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ADM239L Schematic ( PDF Datasheet ) - Analog Devices

Teilenummer ADM239L
Beschreibung CMOS RS-232 Drivers/Receivers
Hersteller Analog Devices
Logo Analog Devices Logo 




Gesamt 16 Seiten
ADM239L Datasheet, Funktion
a
5 V Powered
CMOS RS-232 Drivers/Receivers
ADM223/ADM230L–ADM241L
FEATURES
ADM232L TYPICAL OPERATING CIRCUIT
Single 5 V Power Supply
5V INPUT
Meets All EIA-232-E and V.28 Specifications
120 kB/s Data Rate
On-Board DC-DC Converters
1F
6.3V
C1+ +5V TO +10V VCC
VOLTAGE
C1– DOUBLER
V+
1F
6.3V
1F
6.3V
؎9 V Output Swing with 5 V Supply
Small 1 F Capacitors
Low Power Shutdown 1 A
Receivers Active in Shutdown (ADM223)
؎30 V Receiver Input Levels
Latch-Up FREE
Plug-In Upgrade for MAX223/230-241
Plug-In Upgrade for AD230–AD241
OAPPLICATIONS
Computers
BPeripherals
SModems
Printers
OInstruments
LGENERAL DESCRIPTION
EThe ADM2xx family of line drivers/receivers is intended for all
EIA-232-E and V.28 communications interfaces, especially in
TEapplications where ±12 V is not available. The ADM223,
1F
16V
TTL/CMOS
INPUTS*
T1IN
T2IN
TTL/CMOS
OUTPUTS
R1OUT
R2OUT
C2+ +10V TO –10V
VOLTAGE
C2– INVERTER
V–
T1
T2
R1
R2
GND ADM232L
1F
16V
T1OUT
T2OUT
RS-232
OUTPUTS
R1IN
R2IN
RS-232
INPUTS**
* INTERNAL 400kPULL-UP RESISTOR ON EACH TTL/CMOS INPUT.
** INTERNAL 5kPULL-DOWN RESISTOR ON EACH RS-232 INPUT.
All members of the ADM230L family, except the ADM231L
and the ADM239L, include two internal charge pump voltage
converters that allow operation from a single 5 V supply. These
converters convert the 5 V input power to the ± 10 V required
ADM230L, ADM235L, ADM236L and ADM241L feature a
for RS-232 output levels. The ADM231L and ADM239L are
low power shutdown mode that reduces power dissipation to
less than 5 µW, making them ideally suited for battery powered
designed to operate from 5 V and 12 V supplies. An internal
+12 V to –12 V charge pump voltage converter generates the
equipment. Two receivers remain enabled during shutdown on –12 V supply.
the ADM223. The ADM233L and ADM235L do not require
any external components and are particularly useful in applica-
tions where printed circuit board space is critical.
The ADM2xxL is an enhanced upgrade for the AD2xx family
featuring lower power consumption, faster slew rate and opera-
tion with smaller (1 µF) capacitors.
Table I. Selection Table
Part
Number
ADM223
ADM230L
ADM231L
ADM232L
ADM233L
ADM234L
ADM235L
ADM236L
ADM237L
ADM238L
ADM239L
ADM241L
Power
Supply Voltage
5V
5V
5 V and 7.5 V to 13.2 V
5V
5V
5V
5V
5V
5V
5V
5 V and 7.5 V to 13.2 V
5V
No. of
RS-232
Drivers
4
5
2
2
2
4
5
4
5
4
3
4
No. of
RS-232
Receivers
5
0
2
2
2
0
5
3
3
4
5
5
External
Capacitors
4
4
2
4
None
4
None
4
4
4
2
4
Low Power
Shutdown
(SD)
Yes (SD)
Yes
No
No
No
No
Yes
Yes
No
No
No
Yes
TTL
Three-State
EN
Yes (EN)
No
No
No
No
No
Yes
Yes
No
No
Yes
Yes
No. of
Pins
28
20
14
16
20
16
24
24
24
24
24
28
REV. B
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 that
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
www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 2001






