ISL4221E, ISL4223E ® Data Sheet August 2004 FN6045.1 QFN Packaged, +/-15kV ESD Protected, +2.7V to +5.5V, 150Nanoamp, 250kBps, RS-232 Transmitters/Receivers Features The Intersil ISL422XE devices are 2.7V to 5.5V powered RS-232 transmitters/receivers which meet ElA/TIA-232 and V.28/V.24 specifications, even at VCC = 3.0V. Additionally, they provide ±15kV ESD protection (IEC61000-4-2 Air Gap, and Human Body Model) on transmitter outputs and receiver inputs (RS-232 pins). Targeted applications are PDAs, Palmtops, and hand-held products where the low operational, and even lower standby, power consumption is critical. Efficient on-chip charge pumps, coupled with manual and automatic powerdown functions, reduce the standby supply current to a 150nA trickle. Tiny 5mm x 5mm Quad Flat No-Lead (QFN) packaging and the use of small, low value capacitors ensure board space savings as well. Data rates greater than 250kBps are guaranteed at worst case load conditions. • ESD Protection for RS-232 I/O Pins to ±15kV (IEC61000) The ISL4221E is a 1 driver, 1 receiver device and the ISL4223E is a 2 driver, 2 receiver device that, coupled with the 5x5 QFN package, provide the industry’s smallest, lowest power serial port suitable for PDAs, and hand-held applications. The 5x5 QFN requires 40% less board area than a 20 lead TSSOP, and is nearly 20% thinner. The ISL422XE features an automatic powerdown function that powers down the on-chip power-supply and driver circuits. This occurs when an attached peripheral device is shut off or the RS-232 cable is removed, conserving system power automatically without changes to the hardware or operating system. It powers up again when a valid RS-232 voltage is applied to any receiver input. Table 1 summarizes the features of the ISL422XE, while Application Note AN9863 summarizes the features of each device comprising the 3V RS-232 family. • Available in Near Chip Scale QFN (5mmx5mm) Package which is 40% Smaller than a 20 Lead TSSOP • Meets EIA/TIA-232 and V.28/V.24 Specifications at 3V • RS-232 Compatible with VCC = 2.7V • On-Chip Voltage Converters Require Only Four External 0.1µF Capacitors • Manual and Automatic Powerdown Features • Receiver Hysteresis For Improved Noise Immunity • Guaranteed Minimum Data Rate . . . . . . . . . . . . 250kBps • Wide Power Supply Range. . . . . . . Single +2.7V to +5.5V • Low Supply Current in Powerdown State . . . . . . . . .150nA • Pb-free Available as an Option Applications • Any Space Constrained System Requiring RS-232 Ports - Battery Powered, and Portable Equipment - Hand-Held Products (GPS Receivers, Bar Code Scanners, etc.) - PDAs and Palmtops, Data Cables - Cellular/Mobile Phones, Digital Cameras Related Literature • Technical Brief TB363 “Guidelines for Handling and Processing Moisture Sensitive Surface Mount Devices • ”Technical Brief TB379 “Thermal Characterization of Packages for ICs” • Technical Brief TB389 “PCB Land Pattern Design and Surface Mount Guidelines for QFN Packages” TABLE 1. SUMMARY OF FEATURES PART NUMBER NO. OF NO. OF Tx. Rx. QFN PKG. AVAILABLE? DATA RATE (kBps) Rx. ENABLE FUNCTION? MANUAL POWERDOWN? AUTOMATIC POWERDOWN FUNCTION? ISL4221E 1 1 YES 250 YES YES YES ISL4223E 2 2 YES 250 YES YES YES 1 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. 