CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
3.
θ
JA
is measured with the component mounted on a low effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
Electrical Specifications
Test Conditions: V
CC
= 3V to 5.5V, C
1
- C
4
= 0.1
µ
F; Unless Otherwise Specified.
Typicals are at T
A
= 25°C
TEST CONDITIONS
TEMP
(°C)
MIN
TYP
MAX
UNITS
PARAMETER
DC CHARACTERISTICS
Supply Current, Enabled
Supply Current, Powerdown
All Outputs Unloaded, SHDN = V
CC
, V
CC
= 3.15V
SHDN = GND
25
25
-
-
0.3
1
1
10
mA
µA
LOGIC AND TRANSMITTER INPUTS
Input Logic Threshold Low
Input Logic Threshold High
T
IN
, SHDN
T
IN
, SHDN
V
CC
= 3.3V
V
CC
= 5.0V
Transmitter Input Hysteresis
Input Leakage Current
RECEIVER OUTPUTS
Output Voltage Low
Output Voltage High
RECEIVER INPUTS
Input Voltage Range
Input Threshold Low
V
CC
= 3.3V
V
CC
= 5.0V
Input Threshold High
V
CC
= 3.3V
V
CC
= 5.0V
Input Hysteresis
Input Resistance
TRANSMITTER OUTPUTS
Output Voltage Swing
Output Resistance
Output Short-Circuit Current
Output Leakage Current
V
OUT
=
±12V,
V
CC
= 0V or 3V to 5.5V, SHDN = GND
All Transmitter Outputs Loaded with 3kΩ to Ground
V
CC
= V+ = V- = 0V, Transmitter Output =
±2V
Full
Full
Full
Full
±5.0
300
-
-
±5.4
10M
±35
-
-
-
±60
±25
V
Ω
mA
µA
Full
25
25
25
25
25
25
-25
0.6
0.8
-
-
-
3
-
1.2
1.5
1.5
1.8
0.5
5
25
-
-
2.4
2.4
-
7
V
V
V
V
V
V
kΩ
I
OUT
= 1.6mA
I
OUT
= -1.0mA
Full
Full
-
-
0.4
-
V
V
T
IN
, SHDN
Full
Full
Full
25
Full
-
2.0
2.4
-
-
-
-
-
0.5
±0.01
0.8
-
-
-
±1.0
V
V
V
V
µA
V
CC
-0.6 V
CC
-0.1
4
FN6001.4
January 16, 2005
ISL83385E
Electrical Specifications
Test Conditions: V
CC
= 3V to 5.5V, C
1
- C
4
= 0.1
µ
F; Unless Otherwise Specified.
Typicals are at T
A
= 25°C
(Continued)
TEST CONDITIONS
TEMP
(°C)
MIN
TYP
MAX
UNITS
PARAMETER
TIMING CHARACTERISTICS
Maximum Data Rate
Receiver Propagation Delay
R
L
= 3kΩ, C
L
= 1000pF, One Transmitter Switching
Receiver Input to Receiver
Output, C
L
= 150pF
t
PHL
t
PLH
Full
25
25
25
25
25
25
25
250
-
-
-
-
-
6
4
500
0.15
0.15
100
100
50
-
-
-
-
-
-
-
-
30
30
kbps
µs
µs
µs
ns
ns
V/µs
V/µs
Transmitter Output Enable Time
Transmitter Skew
Receiver Skew
Transition Region Slew Rate
From SHDN Rising Edge to T
OUT
=
±3.7V
t
PHL
- t
PLH
(Note 4)
t
PHL
- t
PLH
C
L
= 150pF to 1000pF
R
L
= 3kΩ to 7kΩ,
Measured From 3V to -3V or
C
L
= 150pF to 2500pF
-3V to 3V, V
CC
= 3.3V
ESD PERFORMANCE
RS-232 Pins (T
OUT
, R
IN
)
Human Body Model
IEC61000-4-2 Air Gap Discharge
IEC61000-4-2 Contact Discharge
All Other Pins
NOTE:
4. Transmitter skew is measured at the transmitter zero crossing points.
Human Body Model
25
25
25
25
-
-
-
-
±15
±15
±8
±3
-
-
-
-
kV
kV
kV
kV
Detailed Description
The ISL83385E operates from a single +3V to +5.5V supply,
guarantees a 250kbps minimum data rate, requires only four
small external 0.1µF capacitors, features low power
consumption, and meets all ElA RS-232C and V.28
specifications. The circuit is divided into three sections: The
charge pump, the transmitters, and the receivers.
All 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.
All devices guarantee a 250kbps data rate for full load
conditions (3kΩ and 1000pF), V
CC
≥
3.0V, with one
transmitter operating at full speed. Under more typical
conditions of V
CC
≥
3.3V, R
L
= 3kΩ, and C
L
= 250pF, one
transmitter easily operates at 900kbps.
Transmitter inputs float if left unconnected (there are no pull-
up resistors), and may cause I
CC
increases. Connect
unused inputs to GND for the best performance.
TABLE 2. POWERDOWN TRUTH TABLE
SHDN TRANSMITTER RECEIVER
INPUT
OUTPUTS
OUTPUTS MODE OF OPERATION
H
L
Active
High-Z
Active
Active
Normal Operation
Manual Powerdown
Charge-Pump
Intersil’s new ISL83385E utilizes regulated on-chip dual
charge pumps as voltage doublers, and voltage inverters to
generate
±5.5V
transmitter supplies from a V
CC
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 over the full V
CC
range; other capacitor combinations can be used as shown
in Table 3. 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.
Receivers
The ISL83385E contains standard inverting receivers that
convert RS-232 signals to CMOS output levels and accept
inputs up to
±30V
while presenting the required 3kΩ to 7kΩ
input impedance (see Figure 1) even if the power is off
(V
CC
= 0V). The receivers’ Schmitt trigger input stage uses
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
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