ISL4241EIR Intersil, ISL4241EIR Datasheet - Page 8

• Manufacturer Part Number: ISL4241EIR
• Description: IC 3DRVR/5RCVR RS232 3V 32-QFN
• Manufacturer: Intersil
• Type: Transceiverr

Specifications of ISL4241EIR

• Number Of Drivers/receivers: 3/5
• Protocol: RS232
• Voltage - Supply: 2.7 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

ISL4241E and ISL4243E monitor receivers remain active
even during manual power-down, making them extremely
useful for Ring Indicator monitoring. Standard receivers
driving powered down peripherals must be disabled to
prevent current flow through the peripheral’s protection
diodes (see Figures 2 and 3). This renders them useless for
wake-up functions, but the corresponding monitor receiver
can be dedicated to this task as shown in Figure 3.
Low Power Operation
These 3V devices require a nominal supply current of
0.3mA, even at V
power-down mode). This is considerably less than the 5mA
to 11mA current required by comparable 5V RS-232 devices,
allowing users to reduce system power simply by switching
to this new family.
ISL4241E
ISL4243E
RECEIVER
PRESENT
SIGNAL
INPUT?
RS-232
YES
YES
N.A.
N.A.
N.A.
N.A.
NO
NO
NO
AT
FORCEOFF
SHDN OR
INPUT
CC
H
H
H
H
H
L
L
L
L
= 5.5V, during normal operation (not in
FORCEON
INPUT
N/A
N/A
N/A
N/A
8
H
X
X
L
L
TABLE 2. POWER-DOWN AND ENABLE LOGIC TRUTH TABLE
INPUT
N/A
N/A
N/A
N/A
N/A
EN
H
H
L
L
TRANSMITTER
OUTPUTS
High-Z
High-Z
High-Z
High-Z
High-Z
Active
Active
Active
Active
ISL4241E, ISL4243E
RECEIVER
OUTPUTS
High-Z
High-Z
High-Z
High-Z
Active
Active
Active
Active
Active
Power-down Functionality
The already low current requirement drops significantly
when the device enters power-down mode. In power-down,
supply current drops to 10nA, because the on-chip charge
pump turns off (V+ collapses to V
and the transmitter outputs three-state. Inverting receiver
outputs disable only in manual power-down; refer to Table 2
for details. This micro-power mode makes the ISL4241E and
ISL4243E ideal for battery powered and portable
applications.
FIGURE 2. POWER DRAIN THROUGH POWERED DOWN
OUTPUTS
R
Active
Active
Active
Active
Active
Active
Active
Active
Active
POWERED
OUTB
DOWN
UART
GND
V
CC
PERIPHERAL
OUTPUT
INVALID
N/A
N/A
N/A
N/A
Rx
Tx
H
H
L
L
L
V
CC
SHDN = GND
V
Manual Power-down
Manual Power-down w/Receiver
Disabled
Normal Operation
Normal Operation w/Receiver
Disabled
Normal Operation
(Auto Power-down Disabled)
Normal Operation
(Auto Power-down Enabled)
Power-down Due to Auto Power-down
Logic
Manual Power-down
Manual Power-down
OUT
= V
MODE OF OPERATION
CC
CC
, V- collapses to GND),
RS-232 CHIP
V
OLD
CURRENT
FLOW
CC
June 10, 2010
FN8037.7