ADM232A_15 Datasheet, PDF (4/11 Pages) Analog Devices – CMOS RS-232 Drivers/Receivers

ADM222/ADM232A/ADM242
V_IN
SHDN
3k⍀
V_OUT
50pF
Figure 5. Shutdown Test Circuit
3V
SHDN
INPUT
0V
t_DT
V+
TRANSMITTER
OUTPUT
V–
+ 5V
– 5V
Figure 6. Transmitter Shutdown Disable Timing
C1
0.1␮F
C2
0.1␮F
5V INPUT
C5
0.1␮F
6.3V
17
2 _C1+
V_CC
4
+5V TO +10V
VOLTAGE DOUBLER
V+
3
C1–
5
C2+ _{+5V TO –10V}
VOLTAGE INVERTER ^V–
7
6
C2–
C3
0.1␮F
C4
0.1␮F
12
T1_IN
TTL/CMOS
INPUTS*
11
T2_IN
TTL/CMOS
OUTPUTS
13
R1_OUT
10
R2_OUT
T1
T2
R1
R2
15
T1_OUT
RS-232
8
OUTPUTS
T2_OUT
14
R1_IN
RS-232
9
INPUTS**
R2_IN
ADM222
GND
18 _SHDN
16 _{* INTERNAL 400k⍀ PULL-UP RESISTOR}
ON EACH TTL/CMOS INPUT
** INTERNAL 5k⍀ PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
Figure 7. ADM222 Typical Operating Circuit
PIN FUNCTION DESCRIPTION
Mnemonic
V_CC
V+
V–
GND
C1+
C1–
C2+
C2–
T_IN
T_OUT
R_IN
R_OUT
NC
EN
SHDN
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 kΩ pull-up
resistor to V_CC 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 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.
NC 1
18 _SHDN
C1+ 2
V+ 3
17 V_CC
16 GND
C1– 4 _ADM222 15 T1_OUT
C2+ 5 TOP VIEW 14 R1_IN
(Not to Scale)
C2– 6
13 R1_OUT
V– 7
12 T1_IN
T2_OUT 8
11 T2_IN
R2_IN 9
10 R2OUT
NC = NO CONNECT
Figure 8. ADM222 DIP and SOIC Pin Configurations
–4–
REV. B