Datasheet ISL4221E Datasheet (intersil)

Page 1

查询ISL4221供应商

ISL4221E, ISL4223E

Data Sheet August 2004

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 speci fications, even at V 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.

= 3.0V. Additionally,

FN6045.1

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

0.1µF 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 f or ICs”

• Technical Brief TB389 “PCB Land Pattern Design and Surface Mount Guidelines for QFN Packages”

TABLE 1. SUMMARY OF FEATURES

PART

NUMBER

ISL4221E 1 1 YES 250 YES YES YES ISL4223E 2 2 YES 250 YES YES YES

NO. OF

Tx.

NO. OF

Rx.

QFN PKG.

AVAILABLE?

DATA RATE

(kBps)

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 321-724-7143

Rx. ENABLE

FUNCTION?

All other trademarks mentioned are the property of their respective owners.

MANUAL

POWERDOWN?

| Intersil (and design) is a registered trademark of Intersil Americas Inc.

AUTOMATIC POWERDOWN

FUNCTION?

Page 2

ISL4221E, ISL4223E

Ordering Information

PART NO. TEMP. RANGE (°C) PACKAGE PKG. DWG. #

ISL4221EIR -40 to 85 16 Ld QFN L16.5x5 ISL4221EIR-T -40 to 85 16 Ld QFN

L16.5x5

Tape & Reel

ISL4221EIRZ-T (Note)

-40 to 85 16 Ld QFN Tape & Reel

L16.5x5

(Pb-free)

ISL4223EIR -40 to 85 20 Ld QFN L20.5x5 ISL4223EIRZ

(Note)

-40 to 85 20 Ld QFN (Pb-free)

L20.5x5

Pinouts

ISL4221E (QFN)

TOP VIEW

FORCEOFF

OUT

INVALID

GND

FORCEON

OUT

V+

C1-

C2+

C2-

C1+

16 14 13 1

V-

6578

Ordering Information (Continued)

PART NO. TEMP. RANGE (°C) PACKAGE PKG. DW G . #

ISL4223EIR-T -40 to 85 20 Ld QFN

Tape & Reel

ISL4223EIRZ-T (Note)

-40 to 85 20 Ld QFN 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.

ISL4223E (QFN)

TOP VIEW

C1+

FORCEOFF

VCCGND

20 19 18 17 16

V+

C1-

C2+

C2-

V-

789106

OUT

INVALID

14 13

FORCEON

L20.5x5

OUT

Pin Descriptions

PIN FUNCTION

V+ Internally generated positive transmitter supply (+5.5V).

V- Internally generated negative transmitter supply (-5.5V).

GND Ground connection.

C1+ External capacitor (voltage doubler) is connected to this lead.

C1- External capacitor (voltage doubler) is connected to this lead.

C2+ External capacitor (voltage inverter) is connected to this lead.

C2- External capacitor (voltage inverter) is connected to this lead. T

OUT

INVALID

FORCEOFF

FORCEON Active high input to override automatic powerdown circuitry thereby keeping transmitters active. (FORCEOFF

System power supply input (2.7V to 5.5V).

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. Active low to shut down transmitters and on-chip power supply. This overrides any automatic circuitry and FORCEON (see Table 2).

Active low receiver enable control.

must be high).

Page 3

Typical Operating Circuits

ISL4221E, ISL4223E

ISL4221E

TTL/CMOS

LOGIC

LEVELS

TTL/CMOS

LOGIC LEVELS

+3.3V

0.1µF

0.1µF C

0.1µF

OUT

16 +

0.1µF

C1+

C1-

C2+

C2-

FORCEON

0.1µF

C1+

C1-

C2+

C2-

FORCEON

FORCEOFF

GND

ISL4223E

FORCEOFF

GND

5kΩ

INVALID

5kΩ

INVALID

V+

V-

V+

V-

0.1µF

OUT

TO POWER CONTROL LOGIC

0.1µF

OUT

TO POWER CONTROL LOGIC

RS-232 LEVELS

Page 4

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

, FORCEOFF, FORCEON, EN . . . . . . . . . . . . . . . -0.3V to 6V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±25V

Output Voltages

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±13.2V

OUT

, INVALID. . . . . . . . . . . . . . . . . . . . . . . . -0.3V to VCC +0.3V

OUT

Short Circuit Duration

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous

OUT

ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . See Specification Table

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:

is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See

1. θ

Tech Brief TB379, and Tech Brief TB389.

