MAXIM MAX3228E

19-2139; Rev 1; 5/04
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
The MAX3228E/MAX3229E are +2.5V to +5.5V powered EIA/TIA-232 and V.28/V.24 communications interfaces 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 protected to ±15kV using IEC 1000-4-2 Air-Gap Discharge,
±8kV using IEC 1000-4-2 Contact Discharge, and
±15kV using the Human Body Model.
The MAX3228E/MAX3229E achieve a 1µA supply current with Maxim’s AutoShutdown™ feature. They save
power without changes to existing BIOS or operating
systems by entering low-power shutdown mode when
the RS-232 cable is disconnected, or when the transmitters of the connected peripherals are off.
The transceivers have a proprietary low-dropout transmitter output stage, delivering RS-232 compliant performance from a +3.1V to +5.5V supply, and RS-232
compatible performance with a supply voltage as low
as +2.5V. The dual charge pump requires only four
small 0.1µF capacitors for operation from a +3.0V supply. Each device is guaranteed to run at data rates of
250kbps while maintaining RS-232 output levels.
The MAX3228E/MAX3229E offer a separate power-supply input for the logic interface, allowing configurable
logic levels on the receiver outputs and transmitter
inputs. Operating over a +1.65V to VCC range, VL provides the MAX3228E/MAX3229E compatibility with multiple logic families.
The MAX3229E contains one receiver and one transmitter. The MAX3228E contains two receivers and two
transmitters. The MAX3228E/MAX3229E are available
in tiny chip-scale packaging and are specified across
the extended industrial temperature range of -40°C to
+85°C.
Features
♦ 6 ✕ 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
♦ Meets 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
Ordering Information
PART
TEMP RANGE
PINPACKAGE
MAX3228EEBV
-40°C to +85°C
6 x 5 UCSP*
MAX3229EEBV
-40°C to +85°C
6 x 5 UCSP*
*Requires solder temperature profile described in the Absolute
Maximum Ratings section.
*UCSP reliability is integrally linked to the user’s assembly
methods, circuit board material, and environment. Refer to the
UCSP Reliabilitly Notice in the UCSP Reliability section of this
data sheet for more information.
Typical Operating Circuits
2.5V TO 5.5V 1.65V TO 5.5V
0.1µF
CBYPASS
0.1µF
A1
C1
C1
0.1µF
D1
A2
Applications
Personal Digital Assistants
Cell Phone Data Lump Cables
C2
0.1µF
Cell Phones
VCC
C1+
C1-
VL
C2+
V-
T1OUT
TTL/CMOS
INPUTS
C3
0.1µF
A4
C4
0.1µF
E3
RS-232
OUTPUTS
VL
T2OUT E4
B6 T2IN
VL
R1IN
D6 R1OUT
TTL/CMOS
OUTPUTS
VL
E6
5kΩ
RS-232
INPUTS
R2IN E5
C6 R2OUT
5kΩ
VL
VL
Pin Configurations appear at end of data sheet.
INVALID
20µA
20µA
AutoShutdown is a trademark of Maxim Integrated Products, Inc.
B1
VL
C2-
Typical Operating Circuits continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
V+
MAX3228E
A6 T1IN
Set-Top Boxes
Hand-Held Devices
A3
A5
E2
FORCEOFF C5
B5 FORCEON
TO POWERMANAGEMENT
UNIT
VL
GND
E1
________________________________________________________________ Maxim Integrated Products
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.
