a High Speed, +5 V, 0.1 µF CMOS RS-232 Drivers/Receivers ADM222/ADM232A/ADM242* FUNCTIONAL BLOCK DIAGRAM FEATURES 200 kB/s Transmission Rate Small (0.1 µF) Charge Pump Capacitors Single 5 V Power Supply Meets All EIA-232-E and V.28 Specifications Two Drivers and Two Receivers On-Board DC-DC Converters ±9 V Output Swing with +5 V Supply ±30 V Receiver Input Levels Pin Compatible with MAX222/MAX232A/MAX242 +5V INPUT 0.1µF 0.1µF 0.1µF VCC C1+ +5V TO +10V V+ VOLTAGE DOUBLER C1– C2+ 0.1µF +5V TO –10V VOLTAGE INVERTER V– 0.1µF C2– APPLICATIONS Computers Peripherals Modems Printers Instruments TTL/CMOS INPUTS* TTL/CMOS OUTPUTS T1IN T1 T1OUT T2IN T2 T2OUT ADM2xx The ADM222, ADM232A, ADM242 are a family of high speed RS-232 line drivers/receivers offering transmission rates up to 200 kB/s. Operating from a single +5 V power supply, a highly efficient on-chip charge pump using small (0.1 µF) external capacitors allows RS-232 bipolar levels to be developed. Two RS-232 drivers and two RS-232 receivers are provided on each device. The devices are fabricated on BiCMOS, an advanced mixed technology process which combines low power CMOS with high speed bipolar circuitry. This allows for transmission rates up to 200 kB/s yet minimizes the quiescent power supply current to under 5 mA. The ADM232A is a pin-compatible, high speed upgrade for the AD232 and for the ADM232L. It is available in 16-pin DIP and in both narrow and wide surface mount (SOIC) packages. The ADM222 contains an additional shutdown (SHDN) function which may be used to disable the device thereby reducing the supply current to 0.1 µA. During shutdown, all transmit/ receive functions are disabled. The ADM222 is available in 18-pin DIP and in a wide surface mount (SOIC) package. R2IN R2 R2OUT GENERAL DESCRIPTION R1IN R1 R1OUT RS-232 OUTPUTS EN SHDN GND RS-232 INPUTS** (ADM242) (ADM222, ADM242) * INTERNAL 400kΩ PULL-UP RESISTOR ON EACH TTL/MOS INPUT ** INTERNAL 5kΩ PULL-DOWN RESISTOR ON EACH RS-232 INPUT ORDERING GUIDE Model Temperature Range Package Option ADM222AN ADM222AR ADM232AAN ADM232AARN ADM232AARW ADM242AN ADM242AR –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C N-18 R-18W N-16 R-16N R-16W N-18 R-18W The ADM242 combines both shutdown (SHDN) and enable (EN) functions. The shutdown function reduces the supply curent to 0.1 mA. During shutdown, the transmitters are disabled but the receivers continue to operate normally. The enable function allows the receiver outputs to be disabled thereby facilitating sharing a common bus. The ADM242 is available in 18-pin DIP and in a wide surface mount (SOIC) package. *Protected by U.S. Patent No. 5,237,209. REV. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A. Tel: 617/329-4700 Fax: 617/326-8703 (V = +5 V ± 10%, C1–C4 = 0.1 µF; all specADM222/ADM232A/ADM242–SPECIFICATIONS ifications T to T unless otherwise noted.) CC MIN Parameter Min Typ RS-232 TRANSMITTERS Output Voltage Swing ±5 ±9 2.0 1.4 1.4 5 Input Logic Threshold Low, VINL Input Logic Threshold High, VINH Logic Pullup Current Data Rate Output Resistance Output Short Circuit Current (Instantaneous) RS-232 RECEIVERS RS-232 Input Voltage Range RS-232 Input Threshold Low RS-232 Input Threshold High RS-232 Input Hysteresis RS-232 Input Resistance TTL/CMOS Output Voltage Low, VOL TTL/CMOS Output Voltage High, VOH TTL/CMOS Output Short-Circuit Current TTL/CMOS Output Short-Circuit Current TTL/CMOS Output Leakage Current EN Input Threshold Low, VINL EN Input Threshold High, VINH 200 300 ±7 –30 0.8 0.2 3 3.5 –2 10 2.0 POWER SUPPLY Power