2004. All Rights Reserved All other trademarks mentioned are the property of their respective owners. ISL4221E, ISL4223E Ordering Information PART NO. Ordering Information (Continued) TEMP. RANGE (°C) PACKAGE PART NO. PKG. DWG. # ISL4221EIR -40 to 85 16 Ld QFN ISL4221EIR-T -40 to 85 16 Ld QFN L16.5x5 Tape & Reel L16.5x5 ISL4221EIRZ-T (Note) -40 to 85 16 Ld QFN L16.5x5 Tape & Reel (Pb-free) ISL4223EIR -40 to 85 20 Ld QFN L20.5x5 ISL4223EIRZ (Note) -40 to 85 20 Ld QFN (Pb-free) L20.5x5 TEMP. RANGE (°C) PACKAGE PKG. DWG. # ISL4223EIR-T -40 to 85 20 Ld QFN L20.5x5 Tape & Reel ISL4223EIRZ-T (Note) -40 to 85 20 Ld QFN L20.5x5 Tape & Reel (Pb-free) 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. Pinouts EN FORCEOFF VCC C1+ EN FORCEOFF VCC GND ISL4223E (QFN) TOP VIEW C1+ ISL4221E (QFN) TOP VIEW 16 15 14 13 20 19 18 17 16 V+ 1 12 GND C1- 2 C2+ C2- C2+ 3 13 R1OUT 4 9 C2- 4 12 FORCEON V- 5 11 T1IN 5 6 7 8 T1IN 6 7 8 9 10 T2IN 10 FORCEON INVALID 3 R2OUT 14 R1IN R2IN 2 T2OUT C1- INVALID 11 T1OUT R1OUT 15 T1OUT R1IN 1 V- V+ Pin Descriptions PIN VCC FUNCTION System power supply input (2.7V 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. TIN TTL/CMOS compatible transmitter Inputs. TOUT RIN ROUT INVALID ±15kV ESD Protected, RS-232 level (nominally ±5.5V) transmitter outputs. ±15kV ESD Protected, RS-232 compatible receiver inputs. TTL/CMOS level receiver outputs. Active low output that indicates if no valid RS-232 levels are present on any receiver input. FORCEOFF Active low to shut down transmitters and on-chip power supply. This overrides any automatic circuitry and FORCEON (see Table 2). FORCEON EN Active high input to override automatic powerdown circuitry thereby keeping transmitters active. (FORCEOFF must be high). Active low receiver enable control. 2 ISL4221E, ISL4223E Typical Operating Circuits ISL4221E +3.3V + 0.1µF 13 16 + C1+ 2 C13 + C2+ 4 C2- C1 0.1µF C2 0.1µF T1IN TTL/CMOS LOGIC LEVELS R1OUT 1 VCC V+ V- 5 + C3 0.1µF C4 + 0.1µF T1 9 11 7 6 T1OUT R1IN RS-232 LEVELS 5kΩ R1 15 EN 14 FORCEOFF 10 FORCEON GND INVALID 8 VCC TO POWER CONTROL LOGIC 12 ISL4223E +3.3V C1 0.1µF C2 0.1µF T1IN T2IN TTL/CMOS LOGIC LEVELS R1OUT R2OUT + 0.1µF 20 + 2 3 + 4 C1+ 17 VCC V+ C1C2+ V- C2T1 11 R1 5kΩ R2 5kΩ 7 EN FORCEOFF INVALID FORCEON GND 16 3 C4 0.1µF + 14 8 12 5 6 13 19 + C3 0.1µF 15 T2 10 1 18 9 T1OUT T2OUT R1IN RS-232 LEVELS R2IN VCC TO POWER CONTROL LOGIC ISL4221E, ISL4223E Absolute Maximum Ratings Thermal Information VCC 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 TIN, FORCEOFF, FORCEON, EN . . . . . . . . . . . . . . . -0.3V to 6V RIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±25V Output Voltages TOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±13.2V ROUT, INVALID. . . . . . . . . . . . . . . . . . . . . . . . -0.3V to VCC +0.3V Short Circuit Duration TOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . See Specification Table Thermal Resistance (Typical, Note 1) θJA (oC/W) 16 Ld QFN Package. . . . . . . . . . . . . . . . . . . . . . . . . 35 20 Ld QFN Package. . . . . . . . . . . . . . . . . . . . . . . . . 32 Moisture Sensitivity (see Technical Brief TB363) QFN Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Level 1 Maximum Junction Temperature (Plastic Package) . . . . . . . 