1
MAX3228E/MAX3229E
General Description
MAX3228E/MAX3229E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
ABSOLUTE MAXIMUM RATINGS
VCC to GND ...........................................................-0.3V to +6.0V
V+ to GND .............................................................-0.3V to +7.0V
V- to GND ..............................................................+0.3V to -7.0V
V+ to |V-| (Note 1) ................................................................+13V
VL to GND..............................................................-0.3V to +6.0V
Input Voltages
T_IN_, FORCEON, FORCEOFF to GND .....-0.3V to (VL + 0.3V)
R_IN_ to GND ...................................................................±25V
Output Voltages
T_OUT to GND ...............................................................±13.2V
R_OUT INVALID to GND ............................-0.3V to (VL + 0.3V)
INVALID to GND..........................................-0.3V to (VCC +0.3V)
Short-Circuit Duration T_OUT to GND........................Continuous
Continuous Power Dissipation (TA = +70°C)
6 ✕ 5 UCSP (derate 10.1mW/°C above TA = +70°C) ...805mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Bump Temperature (Soldering) (Note 2)
Infrared (15s) ...............................................................+200°C
Vapor Phase (20s) .......................................................+215°C
Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
Note 2: This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device
can be exposed to during board level solder attach and rework. This limit permits only the use of the solder profiles recommended in the industry-standard specification, JEDEC 020A, paragraph 7.6, Table 3 for IR/VPR and convection reflow. Preheating is required. Hand or wave soldering is not allowed.
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
(VCC = +2.5V to +5.5V, VL = +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V ±10%, TA = TMIN to TMAX. Typical values are at TA =
+25°C, unless otherwise noted.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
VL Input Voltage Range
VCC Supply Current,
AutoShutdown
VCC Supply Current,
AutoShutdown Disabled
VL Supply Current
VL
ICC
ICC
IL
1.65
VCC + 0.3
V
FORCEON = GND
FORCEOFF = VL, all RIN open
10
FORCEOFF = GND
10
µA
FORCEON, FORCEOFF floating
1
mA
1
mA
FORCEON = FORCEOFF = VL
no load
0.3
FORCEON or FORCEOFF = GND,
VCC = VL =+5V
85
FORCEON, FORCEOFF floating
1
µA
µA
LOGIC INPUTS
Pullup Currents
FORCEON, FORCEOFF to VL
Input Logic Low
T_IN, FORCEON, FORCEOFF
Input Logic High
T_IN, FORCEON, FORCEOFF
Transmitter Input Hysteresis
Input Leakage Current
20
µA
0.4
0.66 ✕ VL
0.5
T_IN
V
V
±0.01
V
±1
µA
RECEIVER OUTPUTS
2
Output Leakage Currents
R_OUT, receivers disabled, FORCEOFF =
GND or in AutoShutdown
±10
µA
Output Voltage Low
IOUT = 0.8mA
0.4
V
Output Voltage High
IOUT = -0.5mA
VL - 0.4 VL - 0.1
_______________________________________________________________________________________
V
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
ELECTRICAL CHARACTERISTICS (continued)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
+25
V
RECEIVER INPUTS
Input Voltage Range
-25
Input Threshold Low
TA = +25°C
Input Threshold High
TA = +25°C
VCC = +3.3V
0.6
1.2
VCC = +5.0V
0.8
1.7
V
VCC = +3.3V
1.3
2.4
VCC = +5.0V
1.8
2.4
Input Hysteresis
0.5
Input Resistance
3
5
V
V
7
kΩ
AUTO SHUTDOWN
Receiver Input Threshold to
INVALID Output High
Figure 3a
Positive threshold
Negative threshold
Receiver Input Threshold to
INVALID Output Low
2.7
-2.7
-0.3
0.3
V
V
Receiver Positive or Negative
Threshold to INVALID High
tINVH
VCC = +5.0V, Figure 3b
1
µs
Receiver Positive or Negative
Threshold to INVALID Low
tINVL
VCC = +5.0V, Figure 3b
30
µs
Receiver Edge to Transmitters
Enabled
tWU
VCC = +5.0V, Figure 3b
100
µs
INVALID OUTPUT
Output Voltage Low
IOUT = 0.3mA
Output Voltage High
IOUT = -0.5mA
0.4
VCC - 0.4
VCC - 0.1
V
V
TRANSMITTER OUTPUTS
VCC Mode Switch Point
(VCC Falling)
T_OUT = ±5.0V to ±3.7V
2.85
3.1
V
VCC Mode Switch Point
(VCC Rising)
T_OUT = ±3.7V to ±5.0V
3.3
3.7
V
VCC Mode Switch Point Hysteresis
Output Voltage Swing
Output Resistance
400
All transmitter
outputs loaded with
3kΩ to ground.
