYP MAX NITS Power Supply Generator V Output. V. V V Output. V. V Supply Current (V CC ) (Note 3) 1 1 ma 1 1 ma Supply Current (V L ) (Note ) 3 ma Supply Current When OFF (V CC ) Shutdown (Note ) µa Driver Disable.1 1 ma Supply Current When OFF (V L ) Shutdown (Note ) µa Driver Disable 3 ma Supply Rise Time, Shutdown to Turn-On C1 = C =.µf, C = C =.1µF. ms ON/OFF Pin Thresholds Input Low Level (Device Shut Down) 1.. V Input High Level (Device Enabled). 1. V ON/OFF Pin Current V V ON/OFF V 1 µa DRIVER DISABLE Pin Thresholds Input Low Level (Drivers Enabled) 1.. V Input High Level (Drivers Disabled). 1. V DRIVER DISABLE Pin Current V V DRIVER DISABLE V µa Oscillator Frequency 13 khz

3 ELECTRICAL CHARA CTERISTICS PARAMETER CONDITIONS MIN TYP MAX NITS Any Driver Output Voltage Swing, Positive, R L = 3k.. V, R L = 3k 3.. V Output Voltage Swing, Negative, R L = 3k.. V, R L = 3k 3.3. V Logic Input Voltage Level Input Low Level (V OT = High) 1.. V Input High Level (V OT = Low). 1. V Logic Input Current.V V IN V µa Output Short-Circuit Current V OT = V ±9 1 ma Output Leakage Current Shutdown V OT = ±3V (Note ) µa Data Rate (Note ) R L = 3k, C L = pf 1 kbaud R L = 3k, C L = pf kbaud Slew Rate R L = 3k, C L = 1pF 1 3 V/µs R L = 3k, C L = pf V/µs Propagation Delay Output Transition t HL High to Low (Note ). 1.3 µs Output Transition t LH Low to High. 1.3 µs Any Receiver Input Voltage Thresholds Input Low Threshold (V OT = High). 1.3 V Input High Threshold (V OT = Low) 1.. V Hysteresis V Input Resistance V IN = ±V 3 kω Receivers 1 Through Output Voltage Output Low, I OT = 1.mA.. V Output High, I OT = 1µA (V L = 3.3V).. V Output Short-Circuit Current Sinking Current, V OT = V CC ma Sourcing Current, V OT = V ma Propagation Delay Output Transition t HL High to Low (Note ) ns Output Transition t LH Low to High 3 ns Output Leakage Current Shutdown (Note ) V OT V CC 1 µa Receiver (Low Q-Current RX) Output Voltage Output Low, I OT = µa.. V Output High, I OT = 1µA (V L = 3V).. V Output Short-Circuit Current Sinking Current, V OT = V CC ma Sourcing Current, V OT = V ma Propagation Delay Output Transition t HL High to Low (Note ) 1 3 µs Output Transition t LH Low to High 1 3 µs The denotes specifications which apply over the full operating temperature range ( C T A C for commercial grade). Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note : Testing done at, V L = 3.3V, and V ON/OFF = 3V, unless otherwise stated. Note 3: Supply current is measured as the average over several charge pump cycles. C = 1µF, C =.1µF, C1 = C =.µf. All outputs are open with all driver inputs tied high. Note : V L supply current is measured with all receiver outputs high. Note : Supply current and leakage current measurements in shutdown are performed with V ON/OFF.1V. Supply current measurements using driver disable are performed with V DRIVER DISABLE 3V. Note : For driver delay measurements, R L = 3k and C L = 1pF. Trigger points are set between the driver s input logic threshold and the output transition to the zero crossing (t HL = 1.V to V and t LH = 1.V to V). Note : For receiver delay measurements, C L = 1pF. Trigger points are set between the receiver s input logic threshold and the output transition to standard TTL/CMOS logic threshold (t HL = 1.3V to.v and t LH = 1.V to.v). Note : Data rate operation guaranteed by slew rate, short-circuit current and propagation delay tests. 3

4 TYPICAL PERFOR A W CE CHARA CTERISTICS Driver Short-Circuit Current Driver Output Voltage Driver Output Voltage SHORT-CIRCIT CRRENT (ma) 3 1 I SC I SC 1 TEMPERATRE ( C) 1331 G1 DRIVER OTPT VOLTAGE (V) OTPT HIGH R 3 L = 3k 3 DRIVERS LOADED 1 TEMPERATRE ( C) 1331 G DRIVER OTPT VOLTAGE (V) 3 OTPT LOW R L = 3k 3 DRIVERS LOADED 1 TEMPERATRE ( C) 1331 G3 Driver Leakage in Shutdown Slew Rate vs Load Capacitance 1 Slew Rate vs Load Capacitance 1 LEAKAGE CRRENT (µa) 1 V OT = 3V V OT = 3V SLEW RATE (V/µs) 1 SLEW SLEW SLEW RATE (V/µs) 1 SLEW SLEW.1 1 TEMPERATRE ( C) 1331 G 1 3 LOAD CAPACITANCE (nf) 1331 G 1 3 LOAD CAPACITANCE (nf) 1331 G SPPLY CRRENT (ma) 3 Supply Current vs Data Rate R L = 3k C L = pf 3 DRIVERS 1 DRIVER THRESHOLD VOLTAGE (V) Receiver Input Thresholds V L = 3.3V INPT HIGH INPT LOW SHORT-CIRCIT CRRENT (ma) Receiver Short-Circuit Current V L = 3.3V I SC 3 I SC 1 1 DATA RATE (kbad) 1131 G. 1 TEMPERATRE ( C) 1331 G 1 TEMPERATRE ( C) 1331 G9

