Ultralow Power +3.3 V, RS-232
Notebook PC Serial Port Drivers/Receivers
ADM560/ADM561
FEATURES
FUNCTIONAL BLOCK DIAGRAM
+3.3V INPUT
RS-232 compatible
Operates with 3 V or 5 V logic
Ultralow power CMOS: 1.3 mA operation
Low power shutdown: 0.2 μA
Suitable for serial port mice
116 kbps data rate
12
14
11
13
C1+
C1–
V
CC
+3.3V TO +6.6V
VOLTAGE
+
+
1µF
10V
C3
0.1µF
+
1µF
DOUBLER
V+
6.3V
15
16
C2+
C2–
+6.6V TO –6.6V
VOLTAGE
INVERTER
17
V–
1µF
10V
C4
+
1µF
10V
1 μF charge pump capacitors
Single +3 V to +3.6 V power supply
Two receivers active in shutdown (ADM560)
7
6
2
3
1
T1
T2
T3
T4
T1
T2
T3
T1
IN
IN
IN
IN
OUT
OUT
OUT
OUT
T2
T3
T4
CMOS
EIA/TIA-232
OUTPUTS
INPUTS
20
APPLICATIONS
Notebook computers
Peripherals
Modems
Printers
21
8
28
9
T4
R1
R1
R2
R3
R4
R5
R1
R2
R3
R4
R5
OUT
OUT
OUT
OUT
OUT
IN
IN
IN
IN
IN
5
4
R2
R3
R4
R5
CMOS
OUTPUTS
Battery-operated equipment
EIA/TIA-232
INPUTS
26
22
27
23
18
25
19
24
ADM560/
ADM561
SHDN (ADM560)
SHDN (ADM561)
EN (ADM560)
EN (ADM561)
GND
10
Figure 1.
GENERAL DESCRIPTION
The ADM560/ADM561 are four driver/five receiver interface
devices designed to meet the EIA-232 standard and operate with
a single +3.3 V power supply. The devices feature an on-board
dc-to-dc converter, eliminating the need for dual 5 V power
supplies. This dc-to-dc converter contains a voltage doubler
and voltage inverter, both of which internally generate 6.6 V
from the input +3.3 V power supply.
device begins communication. The active receivers alert the
processor, and then take the ADM560 out of shutdown mode.
The ADM561 features active high shutdown and an active
low receiver enable. In this device, all receivers are disabled
in shutdown.
The ADM560/ADM561 are fabricated using CMOS technology
for minimal power consumption. They feature a high level of
over-voltage protection and latch-up immunity. The receiver
inputs can withstand up to 25 V levels. The transmitter inputs
can be driven from either 3 V or 5 V logic levels. This allows
operation in mixed 3 V/5 V power supply systems.
The ADM560 and the ADM561 consume only 5 mW making
them ideally suited for battery and other power-sensitive appli-
cations. A shutdown facility is also provided to reduce the power
to 0.66 μW.
The ADM560 contains active low shutdown and an active high
receiver enable signal. In shutdown mode, two receivers remain
active, thereby allowing monitoring of peripheral devices. This
feature allows the device to be shut down until a peripheral
The ADM560/ADM561 are packaged in a 28-lead SOIC and
a 28-lead SSOP package.
Rev. B
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