150oC Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . 300oC Operating Conditions Temperature Range ISL422XEIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40oC to 85oC 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: 1. θJA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech Brief TB379, and Tech Brief TB389. Test Conditions: VCC = 3V to 5.5V, C1 - C4 = 0.1µF; Unless Otherwise Specified. Typicals are at TA = 25oC Electrical Specifications PARAMETER TEST CONDITIONS TEMP (oC) MIN TYP MAX UNITS DC CHARACTERISTICS Supply Current, Automatic Powerdown All RIN Open, FORCEON = GND, FORCEOFF = VCC 25 - 0.15 1 µA Supply Current, Powerdown FORCEOFF = GND 25 - 0.15 1 µA Supply Current, Automatic Powerdown Disabled VCC = 3.15V All Outputs Unloaded, FORCEON = FORCEOFF = VCC 25 - 0.3 1.0 mA Full - - 0.8 V VCC = 3.3V Full 2.0 - - V VCC = 5.0V Full 2.4 - - V LOGIC AND TRANSMITTER INPUTS AND RECEIVER OUTPUTS Input Logic Threshold Low TIN, FORCEON, FORCEOFF, EN Input Logic Threshold High TIN, FORCEON, FORCEOFF, EN Input Leakage Current TIN, FORCEON, FORCEOFF, EN Full - ±0.01 ±1.0 µA Output Leakage Current EN = VCC Full - ±0.05 ±10 µA Output Voltage Low IOUT = 1.6mA Full - - 0.4 V Output Voltage High IOUT = -1.0mA Full - V VCC -0.6 VCC -0.1 AUTOMATIC POWERDOWN (FORCEON = GND, FORCEOFF = VCC) Receiver Input Thresholds to Enable Transmitters ISL422XE Powers Up (See Figure 6) Full -2.7 - 2.7 V Receiver Input Thresholds to Disable Transmitters ISL422XE Powers Down (See Figure 6) Full -0.3 - 0.3 V INVALID Output Voltage Low IOUT = 1.6mA Full - - 0.4 V INVALID Output Voltage High IOUT = -1.0mA Full VCC-0.6 - - V Receiver Threshold to Transmitters Enabled Delay (tWU) 25 - 100 - µs Receiver Positive or Negative Threshold to INVALID High Delay (tINVH) 25 - 1 - µs Receiver Positive or Negative Threshold to INVALID Low Delay (tINVL) 25 - 30 - µs 4 ISL4221E, ISL4223E Test Conditions: VCC = 3V to 5.5V, C1 - C4 = 0.1µF; Unless Otherwise Specified. Typicals are at TA = 25oC (Continued) Electrical Specifications PARAMETER TEST CONDITIONS TEMP (oC) MIN TYP MAX UNITS 25 -25 - 25 V 1.2 - V RECEIVER INPUTS Input Voltage Range Input Threshold Low VCC = 3.3V 25 0.6 VCC = 5.0V 25 0.8 1.5 - V Input Threshold High VCC = 3.3V 25 - 1.5 2.4 V VCC = 5.0V 25 - 1.8 2.4 V Input Hysteresis 25 - 0.5 - V Input Resistance 25 3 5 7 kΩ TRANSMITTER OUTPUTS Output Voltage Swing All Transmitter Outputs Loaded with 3kΩ to Ground Full ±5.0 ±5.4 - V Output Resistance VCC = V+ = V- = 0V, Transmitter Output = ±2V Full 300 10M - Ω Full - ±35 ±60 mA VOUT = ±12V, VCC = 0V or 3V to 5.5V, Automatic Powerdown or FORCEOFF = GND Full - - ±25 µA Maximum Data Rate RL = 3kΩ, CL = 1000pF, One Transmitter Switching Full 250 500 - kBps Receiver Propagation Delay Receiver Input to Receiver Output, CL = 150pF 25 - 0.15 - µs 25 - 0.15 - µs Receiver Output Enable Time Normal Operation 25 - 200 - ns Receiver Output Disable Time Normal Operation 25 - 200 - ns Transmitter Skew tPHL - tPLH (Note 2) 25 - 100 - ns Receiver Skew tPHL - tPLH 25 - 50 - ns Transition Region Slew Rate VCC = 3.3V, RL = 3kΩ to 7kΩ, Measured From 3V to -3V or -3V to 3V CL = 150pF to 2500pF 25 4 - 30 V/µs CL = 150pF to 1000pF 25 6 - 30 V/µs Human Body Model 25 - ±15 - kV IEC61000-4-2 Contact Discharge 25 - ±8 - kV IEC61000-4-2 