1
®
FN6014.2
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143
|
Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2002-2004. All Rights Reserved All other trademarks mentioned are the property of their respective owners.
ICL3237E
±
15kV ESD Protected, 10nA Supply-
Current, +3V to +5.5V, 250k/1Mbps,
RS-232 Transmitters/Receivers
The Intersil ICL3237E contains 3.0V to 5.5V powered
RS-232 transmitters/receivers which meet ElA/TIA-232 and
V.28/V.24 specifications, even at V
CC
= 3.0V. Additionally, it
provides
±
15kV ESD protection (IEC61000-4-2 Air Gap and
Human Body Model) on transmitter outputs and receiver
inputs (RS-232 pins). Targeted applications are cell phones,
PDAs, Palmtops, and notebook and laptop computers where
the low operational, and even lower standby, power
consumption is critical. Efficient on-chip charge pumps,
coupled with the manual powerdown function, reduce the
standby supply current to a 10nA trickle. Small footprint
packaging, and the use of small, low value capacitors ensure
board space savings as well. Data rates greater than 1Mbps
(MBAUD = V
CC
) are guaranteed at worst case load
conditions. The ICL3237E is fully compatible with 3.3V only
systems, mixed 3.3V and 5.0V systems, and 5.0V only
systems.
The ICL3237E is a 5 driver, 3 receiver device that also
includes a noninverting always-active receiver for "wake-up"
capability.
Table 1 summarizes the features of the device represented
by this data sheet, while Application Note AN9863
summarizes the features of each device comprising the
ICL32XX 3V family.
Features
· ESD Protection For RS-232 I/O Pins to
±
15kV (IEC61000)
· Pin Compatible Replacement for MAX3237E
· Pin Selectable, Guaranteed Data Rate . . 250kbps/1Mbps
· Meets EIA/TIA-232 and V.28/V.24 Specifications at 3V
· RS-232 Compatible with V
CC
= 2.7V
· Latch-Up Free
· On-Chip Voltage Converters Require Only Four External
Capacitors
· Manual Powerdown Feature
· Flow Through Pinout
· Rx and Tx Hysteresis For Improved Noise Immunity
· Rx Active in Powerdown; Separate Rx Enable Pin
· Guaranteed Minimum Slew Rate . . . . . . . 6V/
µ
s or 24V/
µ
s
· Wide Power Supply Range. . . . . . . . Single +3V to +5.5V
· Low Supply Current in Powerdown State . . . . . . . . . .10nA
·
Pb-free available
Applications
· Any System Requiring RS-232 Communication Ports
- Battery Powered, Hand-Held, and Portable Equipment
- Laptop Computers, Notebooks, Palmtops
- Modems, Printers and other Peripherals
- Data Cradles and Cables
- Cellular/Mobile Phone
TABLE 1. SUMMARY OF FEATURES
PART
NUMBER
NO. OF
Tx.
NO. OF
Rx.
NO. OF
MONITOR Rx.
(R
OUTB
)
(NOTE 1)
DATA
RATE
(kbps)
Rx. ENABLE
FUNCTION?
READY
OUTPUT?
MANUAL
POWER-
DOWN?
AUTOMATIC
POWERDOWN
FUNCTION?
ICL3237E
5
3
1
250/1000
YES
NO
YES
NO
NOTE:
1. Data rate is selectable via the MBAUD pin.
Data Sheet
July 2004
2
Pinout
ICL3237E (SSOP)
TOP VIEW
C2+
GND
C2-
V-
T1
OUT
T2
OUT
T3
OUT
R1
IN
R2
IN
R3
IN
T5
OUT
EN
SHDN
C1+
V
CC
C1-
T1
IN
T2
IN
R1
OUT
T4
IN
R3
OUT
T5
IN
R1
OUTB
MBAUD
V+
T3
IN
R2
OUT
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
T4
OUT
Ordering Information
PART NUMBER
TEMP.
RANGE (
o
C)
PACKAGE
PKG. DWG.