Supply Current Shutdown Power Supply Current SHDN Input Leakage Current SHDN Input Threshold Low, VINL SHDN Input Threshold High, VINH AC CHARACTERISTICS Transition Region Slew Rate Transmitter Propagation Delay TTL to RS-232 Receiver Propagation Delay RS-232 to TTL Receiver Output Enable Time Receiver Output Disable Time Transmitter Output Enable Time Transmitter Output Disable Time Transmitter + to – Propagation Delay Difference Receiver + to – Propagation Delay Difference Max 0.8 40 ± 22 +30 MAX Units Test Conditions/Comments V All Transmitter Outputs Loaded with 3 kΩ to Ground TIN TIN TIN = 0 V V V µA kB/s Ω mA VCC = V+ = V– = 0 V, VOUT = ± 2 V –10 30 ± 0.05 ± 10 V V V V kΩ V V mA mA µA 1.4 1.4 0.8 V V 4 15 0.1 8 mA mA µA µA V V No Load 3 kΩ Load on Both Outputs CL = 50 pF to 2500 pF, R L = 3 kΩ to 7 k Ω Measured from +3 V to –3 V or –3 V to +3 V tPHLT tPLHT tPHLR tPLHR tER tDR SHDN Goes high SHDN Goes low 1.3 1.8 0.5 5 0.2 2.4 1.0 7 0.4 10 ±1 0.8 2.0 1.4 1.4 6 12 30 V/µs 0.7 0.7 0.2 0.3 125 160 250 3.5 300 100 3.5 3.5 0.5 0.5 500 500 µs µs µs µs ns ns µs µs ns ns VCC = 5 V IOUT = 3.2 mA IOUT = –1.0 mA Source Current (VOUT = GND) Sink Current (VOUT = VCC) SHDN = GND/EN = VCC 0 V ≤ VOUT ≤ VCC Specifications subject to change without notice. –2– REV. 0 ADM222/ADM232A/ADM242 ABSOLUTE MAXIMUM RATINGS * (TA = +25˚C unless otherwise noted) Power Dissipation R-16W . . . . . . . . . . . . . . . . . . . . . 400 mW (Derate 7 mW/°C above +70°C) θJA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . 80°C/W Power Dissipation N-18 . . . . . . . . . . . . . . . . . . . . . . . 400 mW (Derate 7 mW/°C above +70°C) θJA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . 80°C/W Power Dissipation R-18W . . . . . . . . . . . . . . . . . . . . . 400 mW (Derate 7 mW/°C above +70°C) θJA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . 80°C/W Operating Temperature Range Industrial (A Version) . . . . . . . . . . . . . . . . –40°C to +85°C Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . +300°C Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . +215°C Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . +220°C VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +6 V V+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (VCC – 0.3 V) to +13 V V– . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +0.3 V to –13 V Input Voltages TIN . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to (VCC + 0.3 V) R IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 30 V Output Voltages TOUT . . . . . . . . . . . . . . . . . . . . (V+, +0.3 V) to (V–, –0.3 V) ROUT . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to (VCC + 0.3 V) Short Circuit Duration TOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous Power Dissipation N-16 . . . . . . . . . . . . . . . . . . . . . . . 400 mW (Derate 7.5 mW/°C above +70°C) θJA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . 80°C/W Power Dissipation R-16N . . . . . . . . . . . . . . . . . . . . . 400 mW (Derate 7 mW/°C above +70°C) θJA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . 