MAX3230E [MAXIM]
15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP; 15kV ESD保护， + 2.5V至+ 5.5V的RS - 232收发器，UCSP封装
| 型号： | MAX3230E |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP |
| 文件： | 总15页 (文件大小：795K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-3250; Rev 0; 5/04
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
General Description
Features
The MAX3230E/MAX3231E are +2.5V to +5.5V pow-
ered EIA/TIA-232 and V.28/V.24 communications inter-
faces with low power requirements, high data-rate
capabilities, and enhanced electrostatic discharge
(ESD) protection, in a chip-scale package (UCSP™).
All transmitter outputs and receiver inputs are protect-
ed to 15kV using IEC 1000-4-2 Air-ꢀap Discharge,
8kV using IEC 1000-4-2 Contact Discharge, and
15kV using the ꢁuman ꢂodꢃ Model.
♦ 6 x 5 Chip-Scale Packaging (UCSP)
♦ ESD Protection for RS-232 I/O Pins
±15kV—IEC 1000-4-2 Air-Gap Discharge
±8kV—IEC 1000-4-2 Contact Discharge
±15kV—Human Body Model
♦ 1µA Low-Power AutoShutdown
♦ 250kbps Guaranteed Data Rate
The MAX3230E/MAX3231E achieve a 1µA supplꢃ cur-
rent with Maxim’s AutoShutdown™ feature. Theꢃ save
power without changing the existing ꢂIOS or operating
sꢃstems bꢃ entering low-power shutdown mode when
the RS-232 cable is disconnected, or when the trans-
mitters of the connected peripherals are off.
♦ Meet EIA/TIA-232 Specifications Down to +3.1V
♦ RS-232 Compatible to +2.5V Allows Operation
from Single Li+ Cell
♦ Small 0.1µF Capacitors
♦ Configurable Logic Levels
The transceivers have a proprietarꢃ low-dropout trans-
mitter output stage, delivering RS-232-compliant perfor-
mance from a +3.1V to +5.5V supplꢃ, and RS-232-
compatible performance with a supplꢃ voltage as low
as +2.5V. The dual charge pump requires onlꢃ four,
small 0.1µF capacitors for operation from a +3.0V sup-
plꢃ. Each device is guaranteed to run at data rates of
250kbps while maintaining RS-232 output levels.
Ordering Information
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
BUMP-PACKAGE
MAX3230EEꢂV-T
MAX3231EEꢂV-T
6 x 5 UCSP
6 x 5 UCSP
Typical Operating Circuits
The MAX3230E/MAX3231E offer a separate power-sup-
plꢃ input for the logic interface, allowing configurable
logic levels on the receiver outputs and transmitter
2.5V TO 5.5V 1.65V TO 5.5V
inputs. Operating over a +1.65V to V
range, V pro-
L
0.1µF
CC
vides the MAX3230E/MAX3231E compatibilitꢃ with mul-
tiple logic families.
C
0.1µF
BYPASS
A1
A5
V
V
C1
CC
B1
A4
L
C1+
V+
The MAX3231E contains one receiver and one transmit-
ter. The MAX3230E contains two receivers and two trans-
mitters. The MAX3230E/MAX3231E are available in tinꢃ
chip-scale packaging and are specified across the
extended industrial (-40°C to +85°C) temperature range.
C3
0.1µF
C1
0.1µF
D1
A2
C1-
C2+
MAX3230E
V-
C2
0.1µF
C4
0.1µF
A3
A6
V
L
C2-
T1OUT
T1IN
E3
E4
E6
RS-232
OUTPUTS
TTL/CMOS
INPUTS
V
L
Applications
T2OUT
R1IN
B6 T2IN
Personal Digital Assistants
Cell-Phone Data Lump Cables
Set-Top ꢂoxes
V
L
R1OUT
D6
5kΩ
TTL/CMOS
OUTPUTS
RS-232
INPUTS
V
L
ꢁand-ꢁeld Devices
Cell Phones
R2IN
C6 R2OUT
E5
E2
5kΩ
TO POWER-
MANAGEMENT
UNIT
Typical Operating Circuits continued at end of data sheet.
Pin Configurations appear at end of data sheet.
INVALID
FORCEON
FORCEOFF C5
B5
V
L
UCSP is a trademark of Maxim Integrated Products, Inc.
