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FEATURES 200 kB/s Transmission Rate Small (0.1 F) 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 APPLICATIONS Computers Peripherals Modems Printers Instruments
High-Speed, 5 V, 0.1 F CMOS RS-232 Drivers/Receivers ADM222/ADM232A/ADM242*
FUNCTIONAL BLOCK DIAGRAM
5V INPUT 0.1 F VCC +5V TO +10V V+ VOLTAGE DOUBLER +5V TO -10V VOLTAGE INVERTER V- 0.1 F 0.1 F
C1+ 0.1 F C1- C2+ 0.1 F C2-
T1IN TTL/CMOS INPUTS* T2IN R1OUT TTL/CMOS OUTPUTS R2OUT
T1 T2 R1 R2
T1OUT T2OUT R1IN R2IN EN SHDN RS-232 INPUTS** RS-232 OUTPUTS
ADM2xx
(ADM242) (ADM222, ADM242)
GENERAL DESCRIPTION
GND
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 F) 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 that combines low power CMOS with highspeed 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-lead DIP and in both narrow and wide surface-mount (SOIC) packages. The ADM222 contains an additional shutdown (SHDN) function that may be used to disable the device, thereby reducing the supply current to 0.1 A. During shutdown, all transmit/receive
PULL-UP RESISTOR ON EACH TTL/CMOS INPUT ** INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT
* INTERNAL 400k
functions are disabled. The ADM222 is available in 18-lead DIP and in a wide surface-mount (SOIC) package. The ADM242 combines both shutdown (SHDN) and enable (EN) functions. The shutdown function reduces the supply current 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-lead DIP and in a wide surface-mount (SOIC) package.
*Protected by U.S. Patent No. 5,237,209.
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., 2001
ADM222/ADM232A/ADM242-SPECIFICATIONS ifications T
Parameter RS-232 TRANSMITTERS Output Voltage Swing Input Logic Threshold Low, VINL Input Logic Threshold High, VINH Logic Pull-Up 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 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
*Guaranteed by design, not production tested. Specifications subject to change without notice.
(VCC = 5 V
10%. C1-C4 = 0.1 F; all spec-
MIN to TMAX unless otherwise noted.)
Min 5 2.4 200 300
Typ 9 1.7 1.7 12 10
Max
Unit V
Test Conditions/Comments All Transmitter Outputs Loaded with 3 k to Ground TIN TIN TIN = 0 V VCC = V+ = V- = 0 V, VOUT = 2 V
0.8 40
V V A kB/s mA V V V V k V V mA mA A V V mA mA A A V V V/s s s s s ns ns s s ns ns
-30 0.8 0.2 3 3.5 -2 10
+30 1.2 1.6 0.4 5 0.05 -85 35 0.05 1.4 1.4 4 13 0.1 1.4 1.4 8 0.85 1.0 0.1 0.3 125 160 250 3.5 150 200 2.4 1.0 7 0.4
10 0.8
VCC = 5 V TA = 0C to 85C IOUT = 3.2 mA IOUT = -1.0 mA Source Current (VOUT = GND)* Sink Current (VOUT = VCC)* SHDN = GND/EN = VCC 0 V VOUT VCC
2.0
8 10 1 0.8
No Load 3 k Load on Both Outputs
2.0 3
30 3.5 3.5 0.5 0.5 500 500
CL = 50 pF to 1000 pF, RL = 3 k to 7 k 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
-2-
REV. A
ADM222/ADM232A/ADM242
ABSOLUTE MAXIMUM RATINGS*
(TA = 25C unless otherwise noted)
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) RIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 70C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 80C/W Power Dissipation R-16N . . . . . . . . . . . . . . . . . . . . . 400 mW (Derate 7 mW/C above 70C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 80C/W Power Dissipation R-16W . . . . . . . . . . . . . . . . . . . . . 400 mW (Derate 7 mW/C above 70C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 80CW Power Dissipation N-18 . . . . . . . . . . . . . . . . . . . . . . 400 mW (Derate 7 mW/C above 70C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 80C/W
Power Dissipation R-18W . . . . . . . . . . . . . . . . . . . . . 400 mW (Derate 7 mW/C above 70C) JA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 80C/W Operating Temperature Range Industrial (A Version) . . . . . . . . . . . . . . . -40C to +85C Storage Temperature Range . . . . . . . . . . . . -65C to +150C Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . 300C Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . 215C Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220C
*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.
