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ISL4221E, ISL4223E
Data Sheet April 2003 FN6045
QFN Packaged, +/-15kV ESD Protected, +2.7V to +5.5V, 150Nanoamp, 250kBps, RS-232 Transmitters/Receivers
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. 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.
PART NUMBER ISL4221E ISL4223E NO. OF NO. OF Tx. Rx. 1 2 1 2 QFN PKG. AVAILABLE? YES YES DATA RATE (kBps) 250 250
Features
* Available in Near Chip Scale QFN (5mmx5mm) Package which is 40% Smaller than a 20 Lead TSSOP * ESD Protection for RS-232 I/O Pins to 15kV (IEC61000) * 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 0.1F 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
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 Rx. ENABLE FUNCTION? YES YES MANUAL POWERDOWN? YES YES AUTOMATIC POWERDOWN FUNCTION? YES YES
Ordering Information
PART NO. ISL4221EIR ISL4221EIR-T ISL4223EIR ISL4223EIR-T TEMP. RANGE (oC) -40 to 85 -40 to 85 -40 to 85 -40 to 85 PACKAGE 16 Ld QFN 16 Ld QFN Tape & Reel 20 Ld QFN 20 Ld QFN Tape & Reel PKG. NO. L16.5x5 L16.5x5 L20.5x5 L20.5x5
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 (c) Intersil Americas Inc. 2003. All Rights Reserved
ISL4221E, ISL4223E Pinouts
ISL4221E (QFN) TOP VIEW ISL4223E (QFN) TOP VIEW
FORCEOFF
FORCEOFF
VCC
C1+
EN
20 16 V+ C1C2+ C21 2 3 4 5 V6 R1IN 7 R1OUT 8 INVALID 15 14 13 12 GND 11 T1OUT 10 FORCEON 9 T1IN V+ C1C2+ C2V1 2 3 4 5 6 T2OUT
19
18
17
16 15 T1OUT 14 R1IN 13 R1OUT 12 FORCEON 11 T1IN
7 R2IN
8 R2OUT
9 INVALID
10 T2IN
Pin Descriptions
PIN VCC V+ VGND C1+ C1C2+ C2TIN TOUT RIN ROUT INVALID System power supply input (2.7V to 5.5V). Internally generated positive transmitter supply (+5.5V). Internally generated negative transmitter supply (-5.5V). Ground connection. External capacitor (voltage doubler) is connected to this lead. External capacitor (voltage doubler) is connected to this lead. External capacitor (voltage inverter) is connected to this lead. External capacitor (voltage inverter) is connected to this lead. TTL/CMOS compatible transmitter Inputs. 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. FUNCTION
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
GND
VCC
C1+
EN
ISL4221E, ISL4223E Typical Operating Circuits
ISL4221E
+3.3V
+
0.1F
13 VCC 1 V+ V- 5 T1 11 + C3 0.1F C4 + 0.1F T1OUT RS-232 LEVELS
C1 0.1F C2 0.1F
16 + C1+ 2 C13 + C2+ 4 C29
TTL/CMOS LOGIC LEVELS R1OUT
T1IN
7 R1 15 EN 5k
6
R1IN
14 FORCEOFF 10 FORCEON GND 12 INVALID 8
VCC TO POWER CONTROL LOGIC
ISL4223E
+3.3V
+
0.1F 20 + 2 3 + 4 11 C1+ C1C2+ C2-
17 VCC V+ 1 + C3 0.1F C4 0.1F + T1OUT T2OUT RS-232 LEVELS
C1 0.1F C2 0.1F
VT1 T2
5
T1IN T2IN TTL/CMOS LOGIC LEVELS R1OUT
15
10
6
13 R1 5k
14
R1IN
R2OUT
8 19 EN R2 5k
7
R2IN
FORCEOFF 12 FORCEON GND 16 INVALID
18 9
VCC TO POWER CONTROL LOGIC
3
ISL4221E, ISL4223E
Absolute Maximum Ratings
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 Information
Thermal Resistance (Typical, Note 1)
JA (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. JA 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.
