a Low Power, +3.3 V, RS-232 Line Drivers/Receivers ADM3202/ADM3222/ADM1385 FUNCTIONAL BLOCK DIAGRAMS FEATURES 460 kbps Data Rate Specified at +3.3 V Meets EIA-232E Specifications 0.1 F Charge Pump Capacitors Low Power Shutdown (ADM3222E and ADM1385) DIP, SO, SOIC, SSOP and TSSOP Package Options Upgrade for MAX3222/32 and LTC1385 APPLICATIONS General Purpose RS-232 Data Link Portable Instruments Printers Palmtop Computers PDAs +3.3V INPUT 0.1F + 10V C1+ +3.3V TO +6.6V VOLTAGE DOUBLER C1- VCC 0.1F + 10V C2+ +6.6V TO -6.6V VOLTAGE C2- INVERTER V- V+ C3 + 0.1F 6.3V + C5 0.1F C4 + 0.1F 10V T1IN T1 T1OUT T2IN T2 T2OUT CMOS INPUTS EIA/TIA-232 OUTPUTS R1OUT R1 R1IN R2OUT R2 R2IN CMOS OUTPUTS EIA/TIA-232 INPUTS* GND ADM3202 *INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT GENERAL DESCRIPTION +3.3V INPUT The ADM3202/ADM3222/ADM1385 transceivers are high speed, 2-channel RS-232/V.28 interface devices which operate from a single +3.3 V power supply. Low power consumption and a shutdown facility (ADM3222/ ADM1385) makes them ideal for battery powered portable instruments. The ADM3202/ADM3222/ADM1385 conforms to the EIA232E and CCITT V.28 specifications and operates at data rates up to 460 kbps. Four external 0.1 F charge pump capacitors are used for the voltage doubler/inverter permitting operation from a single +3.3 V supply. C1+ +3.3V TO +6.6V VOLTAGE DOUBLER C1- VCC 0.1F + 10V C2+ +6.6V TO -6.6V VOLTAGE INVERTER C2- V- V+ C3 + 0.1F 6.3V CMOS OUTPUTS + C5 0.1F C4 + 0.1F 10V T1IN T1 T1OUT T2IN T2 T2OUT CMOS INPUTS EIA/TIA-232 OUTPUTS R1OUT R1 R1IN R2OUT R2 R2IN EIA/TIA-232 INPUTS* EN The ADM3222 contains additional enable and shutdown circuitry. The EN input may be used to three-state the receiver outputs. The SD input is used to power down the charge pump and transmitter outputs reducing the quiescent current to less than 0.5 A. The receivers remain enabled during shutdown unless disabled using EN. ADM3222 GND SD *INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT +3.3V INPUT C1+ +3.3V TO +6.6V VOLTAGE C1- DOUBLER 0.1F + 10V C2+ +6.6V TO -6.6V VOLTAGE C2- INVERTER 0.1F + 10V The ADM1385 contains a driver disable mode and a complete shutdown mode. The ADM3202 is available in a 16-lead DIP, narrow and wide SOIC as well as a space saving 20-lead TSSOP package. The ADM3222 is available in 18-lead DIP, SO and in 20-lead SSOP and TSSOP. The ADM1385 is available in a 20-lead SSOP package, which is pin compatible with the LTC1385 CG. 0.1F + 10V VCC + C5 0.1F V+ + V- C4 + 0.1F 10V C3 0.1F 6.3V T1IN T1 T1OUT T2IN T2 T2OUT CMOS INPUTS CMOS OUTPUTS EIA/TIA-232 OUTPUTS R1OUT R1 R1IN R2OUT R2 R2IN EIA/TIA-232 INPUTS* DD ADM1385 GND SD *INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT REV. A 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: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 (c) Analog Devices, Inc., 2000 ADM3202/ADM3222/ADM1385-SPECIFICATIONS (VCC = +3.3 V 0.3 V, C1-C4 = 0.1 F. All specifications TMIN to TMAX unless otherwise noted.) Parameter Min Typ Max Unit Test Conditions/Comments DC CHARACTERISTICS Operating Voltage Range VCC Power Supply Current 3.0 3.3 1.3 8 0.01 5.5 2.1 10 0.5 V mA mA A No Load RL = 3 k to GND 0.8 V V V V A A TIN TIN IOUT = 1.6 mA IOUT = -1 mA TIN = GND to VCC* Receivers Disabled Shutdown Supply Current LOGIC Input Logic Threshold Low, VINL Input Logic Threshold High, VINH CMOS Output Voltage Low, VOL CMOS Output Voltage High, VOH Input Leakage Current Output Leakage Current RS-232 RECEIVER EIA-232 Input Voltage Range EIA-232 Input Threshold Low EIA-232 Input Threshold High EIA-232 Input Hysteresis EIA-232 Input Resistance RS-232 TRANSMITTER Output Voltage Swing (RS-232) Output Voltage Swing (RS-562) Transmitter Output Resistance RS-232 Output Short Circuit Current Output Leakage Current TIMING CHARACTERISTICS Maximum Data Rate Receiver Propagation Delay TPHL TPLH Transmitter Propagation Delay Receiver Output Enable Time Receiver Output Disable Time Transmitter Skew Receiver Skew Transition Region Slew Rate 2.0 0.4 VCC - 0.6 0.01 -30 0.6 1 10 +30 V V V V k 3 1.2 1.6 0.4 5 5.0 5.2 V 15 V mA A 2.4 7 3.7 300 25 460 kbps 0.4 0.4 300 200 200 30 300 6 4 10 10 1 1 750 30 30 s s ns ns ns ns ns V/s V/s VCC = 3.3 V. All Transmitter Outputs Loaded with 3 k to Ground VCC = 3.0 V VCC = 0 V, VOUT = 2 V SD = Low, VOUT = 12 V VCC = 3.3 V, RL = 3 k to 7 k, CL = 50 pF to 1000 pF. One Tx Switching RL = 3 k, CL = 1000 pF Measured from +3 V to -3 V or -3 V to +3 V, VCC = +3.3 V RL = 3 k, CL = 1000 pF, TA = +25C RL = 3 k, CL = 2500 pF, TA = +25C *ADM1385: Input leakage current typically -10 A when TIN = GND. Specifications subject to change without notice. -2- REV. A ADM3202/ADM3222/ADM1385 ABSOLUTE MAXIMUM RATINGS* ORDERING GUIDE (TA = +25C unless otherwise noted) VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 V to +6 V V+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . (VCC - 0.3 V) to +14 V V- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +0.3 V to -14 V Input Voltages TIN . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 V to (V+, +0.3 V) RIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 V Output Voltages TOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 V ROUT . . . . . . . . . . . . . . . . . . . . . . . -0.3 V to (VCC + 0.3 V) Short Circuit Duration TOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous Power Dissipation Power Dissipation N-16 . . . . . . . . . . . . . . . . . . . . . 450 mW (Derate 6 mW/C above +50C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . 117C/W Power Dissipation R-16 . . . . . . . . . . . . . . . . . . . . . 450 mW (Derate 6 mW/C above +50C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . 158C/W Power Dissipation RU-16 . . . . . . . . . . . . . . . . . . . 500 mW (Derate 6 mW/C above +50C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . 158C/W Power Dissipation R-18 . . . . . . . . . . . . . . . . . . . . . 450 mW (Derate 6 mW/C above +50C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . 158C/W Power Dissipation RS-20 . . . . . . . . . . . . . . . . . . . . 450 mW (Derate 6 mW/C above +50C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . 158C/W Power Dissipation RU-20 . . . . . . . . . . . . . . . . . . . 450 mW (Derate 6 mW/C above +50C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . 158C/W Operating Temperature Range Industrial (A Version) . . . . . . . . . . . . . . . . -40C to +85C Storage Temperature Range . . . . . . . . . . . . -65C to +150C Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . +300C ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<1500 V Temperature Range Package Options* ADM3202AN ADM3202ARN ADM3202ARW ADM3202ARU -40C to +85C -40C to +85C -40C to +85C -40C to +85C N-16 R-16A R-16 RU-16 ADM3222AN ADM3222ARW ADM3222ARS ADM3222ARU -40C to +85C -40C to +85C -40C to +85C -40C to +85C N-18 R-18 RS-20 RU-20 ADM1385ARS -40C to +85C RS-20 *N = Plastic DIP; R = Small Outline; RS = Shrink Small Outline; RU = Thin Shrink Small Outline. *This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operation sections of this specificatio n is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. REV. A Model -3- ADM3202/ADM3222/ADM1385 PIN FUNCTION DESCRIPTIONS Mnemonic Function VCC V+ Power Supply Input: +3.3 V 0.3 V. Internally Generated Positive Supply (+6 V Nominal). Internally Generated Negative Supply (-6 V Nominal). Ground Pin. Must be connected to 0 V. External Capacitor 1 is connected between these pins. 0.1 F capacitor is recommended but larger capacitors up to 47 F may be used. External Capacitor 2 is connected between these pins. 0.1 F capacitor is recommended but larger capacitors up to 47 F may be used. Transmitter (Driver) Inputs. These inputs accept TTL/CMOS levels. Transmitter (Driver) Outputs. These are RS-232 signal levels (typically 9 V). Receiver Inputs. These inputs accept RS-232 signal levels. An internal 5 k pull-down resistor to GND is connected on each input. Receiver Outputs. These are CMOS output logic levels. (ADM3222) Receiver Enable, Active Low. When low, the receiver outputs are enabled. When high, they are three-stated. (ADM3222) Shutdown Control. Active Low. When low, the charge pump is shut down and the transmitter outputs are disabled. (ADM1385) Shutdown Control. When low, the charge pump is shut down and all transmitters and receivers are disabled. (ADM1385) Driver Disable. When low, the charge pump is turned off and the transmitters are disabled. The receivers remain active. V- GND C1+, C1- C2+, C2- TxIN TxOUT RxIN RxOUT EN SD SD DD PIN CONNECTIONS DIP (N, R Packages) 16 VCC C1+ 1 15 GND V+ 2 14 T1OUT C1- 3 C2+ 4 ADM3202 13 R1IN TOP VIEW C2- 5 (Not to Scale) 12 R1OUT V- 6 11 T1IN