ORDERING GUIDE
Model ADM222AN ADM222AR ADM232AAN ADM232AARN ADM232AARW ADM242AN ADM242AR
Temperature Range -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C
Package Description Plastic DIP Wide SOIC Plastic DIP Narrow SOIC Wide SOIC Plastic DIP Wide SOIC
Package Option N-18 R-18W N-16 R-16N R-16W N-18 R-18W
Test Circuits
3V
3V VIN
VIN
0V
t PLHT
VOUT
t PHLT
V+ 0V V-
t PHLR
t PLHR
VCC
VOUT
50% GND
Figure 1. Transmitter Propagation Delay Timing
Figure 3. Receiver Propagation Delay Timing
3V
3V EN INPUT
EN INPUT 0V
0V
t DR
t ER
3.5V RECEIVER OUTPUT 0.8V
VOH VOH - 0.5V RECEIVER OUTPUT VOL + 0.5V VOL
Figure 2. Receiver Enable Timing
Figure 4. Receiver Disable Timing
REV. A
-3-
ADM222/ADM232A/ADM242
VIN 3k SHDN 50pF VOUT
PIN FUNCTION DESCRIPTION
Mnemonic VCC V+
Function 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 k 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 k 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 and 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.
Figure 5. Shutdown Test Circuit
3V SHDN INPUT 0V
V- GND C1+ C1-
t DT
C2+ C2-
+ 5V
V+
TIN
TRANSMITTER OUTPUT - 5V V-
TOUT RIN
Figure 6. Transmitter Shutdown Disable Timing
ROUT NC
5V INPUT C5 0.1 F 6.3V 2 C1 0.1 F 4 5 C2 0.1 F 6 C1+ C1- C2+ C2- 15 8 14 9
EN
17 C3 0.1 F
VCC 3 +5V TO +10V V+ VOLTAGE DOUBLER +5V TO -10V 7 VOLTAGE INVERTER V-
SHDN
C4 0.1 F T1OUT T2OUT R1IN R2IN SHDN RS-232 INPUTS** RS-232 OUTPUTS
T1IN TTL/CMOS INPUTS* T2IN R1OUT TTL/CMOS OUTPUTS
12 11
T1 T2
NC 1 C1+ 2 V+ 3 C1- 4 C2+ 5
18 17 16
13 R1 10 R2OUT R2
SHDN VCC GND T1OUT
ADM222
GND 16
ADM222
15
18
TOP VIEW 14 R1IN (Not to Scale) C2- 6 13 R1OUT V- 7
12 11 10
PULL-UP RESISTOR ON EACH TTL/CMOS INPUT ** INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT
* INTERNAL 400k
T1IN T2IN R2OUT
T2OUT 8 R2IN 9
NC = NO CONNECT
Figure 7. ADM222 Typical Operating Circuit
Figure 8. ADM222 DIP and SOIC Pin Configurations
-4-
REV. A
ADM222/ADM232A/ADM242
EN 1
18 SHDN 17 VCC 16 GND
C1+ 1 V+ 2 C1- 3 C2+ 4
16 VCC 15 GND 14 T1OUT
C1+ 2 V+ 3 C1- 4 C2+ 5
ADM242
15 T1OUT
ADM232A
13 R1IN
TOP VIEW C2- 5 (Not to Scale) 12 R1OUT V- 6 T2OUT 7 R2IN 8
11 T1IN 10 T2IN 9
TOP VIEW 14 R1IN (Not to Scale) C2- 6 13 R1OUT V- 7
12 T1IN 11 T2IN 10 R2OUT
T2OUT 8 R2IN 9
R2OUT
Figure 9. ADM232A DIP/SOIC Pin Configuration
Figure 11. ADM242 DIP/SOIC Pin Configuration
5V INPUT C5 0.1 F 6.3V 1 C1 0.1 F 3 4 C2 0.1 F 5 C1+ C1- C2+ C2- 14 7 13 8 C5 0.1 F 6.3V C3 0.1 F C1 0.1 F 2 4 5 +5V TO -10V 6 VOLTAGE INVERTER V- C4 0.1 F T1OUT T2OUT R1IN R2IN RS-232 INPUTS** TTL/CMOS OUTPUTS RS-232 OUTPUTS TTL/CMOS INPUTS* C2 0.1 F 6 C1+ C1- C2+ C2-
5V INPUT