5 PI F CTIO S V (Pin 1): Positive Supply Output. V V CC 1.V. This pin requires an external capacitor for charge storage, chosen to minimize ripple to acceptable levels. A minimum size of.1µf is recommended. V CC (Pin ): Power Supply for Charge Pump and Drivers. Proper circuit operation is insured for V CC = 3V to V. operation gives full RS3 compliant performance, 3V operation results in lower driver output amplitude. The V CC pin should be decoupled with a.1µf ceramic capacitor. C1, C1, C, C (Pins 3,,, ): These pins require two external capacitors C.µF. One from C1 to C1, and another from C to C. To maintain charge pump efficiency, the capacitor s effective series resistance should be less than Ω. Low ESR tantalum capacitors work well in this application, small value ceramic capacitors may also be used with minimal reduction in charge pump compliance. DRIVER OT (Pins,, 11): RS3 Driver Outputs. Outputs are in a high impedance state when in shutdown, driver disable, or V CC = V. Outputs are fully short-circuit protected from V 3V to V 3V. Although the outputs are protected, short circuits on one output can load the power supply generator and may disrupt the signal levels of the other outputs. The driver outputs are protected against ESD to ±kv for human body model discharges. Output levels of 3.3V to V are achieved when the circuit is operated with. RX IN (Pins,, 9, ): Receiver Inputs with.v of Hysteresis for Noise Immunity. These pins accept RS3 level signals (±3V) into a protected k terminating resistor. The receiver inputs are protected against ESD to ±kv for human body model discharges. LOW-Q RX IN (Pin 1): Low Power Receiver Input. This receiver remains active in shutdown mode, consuming only µa from supply V L. This receiver has the same input and protection characteristics as receivers RX1 through RX. ON/OFF (Pin 13): A TTL/CMOS Compatible Operating Mode Control. A logic low puts the device in the shutdown mode. All drivers and four of the receivers go to a high impedance state, and the V CC supply may be turned off. A logic high fully enables the transceiver. V L (Pin ): Power Supply for Receivers. This pin should be powered to the same voltage as the logic circuits connected to the receiver outputs, either V or 3V. The V L pin should be decoupled with a.1µf ceramic capacitor. DRIVER DISABLE (Pin 1): A logic high shuts down the charge pump, placing all drivers in a high impedance state. All receivers remain active. Floating the pin, or driving it to a logic low, fully enables the transceiver. A low voltage on the ON/OFF pin supersedes the state of the driver disable control. GND (Pin 1): Ground. LOW-Q RX OT (Pin 1): Low Power Receiver Output. This pin produces the same output levels as standard receivers, with slightly decreased speed and short-circuit current. DRIVER IN (Pins 19, 3, ): RS3 Driver Inputs. Inputs are TTL/CMOS compatible. Tie unused inputs to V CC. RX OT (Pins, 1,, ): Receiver Outputs. RX1 through RX outputs are in a high impedance state when in shutdown mode to allow data line sharing. Outputs, including LOW-Q RX OT, are fully short-circuit protected to ground, V CC, or V L. Output voltage levels are determined by the choice of power supply V L. V (Pin ): Negative Supply Output. V (V CC.V). This pin requires an external charge storage capacitor, chosen to minimize ripple on V. A minimum value of.1µf is recommended.

6 APPLICATI O S I FOR W ATIO Power Saving Operational Modes The has both shutdown and driver disable operating modes. These operating modes can optimize power consumption based upon applications needs. The shutdown control turns off all circuitry except for Low-Q RX. RX operates entirely from the V L power supply, so the power consumption from V CC drops to zero. The V CC power supply may be turned off while in shutdwon, which may allow greater power savings in some systems. When RX detects a signal, this information can be used to wake up the system for full operation. If more than one line must be monitored, the driver disable mode provides a power efficient operating option. The driver disable mode turns off the charge pumps and RS3 drivers, but keeps all five receivers active. Power consumption in driver disable mode is 3mA from V L and less than µa from V CC. Mixed V/3V Operation When operated with and V L = 3.3V supplies, the RS3 drivers meet or exceed all RS3 or V. communication interface standards. Data rates up to 1kbaud are supported, and all standard RS3 compatible mice may be driven by the. 3V Operation operation of the results in lower driver output swing than with. The driver output swing, when operated with, is guaranteed to be at least.v to 3.V, with typical swing being 3.3V to V. This insures compatibility with all commonly used RS3 and RS interface circuits. Table 1 summarizes the receiver input threshold specifications for RS3 circuits from many manufacturers. Table 1. Commonly sed RS3 Interface Circuit Receiver Thresholds INPT LOW THRESHOLD INPT HIGH THRESHOLD MANFACTRER PART NMBER COMPATIBLE MIN TYP MAX MIN TYP MAX Linear Technology LT LT113A LT LT All Others Texas Instruments SN SN19A MAX SNC Maxim MAX3A MAX Sipex SP SP Motorola MC MC9A National DS DSC9A