T2OUT 7 10 T2IN R2IN 8 9 R2OUT EN 1 18 SD C1+ 2 17 VCC V+ 3 16 GND C1- 4 15 T1OUT ADM3222 C2+ 5 TOP VIEW 14 R1IN (Not to Scale) C2- 6 13 R1OUT V- 7 12 T2OUT 8 11 T2IN R2IN 9 10 R2OUT T1IN PIN CONNECTIONS DIP (RS, RU Packages) EN 1 20 SD DD 1 C1+ 2 19 VCC C1+ 2 18 GND 17 T1OUT C1- 4 16 R1IN C2+ 5 V+ 3 C1- 4 C2+ 5 ADM3222 (SSOP TSSOP) TOP VIEW 15 R1 OUT (Not to Scale) 14 NC V- 7 C2- 6 -4- V+ 3 18 GND ADM1385 (SSOP) 17 T1OUT 16 R1IN TOP VIEW 15 R1OUT (Not to Scale) 14 T1IN V- 7 C2- 6 T2OUT 8 13 T1IN T2OUT 8 R2IN 9 12 T2IN R2IN 9 R2OUT 10 11 NC NC = NO CONNECT 20 SD 19 VCC NC 10 13 T2IN 12 R2OUT 11 NC NC = NO CONNECT REV. A ADM3202/ADM3222/ADM1385 Typical Performance Characteristics 6 8 TOUT (HIGH) 6 4 V+ (V) 4 2 2 0 0 -2 -2 V- (V) -4 -4 -6 TOUT (LOW) 0 1000 2000 3000 LOAD CAPACITANCE - pF -6 4000 -8 5000 Figure 1. Transmitter Output Voltage High/Low vs. Load Capacitance @ 230 kbps 0 10 20 CURRENT - mA 30 40 Figure 4. Charge Pump V+, V- vs. Current 12 250 10 200 V- IMPEDANCE 8 150 6 V+ IMPEDANCE 100 4 50 2 0 3 3.5 4.0 4.5 VCC - V 5.0 0 3.0 5.5 3.5 4.0 4.5 5.0 5.5 VCC - V Figure 2. Transmitter Output Voltage High vs. VCC Figure 5. Charge Pump Impedance vs. VCC 8 25 T1OUT (HIGH) - V 6 IDD (mA) @ 250kbps 20 4 2 IDD (mA) @ 160kbps 15 0 IDD (mA) @ 80kbps 10 -2 T1OUT (LOW) - V -4 5 -6 -8 0 2 4 6 CURRENT - mA 8 0 10 Figure 3. Transmitter Output Voltage Low/High vs. Load Current REV. A 0 1000 2000 3000 4000 LOAD CAPACITANCE - pF 5000 Figure 6. Power Supply Current vs. Load Capacitance -5- ADM3202/ADM3222/ADM1385 +3.3V INPUT 0.1F + 10V C1+ 0.1F + 10V C2+ +6.6V TO -6.6V VOLTAGE INVERTER C2- C1- T1IN 2V/DIV T1OUT 5V/DIV +3.3V TO +6.6V VCC VOLTAGE V+ DOUBLER C3 + 0.1F 6.3V V- C4 + 0.1F 10V T1IN T1 T1OUT T2IN T2 T2OUT CMOS INPUTS 1s/DIV Figure 7. 230 kbps Data Transmission CMOS OUTPUTS + C5 0.1F EIA/TIA-232 OUTPUTS R1OUT R1 R1IN R2 R2IN EIA/TIA-232 INPUTS* R2OUT GENERAL DESCRIPTION GND The ADM3202/ADM3222/ADM1385 are RS-232 line drivers/ receivers. Step-up voltage converters coupled with level shifting transmitters and receivers allow RS-232 levels to be developed while operating from a single +3.3 V supply. ADM3202 *INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT +3.3V INPUT CMOS technology is used to keep the power dissipation to an absolute minimum, allowing maximum battery life in portable applications. The ADM3202/ADM3222/ADM1385 is a modification, enhancement and improvement to the AD230-AD241 family and its derivatives. It is essentially plug-in compatible and does not have materially different applications. +3.3V TO +6.6V VCC VOLTAGE V+ DOUBLER 0.1F + 10V C1+ 0.1F + 10V C2+ +6.6V TO -6.6V VOLTAGE INVERTER C2- C1- C3 + 0.1F 6.3V V- C4 + 0.1F 10V T1IN T1 T1OUT T2IN T2 T2OUT CMOS INPUTS CIRCUIT DESCRIPTION The internal circuitry consists of three main sections. These are: CMOS OUTPUTS 1. A charge pump voltage converter 2. 