#
ICL3237ECA
0 to 70
28 Ld SSOP
M28.209
ICL3237ECAZ
(See Note)
0 to 70
28 Ld SSOP
(Pb-free)
M28.209
ICL3237EIA
-40 to 85
28 Ld SSOP
M28.209
ICL3237EIAZ
(See Note)
-40 to 85
28 Ld SSOP
(Pb-free)
M28.209
*Add "-T" suffix to part number for tape and reel packaging.
NOTE: Intersil Pb-free products employ special Pb-free material
sets; molding compounds/die attach materials and 100% matte tin
plate termination finish, which is compatible with both SnPb and
Pb-free soldering operations. Intersil Pb-free products are MSL
classified at Pb-free peak reflow temperatures that meet or exceed
the Pb-free requirements of IPC/JEDEC J Std-020B.
Pin Descriptions
PIN
FUNCTION
V
CC
System power supply input (3.0V to 5.5V).
V+
Internally generated positive transmitter supply (+5.5V).
V-
Internally generated negative transmitter supply (-5.5V).
GND
Ground connection.
C1+
External capacitor (voltage doubler) is connected to this lead.
C1-
External capacitor (voltage doubler) is connected to this lead.
C2+
External capacitor (voltage inverter) is connected to this lead.
C2-
External capacitor (voltage inverter) is connected to this lead.
T
IN
TTL/CMOS compatible transmitter Inputs (Note 2).
T
OUT
±
15kV ESD Protected
,
RS-232 level (nominally
±
5.5V) transmitter outputs.
R
IN
±
15kV ESD Protected
,
RS-232 compatible receiver inputs.
R
OUT
TTL/CMOS level receiver outputs.
R
OUTB
TTL/CMOS level, noninverting, always enabled receiver output.
EN
Active low receiver enable control; doesn't disable R
OUTB
output (Note 2).
SHDN
Active low input to shut down transmitters and on-board power supply, to place device in low power mode (Note 2).
MBAUD
Input low selects 250kbps data rate, and input high selects 1Mbps data rate (Note 2).
NOTE:
2. These input pins incorporate positive feedback resistors. Once the input is driven to a valid logic level, the feedback resistor maintains that logic
level until V
CC
is removed.
ICL3237E
3
Typical Operating Circuit
ICL3237E
NOTES:
3. THE NEGATIVE TERMINAL OF C
3
CAN BE CONNECTED TO EITHER V
CC
OR GND.
4. FOR V
CC
= 3.15V (3.3V -5%), USE C
1
- C
4
= 0.1
µ
F OR GREATER. FOR V
CC
= 3.0V (3.3V -10%), USE C
1
- C
4
= 0.22
µ
F.
26
V
CC
T1
OUT
T2
OUT
T3
OUT
T1
IN
T2
IN
T3
IN
T
1
T
2
T
3
0.1
µ
F
+
0.1
µ
F
+
0.1
µ
F
24
23
5
6
22
7
28
25
27
4
V+
V-
C1+
C1-
C2+
C2-
+
0.1
µ
F
1
3
R1
OUT
R1
IN
8
5k
R2
OUT
R2
IN
9
20
5k
R3
OUT
R3
IN
11
18
5k
21
R1
OUTB
C
1
C
2
+
C
3
C
4
EN
SHDN
13
GND
14
+3.3V
+
0.1
µ
F
16
2
V
CC
TTL/CMOS
LOGIC LEVELS
RS-232
LEVELS
RS-232
LEVELS
R
1
R
2
R
3
15
MBAUD
TO CONTROL LOGIC
+
C
3
(OPTIONAL CONNECTION, NOTE 3)
T4
OUT
T5
OUT
T4
IN
T5
IN
T
4
T
5
19
10
17
12
NOTE 4
NOTE 4
ICL3237E
4
Absolute Maximum Ratings
Thermal Information
V
CC
to Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6V
V+ to Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 7V
V- to Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +0.3V to -7V
V+ to V- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14V
Input Voltages
T
IN
, EN, SHDN, MBAUD . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6V
R
IN
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±
25V
Output Voltages
T
OUT
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±
13.2V
R
OUT
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to V
CC
+0.3V
Short Circuit Duration
T
OUT
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . See Specification Table
Thermal Resistance (Typical, Note 5)
JA
(
o
C/W)