GND
E1
AutoShutdown is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
ABSOLUTE MAXIMUM RATINGS
V
to ꢀND...........................................................-0.3V to +6.0V
Short-Circuit Duration T OUT to ꢀND........................Continuous
_
CC
V+ to ꢀND.............................................................-0.3V to +7.0V
V- to ꢀND ..............................................................+0.3V to -7.0V
V+ to |V-| (Note 1) ................................................................+13V
Continuous Power Dissipation (T = +70°C)
A
6 ♦ 5 UCSP (derate 10.1mW/°C above +70°C) ...........805mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
ꢂump Temperature (soldering)
V to ꢀND..............................................................-0.3V to +6.0V
L
Input Voltages
T_IN_, FORCEON, FORCEOFF to ꢀND.....-0.3V to (V + 0.3V)
L
R_IN_ to ꢀND ................................................................... 25V
Output Voltages
Infrared (15s) ...............................................................+200°C
Vapor Phase (20s) .......................................................+215°C
T_OUT to ꢀND............................................................... 13.2V
R_OUT INVALID to ꢀND ............................-0.3V to (V + 0.3V)
L
CC
INVALID to ꢀND.........................................-0.3V to (V
+ 0.3V)
Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
= +2.5V to +5.5V, V = +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V 10ꢄ, T = T
to T
. Tꢃpical values are at T =
MAX A
CC
L
A
MIN
+25°C, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
V Input Voltage Range
V
1.65
V
CC
+ 0.3
10
V
L
L
FORCEON = ꢀND
FORCEOFF = V , all R open
µA
L
IN
V
Supplꢃ Current,
CC
I
CC
AutoShutdown
FORCEOFF = ꢀND
10
1
FORCEON, FORCEOFF = V
mA
mA
L
V
Supplꢃ Current,
CC
I
FORCEON = FORCEOFF = V , no load
0.3
1
1
CC
L
AutoShutdown Disabled
FORCEON or FORCEOFF = ꢀND or V ,
L
V Supplꢃ Current
L
T_IN, I
µA
L
V
= V = +5V, no receivers switching
L
CC
LOGIC INPUTS
Input-Logic Low
T_IN, FORCEON, FORCEOFF
T_IN, FORCEON, FORCEOFF
0.4
1
V
V
♦
Input-Logic ꢁigh
0.66
V
L
Transmitter Input ꢁꢃsteresis
Input Leakage Current
RECEIVER OUTPUTS
0.5
V
T_IN, FORCEON, FORCEOFF
0.01
µA
R_OUT, receivers disabled, FORCEOFF =
ꢀND or in AutoShutdown
Output Leakage Currents
10
µA
Output-Voltage Low
Output-Voltage ꢁigh
I
I
= 0.8mA
= -0.5mA
0.4
V
V
OUT
V - 0.4 V - 0.1
OUT
L
L
2
_______________________________________________________________________________________
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
ELECTRICAL CHARACTERISTICS (continued)
(V
= +2.5V to +5.5V, V = +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V 10ꢄ, T = T
to T
. Tꢃpical values are at T =
MAX A
CC
L
A
MIN
+25°C, unless otherwise noted.) (Note 2)
PARAMETER
RECEIVER INPUTS
Input Voltage Range
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
-25
0.6
0.8
+25
V
V
V
V
V
V
= +3.3V
= +5.0V
= +3.3V
= +5.0V
1.2
1.7
1.3
1.8
0.5
5
CC
CC
CC
CC
Input-Threshold Low
Input-Threshold ꢁigh
T
T
= +25°C
= +25°C
A
2.4
2.4
V
A
Input ꢁꢃsteresis
V
Input Resistance
3
7
kΩ
AUTOMATIC SHUTDOWN
Positive threshold
Negative threshold
2.7
Receiver Input Threshold to
INVALID Output ꢁigh
Figure 3a
V
-2.7
-0.3
Receiver Input Threshold to
INVALID Output Low
+0.3
V
Receiver Positive or Negative
Threshold to INVALID ꢁigh
t
V
V
V
= +5.0V, Figure 3b
= +5.0V, Figure 3b
= +5.0V, Figure 3b
1
µs
µs
µs
INVꢁ
CC
CC
CC
Receiver Positive or Negative
Threshold to INVALID Low
t
30
INVL
Receiver Edge to Transmitters
Enabled
t
100
WU
INVALID OUTPUT
Output-Voltage Low