16 VCC 2 +5V TO +10V V+ VOLTAGE DOUBLER
17
VCC 3 +5V TO +10V V+ VOLTAGE DOUBLER +5V TO -10V 7 VOLTAGE INVERTER V-
C3 0.1 F
C4 0.1 F T1OUT T2OUT R1IN R2IN RS-232 INPUTS** RS-232 OUTPUTS
T1IN TTL/CMOS INPUTS* T2IN R1OUT TTL/CMOS OUTPUTS R2OUT
11 10
T1 T2
T1IN T2IN R1OUT R2OUT EN
12 11
T1 T2
15
8 14 R1 9
12 R1 9 R2
13
10 1 GND
R2
ADM232A
GND 15 PULL-UP RESISTOR ON EACH TTL/CMOS INPUT ** INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT
ADM242
16
18
SHDN
* INTERNAL 400k
PULL-UP RESISTOR ON EACH TTL/CMOS INPUT ** INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT
* INTERNAL 400k
Figure 10. ADM232A Typical Operating Circuit
Figure 12. ADM242 Typical Operating Circuit
REV. A
-5-
ADM222/ADM232A/ADM242 -Typical Performance Characteristics
15 15 10 V+
Tx O/P VOLTAGE - V
10 Tx O/P HI 5
5
V+, V- - V
0
0
-5 V- -10
-5 Tx O/P LO -10
-15
0
5
10 15 20 LOAD CURRENT - mA
25
30
-15
0
2
4
6 8 10 LOAD CURRENT - mA
12
14
TPC 1. Charge Pump V+, V- vs. Current
TPC 4. Transmitter Output Voltage vs. Current
9 115kBps
TRANSMITTER OUTPUT VOLTAGE - V
7 5 3 1 -1 -3
230kBps
A4
115kBps
100 90
0.010V
460kBps -5 460kBps -7 -9 230kBps
10 0%
5V
5V
100 s
0
500
1000 1500 2000 LOAD CAPACITANCE - pF
2500
3000
TPC 2. Transmitter Baud Rate vs. Load Capacitance
TPC 5. Charge Pump V+, V- Exiting Shutdown
T : 6.2V : 140ns @: -3.5V
T : 6.0V : 600ns @: -2.9V
T
T
CH1
10.0V
CH2
5.00V
M 1.00 s
CH2
-6.4V
CH1
10.0V
CH2
5.00V
M 1.00 s
CH2
-6.4V
TPC 3. Transmitter Unloaded Slew Rate
TPC 6. Transmitter Fully Loaded Slew Rate
-6-
REV. A
ADM222/ADM232A/ADM242
GENERAL INFORMATION
The ADM222/ADM232A/ADM242 are high-speed RS-232 drivers/receivers requiring a single digital 5 V supply. The RS-232 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 stepup 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 contain an internal charge pump voltage doubler and a voltage inverter that generates 10 V from the 5 V input. Four external 0.1 F capacitors are required for the internal charge pump voltage converter. 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.
CIRCUIT DESCRIPTION
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 k pull-up resistor pulls them high forcing the outputs into a low state. As required by the RS-232 standard, the slew rate is limited to less than 30 V/s without the need for an external slew limiting capacitor, and the output impedance in the power-off state is greater than 300 .
Receiver Section
The internal circuitry consists of four main sections. These are: Charge Pump Voltage Converter TTL/CMOS to RS-232 Transmitters RS-232 to TTL/CMOS Receivers Enable and Shutdown Functions.
