Intersil ISL4221EIR-T Qfn packaged, /-15kv esd protected, 2.7v to 5.5v, 150nanoamp, 250kbps, rs-232 transmitters/receiver Datasheet

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
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