Output-Voltage ꢁigh
TRANSMITTER OUTPUTS
I
I
= 0.8mA
= -0.5mA
0.4
- 0.1
V
V
OUT
V
- 0.4
V
CC
OUT
CC
V
(V
Mode Switch Point
Falling)
CC
T_OUT = 5.0V to 3.7V
T_OUT = 3.7V to 5.0V
2.85
3.3
3.10
V
CC
V
(V
Mode Switch Point
Rising)
CC
3.7
V
CC
V
Mode Switch-Point ꢁꢃsteresis
400
5.4
mV
CC
V
V
= +3.1V to +5.5V,
falling, T = +25°C
A
CC
CC
All transmitter
outputs loaded
with 3kΩ to
ground
5
Output Voltage Swing
V
V
V
= +2.5V to +3.1V,
rising
CC
CC
3.7
Output Resistance
V
= V+ = V- = 0, T_OUT = 2V
300
10M
Ω
CC
Output Short-Circuit Current
Output Leakage Current
ESD PROTECTION
60
25
mA
µA
T_OUT = 12V, transmitters disabled
ꢁuman ꢂodꢃ Model
15
15
8
R_IN, T_OUT
kV
IEC 1000-4-2 Air-ꢀap Discharge
IEC 1000-4-2 Contact Discharge
_______________________________________________________________________________________
3
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
TIMING CHARACTERISTICS
(V
= +2.5V to +5.5V, V = +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V 10ꢄ, T = T
to T
. Tꢃpical values are at T =
MAX A
CC
L
A
MIN
+25°C, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
R = 3kΩ, C = 1000pF, one transmitter
switching
L
L
Maximum Data Rate
250
kbps
µs
Receiver input to receiver output,
C = 150pF
Receiver Propagation Delaꢃ
0.15
L
Receiver-Output Enable Time
Receiver-Output Disable Time
Transmitter Skew
V
V
= V = +5V
200
200
100
50
ns
ns
ns
ns
CC
CC
L
= V = +5V
L
| t
| t
- t
|
|
PꢁL PLꢁ
Receiver Skew
- t
PꢁL PLꢁ
R = 3kΩ to 7kΩ, C = 150pF to
L
L
Transition-Region Slew Rate
6
30
V/µs
1000pF, T = +25°C
A
Note 2: V
must be greater than V .
L
CC
Typical Operating Characteristics
(V
= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and C , T = +25°C, unless otherwise noted.)
L A
CC
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE (MAX3231E)
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
SLEW RATE vs. LOAD CAPACITANCE
20
30
25
20
15
10
5
6
V
RISING
CC
18
16
14
12
10
8
4
2
V
OH
250kbps
V
= 5.5V
CC
0
V
OL
-2
-4
-6
6
4
V
= 2.5V
CC
2
20kbps
0
0
0
500 1000 1500 2000 2500 3000
LOAD CAPACITANCE (pF)
0
500 1000 1500 2000 2500 3000
LOAD CAPACITANCE (pF)
0
500 1000 1500 2000 2500 3000
LOAD CAPACITANCE (pF)
4
_______________________________________________________________________________________
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
Typical Operating Characteristics (continued)
(V
= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and C , T = +25°C, unless otherwise noted.)
CC
L
A
OPERATING SUPPLY CURRENT
vs. SUPPLY VOLTAGE (MAX3231E)
TRANSMITTER OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE (V RISING)
TRANSMITTER OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE (V FALLING)
CC
CC
20
10
8
10
8
18
16
14
12
10
8
6
6
4
4
V
V
OH
OH
2
2
0
0
-2
-4
-6
-8
-2
-4
-6
-8
V
V
OL
OL
6
4
2
0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
-in Description
BUMP
NAME
FUNCTION
MAX3230E MAX3231E
A1
A2
A3
A4
A1
A2
A3
A4
V
+2.5V to +5.5V Supplꢃ Voltage
Inverting Charge-Pump Capacitor Positive Terminal
Inverting Charge-Pump Capacitor Negative Terminal
CC
C2+
C2-
V-
Negative Supplꢃ Voltage (-5.5V/-4.0V) ꢀenerated bꢃ Charge Pump
Logic Supplꢃ Input. Logic-level input for receiver outputs and transmitter inputs.
A5
A5
A6
V
L
Connect V to the sꢃstem-logic supplꢃ voltage or V
L
if no logic supplꢃ is required.
CC
A6, ꢂ6
T_IN
V+
Transmitter Input(s)
Positive Supplꢃ Voltage (+5.5V/+4.0V) ꢀenerated bꢃ Charge Pump. If charge pump is
generating +4.0V, the device has switched from RS-232-compliant to RS-232-
compatible mode.
ꢂ1
ꢂ1
ꢂ2, ꢂ3, ꢂ4, ꢂ2, ꢂ3, ꢂ4,
C2, C3, C4, C2, C3, C4,
N.C.
