Intersil ICL32XE devices are 3.0V to 5.5V compliant with ElA/TIA-232 and V.28/V.24 specifications, even at VCC=3.0V. Additionally, ±15kV ESD protection (IEC61000-4-2 air gap and Human Body Model) is provided on the transmitter output and receiver input ( RS-232 pins). Target applications are PDAs, PDAs, notebooks and notebooks where low running, even lower standby power consumption is essential. Efficient on-chip charge pump with manual and automatic power-down (except ICL3232E), reducing standby supply current to 1 µA. Small packages, and the use of small, low-value capacitors ensure that there are savings in board space. Data rates greater than 250kbps are guaranteed under worst-case load conditions. This family is compatible with 3.3V dedicated systems, mixed 3.3V and 5.0V systems and 5.0V dedicated systems. The ICL324XE is a 3 driver 5 receiver device that provides a complete serial port computer suitable for laptops. Both devices also include a non-alternating always-active receiver for the "wake up" function. The ICL3221E, ICL3223E and ICL3243E have an automatic power-off function that turns off the power supply and drive circuits on the chip. System power hardware or operating system changes are automatically saved when connected peripherals are turned off or the RS-232 cable is removed. These are valid RS-232 voltages for any receiver input. Table 1 summarizes the characteristics of the devices shown according to this data sheet, while application note AN9863 summarizes the 3V series containing the ICL32XE

feature

Lead-free (RoHS compliant) available (see ordering information)

RS-232 input/output pins up to ±15kV ESD protection (IEC61000)

Replacement of MAX221E , MAX2222E, max 3223E, max 3232E, max 3241E, max 3243E, SP3243E series ICL3221E is a 5V low power consumption, pin compatible upgrade max 221E

The ICL322E is a 5V low-power, pin-compatible upgrade to the MAX242E and SP312E

ICL3232E is a low-power upgrade of HIN232E , ICL232 and a Pin-compatible competitor device

RS-232 compatible VCC=2.7V

Meets EIA/TIA-232 and V.28/V.24 specifications at 3V

no latch

On-chip voltage converter requires only four external 0.1µF capacitors

Manual and automatic power off function

Guaranteed mouse drivability (ICL324XE only)

Receiver lag for improved noise immunity

Guaranteed minimum data rate. 250kbps

Wide range of power sources. Single +3V to +5.5V

Low supply current in power down state. 1 microamp

application

Any system that requires an RS-232 communication port - Battery powered, handheld and portable devices - Notebooks, notebooks, PDAs - Modems, printers and other peripherals - Digital cameras - Cellular/mobile phones

Absolute Maximum Ratings Thermal Information

VCC is grounded. -0.3V to 6V

V+ is grounded. -0.3V to 7V

voltage to ground. +0.3V to -7V

V+ to V-. 14 volts

Input voltage

Tin, FORCEOFF, FORCEON, EN, SHDN. -0.3V to 6V. 5 volts

The output voltage is 3.2 volts ROUT, invalid. -0.3V to VCC+0.3V

Short circuit duration touted. Continuous electrostatic discharge rating. see spec sheet

operating conditions

temperature range

ICL32XECX. 0°C to 70°C

ICL32XEX series. -40°C to 85°C

Thermal Resistance (Typical, Note 3) θJA (Celsius/Watt)

18 Ld PDIP packets. 80

16 Ld wide SOIC package. 100

16 Ld narrow SOIC package. 115

18 Ld SOIC package. 75

28 Ld SOIC package. 75

16 Ld SSOP packs. 135

20 Ld SSOP pack. 122

Pack of 16 Ld TSSOPs. 145

Pack of 20 Ld TSSOPs. 140

28 Ld SSOP and TSSOP packages. 100

Maximum Junction Temperature (Plastic Packaging). 150 degrees Celsius

Maximum storage temperature range. -65°C to 150°C

Maximum lead temperature (10s for soldering). 300 degrees Celsius (SOIC, SSOP, TSSOP - lead only)

CAUTION: Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a pressure rating and operation of the device under the above or any other conditions stated in the operating section of this specification is not implied.

Note: 3. θJA is measured in free air with components mounted on an inefficient thermal conductivity test board.