Electrical Specifications
Test Conditions: VCC = 3V to 5.5V, C1 - C4 = 0.1F; Unless Otherwise Specified. Typicals are at TA = 25oC TEST CONDITIONS TEMP (oC) MIN TYP MAX UNITS
PARAMETER DC CHARACTERISTICS Supply Current, Automatic Powerdown Supply Current, Powerdown Supply Current, Automatic Powerdown Disabled
All RIN Open, FORCEON = GND, FORCEOFF = VCC FORCEOFF = GND VCC = 3.15V All Outputs Unloaded, FORCEON = FORCEOFF = VCC
25 25 25
-
0.15 0.15 0.3
1 1 1.0
A A mA
LOGIC AND TRANSMITTER INPUTS AND RECEIVER OUTPUTS Input Logic Threshold Low Input Logic Threshold High TIN, FORCEON, FORCEOFF, EN TIN, FORCEON, FORCEOFF, EN TIN, FORCEON, FORCEOFF, EN EN = VCC IOUT = 1.6mA IOUT = -1.0mA VCC = 3.3V VCC = 5.0V Full Full Full Full Full Full Full 2.0 2.4 0.01 0.05 0.8 1.0 10 0.4 V V V A A V V
Input Leakage Current Output Leakage Current Output Voltage Low Output Voltage High
VCC -0.6 VCC -0.1
AUTOMATIC POWERDOWN (FORCEON = GND, FORCEOFF = VCC) Receiver Input Thresholds to Enable Transmitters Receiver Input Thresholds to Disable Transmitters INVALID Output Voltage Low INVALID Output Voltage High Receiver Threshold to Transmitters Enabled Delay (tWU) Receiver Positive or Negative Threshold to INVALID High Delay (tINVH) Receiver Positive or Negative Threshold to INVALID Low Delay (tINVL) ISL422XE Powers Up (See Figure 6) ISL422XE Powers Down (See Figure 6) IOUT = 1.6mA IOUT = -1.0mA Full Full Full Full 25 25 -2.7 -0.3 VCC-0.6 100 1 2.7 0.3 0.4 V V V V s s
25
-
30
-
s
4
ISL4221E, ISL4223E
Electrical Specifications
Test Conditions: VCC = 3V to 5.5V, C1 - C4 = 0.1F; Unless Otherwise Specified. Typicals are at TA = 25oC (Continued) TEST CONDITIONS TEMP (oC) MIN TYP MAX UNITS
PARAMETER RECEIVER INPUTS Input Voltage Range Input Threshold Low VCC = 3.3V VCC = 5.0V Input Threshold High VCC = 3.3V VCC = 5.0V Input Hysteresis Input Resistance TRANSMITTER OUTPUTS Output Voltage Swing Output Resistance Output Short-Circuit Current Output Leakage Current TIMING CHARACTERISTICS Maximum Data Rate Receiver Propagation Delay
25 25 25 25 25 25 25
-25 0.6 0.8 3
1.2 1.5 1.5 1.8 0.5 5
25 2.4 2.4 7
V V V V V V k
All Transmitter Outputs Loaded with 3k to Ground VCC = V+ = V- = 0V, Transmitter Output = 2V VOUT = 12V, VCC = 0V or 3V to 5.5V, Automatic Powerdown or FORCEOFF = GND
Full Full Full Full
5.0 300 -
5.4 10M 35 -
60 25
V mA A
RL = 3k, CL = 1000pF, One Transmitter Switching Receiver Input to Receiver Output, CL = 150pF Normal Operation Normal Operation tPHL - tPLH (Note 2) tPHL - tPLH VCC = 3.3V, RL = 3k to 7k, Measured From 3V to -3V or -3V to 3V CL = 150pF to 2500pF CL = 150pF to 1000pF tPHL tPLH
Full 25 25 25 25 25 25 25 25
250 4 6
500 0.15 0.15 200 200 100 50 -
30 30
kBps s s ns ns ns ns V/s V/s
Receiver Output Enable Time Receiver Output Disable Time Transmitter Skew Receiver Skew Transition Region Slew Rate
ESD PERFORMANCE RS-232 Pins (TOUT, RIN) Human Body Model IEC61000-4-2 Contact Discharge IEC61000-4-2 Air Gap Discharge All Other Pins NOTE: 2. Transmitter skew is measured at the transmitter zero crossing points. Human Body Model 25 25 25 25 15 8 15 2 kV kV kV kV
Detailed Description
The ISL422XE operate from a single +2.7V to +5.5V supply, guarantee a 250kBps minimum data rate, require only four small external 0.1F 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.