Thermal Resistance (Typical, Note 1)

(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) . . . . . . . 150

Maximum Storage Temperature Range. . . . . . . . . . -65

C to 150oC

Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . 300

Operating Conditions

Temperature Range

ISL422XEIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40

C to 85oC

Electrical Specifications Test Conditions: V

Typicals are at T

= 3V to 5.5V, C1 - C4 = 0.1µF; Unless Otherwise Specified.

= 25oC

PARAMETER TEST CONDITIONS

DC CHARACTERISTICS

Supply Current, Automatic Powerdown

Supply Current, Powerdown FORCEOFF Supply Current,

Automatic Powerdown Disabled

Open, FORCEON = GND, FORCEOFF = V

All R

= GND 25 - 0.15 1 µA

All Outputs Unloaded, FORCEON = FORCEOFF

= V

LOGIC AND TRANSMITTER INPUTS AND RECEIVER OUTPUTS

Input Logic Threshold Low T Input Logic Threshold High T

Input Leakage Current T Output Leakage Current EN Output Voltage Low I Output Voltage High I

, FORCEON, FORCEOFF, EN Full - - 0.8 V

, FORCEON, FORCEOFF, ENVCC = 3.3V Full 2.0 - - V

, FORCEON, FORCEOFF, EN Full - ±0.01 ±1.0 µA

= V

= 1.6mA Full - - 0.4 V

OUT

= -1.0mA Full V

OUT

AUTOMATIC POWERDOWN (FORCEON = GND, FORCEOFF Receiver Input Thresholds to

ISL422XE Powers Up (See Figure 6) Full -2.7 - 2.7 V

Enable Transmitters Receiver Input Thresholds to

ISL422XE Powers Down (See Figure 6) Full -0.3 - 0.3 V

Disable Transmitters INVALID INVALID

Output Voltage Low I Output Voltage High I

= 1.6mA Full - - 0.4 V

OUT

= -1.0mA Full VCC-0.6 - - V

OUT

Receiver Threshold to Transmitters Enabled Delay (t

)

Receiver Positive or Negative Threshold to INVALID (t

)

INVH

High Delay

Receiver Positive or Negative Threshold to INVALID (t

)

INVL

Low Delay

TEMP

C) MIN TYP MAX UNITS

(

25 - 0.15 1 µA

VCC = 3.15V 25 - 0.3 1.0 mA

= 5.0V Full 2.4 - - V

Full - ±0.05 ±10 µA

-0.6 V

-0.1 - V

= VCC)

25 - 100 - µs

25 - 1 - µs

25 - 30 - µs

Page 5

ISL4221E, ISL4223E

Electrical Specifications Test Conditions: V

Typicals are at T

PARAMETER TEST CONDITIONS

RECEIVER INPUTS

Input Voltage Range 25 -25 - 25 V Input Threshold Low V

Input Threshold High 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 V Output Short-Circuit Current Full - ±35 ±60 mA Output Leakage Current V

TIMING CHARACTERISTICS

Maximum Data Rate R Receiver Propagation Delay Receiver Input to Receiver

Receiver Output Enable Time Normal Operation 25 - 200 - ns Receiver Output Disable Time Normal Operation 25 - 200 - ns Transmitter Skew t Receiver Skew t Transition Region Slew Rate V

ESD PERFORMANCE

RS-232 Pins (T

All Other Pins Human Body Model 25 - ±2-kV

NOTE:

2. Transmitter skew is measured at the transmitter zero crossing points.

, RIN) Human Body Model 25 - ±15 - kV

OUT

= 3.3V 25 0.6 1.2 - V

= 5.0V 25 0.8 1.5 - V

= 3.3V 25 - 1.5 2.4 V

= 5.0V 25 - 1.8 2.4 V

= V+ = V- = 0V, Transmitter Output = ±2V Full 300 10M - Ω

= ±12V, VCC = 0V or 3V to 5.5V,

OUT

Automatic Powerdown or FORCEOFF

= 3kΩ, CL = 1000pF, One Transmitter Switching Full 250 500 - kBps

Output, C

PHL PHL

Measured From 3V to -3V or -3V to 3V

IEC61000-4-2 Contact Discharge 25 - ±8-kV IEC61000-4-2 Air Gap Discharge 25 - ±15 - kV

= 150pF

- t

PLH

- t

PLH

= 3.3V, RL = 3kΩ to 7kΩ,

= 3V to 5.5V, C1 - C4 = 0.1µF; Unless Otherwise Specified.

= 25oC (Continued)

TEMP

C) MIN TYP MAX UNITS

(

Full - - ±25 µA

= GND

PHL

PLH

(Note 2) 25 - 100 - ns

= 150pF to 2500pF 25 4 - 30 V/µs

= 150pF to 1000pF 25 6 - 30 V/µs

25 - 0.15 - µs 25 - 0.15 - µs

25 - 50 - ns

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 0.1µF capacitors, feature low power consumption, and meet all ElA RS-232C and V.28 specifications even with V into three sections: The charge pump, the transmitters, and the receivers.

= 3.0V. The circuit is divided

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 V supply as low as 3.0V. This a llows 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+

Page 6

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), V

≥ 3.0V, with one

transmitter operating at full speed. Under more typical conditions of V

≥ 3.3V, RL = 3kΩ, and CL = 250pF, one

transmitter easily operates at 900kBps. Transmitter inputs float if left unconnected, and may cause

increases. Connect unused inputs to GND for the best

performance.

Receivers

All the ISL422XE devices contain standard inverting receivers that three-state via the EN 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 (V

= 0V). The receivers’ Schmitt trigger input stage

uses hysteresis to increase noise immunity and decrease errors due to slow input signal transitions.

XIN

-25V ≤ V

FIGURE 1. INVERTING RECEIVER CONNECTIONS

RIN

≤ +25V

GND

5kΩ

control line. All the

XOUT

GND ≤ V

ROUT

≤ V

11mA current required by comparable 5V RS-232 devices, allowing users to reduce system power simply by switching to this new family.

Po werdown 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 V 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.

OUT = VCC

POWERED

DOWN

UART

GND

FIGURE 2. POWER DRAIN THROUGH PO WERED DO WN

PERIPHERAL

WAKE-UP

LOGIC

SHDN

TRANSITION

DETECTOR

, V - collapses to GND),

CURRENT FLOW

OLD

= GND

RS-232 CHIP

ISL422XE

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 whenev e r th e UART powers down. Fig u re 3 a lso s hows 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.

Low Power Operation

These 3V devices require a nominal supply current of

0.3mA, even at V powerdown mode). This is considerably less than the 5mA to

= 5.5V, during normal operation (not in

POWERED

DOWN

UART

FIGURE 3. DISABLED RECEIVERS PREVENT POWER DRAIN

OUT =

= V

HI-Z

OUT

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

Page 7

ISL4221E, ISL4223E

TABLE 2. POWERDOWN AND ENABLE LOGIC TRUTH TABLE

RS-232 SIGNAL

PRESENT AT

RECEIVER INPUT?

NO H H L Active Active L Normal Operation

NO H H H Active High-Z L YES H L L Active Active H Normal Operation YES H L H Active High-Z H

NO H L L High-Z Active L Powerdown Due to Auto Powerdown

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 FORCEON state isn’t critical, as FORCEOFF over FORCEON. Ne vertheless, if strictly manual control over powerdown is desired, the user must strap FORCEON high to disable the automatic po werdown circuitry.

Connecting FORCEOFF the automatic powerdown feature, enabli ng them to function as a manual SHUTDOWN

PWR MGT

LOGIC

CPU

FORCEOFF

INPUT

FORCEON

INPUTENINPUT

input need be driven. The

dominates

and FORCEON together disables

input (see Figure 4).