Air Gap Discharge 25 - ±15 - kV Human Body Model 25 - ±2 - kV Output Short-Circuit Current Output Leakage Current TIMING CHARACTERISTICS tPHL tPLH ESD PERFORMANCE RS-232 Pins (TOUT, RIN) All Other Pins NOTE: 2. Transmitter skew is measured at the transmitter zero crossing points. Detailed Description Charge-Pump The ISL422XE operate from a single +2.7V 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 even with VCC = 3.0V. The circuit is divided into three sections: The charge pump, the transmitters, and the receivers. Intersil’s new ISL422XE devices utilize regulated on-chip dual charge pumps as voltage doublers, and voltage inverters to generate ±5.5V transmitter supplies from a VCC supply as low as 3.0V. This allows them 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. The charge pumps operate discontinuously (i.e., they turn off as soon as the V+ 5 ISL4221E, ISL4223E 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 devices guarantee a 250kBps data rate for full load conditions (3kΩ and 1000pF), VCC ≥ 3.0V, with one transmitter operating at full speed. Under more typical conditions of VCC ≥ 3.3V, RL = 3kΩ, and CL = 250pF, one transmitter easily operates at 900kBps. Transmitter inputs float if left unconnected, and may cause ICC increases. Connect unused inputs to GND for the best performance. 11mA current required by comparable 5V RS-232 devices, allowing users to reduce system power simply by switching to this new family. Powerdown Functionality The already low current requirement drops significantly when the device enters powerdown mode. In powerdown, supply current drops to 150nA, because the on-chip charge pump turns off (V+ collapses to VCC, V- collapses to GND), and the transmitter outputs three-state. Receiver outputs are unaffected by powerdown; refer to Table 2 for details. This micro-power mode makes the ISL422XE ideal for battery powered and portable applications. VCC VCC CURRENT FLOW VCC VOUT = VCC Rx POWERED DOWN UART Receivers Tx All the ISL422XE devices contain standard inverting receivers that three-state via the EN control line. All the receivers 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 (VCC = 0V). The receivers’ Schmitt trigger input stage uses hysteresis to increase noise immunity and decrease errors due to slow input signal transitions. OLD RS-232 CHIP GND SHDN = GND FIGURE 2. POWER DRAIN THROUGH POWERED DOWN PERIPHERAL VCC VCC RXIN -25V ≤ VRIN ≤ +25V TRANSITION DETECTOR RXOUT GND ≤ VROUT ≤ VCC 5kΩ GND FIGURE 1. INVERTING RECEIVER CONNECTIONS Receivers driving a powered down UART must be disabled to prevent current flow through, and possible damage to, the UART’s protection diodes (see Figures 2 and 3). This can be accomplished on the ISL422XE by driving the EN input high whenever the UART powers down. Figure 3 also shows that the INVALID output can be used to determine when the UART should be powered down. When the RS-232 cable is disconnected, INVALID switches low indicating that the UART is no longer needed. Reconnecting the cable drives INVALID back high, indicating that the UART should be powered up. TO WAKE-UP LOGIC ISL422XE VCC INVALID RX POWERED DOWN UART VOUT = HI-Z ROUT TX RIN TIN TOUT EN = VCC FIGURE 3. DISABLED RECEIVERS PREVENT POWER DRAIN Software