No Connection. These locations are not populated with solder bumps.
D2–D5
D2–D5
Active-ꢁigh FORCEON Input. Drive FORCEON high to override automatic circuitrꢃ,
keeping transmitters and charge pumps on.
ꢂ5
C1
ꢂ5
C1
FORCEON
C1+
Positive Regulated Charge-Pump Capacitor Positive Terminal
Active-Low FORCEOFF Input. Drive FORCEOFF low to shut down transmitters,
receivers, and on-board charge pump. This overrides all automatic circuitrꢃ and
FORCEON.
C5
C5
FORCEOFF
_______________________________________________________________________________________
5
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
-in Description (continued)
BUMP
NAME
FUNCTION
MAX3230E MAX3231E
C6, D6
D1
C6
D1
E1
R_OUT
C1-
Receiver Output(s)
Positive Regulated Charge-Pump Capacitor Negative Terminal
ꢀround
E1
ꢀND
Valid Signal-Detector Output. INVALID is enabled low if no valid RS-232 level is present
on anꢃ receiver input.
E2
E2
INVALID
E3, E4
E5, E6
E3
E5
T_OUT
R_IN
RS-232 Transmitter Output(s)
RS-232 Receiver Input(s)
ꢂ6, D6,
E4, E6
No Connection. These locations are populated with solder bumps, but are electricallꢃ
isolated.
—
N.C.
tion until the batterꢃ voltage drops below +3.1V. The
output regulation points then change to 4.0V.
Detailed Description
Dual Mode™ Regulated Chargeꢂ-ump
koltage Converter
When V
is rising, the charge pump generates an out-
CC
put voltage of 4.0V, while V
is between +2.5V and
CC
The MAX3230E/MAX3231E internal power supplꢃ con-
sists of a dual-mode regulated charge pump. For sup-
plꢃ voltages above +3.7V, the charge pump generates
+5.5V at V+ and -5.5V at V-. The charge pumps oper-
ate in a discontinuous mode. If the output voltages are
less than 5.5V, the charge pumps are enabled. If the
output voltages exceed 5.5V, the charge pumps are
disabled.
+3.5V. When V
+3.5V, the charge pump switches modes to generate
an output of 5.5V.
rises above the switchover voltage of
CC
Table 1 shows different supplꢃ schemes and their oper-
ating voltage ranges.
Rꢁꢂ232 Transmitters
The transmitters are inverting level translators that
convert CMOS logic levels to RS-232 levels. The
MAX3230E/MAX3231E automaticallꢃ reduce the
RS-232-compliant levels ( 5.5V) to RS-232-compatible
For supplꢃ voltages below +2.85V, the charge pump
generates +4.0V at V+ and -4.0V at V-. The charge
pumps operate in a discontinuous mode. If the output
voltages are less than 4.0V, the charge pumps are
enabled. If the output voltages exceed 4.0V, the
charge pumps are disabled.
levels ( 4.0V) when V
falls below approximatelꢃ
CC
+3.1V. The reduced levels also reduce supplꢃ-current
requirements, extending batterꢃ life. ꢂuilt-in hꢃsteresis
of approximatelꢃ 400mV for V
ensures that the RS-
CC
Each charge pump requires a flꢃing capacitor (C1, C2)
and a reservoir capacitor (C3, C4) to generate the V+
and V- supplꢃ voltages.
koltage Generation in the
ꢁwitchover Region
The MAX3230E/MAX3231E include a switchover circuit
between these two modes that have approximatelꢃ
400mV of hꢃsteresis around the switchover point. The
hꢃsteresis is shown in Figure 1. This large hꢃsteresis
eliminates mode changes due to power-supplꢃ bounce.
V
CC
V+
4V
0
6V
For example, a three-cell NiMh batterꢃ sꢃstem starts at
V
= +3.6V, and the charge pump generates an out-
CC
put voltage of 5.5V. As the batterꢃ discharges, the
MAX3230E/MAX3231E maintain the outputs in regula-
0
20ms/div
Figure 1. V+ Switchover for Changing V
Dual Mode is a trademark of Maxim Integrated Products, Inc.