28 Ld SSOP Package . . . . . . . . . . . . . . . . . . . . . . .
100
Moisture Sensitivity (see Technical Brief TB363)
SSOP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Level 1
Maximum Junction Temperature (Plastic Package) . . . . . . . 150
o
C
Maximum Storage Temperature Range . . . . . . . . . . -65
o
C to 150
o
C
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . 300
o
C
(Lead Tips Only)
Operating Conditions
Temperature Range
ICL3237EC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0
o
C to 70
o
C
ICL3237EI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40
o
C to 85
o
C
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:
5.
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
= 3.15V to 5.5V, C
1
- C
4
= 0.1
µ
F; V
CC
= 3V, C
1
- C
4
= 0.22
µ
F, Unless Otherwise
Specified. Typicals are at T
A
= 25
o
C
PARAMETER
TEST CONDITIONS
TEMP
(
o
C)
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
Supply Current,
Powerdown Disabled
All Outputs Unloaded, V
CC
= 3.15V, SHDN = V
CC
25
-
0.3
1.0
mA
Supply Current, Powerdown
SHDN = GND
25
-
10
300
nA
LOGIC AND TRANSMITTER INPUTS AND RECEIVER OUTPUTS
Input Logic Threshold Low
T
IN
, EN, SHDN, MBAUD
Full
-
-
0.8
V
Input Logic Threshold High
T
IN
, EN, SHDN,
MBAUD
V
CC
= 3.3V
Full
2.0
-
-
V
V
CC
= 5.0V
Full
2.4
-
-
V
Transmitter Input Hysteresis
25
-
0.5
-
V
Input Leakage Current
T
IN
, EN, SHDN, MBAUD (Note 7)
Full
-
±
0.01
±
1.0
µ
A
Output Leakage Current
EN = V
CC
(Receivers Disabled)
Full
-
±
0.05
±
10
µ
A
Output Voltage Low
I
OUT
= 1.6mA
Full
-
-
0.4
V
Output Voltage High
I
OUT
= -1.0mA
Full
V
CC
-0.6 V
CC
-0.1
-
V
RECEIVER INPUTS
Input Voltage Range
Full
-25
-
25
V
Input Threshold Low
V
CC
= 3.3V
25
0.6
1.2
-
V
V
CC
= 5.0V
25
0.8
1.5
-
V
Input Threshold High
V
CC
= 3.3V to 5.0V
25
-
1.6
2.4
V
Input Hysteresis
25
-
0.5
-
V
Input Resistance
25
3
5
7
k
TRANSMITTER OUTPUTS
Output Voltage Swing
All Transmitter Outputs Loaded with 3k
to Ground
Full
±
5.0
±
5.4
-
V
Output Resistance
V
CC
= V+ = V- = 0V, Transmitter Output =
±
2V
Full
300
10M
-
Output Short-Circuit Current
Full
-
±
35
±
60
mA
Output Leakage Current
V
OUT
=
±
12V, V
CC
= 0V or 3V to 5.5V, SHDN = GND
Full
-
-
±
25
µ
A
ICL3237E
5
TIMING CHARACTERISTICS
Maximum Data Rate
R
L
= 3k
,
One
Transmitter Switching
C
L
= 1000pF
MBAUD = GND
Full
250
700
-
kbps
V
CC
= 3V to 4.5V,
C
L
= 250pF
MBAUD = V
CC
Full
1000
1700
-
kbps
V
CC
= 4.5V to 5.5V,
C
L
= 1000pF
MBAUD = V
CC
Full
1000
1100
-
kbps
Receiver Propagation Delay
Receiver Input to
Receiver Output,
C
L
= 150pF
t
PHL
25
-
0.15
-
µ
s
t
PLH
25
-
0.15
-
µ
s
Receiver Output Enable Time
Normal Operation
25
-
200
-
ns
Receiver Output Disable Time
Normal Operation
25
-
200
-
ns
Transmitter Skew
t
PHL
- t
PLH,
Note 6
MBAUD = GND
25
-
100
ns
MBAUD = V
CC
, V
CC
= 3.0V
25
-
25
ns
Receiver Skew
t
PHL
- t
PLH
, C
L
= 150pF
25
-
50
-
ns
Transition Region Slew Rate
V
CC
= 3.3V,
R
L
= 3k
to 7k
,
Measured From 3V to
-3V or -3V to 3V
C
L
= 150pF to 1000pF MBAUD = GND
25
6
17
30
V/
µ
s
MBAUD = V
CC
25
24
40
150
V/
µ
s
C
L
= 150pF to 2500pF MBAUD = GND
25
4
12
30
V/
µ
s
ESD PERFORMANCE
RS-232 Pins (T
OUT
, R
IN
)