Controlled (Manual) Powerdown Low Power Operation The ISL422XE family provides pins that allow the user to force the IC into the low power, standby state. These 3V devices require a nominal supply current of 0.3mA, even at VCC = 5.5V, during normal operation (not in powerdown mode). This is considerably less than the 5mA to The ISL422XE utilize a two pin approach where the FORCEON and FORCEOFF inputs determine the IC’s 6 ISL4221E, ISL4223E TABLE 2. POWERDOWN AND ENABLE LOGIC TRUTH TABLE RS-232 SIGNAL PRESENT AT RECEIVER INPUT? FORCEOFF FORCEON EN TRANSMITTER RECEIVER INVALID INPUT INPUT INPUT OUTPUTS OUTPUTS OUTPUT MODE OF OPERATION NO H H L Active Active L NO H H H Active High-Z L YES H L L Active Active H YES H L H Active High-Z H NO H L L High-Z Active L NO H L H High-Z High-Z L YES L X L High-Z Active H Manual Powerdown YES L X H High-Z High-Z H Manual Powerdown w/Rcvr. Disabled NO L X L High-Z Active L Manual Powerdown NO L X H High-Z High-Z L Manual Powerdown w/Rcvr. Disabled mode. For always enabled operation, FORCEON and FORCEOFF are both strapped high. To switch between active and powerdown modes, under logic or software control, only the FORCEOFF input need be driven. The FORCEON state isn’t critical, as FORCEOFF dominates over FORCEON. Nevertheless, if strictly manual control over powerdown is desired, the user must strap FORCEON high to disable the automatic powerdown circuitry. Connecting FORCEOFF and FORCEON together disables the automatic powerdown feature, enabling them to function as a manual SHUTDOWN input (see Figure 4). FORCEOFF PWR MGT LOGIC Normal Operation (Auto Powerdown Enabled) Powerdown Due to Auto Powerdown Logic MASTER POWERDOWN LINE 0.1µF FORCEOFF 1MΩ FORCEON ISL422XE FIGURE 5. CIRCUIT TO PREVENT AUTO POWERDOWN FOR 100ms AFTER FORCED POWERUP Automatic Powerdown FORCEON INVALID ISL422XE I/O UART CPU FIGURE 4. CONNECTIONS FOR MANUAL POWERDOWN WHEN NO VALID RECEIVER SIGNALS ARE PRESENT The time to recover from automatic powerdown mode is typically 100µs. 7 POWER MANAGEMENT UNIT Normal Operation (Auto Powerdown Disabled) Even greater power savings is available by using the automatic powerdown function. When no valid RS-232 voltages (see Figure 6) are sensed on any receiver input for 30µs, the charge pump and transmitters powerdown, thereby reducing supply current to 10nA. 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 ISL422XE powers back up whenever it detects a valid RS-232 voltage level on any receiver input. This automatic powerdown feature provides additional system power savings without changes to the existing operating system. Automatic powerdown operates when the FORCEON input is low, and the FORCEOFF input is high. Tying FORCEON high disables automatic powerdown, but manual powerdown is always available via the overriding FORCEOFF input. Table 2 summarizes the automatic powerdown functionality. Some applications may need more time to wake up from shutdown. If automatic powerdown is being utilized, the RS232 device will reenter powerdown if valid receiver levels aren’t reestablished within 30µs of the ISL422XE powering up. Figure 5 illustrates a circuit that keeps the ISL422XE ISL4221E, ISL4223E from initiating automatic powerdown for 100ms after powering up. This gives the slow-to-wake