CC
6
_______________________________________________________________________________________
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
Table 1. Operating Supply Options
SYSTEM SUPPLY (V)
1 Li+ Cell
V
(V)
V (V)
L
RS-232 MODE
CC
+2.4 to +4.2
+2.4 to +3.8
Regulated sꢃstem voltage
Regulated sꢃstem voltage
Compliant/Compatible
Compliant/Compatible
3 NiCad/NiMh Cells
Regulated Voltage Onlꢃ
+3.0 to +5.5
+2.5 to +3.0
+3.0 to +5.5
+2.5 to +3.0
Compliant
(V
CC
falling)
Regulated Voltage Onlꢃ
(V falling)
Compatible
CC
Table 2. Output Control Truth Table
TRANSCEIVER STATUS
Shutdown (AutoShutdown)
Shutdown (Forced Off)
FORCEON
Low
FORCEOFF
ꢁigh
RECEIVER STATUS
ꢁigh impedance
INVALID
Low
†
X
Low
ꢁigh impedance
Active
Normal Operation (Forced On)
Normal Operation (AutoShutdown)
ꢁigh
Low
ꢁigh
†
ꢁigh
Active
ꢁigh
X = Don’t care.
† = INVALID output state is determined by R_IN input levels.
232 output levels do not change if V
is noisꢃ or has a
have been detected on anꢃ receiver inputs. INVALID is
CC
sudden current draw causing the supplꢃ voltage to drop
slightlꢃ. The outputs return to RS-232-compliant levels
functional in anꢃ mode (Figures 2 and 3).
Autoꢁhutdown
The MAX3230E/MAX3231E achieve a 1µA supplꢃ cur-
rent with Maxim’s AutoShutdown feature, which oper-
ates when FORCEON is low and FORCEOFF is high.
When these devices sense no valid signal levels on all
receiver inputs for 30µs, the on-board charge pump
( 5.5V) when V
rises above approximatelꢃ +3.5V.
CC
The MAX3230E/MAX3231E transmitters guarantee a
250kbps data rate with worst-case loads of 3kΩ in par-
allel with 1000pF.
When FORCEOFF is driven to ground, the transmitters
and receivers are disabled and the outputs become
high impedance. When the AutoShutdown circuitrꢃ
senses that all receiver and transmitter inputs are inac-
tive for more than 30µs, the transmitters are disabled
and the outputs go to a high-impedance state. When
the power is off, the MAX3230E/MAX3231E permit the
transmitter outputs to be driven up to 12V.
and drivers are shut off, reducing V
supplꢃ current to
CC
1µA. This occurs if the RS-232 cable is disconnected or
the connected peripheral transmitters are turned off.
The device turns on again when a valid level is applied
to anꢃ RS-232 receiver input. As a result, the sꢃstem
saves power without changes to the existing ꢂIOS or
operating sꢃstem.
The transmitter inputs do not have pullup resistors.
Table 2 and Figure 2c summarize the MAX3230E/
MAX3231E operating modes. FORCEON and
FORCEOFF override AutoShutdown. When neither con-
trol is asserted, the IC selects between these states
automaticallꢃ, based on receiver input levels. Figures
2a, 2b, and 3a depict valid and invalid RS-232-receiver
levels. Figures 3a and 3b show the input levels and tim-
ing diagram for AutoShutdown operation.
Connect unused inputs to ꢀND or V .
L
Rꢁꢂ232 Receivers
The MAX3230E/MAX3231E receivers convert RS-232
signals to logic-output levels. All receivers have invert-
ing tri-state outputs and can be active or inactive. In
shutdown (FORCEOFF = low) or in AutoShutdown, the
MAX3230E/MAX3231E receivers are in a high-imped-
ance state (Table 2).
A sꢃstem with AutoShutdown can require time to wake
up. Figure 4 shows a circuit that forces the transmitters
on for 100ms, allowing enough time for the other sꢃs-
tem to realize that the MAX3230E/MAX3231E are
The MAX3230E/MAX3231E feature an INVALID output
that is enabled low when no valid RS-232 signal levels
_______________________________________________________________________________________
7
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
FORCEOFF
+0.3V
POWER DOWN
TO MAX323 _E
POWER SUPPLY
AND TRANSMITTERS
V
CC
R_IN
-0.3V
30µs
COUNTER
R
INVALID
FORCEON
INVALID
TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1µA IF
ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30µs.
INVALID IS AN INTERNALLY GENERATED SIGNAL
THAT IS USED BY THE AutoShutdown LOGIC
AND APPEARS AS AN OUTPUT OF THE DEVICE.
Figure 2a. MAX323_E Entering 1µA Supply Mode with
AutoShutdown
POWER DOWN IS ONLY AN INTERNAL SIGNAL.
IT CONTROLS THE OPERATIONAL STATUS OF
THE TRANSMITTERS AND THE POWER SUPPLIES.
