ICL3217IB Intersil, ICL3217IB Datasheet - Page 6

• Manufacturer Part Number: ICL3217IB
• Description: IC 5DRVR/3RCVR RS232 3V 24-SOIC
• Manufacturer: Intersil
• Type: Transceiverr

Specifications of ICL3217IB

• Number Of Drivers/receivers: 5/3
• Protocol: RS232
• Voltage - Supply: 3 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 24-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Receivers
The ICL32X7 each contain inverting receivers that convert
RS-232 signals to CMOS output levels and accept inputs up
to ±25V while presenting the required 3kΩ to 7kΩ input
impedance (see Figure 1) even if the power is off
(V
hysteresis to increase noise immunity and decrease errors
due to slow input signal transitions.
Receivers on the ICL3207 are always active. The ICL3217
receivers disable when in the automatic powerdown state,
thereby eliminating the possible current path through a
shutdown peripheral’s input protection diode (see Figures 2
and 3).
Low Power Operation
These 3V devices require a nominal supply current of
0.3mA, even at V
powerdown mode). This is considerably less than the 11mA
current required by comparable 5V RS-232 devices,
allowing users to reduce system power simply by replacing
the old style device with the ICL3207.
Low Power, Pin Compatible Replacement
Pin compatibility with existing 5V products (e.g., MAX207),
coupled with the wide operating supply range, make the
ICL32X7 potential lower power, higher performance drop-in
replacements for existing ‘2X7 5V applications. As long as
the ±5V RS-232 output swings are acceptable, the ICL32X7
devices should work in most 5V applications.
CC
FIGURE 2. POWER DRAIN THROUGH POWERED DOWN
= 0V). The receivers’ Schmitt trigger input stage uses
FIGURE 1. INVERTING RECEIVER CONNECTIONS
POWERED
-25V ≤ V
DOWN
GND
UART
V
CC
PERIPHERAL
RIN
R
GND
V
XIN
CC
CC
≤ +25V
Rx
Tx
V
= 5.5V, during normal operation (not in
CC
SHDN = GND
V
OUT
5kΩ
= V
6
CC
GND ≤ V
RS-232 CHIP
OLD
R
V
CURRENT
FLOW
XOUT
CC
ROUT
≤ V
ICL3207, ICL3217
CC
When replacing a ‘207 or ‘237 device in an existing 5V
application, it is acceptable to terminate C
on the “Typical Operating Circuit”. Nevertheless, terminate
C
from this configuration.
Automatic Powerdown (ICL3217 Only)
Even greater power savings is available by using the
ICL3217 which features an automatic powerdown function.
When no valid RS-232 voltages (see Figure 4) are sensed
on any receiver input for 30µs, the ICL3217 automatically
enters its powerdown state (see Figure 5). In powerdown,
supply current drops to 1µA, because the on-chip charge
pump turns off (V+ collapses to V
and the receiver and transmitter outputs three-state (see
Table 2). This micro-power mode makes the ICL3217 ideal
for battery powered and portable applications. Invalid
receiver levels occur whenever the driving peripheral’s
outputs are shut off (powered down) or when the RS-232
interface cable is disconnected. The ICL3217 powers back
up whenever it detects a valid RS-232 voltage level on any
receiver input (such as when the RS-232 cable is
reconnected). The time to recover from automatic powerdown
mode is typically 100µs.
FIGURE 3. DISABLED RECEIVERS PREVENT POWER DRAIN
TABLE 2. ICL3217 AUTOMATIC POWERDOWN OPERATION
3
RS-232 SIGNAL
POWERED
PRESENT AT
to GND if possible, as slightly better performance results
RECEIVER
DOWN
UART
INPUT?
YES
NO
V
WAKE-UP
CC
LOGIC
TO
R
T
X
X
TRANSITION
* IN AUTOMATIC
DETECTOR
POWERDOWN
TRANSMITTER
V
OUTPUTS
OUT
High-Z
Active
= HI-Z*
V
CC
CC
V-
RECEIVER
OUTPUTS
, V- collapses to GND),
High-Z
Active
ICL3217
3
to V
CC
Normal
Operation
Powerdown
Due to Auto
Powerdown
Logic
OPERATION
MODE
as shown
OF