Electrical specification test conditions: VCC=3V～5.5V, C1～C4=0.1μF; unless otherwise specified. Typical temperature is TA=25°C

Electrical specification test conditions: VCC=3V～5.5V, C1～C4=0.1μF; unless otherwise specified. Typical temperature is TA=25°C (continued)

Note:

4. Measure the transmitter offset at the transmitter zero crossing.

Detailed description

Operating from a single +3V to +5.5V, the ICL32XE interface IC provides and guarantees a minimum data rate of 250kbps with only four small external 0.1µF capacitors, has low power consumption, and meets all ElA RS-232C and V.28 specifications. The circuit is divided into three parts: charge pump, transmitter and receiver. Charge Pumps Intersil's new ICL32XE family employs a regulated on-chip dual charge pump as a voltage doubler and an inverter that generates ±5.5V transmitter power from VCC to provide power as low as 3.0V. This allows these devices to maintain RS-232 compatible output levels over the range of ±10% tolerance 3.3V powered systems. An effective on-chip power supply requires only four small external 0.1µF capacitors for voltage doubler and inverter functions, VCC = 3.3V. See the Capacitor Selection section and Table 3 for capacitor recommendations for other operating conditions. The priming pump operates discontinuously (i.e. shuts down once the V+ and V- supplies are delivered to nominal), resulting in significant power savings. Transmitter The transmitter is a proprietary, low loss, inversion that converts TTL/CMOS inputs to EIA/TIA-232 driver output levels. Coupled with on-chip ±5.5V power supplies, these transmitters provide a true RS-232 level single-supply system voltage range over a wide range. Except for the ICL3232E, all transmitter outputs are disabled when the device enters power-down mode (see Table 2). These outputs may be driven to ±12V when disabled. All devices are guaranteed for 250kbps data rate conditions at full load (3kΩ and 1000pF), VCC ≥ 3.0V, with one transmitter running at full speed. Under more typical conditions of VCC ≥ 3.3V, RL=3kΩ, CL=250pF, 1 transmitter works easily at 900kbps. If not connected, the transmitter input will float and may cause the ICC to increase. It is better to connect unused input to GND performance

receiver

All ICL32XE devices contain standard inversion of the three states (except the ICL3232E) via the EN or FORCEOFF control lines. Additionally, both ICL324XE products include a non-converting (monitor) receiver (indicated by the ROUTB label) that is always active, regardless of the state of any control lines. All receivers convert RS-232 signals to CMOS output levels and accept inputs up to ±25V, while displaying the required 3kΩ to 7kΩ input impedance (see Figure 1) (VCC=0V) even when powered down. The Schmitt Trigger input stage of the receiver uses hysteresis that increases noise immunity and reduces errors due to slow input signal transitions. The LiCl 243E receiver is disabled during forced (manual) power-off, but not during automatic power-off (see Table 2). The ICL3241E and ICL3243E monitor receivers remain active even with manual power down and forced receiver disable, making them useful for ring indicator monitoring. Standard receivers driving powered-down peripherals must be disabled to prevent current flow through the peripheral protection diodes (see Figures 2 and 3). This makes them ineffective for the wake-up function, but the corresponding monitor receiver can be dedicated to this task, as shown in Figure 3

Note: 5. Only applicable to ICL3241E and ICL3243E.

low power operation

These 3V devices require a nominal supply current of 0.3mA, even at VCC=5.5V, during normal operation (not in power-down mode). This is much lower than the 5mA equivalent of the 11mA required by a 5V RS-232 device, allowing users to reduce system power with a simple toggle for this new family. Pin-compatible replacements for 5V devices ICL3221E, ICL3222E, ICL3232E are pin-compatible using existing 5V RS-232 transceivers - see the Capabilities section on the front page for details. This pin compatibility with low ICC and wide operating supply range enables the ICL32XE to reduce power supply, higher performance, and replace existing 5V applications. As long as ±5V RS-232 output swing is acceptable and transmitter input pull-up resistors are not required, the IICL32XXE should work in most 5V applications. C3 can be terminated to VCC when replacing a device in an existing 5V application, operating the circuit as shown in the typical diagram. However, if possible, configure it a little as this will make performance slightly better.

Power off function

(Except for the ICL3232E) The already low current demand drops significantly when the device goes into shutdown mode. When powered down, the supply current drops to 1 µA because the on-chip charge pump is turned off (V+ collapses to VCC, V- collapses to GND) and the transmitter outputs three states. Inverting receiver outputs may or may not be disabled when powered down; see Table 2 for details. This micropower mode makes the ideal device for battery powered and portable applications.