+2.7V
Figure 2c. MAX323_E AutoShutdown Logic
microcontroller (µC) then drives FORCEOFF and
FORCEON like a SHDN input. INVALID can be used to
alert the µC to indicate serial data activitꢃ.
TO MAX323 _E
POWER SUPPLY
R_IN
30µs
COUNTER
R
INVALID
-2.7V
1ꢀ5k EꢁD -rotection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro-
static discharges encountered during handling and
assemblꢃ. The driver outputs and receiver inputs of the
MAX3230E/MAX3231E have extra protection against
static electricitꢃ. Maxim’s engineers have developed
state-of-the-art structures to protect these pins against
ESD of 15kV without damage. The ESD structures
withstand high ESD in all states: normal operation, shut-
down, and power-down. After an ESD event, Maxim’s
E-versions keep working without latchup, whereas
competing RS-232 products can latch and must be
powered down to remove latchup.
TRANSMITTERS ARE ENABLED IF:
ANY RECEIVER INPUT IS GREATER THAN +2.7V OR LESS THAN -2.7V.
ANY RECEIVER INPUT HAS BEEN BETWEEN +0.3V AND -0.3V FOR LESS THAN 30µs.
Figure 2b. MAX323_E with Transmitters Enabled Using
AutoShutdown
active. If the other sꢃstem transmits valid RS-232 sig-
nals within that time, the RS-232 ports on both sꢃstems
remain enabled.
When shut down, the device’s charge pumps are off,
V+ is pulled to V , V- is pulled to ground, and the
CC
transmitter outputs are high impedance. The time
required to exit shutdown is tꢃpicallꢃ 100µs (Figure 3b).
ESD protection can be tested in various waꢃs; the trans-
mitter outputs and receiver inputs of this product familꢃ
are characterized for protection to the following limits:
k Logic ꢁupply Input
L
Unlike other RS-232 interface devices, where the receiv-
1) 15kV using the ꢁuman ꢂodꢃ Model
er outputs swing between 0 and V , the MAX3230E/
CC
MAX3231E feature a separate logic supplꢃ input (V )
L
2) 8kV using the Contact Discharge method specified
in IEC 1000-4-2
that sets V
for the receiver outputs. The transmitter
Oꢁ
inputs (T_IN), FORCEON, and FORCEOFF, are also
3) 15kV using the IEC 1000-4-2 Air-ꢀap method
referred to V . This feature allows maximum flexibilitꢃ in
L
interfacing to different sꢃstems and logic levels. Connect
ESD Test Conditions
ESD performance depends on a varietꢃ of conditions.
Contact Maxim for a reliabilitꢃ report that documents
test setup, test methodologꢃ, and test results.
V
to the sꢃstem’s logic supplꢃ voltage (+1.65V to
L
+5.5V), and bꢃpass it with a 0.1µF capacitor to ꢀND. If
the logic supplꢃ is the same as V , connect V to V
.
CC
L
CC
Alwaꢃs enable V
must be greater than or equal to the V supplꢃ.
before enabling the V supplꢃ. V
CC
L
CC
Human Body Model
Figure 5a shows the ꢁuman ꢂodꢃ Model. Figure 5b
shows the current waveform it generates when dis-
charged into a low impedance. This model consists of a
100pF capacitor charged to the ESD voltage of interest,
L
ꢁoftwareꢂControlled ꢁhutdown
If direct software control is desired, connect FORCEOFF
and FORCEON together to disable AutoShutdown. The
8
_______________________________________________________________________________________
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
which is then discharged into the test device through a
1.5kΩ resistor.
TRANSMITTERS ENABLED, INVALID HIGH
IEC 1000-4-2
The IEC 1000-4-2 standard covers ESD testing and per-
formance of finished equipment. It does not specificallꢃ
refer to ICs. The MAX3230E/MAX3231E aid in designing
equipment that meets Level 4 (the highest level) of IEC
1000-4-2, without the need for additional ESD-protection
components.
+2.7V
INDETERMINATE
+0.3V
0
AutoShutdown, TRANSMITTERS DISABLED,
1µA SUPPLY CURRENT, INVALID LOW
-0.3V
INDETERMINATE
-2.7V
The major difference between tests done using the
ꢁuman ꢂodꢃ Model and IEC 1000-4-2 is a higher peak
current in IEC 1000-4-2, because series resistance is
lower in the IEC 1000-4-2 model. ꢁence, the ESD with-
stands voltage measured to IEC 1000-4-2 and is gener-
allꢃ lower than that measured using the ꢁuman ꢂodꢃ
Model. Figure 6a shows the IEC 1000-4-2 model, and
Figure 6b shows the current waveform for the 8kV IEC
1000-4-2 Level 4 ESD Contact Discharge test.
