ICL3310CB

® CT RODU UCT E TE P L PROD OBSO ITUTE BST LE S U L322 2 IC POSSIB Data Sheet ICL3310 July 2004 FN4995.3 +3V to +5.5V, 1 Microamp, 250kbps, RS-232 Transmitter/Receiver The Intersil ICL3310 contains 3.0V to 5.5V powered RS-232 transmitters/receivers which meet ElA/TIA-232 and V.28/V.24 specifications, even at VCC = 3.0V. Targeted applications are 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 a manual powerdown function reduces the standby supply current to a 1µA trickle. Small footprint 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. This device is fully compatible with 3.3V only systems, mixed 3.3V and 5.0V systems, and 5.0V only systems. The single pin powerdown function (SHDN = 0) disables all the transmitters and receivers, while shutting down the charge pump to minimize supply current drain. Table 1 summarizes the features of the ICL3310, while Application Note AN9863 summarizes the features of each device comprising the ICL32XX 3V family. Features • ±15kV ESD Protected (Human Body Model) • Low Power, Pin Compatible Upgrade for 5V MAX222, SP310A, and LT1X80/A • Single SHDN Pin Disables Transmitters and Receivers • Meets EIA/TIA-232 and V.28/V.24 Specifications at 3V • Latch-Up Free • On-Chip Voltage Converters Require Only Four External 0.1µF Capacitors • Receiver Hysteresis For Improved Noise Immunity • Very Low Supply Current . . . . . . . . . . . . . . . . . . . . 0.3mA • Guaranteed Minimum Data Rate . . . . . . . . . . . . . 250kbps • Guaranteed Minimum Slew Rate . . . . . . . . . . . . . . . 6V/µs • Wide Power Supply Range . . . . . . . Single +3V to +5.5V • Low Supply Current in Powerdown State. . . . . . . . . .±8 ±3 kV kV kV kV Detailed Description ICL3310 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. 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. All 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. Charge-Pump Intersil’s new ICL3310 utilizes 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 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 VCC = 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. 4 ICL3310 Transmitter inputs float if left unconnected (there are no pullup resistors), and may cause ICC increases. Connect unused inputs to GND for the best performance. TABLE 2. POWERDOWN AND ENABLE LOGIC TRUTH TABLE SHDN TRANSMITTER RECEIVER INPUT OUTPUTS OUTPUTS MODE OF OPERATION H L Active High-Z Active High-Z Normal Operation Manual Powerdown Powerdown Functionality The already low current requirement drops significantly when the device enters powerdown mode. In powerdown, supply current drops to 1µA, because the on-chip charge pump turns off (V+ collapses to VCC, V- collapses to GND), and the transmitter and receiver outputs three-state. This micro-power mode makes these devices ideal for battery powered and portable applications. Software Controlled (Manual) Powerdown The ICL3310 may be forced into its low power, standby state via a simple shutdown (SHDN) pin (see Figure 4). Driving this pin high enables normal operation, while driving it low forces the IC into it’s powerdown state. The time required to exit powerdown, and resume transmission is less than 50µs. Connect SHDN to VCC if the powerdown function isn’t needed. VCC VCC CURRENT FLOW VOUT = VCC Rx Receivers The ICL3310 contains standard inverting receivers that three-state via the SHDN control line. Receivers driving powered down peripherals must be disabled to prevent current flow through the peripheral’s protection diodes (see Figures 2 and 3). All the receivers 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 (VCC = 0V). The receivers’ Schmitt trigger input stage uses hysteresis to increase noise immunity and decrease errors due to slow input signal transitions. VCC RXIN -25V ≤ VRIN ≤ +25V GND 5kΩ RXOUT GND ≤ VROUT ≤ VCC VCC POWERED DOWN UART Tx GND SHDN = GND OLD RS-232 CHIP FIGURE 1. INVERTING RECEIVER CONNECTIONS FIGURE 2. POWER DRAIN THROUGH POWERED DOWN PERIPHERAL Low Power Operation This 3V device requires 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 11mA current required by comparable 5V RS-232 devices, allowing users to reduce system power simply by replacing the old style device with the ICL3310. VCC TRANSITION DETECTOR TO WAKE-UP LOGIC VCC VICL3310 Low Power, Pin Compatible Replacement Pin compatibility with existing 5V products (e.g., MAX222), coupled with the wide operating supply range, make the ICL3310 a potential lower power, higher performance dropin replacement for existing 5V applications. As long as the ±5V RS-232 output swings are acceptable, and transmitter pull-up resistors aren’t required, the ICL3310 should work in most 5V applications. When replacing a device in an existing 5V application, it is acceptable to terminate C3 to VCC as shown on the “Typical Operating