ICL3244E Intersil Corporation, ICL3244E Datasheet - Page 8

• Manufacturer Part Number: ICL3244E
• Description: (ICL3224E - ICL3244E) RS-232 Transceivers
• Manufacturer: Intersil Corporation

Electrical Specifications
NOTE:
Detailed Description
These ICL32XXE interface ICs operate from a single +3V to
+5.5V supply, guarantee a 250kbps minimum data rate,
require only four small external 0.1µF capacitors, feature low
power consumption, and meet all ElA RS-232C and V.28
specifications. The circuit is divided into three sections: The
charge pump, the transmitters, and the receivers.
Charge-Pump
Intersil’s new ICL32XXE family utilizes regulated on-chip
dual charge pumps as voltage doublers, and voltage
inverters to generate ±5.5V transmitter supplies from a V
supply as low as 3.0V. This allows these devices to maintain
RS-232 compliant output levels over the ±10% tolerance
range of 3.3V powered systems. The efficient on-chip power
supplies require only four small, external 0.1µF capacitors
for the voltage doubler and inverter functions at V
See the “Capacitor Selection” section, and Table 3 for
capacitor recommendations for other operating conditions.
The charge pumps operate discontinuously (i.e., they turn off
as soon as the V+ and V- supplies are pumped up to the
nominal values), resulting in significant power savings.
Transmitters
The transmitters are proprietary, low dropout, inverting
drivers that translate TTL/CMOS inputs to EIA/TIA-232
output levels. Coupled with the on-chip ±5.5V supplies, these
transmitters deliver true RS-232 levels over a wide range of
single supply system voltages.
Transmitter outputs disable and assume a high impedance
state when the device enters the powerdown mode (see
Table 2). These outputs may be driven to ±12V when
disabled.
Receiver Skew
Transition Region Slew Rate
ESD PERFORMANCE
RS-232 Pins (T
All Other Pins
2. An “edge” is defined as a transition through the transmitter or receiver input thresholds.
PARAMETER
OUT
, R
IN
)
8
Test Conditions: V
Typicals are at T
t
V
R
Measured From 3V to -3V or -3V
to 3V
Human Body Model
IEC61000-4-2 Contact Discharge
IEC61000-4-2 Air Gap Discharge
Human Body Model
PHL
CC
L
= 3kΩ to 7kΩ,
= 3.3V,
- t
PLH
ICL3224E, ICL3226E, ICL3244E
A
CC
= 25°C (Continued)
CC
TEST CONDITIONS
= 3V to 5.5V, C
= 3.3V.
CC
C
C
1
L
L
- C
= 150pF to 1000pF
= 150pF to 2500pF
4
All devices guarantee a 250kbps data rate for full load
conditions (3kΩ and 1000pF), V
transmitter operating at full speed. Under more typical
conditions of V
transmitter easily operates at 1Mbps.
Transmitter inputs float if left unconnected, and may cause
I
performance.
Receivers
All the ICL32XXE devices contain standard inverting
receivers, but only the ICL3244E receivers can three-state,
via the FORCEOFF control line. Additionally, the ICL3244E
includes a noninverting (monitor) receiver (denoted by the
R
any control lines. Both receiver types 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
Schmitt trigger input stage uses hysteresis to increase noise
immunity and decrease errors due to slow input signal
transitions.
CC
= 0.1
OUTB
increases. Connect unused inputs to GND for the best
µ
FIGURE 1. INVERTING RECEIVER CONNECTIONS
-25V ≤ V
F; Unless Otherwise Specified.
label) that is always active, regardless of the state of
RIN
R
GND
CC
V
XIN
CC
≤ +25V
TEMP
≥ 3.3V, R
(°C)
25
25
25
25
25
25
25
5kΩ
MIN
L
6
4
-
-
-
-
-
= 3kΩ, and C
CC
CC
≥ 3.0V, with one
TYP
GND ≤ V
±15
±15
50
±8
±3
8
-
= 0V). The receivers’
R
XOUT
L
ROUT
= 250pF, one
MAX
30
30
-
-
-
-
-
≤ V
CC
UNITS
V/µs
V/µs
kV
kV
kV
kV
ns