VCC = +3.1V to
+5.5V, VCC falling
(TA = +25°C)
±5
VCC = +2.5V to
+3.1V, VCC rising
±3.7
VCC = V+ = V- = 0, T_OUT = ±2V
±5.4
V
300
Ω
10M
Output Short-Circuit Current
Output Leakage Current
mV
T_OUT = ±12V, transmitters disabled
±60
mA
±25
µA
ESD PROTECTION
R_IN, T_OUT
Human Body Model
±15
IEC 1000-4-2 Air-Gap Discharge
±15
IEC 1000-4-2 Contact Discharge
±8
kV
_______________________________________________________________________________________
3
MAX3228E/MAX3229E
(VCC = +2.5V to +5.5V, VL = +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V ±10%, TA = TMIN to TMAX. Typical values are at TA =
+25°C, unless otherwise noted.) (Note 3)
TIMING CHARACTERISTICS
(VCC = +2.5V to +5.5V, VL = +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V ±10%, TA = TMIN to TMAX. Typical values are at TA =
+25°C, unless otherwise noted.) (Note 3)
PARAMETER
CONDITIONS
MIN
Maximum Data Rate
RL = 3kΩ, CL = 1000pF, one transmitter
switching
250
Receiver Propagation Delay
Receiver input to receiver output,
CL = 150pF
0.15
µs
Receiver Output Enable-Time
VCC = VL = +5V
200
ns
SYMBOL
Receiver Output Disable-Time
TYP
MAX
UNITS
kbps
200
ns
Transmitter Skew
| tPHL - tPLH |
100
ns
Receiver Skew
| tPHL - tPLH |
50
ns
VCC = VL = +5V
RL = 3kΩ to 7kΩ, CL = 150pF to
1000pF, TA = +25°C
Transition Region Slew Rate
6
30
V/µs
Note 3: VCC must be greater than VL.
Typical Operating Characteristics
(VCC = +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and CL, TA = +25°C, unless otherwise noted.)
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
2
SLEW RATE (V/µs)
VOH
0
VOL
-2
20
10
5
-6
0
500
1000
1500
2000
LOAD CAPACITANCE (pF)
2500
3000
VCC = 5.5V
15
-4
0
4
VCC = 2.5V
MAX3228E/9E toc03
25
20
OPERATING SUPPLY CURRENT (mA)
4
30
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE (MAX3229E)
MAX3228E/9E toc02
VCC RISING
SLEW RATE vs. LOAD CAPACITANCE
MAX3228E/9E toc01
6
TRANSMITTER OUTPUT VOLTAGE (V)
MAX3228E/MAX3229E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
18
16
14
250kbps
12
10
8
6
4
2
20kbps
0
0
500
1000
1500
2000
LOAD CAPACITANCE (pF)
2500
3000
0
500
1000
1500
2000
LOAD CAPACITANCE (pF)
_______________________________________________________________________________________
2500
3000
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
TRANSMITTER OUTPUT VOLTAGE vs.
SUPPLY VOLTAGE (VCC RISING)
14
12
10
8
6
4
8
6
4
0
-2
-6
0
-8
3.0
3.5
4.0
4.5
5.0
5.5
VOL
-4
2
2.5
VOH
2
10
MAX3228E/9E toc06
16
MAX3228E/9E toc05
18
10
TRANSMITTER OUTPUT VOLTAGE (V)
MAX3228E/9E toc04
OPERATING SUPPLY CURRENT (mA)
20
TRANSMITTER OUTPUT VOLTAGE vs.
SUPPLY VOLTAGE (VCC FALLING)
TRANSMITTER OUTPUT VOLTAGE (V)
OPERATING SUPPLY CURRENT
vs. SUPPLY VOLTAGE (MAX3229E)
8
6
4
VOH
2
0
-2
VOL
-4
-6
-8
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
Pin Description
PIN
MAX3228E
MAX3229E
NAME
FUNCTION
A1
A1
VCC
+2.5V to +5.5V Supply Voltage
A2
A2
C2+
Positive Terminal of Inverting Charge-Pump Capacitor
A3
A3
C2-
A4
A4
V-
-5.5V/-4.0V Generated by Charge Pump
A5
A5
VL
Logic-Level Input for Receiver Outputs and Transmitter Inputs. Connect VL to the
system logic supply voltage or VCC if no logic supply is required.