TRANSMITTERS ENABLED, INVALID HIGH
a)
RECEIVER
INPUT
INVALID
REGION
VOLTAGE
(V)
The Air-ꢀap test involves approaching the device with a
charged probe. The Contact Discharge method connects
the probe to the device before the probe is energized.
V
CC
0
Machine Model
The Machine Model for ESD tests all pins using a 200pF
storage capacitor and zero discharge resistance. Its
objective is to emulate the stress caused bꢃ contact that
occurs with handling and assemblꢃ during manufactur-
ing. Of course, all pins require this protection during
manufacturing, not just RS-232 inputs and outputs.
Therefore, after PC board assemblꢃ, the Machine Model
is less relevant to I/O ports.
INVALID
OUTPUT
(V)
t
t
INVH
INVL
t
WU
V+
V
CC
0
V-
Applications Information
b)
Capacitor ꢁelection
The capacitor tꢃpe used for C1–C4 is not critical for
proper operation; either polarized or nonpolarized
capacitors can be used. ꢁowever, ceramic chip capaci-
tors with an X7R or X5R dielectric work best. The charge
pump requires 0.1µF capacitors for 3.3V operation. For
other supplꢃ voltages, see Table 3 for required capaci-
tor values. Do not use values smaller than those listed in
Table 3. Increasing the capacitor values (e.g., bꢃ a fac-
tor of 2) reduces ripple on the transmitter outputs and
slightlꢃ reduces power consumption. C2, C3, and C4
can be increased without changing the vaue of C1.
Figure 3. AutoShutdown Trip Levels
POWER-
MANAGEMENT
UNIT
MASTER SHDN LINE
0.1µF
1MΩ
FORCEOFF FORCEON
MAX3230E
MAX3231E
Caution: Do not increase C1 without also increasing
the values of C2, C3, and C4 to maintain the proper
ratios (C1 to the other capacitors).
Figure 4. AutoShutdown with Initial Turn-On to Wake Up a
Mouse or Another System
When using the minimum required capacitor values,
make sure the capacitor value does not degrade exces-
sivelꢃ with temperature. If in doubt, use capacitors with
_______________________________________________________________________________________
9
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
I
R
C
1MΩ
R 1500Ω
D
100%
DISCHARGE
RESISTANCE
CHARGE-CURRENT-
LIMIT RESISTOR
90%
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
C
100pF
STORAGE
CAPACITOR
s
SOURCE
10%
Figure 5a. Human Body ESD Test Models
t
= 0.7ns to 1ns
r
t
30ns
60ns
I
P
100%
90%
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Figure 6b. IEC 1000-4-2 ESD Generator Current Waveform
I
r
AMPERES
Table 3. Required Capacitor Values
36.8%
V
(V)
C1, C
(µF)
C2, C3, C4 (µF)
CC
BYPASS
0.22
2.5 to 3.0
3.0 to 3.6
4.5 to 5.5
3.0 to 5.5
0.22
0.1
0.33
1
10%
0
0.1
TIME
0
t
RL
0.047
0.22
t
DL
CURRENT WAVEFORM
Figure 5b. Human Body Model Current Waveform
supplꢃ noise, use a capacitor of the same value as the
charge-pump capacitor C1. Connect bꢃpass capaci-
tors as close to the IC as possible.
R
C
50MΩ TO 100MΩ
R 330Ω
D
Transmitter Outputs when
Exiting ꢁhutdown
DISCHARGE
RESISTANCE
CHARGE-CURRENT-
LIMIT RESISTOR
Figure 7 shows a transmitter output when exiting shut-
down mode. The transmitter is loaded with 3kΩ in par-
allel with 1000pF. The transmitter output displaꢃs no
ringing or undesirable transients as it comes out of
shutdown, and is enabled onlꢃ when the magnitude of
V- exceeds approximatelꢃ -3V.
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
C
s
150pF
STORAGE
CAPACITOR
SOURCE
High Data Rates
The MAX3230E/MAX3231E maintain the RS-232 5.0V
minimum transmitter output voltage even at high data
rates. Figure 8 shows a transmitter loopback test cir-
cuit. Figure 9 shows a loopback test result at 120kbps,
and Figure 10 shows the same test at 250kbps. For
Figure 9, the transmitter was driven at 120kbps into an
RS-232 load in parallel with 1000pF. For Figure 10, a
single transmitter was driven at 250kbps and loaded
with an RS-232 receiver in parallel with 1000pF.
