SP232A Enhanced RS-232 Line Drivers/Receivers FEATURES • Operates from a Single +5V Power Supply • Meets all RS-232F and ITU V.28 Specifications • Operates with 0.μF Ceramic Capacitors • High Data rate - 20kbps under load • Low power CMOS Operation • +/-2kV Human Body Model ESD Protection • Lead Free packaging available DESCRIPTION The SP232A is a line driver and receiver pair that meets the specifications of RS-232 and V.28 serial protocols. This device is pin-to-pin compatible with popular industry standard pinouts. The SP232A offers 20kbps data rate under load, small ceramic type 0.μF charge pump capacitors and overall ruggedness for comercial applications. The SP232A features Exar's BiCMOS design allowing for low power operation without sacrificing performance. This device is avaialble in plastic DIP, SOICW and nSOIC packages operating over the commercial and industrial temperature ranges. Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • Fax (50)668-707 • www.exar.com SP232A_00_05308 

AbSoLUTE MAxiMUM RATingS These are stress ratings only and functional opera- tion of the device at these ratings or any other above those indicated in the operation sections of the speci- fications below are not implied. Exposure to absolute maximum ratings conditions for extended periods of time may affect reliability. Short Circuit duration Supply Voltage (VCC)...............................................+ 6V Tout.....................................................Continuous V+........................................................................... (Vcc-0.3V) to +.0V Package Power Dissipation: V- .............................................................................-.0V Plastic DIP...............................................375mW Input Voltages (derate 7mW/°C above +70°C) Tin.....................................................-0.3V to (Vcc + 0.3V) Small Outline...........................................375mW Rin............................................................................+/-5V (derate 7mW/°C above +70°C) Output Voltages Storage Temperature..................-65°C to +50°C Tout...............................................(V+, +0.3V) to (V-, -0.3V Lead Temperature (soldering, 0s).......... +300°C Rout...................................................-0.3V to (Vcc + 0.3V) ELECTRiCAL CHARACTERiSTiCS Vcc=5V ±0%, 0.μF charge pump capacitors, Tmin to Tmax, unless otherwise noted, Typical values are Vcc=5V and Ta=25°C PARAMETER TEST ConDiTionS Min TYP MAx UniT TTL inPUT Logic Threshold LOW Tin 0.8 Volts Logic Threshold HIGH Tin 2.0 Volts Logic Pull-Up Current Tin = 0V 5 200 μA TTL oUTPUT Output Voltge LOW iouT = 3.2 mA: Vcc = +5V 0.4 Volts Output Voltage HIGH iouT = -1.0 mA 3.5 Volts RS-232 oUTPUT all Transmitter outputs loaded output Voltage Swing +/-5.0 +/-6.5V Volts with 3k ohms to GND Output Resistance Vcc = 0V, Vout = +/-2V 300 Ohms Output Short Circuit Current Infinite Duration +/-8 mA Maximum Data Rate CL = 2500pF, RL = 3kΩ 20 240 kbps RS-232 inPUT Voltage Range -5 +5 Volts Voltage Threshold LOW Vcc = 5V, Ta=25°C 0.8 .2 Volts Voltage Threshold HIGH Vcc = 5V, Ta=25°C .7 2.4 Volts Hysteresis Vcc = 5V, Ta=25°C 0.2 0.5 .0 Volts Resistance Ta=25°C, -15V ≤ Vin ≤ +15V 3 5 7 kΩ Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • Fax (50)668-707 • www.exar.com SP232A_00_05308 2