80°C/W *This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. Test Circuits +3V +3V VIN VIN tPHLR tPHLT tPLHT 0V tPLHR V+ VOUT VCC VOUT 0V 50% GND V– Figure 1. Transmitter Propagation Delay Timing Figure 3. Receiver Propagation Delay Timing 3V +3V EN INPUT EN INPUT 0V 0V tDR tER VOH +3.5V VOH –0.5V RECEIVER OUTPUT RECEIVER OUTPUT +0.8V VOL + 0.5V VOL Figure 2. Receiver Enable Timing REV. 0 Figure 4. Receiver Disable Timing –3– ADM222/ADM232A/ADM242 PIN FUNCTION DESCRIPTION VIN VOUT 3kΩ SHDN 50pF Mnemonic Function VCC V+ Power Supply Input, +5 V ± 10%. Internally generated positive supply (+10 V nominal). Internally generated negative supply (–10 V nominal). Ground Pin. Must be connected to 0 V. External capacitor 1, (+ terminal) is connected to this pin. External capacitor 1, (– terminal) is connected to this pin. External capacitor 2, (+ terminal) is connected to this pin. External capacitor 2, (– terminal) is connected to this pin. Transmitter (Driver) Inputs. These inputs accept TTL/CMOS levels. An internal 400 kΩ pull-up resistor to VCC is connected on each input. Transmitter (Driver) Outputs. These are RS-232 levels (typically ± 9 V). Receiver Inputs. These inputs accept RS-232 signal levels. An internal 5 kΩ pull-down resistor to GND is connected on each of these inputs. Receiver Outputs. These are TTL/CMOS levels. No Connect. No connections are required to this pin. (ADM242 Only) Active Low Digital Input. May be used to enable or disable (three-state) both receiver outputs. (ADM222 & ADM242) Active Low Digital Input. May be used to disable the device so that the power consumption is minimized. On the ADM222 all drivers and receivers are disabled. On the ADM242 the drivers are disabled but the receivers remain enabled. V– Figure 5. Shutdown Test Circuit GND C1+ C1– 3V SHDN INPUT C2+ 0V C2– tDT TIN V+ + 5V TOUT TRANSMITTER OUTPUT RIN – 5V V– ROUT NC Figure 6. Transmitter Shutdown Disable Timing EN SHDN +5V INPUT C5 0.1µF 6.3V 2 C1 0.1µF 4 5 C2 0.1µF 6 17 VCC C1+ C1– C2+ +5V TO +10V V+ VOLTAGE DOUBLER 3 +5V TO –10V VOLTAGE INVERTER V– 7 15 T1IN T1OUT T1 RS-232 OUTPUTS 8 11 T2IN T2OUT T2 13 14 R1OUT TTL/CMOS OUTPUTS C4 0.1µF C2– 12 TTL/CMOS INPUTS* C3 0.1µF R1IN R1 10 9 R2OUT R2IN R2 ADM222 GND 16 RS-232 INPUTS** 18 SHDN * INTERNAL 400kΩ PULL-UP RESISTOR ON EACH TTL/MOS INPUT NC 1 18 SHDN C1+ 2 17 VCC V+ 3 16 GND C1– 4 15 T1OUT C2+ 5 6 TOP VIEW 14 (Not to Scale) 13 R1IN C2– V– 7 12 T1IN T2OUT 8 11 T2IN R2IN 9 10 R2OUT ADM222 R1OUT ** INTERNAL 5kΩ PULL-DOWN RESISTOR ON EACH RS-232 INPUT NC = NO CONNECT Figure 7. ADM222 Typical Operating Circuit Figure 8. ADM222 DIP & SOIC Pin Configurations –4– REV. 0 ADM222/ADM232A/ADM242 C1+ 1 16 VCC V+ 2 15 GND C1– 3 C2+ 4 C2– 5 V– 6 EN 1 18 SHDN C1+ 2 17 V+ 3 16 GND 14 T1OUT ADM232A 13 4 5 C2– 6 V– 7 12 T1IN T2OUT 8 11 T2IN R2IN 9 10 TOP VIEW 12 R1OUT (Not to Scale) 11 T1IN 7 10 T2IN R2IN 8 9 R2OUT Figure 9. ADM232A DIP/SOIC Pin Configuration ADM242 C1 0.1µF 3 4 C2 0.1µF TTL/CMOS INPUTS* T1IN T2IN TTL/CMOS OUTPUTS 5 R2OUT 9 2 2 C1 0.1µF C2+ +5V TO –10V V– VOLTAGE INVERTER C2– T1 T2 R1 R2 6 C2 0.1µF C4 0.1µF 14 7 13 8 T1OUT T2OUT R1IN TTL/CMOS INPUTS* RS-232 OUTPUTS TTL/CMOS OUTPUTS* RS-232 INPUTS** R1OUT R2OUT 6 EN C3 0.1µF 3 C2+ 7 +5V TO –10V V– VOLTAGE INVERTER C2– 12 11 T1OUT 8 T2 T2OUT R1 10 R2 1 16 C4 0.1µF 15 T1 GND * INTERNAL 400kΩ PULL-UP RESISTOR 17 VCC +5V TO +10V V+ VOLTAGE DOUBLER C1– C1+ R1OUT 13 R2OUT R2IN GND 15 T1IN T2IN ADM232A ADM242 14 9 18 R1IN RS-232 OUTPUTS RS-232 INPUTS** R2IN SHDN * INTERNAL 400kΩ PULL-UP RESISTOR ON EACH TTL/MOS INPUT ON EACH TTL/MOS INPUT ** INTERNAL 5kΩ PULL-DOWN RESISTOR ** INTERNAL 5kΩ PULL-DOWN RESISTOR ON EACH RS-232 INPUT ON EACH RS-232 INPUT Figure 10. ADM232A Typical Operating Circuit REV. 0 4 5 10 12 C3 0.1µF VCC 11 R1OUT C5 0.1µF 6.3V +5V TO +10V V+ C1–VOLTAGE DOUBLER R1IN +5V INPUT +5V INPUT C1+ 15 TOP VIEW 14 (Not to Scale) 13 Figure 11. ADM242 DIP/SOIC Pin Configuration C5 0.1µF 6.3V 1 T1OUT C1– C2+ R1IN T2OUT VCC Figure 12. ADM242 Typical