Charge-Pump
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 0.1F 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. to 11mA current required by comparable 5V RS-232 devices, allowing users to reduce system power simply by switching to this new family.
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 (3k and 1000pF), VCC 3.0V, with one transmitter operating at full speed. Under more typical conditions of VCC 3.3V, RL = 3k, 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.
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 VOUT = VCC Rx POWERED DOWN UART Tx GND SHDN = GND OLD RS-232 CHIP
VCC
Receivers
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 3k to 7k 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 5k RXOUT GND VROUT VCC
FIGURE 2. POWER DRAIN THROUGH POWERED DOWN PERIPHERAL
VCC
TRANSITION DETECTOR TO WAKE-UP LOGIC VCC ISL422XE
FIGURE 1. INVERTING RECEIVER CONNECTIONS
INVALID
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.
RX POWERED DOWN UART
VOUT = HI-Z ROUT RIN
TX
TIN TOUT EN = VCC
FIGURE 3. DISABLED RECEIVERS PREVENT POWER DRAIN
Software Controlled (Manual) Powerdown
The ISL422XE family provides pins that allow the user to force the IC into the low power, standby state. The ISL422XE utilize a two pin approach where the FORCEON and FORCEOFF inputs determine the IC's
Low Power Operation
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
6
ISL4221E, ISL4223E
TABLE 2. POWERDOWN AND ENABLE LOGIC TRUTH TABLE RS-232 SIGNAL PRESENT AT RECEIVER INPUT? NO NO YES YES NO NO YES YES NO NO FORCEOFF FORCEON EN TRANSMITTER RECEIVER INVALID INPUT INPUT INPUT OUTPUTS OUTPUTS OUTPUT H H H H H H L L L L H H L L L L X X X X L H L H L H L H L H Active Active Active Active High-Z High-Z High-Z High-Z High-Z High-Z Active High-Z Active High-Z Active High-Z Active High-Z Active High-Z L L H H L L H H L L
MODE OF OPERATION Normal Operation (Auto Powerdown Disabled) Normal Operation (Auto Powerdown Enabled) Powerdown Due to Auto Powerdown Logic Manual Powerdown Manual Powerdown w/Rcvr. Disabled Manual Powerdown 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 FORCEON
POWER MANAGEMENT UNIT
MASTER POWERDOWN LINE 0.1F 1M
FORCEOFF
FORCEON
ISL422XE
FIGURE 5. CIRCUIT TO PREVENT AUTO POWERDOWN FOR 100ms AFTER FORCED POWERUP
Automatic Powerdown
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 30s, 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 30s of the ISL422XE powering up. Figure 5 illustrates a circuit that keeps the ISL422XE
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 100s.
7
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 100s. circuitry. When automatic powerdown is utilized, INVALID = 0 indicates that the ISL422XE is in powerdown mode.
RECEIVER INPUTS INVALID } REGION
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 30s -0.3V INDETERMINATE - POWERDOWN MAY OR MAY NOT OCCUR -2.7V VALID RS-232 LEVEL - ISL422XE IS ACTIVE
TRANSMITTER OUTPUTS VCC 0 AUTOPWDN V+ VCC 0 V-
INVALID OUTPUT
tINVL
tINVH PWR UP
FIGURE 7. AUTOMATIC POWERDOWN AND INVALID TIMING DIAGRAMS
Capacitor Selection
The charge pumps require 0.1F, 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 0.1F 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.
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 30s (see Figure 7). INVALID switches back high 1s 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
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 3k in parallel with 2500pF.
8
ISL4221E, ISL4223E
Note that the transmitters enable only when the magnitude of the supplies exceed approximately 3V.
5V/DIV. FORCEOFF T1
5V/DIV. T1IN
T1OUT 2V/DIV.