Human Body Model
25
-
±
15
-
kV
IEC61000-4-2 Air Gap Discharge
25
-
±
15
-
kV
IEC61000-4-2 Contact Discharge
25
-
±
8
-
kV
All Other Pins
Human Body Model
25
-
±
2.5
-
kV
NOTES:
6. Skew is measured at the input switching points (1.4V).
7. These inputs utilize a positive feedback resistor. The input current is negligible when the input is at either supply rail.
Electrical Specifications
Test Conditions: V
CC
= 3.15V to 5.5V, C
1
- C
4
= 0.1
µ
F; V
CC
= 3V, C
1
- C
4
= 0.22
µ
F, Unless Otherwise
Specified. Typicals are at T
A
= 25
o
C (Continued)
PARAMETER
TEST CONDITIONS
TEMP
(
o
C)
MIN
TYP
MAX
UNITS
ICL3237E
6
Detailed Description
The ICL3237E operates from a single +3V to +5.5V supply,
guarantees a 1Mbps minimum data rate (MBAUD = V
CC
),
requires only four small external 0.1
µ
F (0.22
µ
F for
V
CC
= 3.0V) capacitors, features low power consumption,
and meets all EIA/TIA-232 and V.28 specifications. The
circuit is divided into three sections: The charge pump, the
transmitters, and the receivers.
Charge-Pump
Intersil's new ICL32XX family 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 0.1
µ
F capacitors for the
voltage doubler and inverter functions at V
CC
= 3.3V. 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.
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.
The ICL3237E guarantees a 1Mbps data rate
(MBAUD = V
CC
) for full load conditions (3k
and 250pF),
V
CC
3.0V, with one transmitter operating at full speed.
Under more typical conditions of V
CC
3.3V, C
1-4
= 0.1
µ
F,
R
L
= 3k
, and C
L
= 250pF, one transmitter easily operates
at 1.7Mbps.
Transmitter inputs incorporate an active positive feedback
resistor that maintains the last driven input state in the
absence of a forcing signal. Unused transmitter inputs may
be left unconnected.
Receivers
The ICL3237E contains standard inverting receivers that
tristate only when the EN control line is driven high.
Additionally, it includes a noninverting (monitor) receiver
(denoted by the R
OUTB
label) that is always active,
regardless of the state of any control lines. All the receivers
convert RS-232 signals to CMOS output levels and accept
inputs up to
±
25V while presenting the required 3k
to 7k
input impedance (see Figure 1) even if the power is off
(V
CC
= 0V). The receivers' Schmitt trigger input stage uses
hysteresis to increase noise immunity and decrease errors
due to slow input signal transitions.
Monitor receivers remain active even during manual
powerdown and forced receiver disable, 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.
Powerdown Functionality
This 3V device requires a nominal supply current of 0.3mA
during normal operation (not in powerdown mode). This is
considerably less than the 5mA to 11mA current required of
5V RS-232 devices. The already low current requirement
drops significantly when the device enters powerdown mode.
In powerdown, supply current drops to 10nA, because the
on-chip charge pump turns off (V+ collapses to V
CC
, V-
collapses to GND), and the transmitter outputs tristate. This
micro-power mode makes the ICL3237E ideal for battery
powered and portable applications.
