ADM232A_15 Datasheet, PDF (1/11 Pages) Analog Devices – CMOS RS-232 Drivers/Receivers

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High-Speed, 5 V, 0.1 ␮F
CMOS RS-232 Drivers/Receivers
ADM222/ADM232A/ADM242
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
GENERAL DESCRIPTION
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 that 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-lead DIP
and in both narrow and wide surface-mount (SOIC) packages.
The ADM222 contains an additional shutdown (SHDN) func-
tion that may be used to disable the device, thereby reducing the
supply current to 0.1 µA. During shutdown, all transmit/receive
FUNCTIONAL BLOCK DIAGRAM
5V INPUT
0.1␮F
0.1␮F
0.1␮F
C1+
V_CC
+5V TO +10V
VOLTAGE DOUBLER
V+
C1–
C2+ _{+5V TO –10V}
VOLTAGE INVERTER ^V–
C2–
0.1␮F
0.1␮F
TTL/CMOS
INPUTS*
T1_IN
T2_IN
TTL/CMOS
OUTPUTS
R1_OUT
R2_OUT
T1
T1_OUT
RS-232
OUTPUTS
T2
T2_OUT
R1
R1_IN
RS-232
INPUTS**
R2
R2_IN
ADM2xx
GND
EN
SHDN
(ADM242)
(ADM222, ADM242)
* INTERNAL 400k⍀ PULL-UP RESISTOR
ON EACH TTL/CMOS INPUT
** INTERNAL 5k⍀ PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
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 dis-
abled 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.
REV. B
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