R1OUT T2 VCC = +3.3V C1 - C4 = 0.1F TIME (20s/DIV.) VCC = +3.3V C1 - C4 = 0.1F 5s/DIV.
FIGURE 10. LOOPBACK TEST AT 120kBps
FIGURE 8. TRANSMITTER OUTPUTS WHEN EXITING POWERDOWN
5V/DIV. T1IN
Operation Down to 2.7V
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 0.1F + R1OUT VCC = +3.3V C1 - C4 = 0.1F 2s/DIV.
FIGURE 11. LOOPBACK TEST AT 250kBps
Interconnection with 3V and 5V Logic
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.
TABLE 3. LOGIC FAMILY COMPATIBILITY WITH VARIOUS SUPPLY VOLTAGES VCC SYSTEM POWER-SUPPLY SUPPLY VOLTAGE VOLTAGE (V) (V) 3.3 3.3 5 3.3
+ C1
C1+ C1-
VCC
V+
+ C3
ISL422XE + C2 C2TIN ROUT FORCEON VCC FORCEOFF 5k TOUT RIN 1000pF C2+ VC4 +
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.
5 5
FIGURE 9. TRANSMITTER LOOPBACK TEST CIRCUIT
9
ISL4221E, ISL4223E 15kV ESD Protection
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.
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.
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.
10
ISL4221E, ISL4223E Typical Performance Curves
6 TRANSMITTER OUTPUT VOLTAGE (V) 4 2 1 TRANSMITTER AT 250kBps OTHER TRANSMITTERS AT 30kBps 0 -2 -4 -6 VOUT 5 VOUT+ 20 SLEW RATE (V/s)
VCC = 3.3V, TA = 25oC
25
15 -SLEW +SLEW 10
0
1000
2000
3000
4000
5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
FIGURE 12. TRANSMITTER OUTPUT VOLTAGE vs LOAD CAPACITANCE
45 ISL4221E 40 SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 35 30 25 20 15 10 5 0 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) 20kBps 120kBps 250kBps
FIGURE 13. SLEW RATE vs LOAD CAPACITANCE
45 ISL4223E 40 250kBps 35 30 25 20 15 10 5 0 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) 20kBps 120kBps
FIGURE 14. SUPPLY CURRENT vs LOAD CAPACITANCE WHEN TRANSMITTING DATA
3.5 3.0 SUPPLY CURRENT (mA) 2.5 NO LOAD ALL OUTPUTS STATIC
FIGURE 15. SUPPLY CURRENT vs LOAD CAPACITANCE WHEN TRANSMITTING DATA
Die Characteristics
SUBSTRATE POTENTIAL (POWERED UP): GND TRANSISTOR COUNT:
2.0 1.5 1.0 0.5 0 2.5
ISL4221E: 286 ISL4223E: 357 PROCESS: Si Gate CMOS
3.0
3.5
4.0
4.5
5.0
5.5
6.0
SUPPLY VOLTAGE (V)
FIGURE 16. SUPPLY CURRENT vs SUPPLY VOLTAGE
11
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 A A1 A2 A3 b D D1 D2 E E1 E2 e k L L1 N Nd Ne P 4 0.25 0.35 2.55 2.55 0.28 MIN 0.80 NOMINAL 0.90 0.20 REF 0.33 5.00 BSC 4.75 BSC 2.70 5.00 BSC 4.75 BSC 2.70 0.80 BSC 0.60 16 4 4 0.60 12 0.75 0.15 2.85 2.85 0.40 MAX 1.00 0.05 1.00 NOTES 9 9 5, 8 9 7, 8 9 7, 8 8 10 2 3 3 9 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 & 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 A A1 A2 A3 b D D1 D2 E E1 E2 e k L L1 N Nd Ne P 0.25 0.35 2.95 2.95 0.23 MIN 0.80 NOMINAL 0.90 0.20 REF 0.28 5.00 BSC 4.75 BSC 3.10 5.00 BSC 4.75 BSC 3.10 0.65 BSC 0.60 20 5 5 0.60 12 0.75 0.15 3.25 3.25 0.38 MAX 1.00 0.05 1.00 NOTES 9 9 5, 8 9 7, 8 9 7, 8 8 10 2 3 3 9 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 & 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.
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