3.3 V logic to EIA-232 transmitters 3. EIA-232 to 5 V logic receivers. R1OUT R1 R1IN R2OUT R2 R2IN ADM3222 EN + C5 0.1F GND EIA/TIA-232 OUTPUTS EIA/TIA-232 INPUTS* SD Charge Pump DC-DC Voltage Converter *INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT The charge pump voltage converter consists of a 200 kHz oscillator and a switching matrix. The converter generates a 6.6 V supply from the input +3.3 V level. This is done in two stages using a switched capacitor technique as illustrated below. First, the +3.3 V input supply is doubled to +6.6 V using capacitor C1 as the charge storage element. The +6.6 V level is then inverted to generate -6.6 V using C2 as the storage element. C3 is shown connected between V+ and VCC, but is equally effective if connected between V+ and GND. +3.3V INPUT Capacitors C3 and C4 are used to reduce the output ripple. Their values are not critical and can be increased if desired. Capacitor C3 is shown connected between V+ and VCC. It is also acceptable to connect this capacitor between V+ and GND. +3.3V TO +6.6V VCC VOLTAGE V+ DOUBLER 0.1F + 10V C1+ 0.1F + 10V C2+ +6.6V TO -6.6V VOLTAGE INVERTER C2- C1- V- + C3 0.1F 6.3V C4 + 0.1F 10V T1IN T1 T1OUT T2IN T2 T2OUT CMOS INPUTS CMOS OUTPUTS If desired, larger capacitors (up to 10 F) can be used for capacitors C1-C4. R1OUT R1 R1IN R2OUT R2 R2IN DD ADM1385 GND + C5 0.1F EIA/TIA-232 OUTPUTS EIA/TIA-232 INPUTS* SD *INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT Figure 8. Typical Operating Circuits -6- REV. A ADM3202/ADM3222/ADM1385 S1 Receiver Section S3 VCC V+ = 2VCC C1 + S2 The receivers are inverting level-shifters that accept RS-232 input levels and translate them into 3 V logic output levels. The inputs have internal 5 k pull-down resistors to ground and are also protected against overvoltages of up to 30 V. Unconnected inputs are pulled to 0 V by the internal 5 k pull-down resistor. This, therefore, results in a Logic 1 output level for unconnected inputs or for inputs connected to GND. + C3 S4 VCC GND INTERNAL OSCILLATOR Figure 9. Charge Pump Voltage Doubler S1 FROM VOLTAGE DOUBLER The receivers have Schmitt trigger inputs with a hysteresis level of 0.4 V. This ensures error-free reception for both noisy inputs and for inputs with slow transition times. S3 V+ GND C2 + C4 S2 + S4 V- = -(V+) GND HIGH BAUD RATE The ADM3202E/ADM3222E feature high slew rates permitting data transmission at rates well in excess of the EIA/RS-232E specifications. RS-232 voltage levels are maintained at data rates up to 460 kbps even under worst case loading conditions. This allows for high speed data links between two terminals or indeed it is suitable for the new generation ISDN modem standards which requires data rates of 230 kbps. The slew rate is internally controlled to less than 30 V/s in order to minimize EMI interference. INTERNAL OSCILLATOR Figure 10. Charge Pump Voltage Inverter Transmitter (Driver) Section The