Software Controlled (Manual) Powerdown
On the ICL3237E, the powerdown control is via a simple
shutdown (SHDN) pin. Driving this pin high enables normal
operation, while driving it low forces the IC into it's
powerdown state. Connect SHDN to V
CC
if the powerdown
function isn't needed. Note that all the receiver outputs
remain enabled during shutdown (see Table 2). For the
lowest power consumption during powerdown, the receivers
should also be disabled by driving the EN input high (see
next section, and Figures 2 and 3). The time required to exit
powerdown, and resume transmission is only 100
µ
s.
R
XOUT
GND
V
ROUT
V
CC
5k
R
XIN
-25V
V
RIN
+25V
GND
V
CC
FIGURE 1. INVERTING RECEIVER CONNECTIONS
ICL3237E
7
Receiver ENABLE Control
This device also features an EN input to control the receiver
outputs. Driving EN high disables all the inverting (standard)
receiver outputs placing them in a high impedance state.
This is useful to eliminate supply current, due to a receiver
output forward biasing the protection diode, when driving the
input of a powered down (V
CC
= GND) peripheral (see
Figure 2). The enable input has no effect on transmitter nor
monitor (R
OUTB
) outputs.
MegaBaud Selection
In normal operating mode (MBAUD = GND), the ICL3237E
transmitters guarantee a 250kbps data rate with worst-case
loads of 3k
in parallel with 1000pF. This provides
compatibility with PC-to-PC communication software, such
as LaplinkTM.
For higher speed serial communications, the ICL3237E
features MegaBaud operation. In MegaBaud operating mode
(MBAUD = V
CC
), the ICL3237E transmitters guarantee a
1Mbps data rate with worst-case loads of 3k
in parallel with
250pF for 3.0V < V
CC
< 4.5V. For 5V
±
10% operation, the
ICL3237E transmitters guarantee a 1Mbps data rate with
worst-case loads of 3k
in parallel with 1000pF.
Capacitor Selection
The charge pumps require 0.1
µ
F capacitors for 3.3V (5%
tolerance) operation. For other supply voltages refer to Table
3 for capacitor values. Do not use values smaller than those
listed in Table 3. Increasing the capacitor values (by a factor
of 2) reduces ripple on the transmitter outputs and slightly
reduces power consumption. C
2
, C
3
, and C
4
can be
increased without increasing C
1
's value, however, do not
increase C
1
without also increasing C
2
, C
3
, and C
4
to
maintain the proper ratios (C
1
to the other capacitors).
When using minimum required capacitor values, make sure
that capacitor values do not degrade excessively with
temperature. If in doubt, use capacitors with a larger nominal
value. The capacitor's equivalent series resistance (ESR)
usually rises at low temperatures and it influences the
amount of ripple on V+ and V-.
Power Supply Decoupling
In most circumstances a 0.1
µ
F bypass capacitor is
adequate. In applications that are particularly sensitive to
power supply noise, decouple V
CC
to ground with a
capacitor of the same value as the charge-pump capacitor C
1
.
Connect the bypass capacitor as close as possible to the IC.
TABLE 2. POWERDOWN AND ENABLE LOGIC TRUTH TABLE
SHDN INPUT
EN INPUT
TRANSMITTER OUTPUTS
RECEIVER OUTPUTS
R
OUTB
OUTPUT
MODE OF OPERATION
L
L
High-Z
Active
Active
Manual Powerdown
L
H
High-Z
High-Z
Active
Manual Powerdown w/Rcvr. Disabled
H
L
Active
Active
Active
Normal Operation
H
H
Active
High-Z
Active
Normal Operation w/Rcvr. Disabled
FIGURE 2. POWER DRAIN THROUGH POWERED DOWN
PERIPHERAL
OLD
V
CC
POWERED
GND
SHDN = GND
V
CC
Rx
Tx
V
CC
CURRENT
V
OUT
=
V
CC
FLOW
RS-232 CHIP
DOWN
UART
FIGURE 3. DISABLED RECEIVERS PREVENT POWER DRAIN
ICL3237E
TRANSITION
R
X
T
X
R1
OUTB
R1
OUT
T1
IN
V
CC
V
CC
TO
R1
IN
T1
OUT
V
OUT
=
HI-Z
POWERED
SHDN = GND, EN = V
CC
DETECTOR
DOWN
UART
WAKE-UP
LOGIC
TABLE 3. REQUIRED CAPACITOR VALUES
V
CC
(V)
C
1
(
µ
F)
C
2
, C
3
, C
4
(
µ
F)
3.0 to 3.6 (3.3V
±
10%)
0.22
0.22
3.15 to 3.6 (3.3V
±
5%)
0.1
0.1
4.5 to 5.5
0.047
0.33
3.0 to 5.5
0.22
1.0
ICL3237E
Laplink® is a registered trademark of Traveling Software.