7 ESD PROTECTIO The RS3 line inputs of the have on-chip protection from ESD transients up to ±kv. The protection structures act to divert the static discharge safely to system ground. In order for the ESD protection to function effectively, the power supply and ground pins of the must be connected to ground through low impedances. The power supply decoupling capacitors and charge pump storage capacitors provide this low impedance in normal application of the circuit. The only constraint is that low ESR capacitors must be used for bypassing and charge storage. ESD testing must be done with pins V CC, V L, V, V and GND shorted to ground or connected with low ESR capacitors..1µf RS3 LINE PINS PROTECTED TO ±kv V 1 V V CC.1µF 3.µF DRIVER 1 OT RX1 IN DRIVER OT RX IN 9 RX3 IN RX IN 11 DRIVER 3 OT 1 RX IN (LOW-Q) 13 ON/OFF 3.3V ESD Test Circuit.1µF V.1µF.µF DRIVER 1 IN RX1 OT DRIVER IN RX OT RX3 OT RX OT DRIVER 3 IN RX OT (LOW-Q) GND DRIVER DISABLE NC 1331 ESD TC PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. G Package -Lead Plastic SSOP (.9) (LTC DWG # --)..1** (..3).. ( ).39.* (..33) (.13.)..3 (..9) *DIMENSIONS DO NOT INCLDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED." (.1mm) PER SIDE ** DIMENSIONS DO NOT INCLDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED." (.mm) PER SIDE. (.) BSC..1 (..3).. (..1) (..9) G SSOP 9 NW Package -Lead PDIP (Wide.) (LTC DWG # --1).. (1. 1.).1 (.31) MIN.1 ±. (3. ±.1).. ( ). (1.) TYP 1.* (3.9) MAX (.9.31) ( ).1 (3.1) MIN.3. (.9.3) *THESE DIMENSIONS DO NOT INCLDE MOLD FLASH OR PROTRSIONS. MOLD FLASH OR PROTRSIONS SHALL NOT EXCEED. INCH (.mm). ±. (. ±.).1 ±.3 (. ±.) * (1..) N 119 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.

PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. SW Package -Lead Plastic Small Outline (Wide.3) (LTC DWG # --1).91.99** (.391.9).9.1* (1. 1.)..9 (..3).93. (.3.).3. (.9 1.

8 PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. SW Package -Lead Plastic Small Outline (Wide.3) (LTC DWG # --1).91.99** (.391.9).9.1* (1. 1.)..9 (..3).93. (.3.).3. (.9 1.3) TYP.9.13 (.9.33) NOTE 1.1. (. 1.). (1.) TYP..19 (.3.) TYP NOTE: 1. PIN 1 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." (.1mm) PER SIDE ** DIMENSION DOES NOT INCLDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED." (.mm) PER SIDE..1 (..3) NOTE (..3) S (WIDE) 99 TYPICAL APPLICATI O Mixed V/3V Supply Operation.1µF V.1µF DRIVER 1 OT RX1 IN DRIVER OT RX IN TO LINE RX3 IN RX IN DRIVER 3 OT RX IN (LOW-Q) ON/OFF V L = 3.3V V DRIVER 1 IN RX1 OT DRIVER IN RX OT RX3 OT RX OT DRIVER 3 IN RX OT (LOW-Q) GND DRIVER DISABLE NC.1µF TO LOGIC.1µF RECEIVER OTPT C L = pf DRIVER OTPT R L = 3k C L = pf INPT 1331 TA 1331 TA3 RELATED PARTS PART NMBER DESCRIPTION COMMENTS LT113A/LT1A V RS3 Transceivers with Small Capacitors kv ESD LT113A 3-DR/-RX RS3 Transceiver 1kV ESD LTC139 V Low Power, 3-DR/-RX RS3 Transceiver RXs Active in Shutdown LTC13 3.3V Low Power EIA/TIA- Transceiver LT1/LT11 -DR/-RX RS3 Transceivers 1kV ESD Linear Technology Corporation 13 McCarthy Blvd., Milpitas, CA 93-1 ()3-19 FAX: () fa LT/TP 99 REV A K PRINTED IN SA LINEAR TECHNOLOGY CORPORATION 1993

LT1537 Advanced Low Power 5V RS232 Transceiver with Small Capacitors U S DESCRIPTIO

LT1537 Advanced Low Power 5V RS232 Transceiver with Small Capacitors U S DESCRIPTIO Advanced Low Power V RS232 Transceiver with Small Capacitors FEATRES Low Cost ses Small Capacitors:,.2µF 1µA Supply Current in Shutdown 12kBaud Operation for, C L = 2pF 2kBaud Operation for, C L = 1pF