ADM239L Datasheet, Funktion
ADM223/ADM230LADM241L
5V INPUT
1F
6.3V
C1+ +5V TO +10V VCC
VOLTAGE
C1DOUBLER
V+
1F
6.3V
1F
6.3V
T1OUT 1
T2OUT 2
T2IN 3
16 T3OUT
15 T4OUT
14 T4IN
1F
16V
T1IN
C2+ +10V TO 10V
VOLTAGE
C2INVERTER
V
T1
1F
16V
T1OUT
T1IN 4
ADM234L 13 T3IN
TOP VIEW
T2IN
T2
T2OUT
GND 5 (Not to Scale) 12 V
VCC 6
C1+ 7
V+ 8
11 C2
10 C2+
9 C1
OFigure 9. ADM234L DIP/SOIC Pin Configuration
BSOLETT4OUT 1
ET3OUT 2
24 R3IN
23 R3OUT
TTL/CMOS
INPUTS*
T3IN
T4IN
T3
T4
GND ADM234L
RS-232
T3OUT OUTPUTS
T4OUT
* INTERNAL 400kPULL-UP RESISTOR ON EACH TTL/CMOS INPUT.
Figure 10. ADM234L Typical Operating Circuit
5V INPUT
1F
TTL/CMOS
INPUTS*
T1IN
T2IN
T3IN
VCC
T1
T2
T3
T1OUT
T2OUT
T3OUT
RS-232
OUTPUTS
T1OUT 3
22 T5IN
T4IN
T4
T4OUT
T2OUT 4
R2IN 5
R2OUT 6
T2IN 7
T1IN 8
R1OUT 9
ADM235L
TOP VIEW
(Not to Scale)
21 SD
20 EN
19 T5OUT
18 R4IN
17 R4OUT
16 T4IN
T5IN
R1OUT
R2OUT
TTL/CMOS
OUTPUTS R3OUT
T5
R1
R2
R3
T5OUT
R1IN
R2IN
R3IN
RS-232
INPUTS**
R1IN 10
GND 11
VCC 12
15 T3IN
14 R5OUT
13 R5IN
R4OUT
R5OUT
R4 R4IN
R5 R5IN
EN
GND ADM235L
SD
Figure 11. ADM235L DIP Pin Configuration
* INTERNAL 400kPULL-UP RESISTOR ON EACH TTL/CMOS INPUT.
** INTERNAL 5kPULL-DOWN RESISTOR ON EACH RS-232 INPUT.
Figure 12. ADM235L Typical Operating Circuit
–6– REV. B

6 Page









ADM239L pdf, datenblatt
ADM223/ADM230LADM241L
1T
T
T
SD
V+ 1
2
Tx INPUT
T
T
Tx OUTPUT
V
CH1 5.00V CH2 5.00V M50.0s CH1
CH3 5.00V BW V+, VEXITING SD
3.1V
CH1 5.00V CH2 5.00V M1.00s CH1 800mV
Figure 30. Charge Pump, V+, V– Exiting Shutdown
Figure 31. Transmitter Output Loaded Slew Rate
1 T Tx INPUT
T
2
O Tx OUTPUT
BSCH1 5.00V CH2 5.00V M1.00s CH1 800mV
OFigure 32. Transmitter Output Unloaded Slew Rate
LEGENERAL INFORMATION
CIRCUIT DESCRIPTION
TEThe ADM223/ADM230L–ADM241L family of RS-232 drivers/ The internal circuitry in the ADM230L–ADM241L consists of
receivers are designed to solve interface problems by meeting three main sections. These are:
the EIA-232-E specifications while using a single digital 5 V
supply. The EIA-232-E standard requires transmitters which
will deliver ± 5 V minimum on the transmission channel and
receivers which can accept signal levels down to ± 3 V. The
ADM223/ADM230L–ADM241L meet these requirements by
integrating step up voltage converters and level shifting trans-
mitters and receivers onto the same chip. CMOS technology is
used to keep the power dissipation to an absolute minimum. A
comprehensive range of transmitter/receiver combinations is
available to cover most communications needs.
The ADM223, ADM230L, ADM235L, ADM236L and
ADM241L are particularly useful in battery powered systems as
(a) A charge pump voltage converter
(b) RS-232 to TTL/CMOS receivers
(c) TTL/CMOS to RS-232 transmitters
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 as illustrated in Figures 33 and 34.
First, the 5 V input supply is doubled to 10 V using capacitor
C1 as the charge storage element. The 10 V level is then inverted
to generate –10 V using C2 as the storage element.
they feature a low power shutdown mode which reduces power
dissipation to less than 5 µW.
VCC
S1
S3
V+ = 2VCC
The ADM233L and ADM235L are designed for applications
where space saving is important as the charge pump capaci-
tors are molded into the package.
GND
C1
S2
C3
S4
VCC
The ADM231L and ADM239L include only a negative charge
pump converter and are intended for applications where a posi-
tive 12 V is available.
To facilitate sharing a common line or for connection to a micro-
processor data bus the ADM235L, ADM236L, ADM239L and
ADM241L feature an enable (EN, EN) function. When disabled,
the receiver outputs are placed in a high impedance state.
INTERNAL
OSCILLATOR
Figure 33. Charge-Pump Voltage Doubler
–12–
REV. B

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