8
Operation Down to 2.7V
ICL3237E transmitter outputs meet RS-562 levels (
±
3.7V), at
the full data rate, with V
CC
as low as 2.7V. RS-562 levels
typically ensure inter operability with RS-232 devices.
Transmitter Outputs when Exiting
Powerdown
Figure 4 shows the response of two transmitter outputs
when exiting powerdown mode. As they activate, the two
transmitter outputs properly go to opposite RS-232 levels,
with no glitching, ringing, nor undesirable transients. Each
transmitter is loaded with 3k
in parallel with 2500pF. Note
that the transmitters enable only when the magnitude of the
supplies exceed approximately 3V.
High Data Rates
The ICL3237E maintains the RS-232
±
5V minimum
transmitter output voltages even at high data rates. Figure 5
details a transmitter loopback test circuit, and Figure 6
illustrates the standard speed loopback test result for a
single transmitter driving 1000pF and an RS-232 load at
250kbps. Figure 7 shows the MegaBaud loopback results for
a single transmitter driving 250pF and an RS-232 load at
1Mbps. The static transmitters were also loaded with an
RS-232 receiver.
TIME (20
µ
s/DIV.)
T1
T2
2V/DIV
5V/DIV
V
CC
= +3.3V
SHDN
FIGURE 4. TRANSMITTER OUTPUTS WHEN EXITING
POWERDOWN
C1 - C4 = 0.1
µ
F
FIGURE 5. TRANSMITTER LOOPBACK TEST CIRCUIT
FIGURE 6. LOOPBACK TEST AT 250kbps (C
L
= 1000pF)
FIGURE 7. LOOPBACK TEST AT 1Mbps (C
L
= 250pF)
ICL3237E
V
CC
C
1
C
2
C
4
C
3
+
+
+
+
C
L
V+
V-
5k
T
IN
R
OUT
C1+
C1-
C2+
C2-
R
IN
T
OUT
+
V
CC
0.1
µ
F
V
CC
EN
SHDN
MBAUD
GND or V
CC
T1
IN
T1
OUT
R1
OUT
2
µ
s/DIV.
5V/DIV.
V
CC
= +3.3V
C1 - C4 = 0.1
µ
F
MBAUD = GND
T1
IN
T1
OUT
R1
OUT
0.5
µ
s/DIV.
5V/DIV.
V
CC
= +3.3V
C1 - C4 = 0.1
µ
F
MBAUD = V
CC
ICL3237E
9
Interconnection with 3V and 5V Logic
The ICL3237E directly interfaces with 5V CMOS and TTL
logic families. Nevertheless, with the ICL32XX at 3.3V, and
the logic supply at 5V, AC, HC, and CD4000 outputs can
drive ICL32XX inputs, but ICL32XX outputs do not reach the
minimum V
IH
for these logic families. See Table 4 for more
information.
±
15kV ESD Protection
All pins on ICL32XX devices include ESD protection
structures, but the ICL32XXE family incorporates advanced
structures which allow the RS-232 pins (transmitter outputs
and receiver inputs) to survive ESD events up to
±
15kV. The
RS-232 pins are particularly vulnerable to ESD damage
because they typically connect to an exposed port on the
exterior of the finished product. Simply touching the port
pins, or connecting a cable, can cause an ESD event that
might destroy unprotected ICs. These new ESD structures
protect the device whether or not it is powered up, protect
without allowing any latchup mechanism to activate, and
don't interfere with RS-232 signals as large as
±
25V.