Circuit”. Nevertheless, terminate C3 to GND if possible, as slightly better performance results from this configuration. RX POWERED DOWN UART VOUT = HI-Z TX FIGURE 3. DISABLED RECEIVERS PREVENT POWER DRAIN 5 ICL3310 SHDN PWR MGT LOGIC 5V/DIV. SHDN T1 ICL3310 2V/DIV. I/O UART CPU T2 VCC = +3.3V C1 - C4 = 0.1µF TIME (20µs/DIV.) FIGURE 5. TRANSMITTER OUTPUTS WHEN EXITING POWERDOWN FIGURE 4. CONNECTIONS FOR MANUAL POWERDOWN High Data Rates The ICL3310 maintain the RS-232 ±5V minimum transmitter output voltages even at high data rates. Figure 6 details a transmitter loopback test circuit, and Figure 7 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 8 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 0.1µF + Capacitor Selection The charge pumps require 0.1µF or greater capacitors for operation with 3.3V ≤ VCC ≤ 5.5V. Increasing the capacitor values (by a factor of 2) reduces ripple on the transmitter outputs and slightly reduces power consumption. C2 , C3 , and C4 can be increased without increasing C1’s value, however, do not increase C1 without also increasing C2 , C3 , and C4 to maintain the proper ratios (C1 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-. + C1 C1+ C1- VCC V+ + C3 ICL3310 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. + C2 C2+ C2TIN ROUT TOUT V- C4 + RIN 5k 1000pF Transmitter Outputs when Exiting Powerdown Figure 5 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. Note that the transmitters enable only when the magnitude of the supplies exceed approximately 3V. VCC SHDN FIGURE 6. TRANSMITTER LOOPBACK TEST CIRCUIT 6 ICL3310 5V/DIV. T1IN Interconnection with 3V and 5V Logic The ICL3310 directly interface with most 5V logic families, including ACT and HCT CMOS. See Table 3 for more information on possible combinations of interconnections. TABLE 3. LOGIC FAMILY COMPATIBILITY WITH VARIOUS SUPPLY VOLTAGES VCC SYSTEM POWER-SUPPLY SUPPLY VOLTAGE VOLTAGE (V) (V) VCC = +3.3V C1 - C4 = 0.1µF 5µs/DIV. T1OUT R1OUT COMPATIBILITY Compatible with all CMOS families. Compatible with all TTL and CMOS logic families. Compatible with ACT and HCT CMOS, and with TTL. Incompatible with AC, HC, or CD4000 CMOS. 3.3 5 5 3.3 5 3.3 FIGURE 7. LOOPBACK TEST AT 120kbps 5V/DIV. T1IN T1OUT R1OUT VCC = +3.3V C1 - C4 = 0.1µF 2µs/DIV. FIGURE 8. LOOPBACK TEST AT 250kbps Typical Performance Curves 6.0 TRANSMITTER OUTPUT VOLTAGE (V) 4.0 2.0 1 TRANSMITTER AT 250kbps 1 TRANSMITTER AT 30kbps 0 -2.0 -4.0 -6.0 VCC = 3.3V, TA = 25oC 25 VOUT+ 20 SLEW RATE (V/µs) 15 -SLEW +SLEW 10 VOUT 5 0 1000 2000 3000 4000 5000 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) FIGURE 9. TRANSMITTER OUTPUT VOLTAGE vs LOAD CAPACITANCE FIGURE 10. SLEW RATE vs LOAD CAPACITANCE 7 ICL3310 Typical Performance Curves 45 40 SUPPLY CURRENT (mA) 35 30 25 20 15 10 5 0 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 20kbps 120kbps SUPPLY CURRENT (mA) 250kbps VCC = 3.3V, TA = 25oC (Continued) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 NO LOAD ALL OUTPUTS STATIC SUPPLY VOLTAGE (V) FIGURE 11. SUPPLY CURRENT vs LOAD CAPACITANCE WHEN TRANSMITTING DATA FIGURE 12. SUPPLY CURRENT vs SUPPLY VOLTAGE Die Characteristics SUBSTRATE POTENTIAL (POWERED UP): GND TRANSISTOR COUNT: 338 PROCESS: Si Gate CMOS 8 ICL3310 Small Outline Plastic Packages (SOIC) N INDEX AREA E -B1 2 3 SEATING PLANE -AD -CA h x 45o H 0.25(0.010) M BM M18.3 (JEDEC MS-013-AB ISSUE C) 18 LEAD WIDE BODY SMALL OUTLINE PLASTIC PACKAGE INCHES SYMBOL A L MILLIMETERS MIN 2.35 0.10 0.33 0.23 11.35 7.40 MAX 2.65 0.30 0.51 0.32 11.75 7.60 NOTES 9 3 4 5 6 7 8o Rev. 0 12/93 MIN 0.0926 0.0040 0.013 0.0091 0.4469 0.2914 MAX 0.1043 0.0118 0.0200 0.0125 0.4625 0.2992 A1 B C D E α µ A1 0.10(0.004) C e H h L N 0.050 BSC 0.394 0.010 0.016 18 0o 8o 0.419 0.029 0.050 1.27 BSC 10.00 0.25 0.40 18 0o 10.65 0.75 1.27 e B 0.25(0.010) M C AM BS NOTES: 1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of Publication Number 95. 2. Dimensioning and tolerancing per ANSI Y14.5M-1982. 3. Dimension “D” does not include mold flash, protrusions or gate burrs. Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006 inch) per side. 4. Dimension “E” does not include interlead flash or protrusions. Interlead flash and protrusions shall not exceed 0.25mm (0.010 inch) per side. 5. The chamfer on the body is optional. If it is not present, a visual index feature must be located within the crosshatched area. 6. “L” is the length of terminal for soldering to a substrate. 7. “N” is the number of terminal positions. 8. Terminal numbers are shown for reference only. 9. The lead width “B”, as measured 0.36mm (0.014 inch) or greater above the seating plane, shall not exceed a maximum value of 0.61mm (0.024 inch) 10. Controlling dimension: MILLIMETER. Converted inch dimensions are not necessarily exact. α 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 9