ELECTRiCAL CHARACTERiSTiCS Vcc=5V ±0%, 0.μF charge pump capacitors, Tmin to Tmax, unless otherwise noted, Typical values are Vcc=5V and Ta=25°C DYnAMiC CHARACTERiSTiCS Driver Propagation Delay TTL to RS_232; CL = 50pF .5 3.0 μs Receiver Propagation Delay RS-232 to TTL, 0. .0 μs Instantaneous Slew Rate CL = 10pF, RL = 3-7kΩ 30 V/ μs CL = 2500pF, RL = 3kΩ; Transition Region Slew Rate Measured from +3V to -3V or 0 V/ μs -3V to +3V PoWER REQUiREMEnTS Vcc Power Supply Current No Load, Vcc = 5V, Ta=25°C .5 5 mA All Transmitters RL = 3kΩ, Vcc Power Supply Current, Loaded  mA Ta=25°C Pin ASSignMEnTS Pin number Pin name Pin Function Positive terminal of the voltage doubler charge pump  C+ capacitor 2 V+ +6.5V generated by the charge pump Negative terminal of the voltage doubler charge pump 3 C- capacitor 4 C2+ Positive terminal of the inverting charge pump capacitor 5 C2- Negative terminal of the inverting charge pump capacitor 6 V- -6.7V generated by the charge pump 7 T2OUT RS-232 driver output 8 R2IN RS-232 receiver input 9 R2OUT TTL/CMOS receiver output 0 T2IN TTL/CMOS driver input  TIN TTL/CMOS driver input 2 ROUT TTL/CMOS receiver output 3 RIN RS-232 receiver input 4 TOUT RS-232 driver output 5 GND Ground 6 Vcc 5V supply voltage Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • Fax (50)668-707 • www.exar.com SP232A_00_05308 3

DESCRiPTion DETAiLED DESCRiPTion The SP232A transceiver is a two driver and two Charge pump receiver device that meets the EIA/TIA- 232 and The charge pump is a patented design and V.28 serial communication protocol. The device uses a unique approach compared to older less is pin-to-pin compatible with popular industry efficient designs. The charge pump requires 4 standard pinouts. The SP232A offers 20kbps external capacitors and uses a four phase volt- data rate, 0V/μs slew rate and a regulated age shifting technique. The internal power sup- charge pump that operates from a single 5V ply consists of a regulated dual charge pump supply. The proprietary on-board charge pump that provides output voltages of +/-6.5V. This generates a regulated output of +/-6.5V for RS- is important to maintain compliant RS-232 lev- 232 compliant voltage levels. els regardless of power supply fluctuations. The charge pump operates in a discontinous Theory of operation mode using an internal oscillator. If the voltages The SP232A is made up of three basic circuit are less than a magnitude of 6.5V, the charge blocks: . Driver, 2. Receiver, and 3. charge pump is enabled. If the output voltage exceed pump. a magnitude of 6.5V then the charge pump is disabled. The internal oscillator controls the four Drivers phases of the voltage shifting. A description of The drivers are inverting level transmitters that each phase follows: convert TTL or CMOS logic levels to EIA/TIA- 232 levels with an inverted sense relative to the Phase 1 input logic levels. Typically, the RS-232 output Vss charge store and double: The positive ter- voltage swing is +/-6.5V with no load and +/- minals of capacitors C and C2 are charged 5.0V minimum when fully loaded. The driver out- from Vcc with their negative terminals initially puts are protected against infinite short-circuits connected to ground. C+ is then connected to ground without degradation in reliability. to ground and the stored charge from C- is superimposed onto C2-. Since C2+ is still con- The drivers can guarantee output data rates of nected to Vcc the voltage potential across C2 is 20Kbps under worst case loading of 3k ohms now 2 x Vcc. and 2500pF. Phase 2 The driver output Slew Rate is internally limited Vss transfer and invert: Phase two connects to 30V/μs in order to meet the EIA standards the negative terminal of C2 to the Vss storage (EIA-232F). Additionally, the driver output LOW capacitor and the positive terminal of C2 to to HIGH transition meet the monotonicity output ground. This transfers the doubled and inverted requirements of the standard. (V-) voltage onto C4. Meanwhile, capacitor C is charged from Vcc in order to prepare it for its Receivers next phase. The receivers convert EIA/TIA-232 signal levels to TTL or CMOS logic output levels. Since the Phase 3 input is usually from a transmission line, where Vdd charge store and double: Phase three is long cable length and system interference can identical to the first phase. The positive termi- degrade the signal, the receiver inputs have a nals of C and C2 are charged from Vcc with typical hysteresis margin of 500mV. This en- their negative terminals initially connected to sures that the receiver is virtually immune to ground. C+ is then connected to ground and noisy transmission lines. Should a input be left the stored charge from C- is superimposed unconnected, an internal 5Kohm pull-down re- onto C2-. Since C2+ is still connected to Vcc sistor to ground will commit the output of the re- the voltage potential across capacitor C2 is now ceiver to a logic HIGH state. The input voltage 2 x Vcc. range for the SP232A Receiver is +/-5V. Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • Fax (50)668-707 • www.exar.com SP232A_00_05308 4