peripheral circuit time to reestablish valid RS-232 output levels. The time to recover from automatic powerdown mode is typically 100µs. circuitry. When automatic powerdown is utilized, INVALID = 0 indicates that the ISL422XE is in powerdown mode. RECEIVER INPUTS INVALID } REGION TRANSMITTER OUTPUTS INVALID Output The INVALID output always indicates whether or not a valid RS-232 signal (see Figure 6) is present at any of the receiver inputs (see Table 2), giving the user an easy way to determine when the interface block should power down. Invalid receiver levels occur whenever the driving peripheral’s outputs are shut off (powered down) or when the RS-232 interface cable is disconnected. In the case of a disconnected interface cable where all the receiver inputs are floating (but pulled to GND by the internal receiver pull down resistors), the INVALID logic detects the invalid levels and drives the output low. The power management logic then uses this indicator to power down the interface block. Reconnecting the cable restores valid levels at the receiver inputs, INVALID switches high, and the power management logic wakes up the interface block. INVALID can also be used to indicate the DTR or RING INDICATOR signal, as long as the other receiver inputs are floating, or driven to GND (as in the case of a powered down driver). VALID RS-232 LEVEL - ISL422XE IS ACTIVE 2.7V INDETERMINATE - POWERDOWN MAY OR MAY NOT OCCUR 0.3V INVALID LEVEL - POWERDOWN OCCURS AFTER 30µs -0.3V INDETERMINATE - POWERDOWN MAY OR MAY NOT OCCUR -2.7V VALID RS-232 LEVEL - ISL422XE IS ACTIVE FIGURE 6. DEFINITION OF VALID RS-232 RECEIVER LEVELS INVALID switches low after invalid levels have persisted on all of the receiver inputs for more than 30µs (see Figure 7). INVALID switches back high 1µs after detecting a valid RS-232 level on a receiver input. INVALID operates in all modes (forced or automatic powerdown, or forced on), so it is also useful for systems employing manual powerdown 8 INVALID OUTPUT VCC tINVL tINVH 0 AUTOPWDN PWR UP V+ VCC 0 V- FIGURE 7. AUTOMATIC POWERDOWN AND INVALID TIMING DIAGRAMS Capacitor Selection The charge pumps require 0.1µF, or greater, capacitors for proper operation. Increasing the capacitor values (by a factor of 2) reduces ripple on the transmitter outputs and slightly reduces power consumption. 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 0.1µF bypass capacitor is adequate. In applications that are particularly sensitive to power supply noise, decouple VCC to ground with a capacitor of the same value as the charge-pump capacitor C1. Connect the bypass capacitor as close as possible to the IC. Transmitter Outputs when Exiting Powerdown Figure 8 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 3kΩ in parallel with 2500pF. ISL4221E, ISL4223E Note that the transmitters enable only when the magnitude of the supplies exceed approximately 3V. 5V/DIV. 5V/DIV. T1IN FORCEOFF T1 T1OUT 2V/DIV. R1OUT VCC = +3.3V C1 - C4 = 0.1µF T2 VCC = +3.3V C1 - C4 = 0.1µF 5µs/DIV. FIGURE 10. LOOPBACK TEST AT 120kBps TIME (20µs/DIV.) FIGURE 8. TRANSMITTER OUTPUTS WHEN EXITING POWERDOWN Operation Down to 2.7V 5V/DIV. T1IN ISL422XE transmitter outputs meet RS-562 levels (±3.7V), at the full data rate, with VCC as low as 2.7V. RS-562 