Operating Circuit –5– ADM222/ADM232A/ADM242–Typical Performance Characteristics 10 VCC = ±5V TA = +25°C VCC = ±5V TA = +25°C 10 V+ | V– | 8 6 4 2 2 5 0 AAA 6 4 0 TOUT HIGH 8 TOUT – V V+, ( | V– | ) – V 12 AA AA 12 10 0 15 | TOUT LOW | 0 2 6 4 I+, ( | I– | ) – mA Figure 13. Charge Pump V+, V– vs. Current 8 IOUT – mA 10 12 14 Figure 16. Transmitter Output Voltage vs. Current TRANSMITTER OUTPUT VOLTAGE – V 9 8 20kB 60kB 7 120kB A4 0.010V 100 90 6 200kB 5 4 10 0% VCC = +5V TA = +25°C TX1 = +5V; TX2 = 0V – 5V SQUARE WAVE BOTH TX OUTPUTS LOADED WITH 3k//CL 3 400kB 500kB 5V 5V 100µs 2 1000 0 2000 3000 4000 LOAD CAPACITANCE – pF Figure 14. Transmitter Baud Rate vs. Load Capacitance A2 Figure 17. Charge Pump V+, V– Exiting Shutdown 2.4V 100 100 90 90 10 10 0% 0% 5V 5V 1µs Figure 15. Transmitter Unloaded Slew Rate A1 –0.6 V 5V 5V 1 µs Figure 18. Transmitter Fully Loaded Slew Rate –6– REV. 0 ADM222/ADM232A/ADM242 As required by the RS-232 standard, the slew rate is limited to less than 30 V/µs without the need for an external slew limiting capacitor, and the output impedance in the power-off state is greater than 300 Ω. GENERAL INFORMATION The ADM222/ADM232A/ADM242 are high speed RS-232 drivers/receivers requiring a single digital +5 V supply. The RS232 standard requires transmitters that will deliver ± 5 V minimum on the transmission channel and receivers that can accept signal levels down to ± 3 V. The parts achieve this by integrating step up voltage converters and level shifting transmitters and receivers onto the same chip. CMOS technology is used to keep the power dissipation to an absolute minimum. All devices contains an internal charge pump voltage doubler and a voltage inverter that generates ± 10 V from the +5 V input. Four external 0.1 µF capacitors are required for the internal charge pump voltage converter. Receiver Section The receivers are inverting level shifters which accept RS-232 input levels (± 3 V to ± 15 V) and translate them into 5 V TTL/ CMOS levels. The inputs have internal 5 kΩ pull-down resistors to ground and are also protected against overvoltages of up to ± 30 V. The guaranteed switching thresholds are 0.8 V minimum and 2.4 V maximum which are well within the ± 3 V RS232 requirement. The low level threshold is deliberately positive as it ensures that an unconnected input will be interpreted as a low level. The ADM222/ADM232A/ADM242 is a modification, enhancement and improvement to the AD230-AD241 family and derivatives thereof. It is essentially plug-in compatible and does not have materially different applications. The receivers have Schmitt trigger input with a hysteresis level of 0.5 V. This ensures error free-reception for both noisy inputs and for inputs with slow transition times Enable and Shutdown Functions CIRCUIT DESCRIPTION The internal circuitry consists of four main sections. These are: On the ADM222, both receivers are fully disabled during shutdown. A Charge Pump Voltage Converter TTL/CMOS to RS-232 Transmitters RS-232 to TTL/CMOS Receivers Enable and Shutdown Functions. On the ADM242, both receivers continue to operate normally. This function is useful for monitoring activity so that when it occurs, the device can be taken out of the shutdown mode. The ADM242 also contains a receiver enable function (EN) which can be used to fully disable the receivers, independent of SHDN. Charge Pump DC-DC Voltage Converter The Charge Pump Voltage converter consists of an oscillator and a switching matrix. The converter generates a ± 10 V supply from the input 5 V