FORCEOFF

FORCEON

INVALID

ISL422XE

I/O

UART

TRANSMITTER

OUTPUTS

RECEIVER

OUTPUTS

POWER

MANAGEMENT

FIGURE 5. CIRCUIT TO PREVENT AUT O PO WERDO WN FOR

INVALID

OUTPUT MODE OF OPERATION

(Auto Powerdown Disabled)

(Auto Powerdown Enabled)

Logic

MASTER POWERDO WN LINE

UNIT

FORCEOFF

100ms AFTER FORCED POWERUP

0.1µF

ISL422XE

1MΩ

FORCEON

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 30µs, the charge pump and transmitters powerdown, thereby reducing supply current to 10nA. Invalid receiver lev els 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 e xisting operating system.

FIGURE 4. CONNECTIONS FOR MANUAL POWERDO WN

WHEN NO VALID RECEIVER SIGNALS ARE PRESENT

The time to recover from automatic powerdown mode is typically 100µs.

Automatic powerdown operates when the FORCEON input is low, and the FORCEOFF

input is high. Tying FORCEON high disables automatic powerdown, but manual powerdo wn is always av ailable 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

Page 8

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.

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 and drives the output low. The power management logic then uses this indicator to power down the interface block. Reconnecting the cable restores valid lev els at the receiv er inputs, INVALID

switches high, and the power management logic wakes up the interface block. INVALID 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).

2.7V

0.3V

-0.3V

-2.7V

FIGURE 6. DEFINITION OF VALID RS-232 RECEIVER LEVELS

VALID RS-232 LEVE L - IS L422XE IS ACTIVE

INDETERMINATE - POWERDOWN MAY OR

INVALID LEVEL - POWERDOWN OCCURS AFTER 30µs

INDETERMINATE - POWERDOWN MAY OR

VALID RS-232 LE VEL - ISL422XE IS ACTIVE

logic detects the invalid levels

can also be

MAY NOT OCCUR

circuitry. When automatic powerdown is utilized, INVALID

0 indicates that the ISL422XE is in powerdown mode.

RECEIVER

INPUTS

TRANSMITTER

OUTPUTS

INVALID

OUTPUT

FIGURE 7. AUTOMA TIC PO WERDO WN AND INV ALID TIMING

AUTOPWDN

V+

V-

DIAGRAMS

INVL

INVH

INVALID

}

REGION

PWR UP

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-

Po wer Supply Decoupling

In most circumstances a 0.1µF bypass capacitor is adequate. In applications that are particularly sensitive to power supply noise, decouple V capacitor of the same value as the charge-pump capacitor C Connect the bypass capacitor as close as possible to the IC.

to ground with a

INVALID

switches low after invalid levels have persisted on all of the receiver inputs for more than 30µs (see Figure 7). INVALID RS-232 level on a receiver input. INVALID

switches back high 1µs after detecting a valid

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 3kΩ in parallel with 2500pF.

Page 9

ISL4221E, ISL4223E

Note that the transmitters enable only when the magnitude of the supplies exceed approximately 3V.

5V/DIV.

2V/DIV.

FIGURE 8. TRANSMITTER OUTPUTS WHEN EXITING

FORCEOFF

VCC = +3.3V C1 - C4 = 0.1µF

TIME (20µs/DIV.)

POWERDOWN

5V/DIV.

OUT

5V/DIV.

VCC = +3.3V C1 - C4 = 0.1µF

5µs/DIV.

FIGURE 10. LOOPBACK TEST AT 120kBps

Operation Down to 2.7V

ISL422XE transmitter outputs meet RS-562 levels (±3.7V), at the full data rate, with V

as low as 2.7V. RS-562 levels

typically ensure inter operability with RS-232 devices.

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.

0.1µF

FIGURE 9. TRANSMITTER LOOPBACK TEST CIRCUIT

C1+

C1-

ISL422XE

C2+

C2-

OUT

FORCEON

FORCEOFF

OUT

V+

V-

1000pF

OUT

VCC = +3.3V C1 - C4 = 0.1µF

2µs/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 V more information.