DESCRiPTion Phase 4 Vdd transfer. The fourth phase connects the The clock rate of the charge pump typically op- negative terminal of C2 to ground and the posi- erates greater than 70kHz allowing the pump to tive terminal of C2 to the Vdd storage capacitor . operate efficiently with small 0.1uF capacitors. This transfers the doubled (V+) voltage onto C3. Efficient operation depends on rapid charging Meanwhile, capacitor C is charged from Vcc to and discharging of C and C2. Therefore, the prepare it for its next phase. capacitors should be mounted as close as pos- sible to the IC and have a low ESR (equivalent Under lightly loaded conditions, the intelligent series resistance). Inexpensive, surface mount pump oscillator maximizes efficiency by running ceramic capacitors are ideal for use on charge only as needed to maintain V+ and V- voltage pump. If polarized capacitors are used the posi- levels. Since interface transceivers spend most tive and negative terminals should be connect- of their time at idle, this power-efficient innova- ed as shown on the typical operating circuit. A tion can greatly reduce total power consump- diagram of the 4 individual phases is shown in tion. This improvement is made possible by Figure . the independent phase sequences of the Exar charge pump design. + V CC - Phase 2 – Vss transfer from C2 to C4. Meanwhile C 1 is charged to Vcc + + C + C + V+ C 3 V 1 2 CC Phases 1 and 3: Store/Double. e - e - - Double charge from C 1 onto C2. e - + C 2 is now charged to -2xVcc C 4 Vss + C + C + V+ C 3 Patented 5,306,954 1 2 e - e - V- + + V C CC - 4 Phas e 4 V D D transfer from C2 to C3. Meanwhile C1 is charged to Vcc V DD e + e + + C + C + V+ C 3 1 2 e - V- + C 4 Figure . Charge pump phases Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • Fax (50)668-707 • www.exar.com SP232A_00_05308 5

TYPiCAL PERFoRMAnCE CHARACTERiSTiCS Figure 5, Charge pump outputs at Figure 2, Charge pump waveforms with no start up ( = Vcc, 2 = V+, 3 = V-). load ( = C+, 2 = C2+, 3 = V+, 4 = V-). Figure 3, Charge pump waveforms when fully loaded with 3k ohms ( = C+, 2 = C2+, 3 = V+, 4 = V-). Figure 6, Typical Application circuit Figure 4, Loopback results at 60kHZ and 2500pF load ( = TXin, 2 = TXout/RXin, 3 = RXout). Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • Fax (50)668-707 • www.exar.com SP232A_00_05308 6

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • Fax (50)668-707 • www.exar.com SP232A_00_05308 7

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • Fax (50)668-707 • www.exar.com SP232A_00_05308 8

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • Fax (50)668-707 • www.exar.com SP232A_00_05308 9

ORDERING INFORMATION Part numberLEAD FREE Tape & Reel Temperature range Package Type SP232ACN -L /TR From 0 to +700C 6 pin nSOIC SP232ACT -L /TR From 0 to +700C 16 pin WSOIC SP232ACP -L /TR From 0 to +700C 6 pin PDIP SP232AEN -L /TR From -40 to +850C 6 pin nSOIC SP232AET -L /TR From -40 to +850C 16 pin WSOIC SP232AEP -L /TR From -40 to +850C 6 pin PDIP All packages are available as lead free (RoHS compliant). To order add “-L” suffix to part number. For Tape and Reel add “/TR”. Reel quantity is 2,500 for NSOIC. Example: SP232ACN-L/TR = lead free and Tape and Reel. SP232ACN/TR = standard with Tape and Reel. Notice EXAR Corporation reserves the right to make changes to any products contained in this publication in order to improve design, performance or reliabil- ity. EXAR Corporation assumes no representation that the circuits are free of patent infringement. Charts and schedules contained herein are only for illustration purposes and may vary depending upon a user's specific application. While the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in writting, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized ; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Copyright 2008 EXAR Corporation Datasheet May 2008 Send your Interface technical inquiry with technical details to: customersupport@exar.com Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • Fax (50)668-707 • www.exar.com SP232A_00_05308 0

Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: E xar: SP232AET-L SP232ACN-L SP232ACP-L SP232AEN-L SP232ACT-L SP232AEP-L SP232ACN-L/TR SP232AEN- L/TR SP232AET-L/TR SP232ACT-L/TR