level. This is done in two stages using a switched capacitor technique. The 5 V input supply is doubled to 10 V using capacitor C1 as the charge storage element. The –10 V level is also generated from the input 5 V supply using C1 and C2 as the storage elements. APPLICATIONS INFORMATION A selection of typical operating circuits is shown in Figures 13 to 19. Capacitors C3 and C4 are used to reduce the output ripple. Their values are not critical and can be reduced if higher levels of ripple are acceptable. The charge pump capacitors C1 and C2 may also be reduced at the expense of higher output impedance on the V+ and V– supplies. A1 2.0V 5V 5V 100 90 The V+ and V– supplies may also be used to power external circuitry if the current requirements are small. Please refer to the typical performance characteristics which shows the V+, V– output voltage vs. current. 10 0% 5µS In the shutdown mode the charge pump is disabled and V+ decays to VCC while V– decays to 0 V. Figure 19. Transmitter Output Disable Timing Transmitter (Driver) Section The Drivers convert TTL/CMOS input levels into RS-232 output levels. With VCC = +5 V and driving a typical RS-232 load, the output voltage swing is ± 9 V. Even under worst case conditions the drivers are guaranteed to meet the ± 5 V RS-232 minimum requirement. The input threshold levels are both TTL and CMOS compatible with the switching threshold set at VCC /4. With a nominal VCC = 5 V the switching threshold is 1.25 V typical. Unused inputs may be left unconnected, as an internal 400 kΩ pull- up resistor pulls them high forcing the outputs into a low state. REV. 0 –7– ADM222/ADM232A/ADM242 OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 16-Pin Plastic DIP (N-16) 9 9 16 0.280 (7.11) 0.240 (6.10) PIN 1 1 8 8 1 0.060 (1.52) 0.015 (0.38) 0.210 (5.33) 0.0098 (0.25) 0.0040 (0.10) 16-Lead Wide SOIC (R-16W) 0.0500 (1.27) 0.0192 (0.49) 0.0138 (0.35) BSC 10 18 0.2992 (7.60) 0.2914 (7.40) 0.419 (10.65) 1 0.4193 (10.65) 0.3937 (10.00) 8 PIN 1 9 1 0.030 (0.75) 0.413 (10.50) 0.012 (0.3) 0.019 (0.49) 0.1043 (2.65) 0.0926 (2.35) 0.4625 (11.75) 0.4469 (11.35) 0.104 (2.65) 0.05 (1.27) REF 0.0500 (1.27) 0.0160 (0.41) 18-Lead Wide SOIC (R-18W) 9 0.299 (7.60) 0.0099 (0.25) 0.0075 (0.19) 0.0291 (0.74) x 45° 0.0098 (0.25) 0.042 (1.07) 0.013 (0.32) 0.0118 (0.30) 0.0040 (0.10) 0.0500 (1.27) BSC 0.0192 (0.49) 0.0138 (0.35) 0.0125 (0.32) 0.0091 (0.23) 8° 0° 0.0500 (1.27) 0.0157 (0.40) 18-Pin Plastic DIP (N-18) 18 10 1 9 PRINTED IN U.S.A. 16 0.0196 (0.50) 0.0099 (0.25) 0°– 8° 0.015 (0.381) 0.008 (0.204) SEATING PLANE 0.070 (1.77) 0.045 (1.15) 0.0688 (1.75) 0.0532 (1.35) 0.3937 (10.00) 0.3859 (9.80) 0.195 (4.95) 0.115 (2.93) 0.150 (3.81) 0.200 (5.05) 0.125 (3.18) 0.100 (2.54) BSC 0.2440 (6.20) 0.2284 (5.80) 0.1574 (4.00) 0.1497 (3.80) 0.325 (8.25) 0.300 (7.62) 0.840 (21.33) 0.745 (18.93) 0.022 (0.558) 0.014 (0.356) C1877–7.5–1/94 16 16-Lead Narrow SOIC (R-16N) 0.280 (7.11) 0.240 (6.10) PIN 1 0.325 (8.25) 0.300 (7.62) 0.925 (23.49) 0.845 (21.47) 0.060 (1.52) 0.015 (0.38) 0.210 (5.33) MAX 0.130 (3.30) MIN 0.160 (4.06) 0.115 (2.93) 0.022 (0.558) 0.014 (0.356) 0.100 (2.54) BSC 0.070 (1.77) 0.045 (1.15) –8– 0.195 (4.95) 0.115 (2.93) 0.015 (0.381) 0.008 (0.204) SEATING PLANE REV. 0 ADM222/ADM232A/ADM242 ORDERING GUIDE Model Temperature Range Package Option* ADM222AN ADM222AR ADM232AAN ADM232AARN ADM232AARW ADM242AN ADM242AR –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C N-18 R-18W N-16 R-16N R-16W N-18 R-18W *For outline information see Package Information section. REV. 0 –9–