T ABLE 3. LOGIC F AMILY COMP ATIBILITY WITH VARIOUS

SYSTEM

POWER-SUPPLY

VOLTAGE

(V)

3.3 3.3 Compatible with all CMOS

5 5 Compatible with all TTL and

5 3.3 Compatible with ACT and HCT

for these logic families. See Table 3 for

SUPPLY VOLTAGES

SUPPLY

VOLTAGE

(V) COMPATIBILITY

families.

CMOS logic families.

CMOS, and with TTL. ISL422XE outputs are incompatible with AC, HC, and CD4000 CMOS inputs.

Page 10

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 por t pi ns, or connecting a cable, can cause an ESD event that might destroy unprotected ICs. These new ESD structures protect the device whether or not it is powered up, protect without allowing any latchup mechanism to activate, and don’t interfere with RS-232 signals as large as ±25V.

Human Body Model (HBM) Testing

As the name implies, this test method emulates the ESD event delivered to an IC during human handling. The tester delivers the charge through a 1.5kΩ 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.

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 de vices at voltages higher than ±8kV. All “E” family devices survive ±8kV contact discharges on the RS-232 pins.

Page 11

ISL4221E, ISL4223E

Typical Performance Curves V

1 TRANSMITTER AT 250kBps OTHER TRANSMITTERS AT 30kBps

-2

-4

TRANSMITTER OUTPUT VOLTAGE (V)

-6 1000 2000 3000 4000 50000

LOAD CAPACITANCE (pF)

= 3.3V, TA = 25oC

OUT

FIGURE 12. TRANSMITTER OUTPUT VOL TAGE vs LOAD

CAPACITANCE

ISL4221E

40 35 30 25 20 15

SUPPLY CURRENT (mA)

5 0

0 1000 2000 3000 4000 5000

LOAD CAPACITANCE (pF)

250kBps

120kBps

20kBps

FIGURE 14. SUPPL Y CURRENT vs LOAD CAPACIT ANCE

WHEN TRANSMITTING DATA

3.5

3.0

2.5

2.0

1.5

1.0

SUPPLY CURRENT (mA)

0.5

NO LOAD ALL OUTPUTS STATIC

-SLEW

SLEW RATE (V/µs)

0 1000 2000 3000 4000 5000

+SLEW

LOAD CAPACITANCE (pF)

FIGURE 13. SLEW RATE vs LOAD CAPACITANCE

ISL4223E

40 35 30 25 20 15

SUPPLY CURRENT (mA)

5 0

0 1000 2000 3000 4000 5000

LOAD CAPACITANCE (pF)

250kBps

120kBps

20kBps

FIGURE 15. SUPPLY CURRENT vs LOAD CAPACITANCE

WHEN TRANSMITTING DATA

Die Characteristics

SUBSTRATE POTENTIAL (POWERED UP):

GND

TRANSISTOR COUNT:

ISL4221E: 286 ISL4223E: 357

PROCESS:

Si Gate CMOS

2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 SUPPLY VOLTAGE (V)

FIGURE 16. SUPPLY CURRENT vs SUPPLY VOLTAGE

Page 12

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 0.80 0.90 1.00 A1 - - 0.05 A2 - - 1.00 9 A3 0.20 REF 9

b 0.28 0.33 0.40 5, 8

D 5.00 BSC D1 4.75 BSC 9 D2 2.55 2.70 2.85 7, 8

E 5.00 BSC E1 4.75 BSC 9 E2 2.55 2.70 2.85 7, 8

e 0.80 BSC -

k0.25 - - -

L 0.35 0.60 0.75 8 L1 - - 0.15 10

N162 Nd 4 3 Ne 4 4 3

P- -0.609

θ --129

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.

NOTESMIN NOMINAL MAX

Rev. 2 10/02

Page 13

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 0.80 0.90 1.00 A1 - - 0.05 A2 - - 1.00 9 A3 0.20 REF 9

b 0.23 0.28 0.38 5, 8

D 5.00 BSC D1 4.75 BSC 9 D2 2.95 3.10 3.25 7, 8

E 5.00 BSC E1 4.75 BSC 9 E2 2.95 3.10 3.25 7, 8

e 0.65 BSC -

k0.25 - - -

L 0.35 0.60 0.75 8 L1 - - 0.15 10

N202 Nd 5 3 Ne 5 3