Figure 6a. IEC 1000-4-2 ESD Test Model
a larger nominal value. The capacitor’s equivalent series
resistance (ESR) usuallꢃ rises at low temperatures and
influences the amount of ripple on V+ and V-.
-owerꢂꢁupply Decoupling
In most circumstances, a 0.1µF V
bꢃpass capacitor
CC
is adequate. In applications that are sensitive to power-
10
_____________________________________________________________________________________
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
5V
5V/div
T_IN
FORCEON =
FORCEOFF
0
0
5V
T_OUT
R_OUT
0
-5V
5V
0
2V/div
0
T_OUT
4µs/div
4µs/div
Figure 9. Loopback Test Result at 120kbps
Figure 7. Transmitter Outputs Exiting Shutdown or Powering Up
V
V
L
CC
CC
5V
0.1µF
C3
0.1µF
C1
T_IN
0
V
V
L
C1+
V+
V-
5V
C1-
C2+
T_OUT
MAX3231E
0
C2
C4
-5V
5V
0
C2-
V
V
L
L
T1IN
T1OUT
R_OUT
1000pF
R1IN
R1OUT
4µs/div
5kΩ
Figure 10. Loopback Test Result at 250kbps
TO POWER-
MANAGEMENT UNIT
INVALID
FORCEON
FORCEOFF
V
L
GND
Figure 8. Transmitter Loopback Test Circuit
UCꢁ- Applications Information
Chip Information
For the latest application details on UCSP construction,
dimensions, tape carrier information, PC board tech-
niques, bump-pad laꢃout, and recommended reflow tem-
perature profile, as well as the latest information on
reliabilitꢃ testing results, refer to the Application Note
UCSP—A Wafer-Level Chip-Scale Package available on
Maxim’s website at www.maxim-ic.com/ucsp.
TRANSISTOR COUNT: 698
PROCESS: CMOS
______________________________________________________________________________________ 11
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
Typical Operating Circuits
(continued)
2.5V TO 5.5V 1.65V TO 5.5V
C
0.1µF
BYPASS
0.1µF
A1
A5
V
CC
V
C1
B1
A4
L
C1+
V+
C3
C1
0.1µF
0.1µF
D1
A2
C1-
C2+
MAX3231E
V-
C4
C2
0.1µF
0.1µF
A3
A6
V
L
C2-
T1OUT
T1IN
E3
E5
V
L
RS-232
TTL/CMOS
R1IN
C6 R1OUT
5kΩ
TO POWER-
MANAGEMENT
UNIT
E2
INVALID
FORCEON
FORCEOFF C5
B5
V
L
GND
E1
12 ______________________________________________________________________________________
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
-in Configurations
TOP VIEW
C2+
N.C.
N.C.
N.C.
C2-
N.C.
N.C.
N.C.
A
V
V-
V
T1IN
CC
L
V+
B
N.C.
N.C.
FON
T2IN
C
FOFF
R2OUT
C1+
C1-
N.C.
D
E
N.C.
R1OUT
INV
2
R2IN
5
R1IN
6
GND
1
T1OUT
3
T2OUT
4
FON = FORCEON
FOFF = FORCEOFF
INV = INVALID
MAX3230E
______________________________________________________________________________________ 13
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
-in Configurations (continued)
TOP VIEW
C2+
N.C.
N.C.
N.C.
C2-
N.C.
N.C.
N.C.
A
V
V-
V
T1IN
CC
L
V+
B
N.C.
N.C.
FON
N.C.
C
FOFF
R1OUT
C1+
C1-
N.C.
D
E
N.C.
N.C.
INV
2
R1IN
5
N.C.
6
GND
1
T1OUT
3
N.C.
4
FON = FORCEON
FOFF = FORCEOFF
INV = INVALID
MAX3231E
14 ______________________________________________________________________________________
1ꢀ5k EꢁDꢂ-rotected +2.ꢀk to +ꢀ.ꢀk
Rꢁꢂ232 Transceivers in UCꢁ-
-ac5age Information
(The package drawing(s) in this data sheet maꢃ not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
PACKAGE OUTLINE, 6x5 UCSP
1
21-0123
G
1
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated -roducts, 120 ꢁan Gabriel Drive, ꢁunnyvale, CA 94086 408ꢂ737ꢂ7600 ____________________ 15
© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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