drivers convert 3.3 V logic input levels into RS-232 output levels. With VCC = +3.3 V and driving an RS-232 load, the output voltage swing is typically 6 V. OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 16-Lead Narrow Body SOIC (R-16A) 16-Lead Plastic DIP (N-16) 0.3937 (10.00) 0.3859 (9.80) 0.840 (21.34) 0.745 (18.92) 16 9 1 8 PIN 1 0.280 (7.11) 0.240 (6.10) 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) 0.070 (1.77) SEATING 0.045 (1.15) PLANE 0.0500 SEATING (1.27) PLANE BSC 16-Lead Thin Shrink Small Outline (TSSOP) (RU-16) 9 8 REV. A 16 9 1 8 PIN 1 PIN 1 0.006 (0.15) 0.002 (0.05) 0.0256 SEATING (0.65) PLANE BSC 8 0.0099 (0.25) 0 0.0500 (1.27) 0.0160 (0.41) 0.0075 (0.19) 0.4133 (10.50) 0.3977 (10.00) 0.256 (6.50) 0.246 (6.25) 0.177 (4.50) 0.169 (4.30) 1 0.0192 (0.49) 0.0138 (0.35) 0.0196 (0.50) x 45 0.0099 (0.25) 16-Lead Wide Body SOIC (R-16) 0.201 (5.10) 0.193 (4.90) 16 0.0688 (1.75) 0.0532 (1.35) PIN 1 0.0098 (0.25) 0.0040 (0.10) 0.015 (0.381) 0.008 (0.204) 0.2440 (6.20) 0.2284 (5.80) 0.0433 (1.10) MAX 0.0118 (0.30) 0.0075 (0.19) 8 0 0.0079 (0.20) 0.0035 (0.090) 0.0118 (0.30) 0.0040 (0.10) 0.028 (0.70) 0.020 (0.50) 0.0500 (1.27) BSC -7- 0.4193 (10.65) 0.3937 (10.00) 0.100 (2.54) BSC 9 8 0.2992 (7.60) 0.2914 (7.40) 0.022 (0.558) 0.014 (0.356) 16 0.1574 (4.00) 0.1497 (3.80) 1 0.325 (8.26) 0.300 (7.62) 0.195 (4.95) 0.115 (2.93) 0.1043 (2.65) 0.0926 (2.35) 0.0192 (0.49) SEATING 0.0138 (0.35) PLANE 0.0291 (0.74) x 45 0.0098 (0.25) 0.0125 (0.32) 0.0091 (0.23) 8 0.0500 (1.27) 0 0.0157 (0.40) ADM3202/ADM3222/ADM1385 18-Lead Plastic DIP (N-18) 18-Lead Wide Body SOIC (R-18) 0.925 (23.49) 0.845 (21.47) 1 9 0.060 (1.52) 0.015 (0.38) 18 10 1 9 0.325 (8.25) 0.300 (7.62) 0.195 (4.95) 0.115 (2.93) 0.130 (3.30) MIN 0.070 (1.77) SEATING PLANE 0.045 (1.15) 0.015 (0.381) 0.008 (0.204) PIN 1 20-Lead Shrink Small Outline (SSOP) (RS-20) 0.295 (7.50) 0.271 (6.90) 0.260 (6.60) 0.252 (6.40) 11 1 SEATING PLANE 10 20 11 1 10 PIN 1 0.0433 (1.10) MAX 0.0256 (0.65) 0.0118 (0.30) BSC 0.0075 (0.19) 8 0 0.0079 (0.20) 0.0035 (0.090) 0.07 (1.78) 0.066 (1.67) 0.078 (1.98) PIN 1 0.068 (1.73) 0.028 (0.70) 0.020 (0.50) 0.008 (0.203) 0.002 (0.050) 0.0256 (0.65) BSC 8 SEATING 0.009 (0.229) 0 PLANE 0.005 (0.127) 0.037 (0.94) 0.022 (0.559) PRINTED IN U.S.A. 0.006 (0.15) 0.002 (0.05) 0.311 (7.9) 0.301 (7.64) 0.256 (6.50) 0.246 (6.25) 0.177 (4.50) 0.169 (4.30) 20 0.0291 (0.74) x 45 0.0098 (0.25) 8 0.0500 (1.27) 0.0500 0.0192 (0.49) 0 0.0157 (0.40) (1.27) 0.0138 (0.35) SEATING 0.0125 (0.32) PLANE BSC 0.0091 (0.23) 0.0118 (0.30) 0.0040 (0.10) 20-Lead Thin Shrink Small Outline (TSSOP) (RU-20) 0.1043 (2.65) 0.0926 (2.35) 0.212 (5.38) 0.205 (5.21) PIN 1 0.210 (5.33) MAX 0.160 (4.06) 0.115 (2.93) 0.022 (0.558) 0.100 0.014 (0.356) (2.54) BSC 0.280 (7.11) 0.240 (6.10) C00071-0-8/00 (rev. A) 10 0.4193 (10.65) 0.3937 (10.00) 18 0.2992 (7.60) 0.2914 (7.40) 0.4625 (11.75) 0.4469 (11.35) -8- REV. A