Software-Controlled (Manual) Power-Down Most devices in the ICL32XE family provide a feature that allows the user to force the IC into a low-power standby state. On the ICL322E and ICL3241E, power-down control is via a simple shutdown (SHDN) pin. Driving this pin high makes it work, while driving it puts the IC into a power-down state. If the power-off function is not required. Note that all receiver outputs remain enabled during shutdown (see Table 2). The receiver should also be disabled by driving the EN input high for lowest power consumption when powered down (see next section, Figure 2 and Figure 3). The ICL3221E, ICL3223E and ICL3243E use two pins at the FORCEON and FORCEOFF inputs to determine the mode of the IC. FORCEON and FORCEOFF are both tied high for always-on operations. To switch between active mode and power down mode or software control under logic, simply force the input driver off. FORCEON status does not matter because FORCEOFF is above the mighty. Nonetheless, the user must tie a force high to disable the auto-shutdown circuit if the power-off is to be controlled strictly according to the manual. The ICL3243E inverted (standard) receiver output is disabled when the device is in a manual shutdown state, thus eliminating a possible current path through the shutdown input protection diodes for peripherals (see Figures 2 and 3).

The invalid output always indicates the presence of an RS-232 signal at any receiver input (see Table 2), providing the user with an easy way to determine that the interface block should be powered down. If the interface cable is disconnected for all receiver inputs that are floating (but pulled by the internal receiver resistors below GND), the invalid logic detects the invalid level and lowers the output. The power management logic then uses this indicator to power down the interface block. Reconnecting the cable restores the receiver's active level input, inactive switch high, and power management logic to wake up the interface block. Inactive can also be used to indicate DTR or ring indicator signals, as long as the other receiver inputs are floating, or driven to GND (eg the driver is powered down). Connect FORCEOFF and FORCEON together to disable the auto power-off feature, enabling them to function as manual shutdown inputs (see Figure 4).

For any of the above control schemes, the time required to exit the power outage, resume the transfer is only 100 microseconds and the mouse or other application may take more time to wake up from the shutdown. If auto-shutdown is in use, the RS-232 device will re-power down if the receiver level is active and has not re-established within 30 microseconds of the ICL32XE powering up. Figure 5 shows a circuit that keeps the ICL32XE powered up 100ms after initiating an automatic shutdown. This allows time for slow wake-up peripheral circuits to re-establish valid RS-232 output levels.

Automatic power-off

(ICL3221E, ICL3223E, ICL3243E only) By using a device with automatic power-off. When no valid RS-232 voltage is detected (see Figure 6) on any receiver input for 30 µs, the charge pump and transmitter are powered down, reducing supply current by 1 µA. Whenever the output of the drive peripheral is turned off (power off) or the RS-232 interface cable is disconnected. The ICL32XE activates backup power when a valid RS-232 voltage is detected at any receiver input level. Auto Shutdown This feature does not use changes to existing operating systems.

When the input is forced to automatically power off low, the forced shutdown input is high. High binding force disables automatic shutdown, but manual shutdown is always available by overriding the FORCEOFF input. Table 2 summarizes the automatic power-off functions. Devices with an automatic shutdown feature include an inactive output signal that toggles low to indicate that an inactive level is present on all receiver inputs for greater than 30 microseconds (see Figure 7). Inactive switch high for 1 microsecond after a valid RS-232 level is detected at the receiver input. Invalid operation in all modes (forced or automatic off or forced on), so it is also useful for systems with manual power-off circuits. When automatic shutdown is used, INVALID=0 indicates that the ICL32XE is in shutdown mode.

Receiver Enable Control

(ICL3221E, ICL3222E, ICL3223E, ICL324E only) Some devices also have an EN input to control the receiver output. Driving at high speeds will disable all reverse (standard) receiver output impedance states. This helps eliminate supply current, due to the receiver output forward-biased protection diode, when driving a powered-down input (VCC = GND) to peripherals (see Figure 2). Enable input to transmitter or monitor (ROUTB) output. Capacitor Selection The charge pump requires a 3.3V 0.1µF capacitor to operate. See Table 3 for capacitance values for other supply voltages. Do not use values smaller than those listed in Table 3. Increasing the capacitor value (by a factor of 2) reduces the ripple at the transmitter output and slightly reduces power consumption. C2, C3, and C4 can be values that increase without increasing C1, however, increasing C1 without increasing C2, C3, and C4 maintains the proper ratio (ratio of C1 to other capacitors). When using the minimum required capacitance value, make sure that the capacitance value does not vary with temperature. When in doubt, use a capacitor with a larger nominal value. Capacitor Equivalent Series Resistance (ESR) typically rises at low temperatures and it affects the amount of ripple on V+ and V-.