Human Body Model (HBM) Testing
As the name implies, this test method emulates the ESD
event delivered to an IC during human handling. The tester
delivers the charge through a 1.5k
current limiting resistor,
making the test less severe than the IEC61000 test which
utilizes a 330
limiting resistor. The HBM method
determines an ICs ability to withstand the ESD transients
typically present during handling and manufacturing. Due to
the random nature of these events, each pin is tested with
respect to all other pins. The RS-232 pins on "E" family
devices can withstand HBM ESD events to
±
15kV.
IEC61000-4-2 Testing
The IEC61000 test method applies to finished equipment,
rather than to an individual IC. Therefore, the pins most likely
to suffer an ESD event are those that are exposed to the
outside world (the RS-232 pins in this case), and the IC is
tested in its typical application configuration (power applied)
rather than testing each pin-to-pin combination. The lower
current limiting resistor coupled with the larger charge
storage capacitor yields a test that is much more severe than
the HBM test. The extra ESD protection built into this
device's RS-232 pins allows the design of equipment
meeting level 4 criteria without the need for additional board
level protection on the RS-232 port.
AIR-GAP DISCHARGE TEST METHOD
For this test method, a charged probe tip moves toward the
IC pin until the voltage arcs to it. The current waveform
delivered to the IC pin depends on approach speed,
humidity, temperature, etc., so it is difficult to obtain
repeatable results.The "E" device RS-232 pins withstand
±
15kV air-gap discharges.
CONTACT DISCHARGE TEST METHOD
During the contact discharge test, the probe contacts the
tested pin before the probe tip is energized, thereby
eliminating the variables associated with the air-gap
discharge. The result is a more repeatable and predictable
test, but equipment limits prevent testing devices at voltages
higher than
±
8kV. All "E" family devices survive
±
8kV contact
discharges on the RS-232 pins.
TABLE 4. LOGIC FAMILY COMPATIBILITY WITH VARIOUS
SUPPLY VOLTAGES
SYSTEM
POWER-SUPPLY
VOLTAGE
(V)
V
CC
SUPPLY
VOLTAGE
(V)
COMPATIBILITY
3.3
3.3
Compatible with all CMOS
families.
5
5
Compatible with all TTL and
CMOS logic families.
5
3.3
Compatible with ACT and HCT
CMOS, and with TTL. ICL32XX
outputs are incompatible with AC,
HC, and CD4000 CMOS inputs.
ICL3237E
10
Typical Performance Curves
V
CC
= 3.3V, T
A
= 25
o
C
FIGURE 8. LOW SPEED TRANSMITTER OUTPUT VOLTAGE
vs LOAD CAPACITANCE
FIGURE 9. HIGH SPEED TRANSMITTER OUTPUT VOLTAGE
vs LOAD CAPACITANCE
FIGURE 10. LOW SPEED SLEW RATE vs LOAD CAPACITANCE
FIGURE 11. HIGH SPEED SLEW RATE vs LOAD
CAPACITANCE
FIGURE 12. LOW SPEED SUPPLY CURRENT vs LOAD
CAPACITANCE WHEN TRANSMITTING DATA
FIGURE 13. HIGH SPEED SUPPLY CURRENT vs LOAD
CAPACITANCE WHEN TRANSMITTING DATA
-6
-4
-2
0
2
4
6
1000
2000
3000
4000
5000
0
LOAD CAPACITANCE (pF)
TRAN
S
M