levels typically ensure inter operability with RS-232 devices. T1OUT High Data Rates The ISL422XE maintain the RS-232 ±5V minimum transmitter output voltages even at high data rates. Figure 9 details a transmitter loopback test circuit, and Figure 10 illustrates the loopback test result at 120kBps. For this test, all transmitters were simultaneously driving RS-232 loads in parallel with 1000pF, at 120kBps. Figure 11 shows the loopback results for a single transmitter driving 1000pF and an RS-232 load at 250kBps. The static transmitters were also loaded with an RS-232 receiver. VCC + VCC C1+ V+ C1 C1V- C2+ TABLE 3. LOGIC FAMILY COMPATIBILITY WITH VARIOUS SUPPLY VOLTAGES TOUT RIN ROUT FORCEON VCC Interconnection with 3V and 5V Logic C4 + C2TIN 2µs/DIV. FIGURE 11. LOOPBACK TEST AT 250kBps + C3 ISL422XE + C2 VCC = +3.3V C1 - C4 = 0.1µF The ISL422XE directly interface with 5V CMOS and TTL logic families. Nevertheless, with the ISL422XE at 3.3V, and the logic supply at 5V, AC, HC, and CD4000 outputs can drive ISL422XE inputs, but ISL422XE outputs do not reach the minimum VIH for these logic families. See Table 3 for more information. + 0.1µF R1OUT 1000pF SYSTEM POWER-SUPPLY VOLTAGE (V) VCC SUPPLY VOLTAGE (V) 3.3 3.3 5 5 5 3.3 5k FORCEOFF FIGURE 9. TRANSMITTER LOOPBACK TEST CIRCUIT 9 COMPATIBILITY Compatible with all CMOS families. Compatible with all TTL and CMOS logic families. Compatible with ACT and HCT CMOS, and with TTL. ISL422XE outputs are incompatible with AC, HC, and CD4000 CMOS inputs. ISL4221E, ISL4223E ±15kV ESD Protection IEC61000-4-2 Testing All pins on ISL422XE devices include ESD protection structures, but the RS-232 pins (transmitter outputs and receiver inputs) incorporate advanced structures which allow them 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. 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. Human Body Model (HBM) Testing AIR-GAP DISCHARGE TEST METHOD 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 1.5kΩ current limiting resistor, making the test less severe than the IEC61000 test which utilizes a 330Ω 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. 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. 10 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. ISL4221E, ISL4223E Typical Performance Curves VCC = 3.3V, TA = 25oC 25 VOUT+ 4 20 SLEW RATE (V/µs) TRANSMITTER OUTPUT VOLTAGE (V) 6 2 1 TRANSMITTER AT 250kBps OTHER TRANSMITTERS AT 30kBps 0 -2 15 -SLEW +SLEW 10 VOUT - -4 -6 0 1000 2000 3000 4000 5 5000 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) FIGURE 12. TRANSMITTER OUTPUT VOLTAGE vs LOAD CAPACITANCE FIGURE 13. SLEW RATE vs LOAD CAPACITANCE 45 45 ISL4221E ISL4223E 40 40 SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 250kBps 35 250kBps 30 25 20 120kBps 15 10 20kBps 5 35 30 25 120kBps 20 15 20kBps 10 5 0 0 1000 2000 3000 4000 5000 0 0 1000 LOAD CAPACITANCE (pF) Die Characteristics 3.5 NO LOAD ALL OUTPUTS STATIC 3.0 SUBSTRATE POTENTIAL (POWERED UP): GND 2.5 TRANSISTOR COUNT: 2.0 ISL4221E: 286 ISL4223E: 357 1.5 PROCESS: 1.0 Si Gate CMOS 0.5 0 2.5 3000 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) FIGURE 16. SUPPLY CURRENT vs SUPPLY VOLTAGE 11 4000 5000 FIGURE 15. SUPPLY CURRENT vs LOAD CAPACITANCE WHEN TRANSMITTING DATA FIGURE 14. SUPPLY