Power decoupling

In most cases, a 0.1µF bypass capacitor is sufficient. For power supply noise, use a capacitor of the same value as the charge pump capacitor C1. Place bypass capacitors as close to the IC as possible. Operating voltage down to 2.7V The ICL32XE transmitter output meets RS-562 levels (±3.7V) with VCC as low as 2.7V at full data rate. RS-562 levels generally ensure interoperability with RS-232 devices. Transmitter outputs upon exiting power down Figure 8 shows the response of both transmitter outputs when exiting shutdown mode. Transmitter outputs go correctly to opposite RS-232 levels when they are activated, with no flickering, rattling, or unwanted transients. Each transmitter is loaded with 3kΩ in parallel with 2500pF. Note only when the power supply exceeds about 3V.

Mouse Maneuverability

The ICL3241E and ICL3243E are designed to supply the serial mouse supply voltage during low power operation. Figure 9 shows the voltage at the transmitter output load current as the load current increases. On-chip switching regulators ensure that the transmitters are at least ±5V worst-case (15mAV+ transmitters in parallel, 7.3mA for single V- transmitters). This auto-off function does not work with mouse, so FORCEOFF and FORCEON should be connected to VCC

high data rate

The ICL32XE maintains the RS-232 ±5V minimum output voltage from the transmitter even at high data rates. Figure 10 details the transmitter loopback test circuit, and Figure 11 shows the 120kbps loopback test results. For this test, all transmitters simultaneously drive RS-232 at 120kbps with 1000pF parallel loading. Figure 12 shows the results of a single transmitter driving a 1000pF loopback and an RS-232 load of 250kbps. The electrostatic transmitter also houses an RS-232 receiver.

Interconnects with 3V and 5V logic The ICL32XX interfaces directly with 5V CMOS and TTL logic families. However, the ICL32XX's voltage is 3.3V, and supplies from the logic 5V, AC, HC, and CD4000 outputs can drive the ICL32XX inputs, but the ICL32XX outputs fall short of these logic families. See Table 4 for more information.

5kV ESD Protection All pins on the ICL32XX devices include ESD protection structures, but the ICL32XE series incorporates an advanced structure that allows RS-232 pins (transmitter outputs as well as receiver inputs) to withstand ESD up to ±15kV survive the event. The RS-232 pins are particularly vulnerable to ESD damage as they are usually connected to the finished look. Simply touching port pins or connecting cables can cause an ESD event that can destroy an unprotected IC. These new ESD structures protect the device from not allowing any locking mechanisms to activate, whether the device is powered or not, and do not interfere with the ±25V RS-232 signal. Human Body Model Testing As the name suggests, this test method simulates the delivery of ESD events to the IC during human handling. The tester supplied the charge through a 1.5kΩ current limiting resistor, making the test less severe than the IEC61000 test with a 330Ω limiting resistor. The HBM method to determine an IC's ability to withstand ESD transients typically occurs during handling and manufacturing. Due to the randomness of these events, each pin is used to respect all other pins. RS-232 pin devices on the "E" series withstand HBM ESD events to ±15kV

IEC61000-4-2 test

The IEC 61000 test method applies to a finished device, not a stand-alone integrated circuit. So the ones most likely to suffer from ESD events are those exposed to the outside world (in this case the RS-232 pins) and the IC is tested in its typical application configuration (power up) rather than testing each pin The combination. The lower layer with a large charge-coupled current-limiting resistive storage capacitor yields a test better than the HBM test. Built-in RS-232 pins for additional ESD protection devices allow designing equipment to meet Class 4 standards without adding level protection on the board's RS-232 ports. Air Gap Discharge Test Method For this test method, the tip of the live probe is pointed toward the IC pin until the voltage arcs to it. The current waveform delivered to the IC pins depends on approach speed, humidity, temperature, etc., so it is difficult to obtain repeatable results. The "E" device RS-232 pin withstands 5kV air gap discharge. Contact Discharge Test Method During the contact discharge test, the probe contacts the test pin before the probe tip is energized, thus eliminating the variable in and out associated with the air gap. The result is a more repeatable and predictable test, but device limitations prevent testing the device at voltages higher than ±8kV. All "E" series devices can withstand ±8kV contact voltage RS-232 pin discharge.