ITTER OUTPUT V
O
L
T
A
G
E (V)
1 TRANSMITTER AT 250kbps
V
OUT
+
V
OUT
-
OTHER TRANSMITTERS AT 30kbps
MBAUD = GND
-6
-4
-2
0
2
4
6
1000
2000
3000
4000
5000
0
LOAD CAPACITANCE (pF)
TRAN
S
M
ITTER OUTPUT V
O
L
T
A
G
E (V)
1 TRANSMITTER AT 1Mbps
V
OUT
+
V
OUT
-
OTHER TRANSMITTERS AT 30kbps
MBAUD = V
CC
LOAD CAPACITANCE (pF)
SLEW RA
TE (V
/
µ
s)
0
1000
2000
3000
4000
5000
5
10
15
20
25
+SLEW
-SLEW
MBAUD = GND
-SLEW
LOAD CAPACITANCE (pF)
SLEW RA
TE (V
/
µ
s)
0
1000
2000
3000
4000
5000
10
30
50
-SLEW
+SLEW
70
90
MBAUD = V
CC
0
20
25
30
35
40
55
45
50
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
SUP
P
L
Y
CU
RRE
N
T
(mA
)
20kbps
250kbps
120kbps
MBAUD = GND
20
30
40
50
80
60
70
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
SUP
P
L
Y
CU
RRE
N
T
(mA
)
120kbps
1Mbps
250kbps
90
MBAUD = V
CC
ICL3237E
11
Die Characteristics
SUBSTRATE POTENTIAL (POWERED UP):
GND
TRANSISTOR COUNT:
619
PROCES
Si Gate CMOS
FIGURE 14. SUPPLY CURRENT vs SUPPLY VOLTAGE
Typical Performance Curves
V
CC
= 3.3V, T
A
= 25
o
C (Continued)
SUPP
L
Y
CURRENT
(m
A)
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
0
0.5
1.0
1.5
2.0
SUPPLY VOLTAGE (V)
2.5
3.0
3.5
NO LOAD
ALL OUTPUTS STATIC
ICL3237E
12
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation's quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
Shrink Small Outline Plastic Packages (SSOP)
NOTES:
8. Symbols are defined in the "MO Series Symbol List" in Section 2.2
of Publication Number 95.
9. Dimensioning and tolerancing per ANSI Y14.5M-1982.
10. Dimension "D" does not include mold flash, protrusions or gate
burrs. Mold flash, protrusion and gate burrs shall not exceed
0.20mm (0.0078 inch) per side.
11. Dimension "E" does not include interlead flash or protrusions. In-
terlead flash and protrusions shall not exceed 0.20mm (0.0078
inch) per side.
12. The chamfer on the body is optional. If it is not present, a visual
index feature must be located within the crosshatched area.
13. "L" is the length of terminal for soldering to a substrate.
14. "N" is the number of terminal positions.
15. Terminal numbers are shown for reference only.
16. Dimension "B" does not include dambar protrusion. Allowable
dambar protrusion shall be 0.13mm (0.005 inch) total in excess of
"B" dimension at maximum material condition.
17. Controlling dimension: MILLIMETER. Converted inch dimensions
are not necessarily exact.
INDEX
AREA
E
D
N
1
2
3
-B-
0.25(0.010)
C A
M
B S
e
-A-
L
B
M
-C-
A1
A
SEATING PLANE
0.10(0.004)
C
H
µ
0.25(0.010)
B
M
M
0.25
0.010
GAUGE
PLANE
A2
M28.209
(JEDEC MO-150-AH ISSUE B)
28 LEAD SHRINK SMALL OUTLINE PLASTIC PACKAGE
SYMBOL
INCHES
MILLIMETERS
NOTES
MIN
MAX
MIN
MAX
A
-
0.078
-
2.00
-
A1
0.002
-
0.05
-
-
A2
0.065
0.072
1.65
1.85
-
B
0.009
0.014
0.22
0.38
9
C
0.004
0.009
0.09
0.25
-
D
0.390
0.413
9.90
10.50
3
E
0.197
0.220
5.00
5.60
4
e
0.026 BSC
0.65 BSC
-
H
0.292
0.322
7.40
8.20
-
L
0.022
0.037
0.55
0.95
6
N
28
28
7
0
o
8
o
0
o
8
o
-
Rev. 1 3/95
ICL3237E
PDF 
ZIP