Charge Pump DC-DC Voltage Converter
The receivers are inverting level-shifters that accept RS-232 input levels ( 3 V to 15 V) and translate them into 5 V TTL/ CMOS levels. The inputs have internal 5 k 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 RS-232 requirement. The low level threshold is deliberately positive as it ensures that an unconnected input will be interpreted as a low level. 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
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. 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. 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. In the shutdown mode the charge pump is disabled and V+ decays to VCC while V- decays to 0 V.
Transmitter (Driver) Section
On the ADM222, both receivers are fully disabled during shutdown. 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.
APPLICATIONS INFORMATION
A selection of typical operating circuits is shown in TPCs 1-6 and Figure 13.
A1
100 90
2.0V
10 0%
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.
5V
5V
5s
Figure 13. Transmitter Output Disable Timing
REV. A
-7-
ADM222/ADM232A/ADM242
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
16-Lead Plastic DIP (N-16)
0.840 (21.34) 0.745 (18.92)
16 1 9 8
16-Lead Narrow SOIC (R-16N)
0.3937 (10.00) 0.3859 (9.80)
0.280 (7.11) 0.240 (6.10) 0.325 (8.25) 0.300 (7.62) 0.195 (4.95) 0.115 (2.93) 0.015 (0.381) 0.008 (0.204)
0.1574 (4.00) 0.1497 (3.80)
16 1
9 8
0.2440 (6.20) 0.2284 (5.80)
PIN 1 0.060 (1.52) 0.015 (0.38) 0.210 (5.33) MAX 0.130 (3.30) 0.160 (4.06) MIN 0.115 (2.93) 0.022 (0.558) 0.100 0.070 (1.77) SEATING PLANE (2.54) 0.014 (0.356) 0.045 (1.15) BSC
PIN 1
0.050 (1.27) BSC
0.0688 (1.75) 0.0532 (1.35)
0.0196 (0.50) 0.0099 (0.25)
45
0.0098 (0.25) 0.0040 (0.10)
8 0.0192 (0.49) SEATING 0 0.0099 (0.25) 0.0138 (0.35) PLANE 0.0075 (0.19)
0.0500 (1.27) 0.0160 (0.41)
16-Lead Wide SOIC (R-16W)
0.4133 (10.50) 0.3977 (10.00)
18-Lead Wide SOIC (R-18W)
0.4625 (11.75) 0.4469 (11.35)
16
9
18
10
0.2992 (7.60) 0.2914 (7.40)
1 8
0.2992 (7.60) 0.2914 (7.40)
1 9
0.4193 (10.65) 0.3937 (10.00)
0.4193 (10.65) 0.3937 (10.00)
PIN 1
0.050 (1.27) BSC
0.1043 (2.65) 0.0926 (2.35)
0.0291 (0.74) 0.0098 (0.25)
45
PIN 1
0.1043 (2.65) 0.0926 (2.35)
0.0291 (0.74) 0.0098 (0.25)
45
0.0118 (0.30) 0.0040 (0.10)
8 0.0192 (0.49) SEATING 0 0.0125 (0.32) 0.0138 (0.35) PLANE 0.0091 (0.23)
0.0500 (1.27) 0.0157 (0.40)
0.0118 (0.30) 0.0500 0.0040 (0.10) (1.27) BSC
8 0 0.0192 (0.49) SEATING 0.0125 (0.32) 0.0138 (0.35) PLANE 0.0091 (0.23)
0.0500 (1.27) 0.0157 (0.40)
18-Lead Plastic DIP (N-18)
0.925 (23.49) 0.845 (21.47)
18 1 10 9
0.280 (7.11) 0.240 (6.10) 0.060 (1.52) 0.015 (0.38) 0.325 (8.25) 0.300 (7.62) 0.195 (4.95) 0.115 (2.93) 0.015 (0.381) 0.008 (0.204)
PIN 1 0.210 (5.33) MAX 0.160 (4.06) 0.115 (2.93) 0.022 (0.558) 0.014 (0.356)
0.130 (3.30) MIN 0.100 0.070 (1.77) SEATING PLANE (2.54) 0.045 (1.15) BSC
-8-
REV. A
PRINTED IN U.S.A.
C01213-0-1/01 (rev. A)

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