CURRENT vs LOAD CAPACITANCE WHEN TRANSMITTING DATA SUPPLY CURRENT (mA) 2000 LOAD CAPACITANCE (pF) 6.0 ISL4221E, ISL4223E Quad Flat No-Lead Plastic Package (QFN) Micro Lead Frame Plastic Package (MLFP) L16.5x5 16 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE (COMPLIANT TO JEDEC MO-220VHHB ISSUE C) MILLIMETERS SYMBOL MIN NOMINAL MAX NOTES A 0.80 0.90 1.00 - A1 - - 0.05 - A2 - - 1.00 9 A3 b 0.20 REF 0.28 D 0.40 5, 8 5.00 BSC D1 D2 0.33 9 - 4.75 BSC 2.55 2.70 9 2.85 7, 8 E 5.00 BSC - E1 4.75 BSC 9 E2 2.55 e 2.70 2.85 7, 8 0.80 BSC - k 0.25 - - - L 0.35 0.60 0.75 8 L1 - - 0.15 10 N Nd 16 2 4 3 Ne 4 4 3 P - - 0.60 9 θ - - 12 9 Rev. 2 10/02 NOTES: 1. Dimensioning and tolerancing conform to ASME Y14.5-1994. 2. N is the number of terminals. 3. Nd and Ne refer to the number of terminals on each D and E. 4. All dimensions are in millimeters. Angles are in degrees. 5. Dimension b applies to the metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. 6. The configuration of the pin #1 identifier is optional, but must be located within the zone indicated. The pin #1 identifier may be either a mold or mark feature. 7. Dimensions D2 and E2 are for the exposed pads which provide improved electrical and thermal performance. 8. Nominal dimensions are provided to assist with PCB Land Pattern Design efforts, see Intersil Technical Brief TB389. 9. Features and dimensions A2, A3, D1, E1, P & θ are present when Anvil singulation method is used and not present for saw singulation. 10. Depending on the method of lead termination at the edge of the package, a maximum 0.15mm pull back (L1) maybe present. L minus L1 to be equal to or greater than 0.3mm. 12 ISL4221E, ISL4223E Quad Flat No-Lead Plastic Package (QFN) Micro Lead Frame Plastic Package (MLFP) L20.5x5 20 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE (COMPLIANT TO JEDEC MO-220VHHC ISSUE C) MILLIMETERS SYMBOL MIN NOMINAL MAX NOTES A 0.80 0.90 1.00 - A1 - - 0.05 - A2 - - 1.00 9 A3 b 0.20 REF 0.23 D 0.38 5, 8 5.00 BSC D1 D2 0.28 9 - 4.75 BSC 2.95 3.10 9 3.25 7, 8 E 5.00 BSC - E1 4.75 BSC 9 E2 2.95 e 3.10 3.25 7, 8 0.65 BSC - k 0.25 - - - L 0.35 0.60 0.75 8 L1 - - 0.15 10 N 20 2 Nd 5 3 Ne 5 3 P - - 0.60 9 θ - - 12 9 Rev. 3 10/02 NOTES: 1. Dimensioning and tolerancing conform to ASME Y14.5-1994. 2. N is the number of terminals. 3. Nd and Ne refer to the number of terminals on each D and E. 4. All dimensions are in millimeters. Angles are in degrees. 5. Dimension b applies to the metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. 6. The configuration of the pin #1 identifier is optional, but must be located within the zone indicated. The pin #1 identifier may be either a mold or mark feature. 7. Dimensions D2 and E2 are for the exposed pads which provide improved electrical and thermal performance. 8. Nominal dimensions are provided to assist with PCB Land Pattern Design efforts, see Intersil Technical Brief TB389. 9. Features and dimensions A2, A3, D1, E1, P & θ are present when Anvil singulation method is used and not present for saw singulation. 10. Depending on the method of lead termination at the edge of the package, a maximum 0.15mm pull back (L1) maybe present. L minus L1 to be equal to or greater than 0.3mm. 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 13