A6, B6
A6
T_IN
B1
B1
V+
B2, B3, B4,
C2, C3, C4,
D2, D3, D4,
D5
B2, B3, B4,
C2, C3, C4,
D2, D3, D4,
D5
N.C.
B5
B5
FORCEON
FORCEON Input, Active-High. Drive FORCEON high to override automatic circuitry,
keeping transmitters and charge pumps on. Pulls itself high internally if not connected.
—
B6, D6,
E4, E6
N.C.
No Connection. These locations are populated with solder bumps, but are electrically
isolated.
C1
C1
C1+
Positive Terminal of Positive Regulated Charge-Pump Capacitor
Negative Terminal of Inverting Charge-Pump Capacitor
Transmitter Input(s)
+5.5V/+4.0V Generated by Charge Pump. If charge pump is generating +4.0V, the part
has switched from RS-232 compliant to RS-232 compatible mode.
No Connection. These locations are not populated with solder bumps.
_______________________________________________________________________________________
5
MAX3228E/MAX3229E
Typical Operating Characteristics (continued)
(VCC = +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and CL, TA = +25°C, unless otherwise noted.)
MAX3228E/MAX3229E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
Pin Description (continued)
PIN
NAME
FUNCTION
MAX3228E
MAX3229E
C5
C5
FORCEOFF
C6, D6
C6
R_OUT
D1
D1
C1-
Negative Terminal of Positive Regulated Charge-Pump Capacitor
E1
E1
GND
Ground
E2
E2
INVALID
E3, E4
E3
T_OUT
E5, E6
E5
R_IN
FORCEOFF Input, Active-Low. Drive FORCEOFF low to shut down transmitters,
receivers, and on-board charge pump. This overrides all automatic circuitry and
FORCEON. Pulls itself high internally if not connected.
Receiver Output(s)
Output of Valid Signal Detector. INVALID is enabled low if no valid RS-232 level is
present on any receiver input.
RS-232 Transmitter Output(s)
RS-232 Receiver Input(s)
Table 1. Operating Supply Options
SYSTEM SUPPLY (V)
VCC (V)
VL (V)
RS-232 MODE
1 Li+ Cell
+2.4 to +4.2
Regulated System Voltage
Compliant/Compatible
3 NiCad/NiMh Cells
+2.4 to +3.8
Regulated System Voltage
Compliant/Compatible
Regulated Voltage Only
(VCC falling)
+3.0 to +5.5
+3.0 to +5.5
Compliant
Regulated Voltage Only
(VCC falling)
+2.5 to +3.0
+2.5 to +3.0
Compatible
Detailed Description
Dual-Mode Regulated Charge-Pump
Voltage Converter
The MAX3228E/MAX3229E internal power supply consists of a dual-mode regulated charge pump. For supply voltages above +3.7V, the charge pump will
generate +5.5V at V+ and -5.5V at V-. The charge
pumps operate 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.
For supply voltages below +2.85V, the charge pump
will generate +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.
The MAX3228E/MAX3229E include a switchover circuit
between these two modes that have approximately
400mV of hysteresis around the switchover point. The
hysteresis is shown in Figure 1. This large hysteresis
eliminates mode changes due to power-supply
bounce.
For example, a three-cell NiMh battery system starts at
VCC = +3.6V, and the charge pump will generate an
output voltage of ±5.5V. As the battery discharges, the
VCC
4V
0
V+
6V
Each charge pump requires a flying capacitor (C1, C2)
and a reservoir capacitor (C3, C4) to generate the V+
and V- supply voltages.
Voltage Generation in the
Switchover Region
6
0
20ms/div
Figure 1. V+ Switchover for Changing VCC
_______________________________________________________________________________________
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
R_IN
-0.3V
30µs
COUNTER
R
TO MAX322 _E
POWER SUPPLY
AND TRANSMITTERS
R_IN
30µs
COUNTER
R
INVALID
*TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1µA IF
ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30µs.
-2.7V
TO MAX322 _E
POWER SUPPLY
INVALID
*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 2a. MAX322_E Entering 1µA Supply Mode via
AutoShutdown
Figure 2b. MAX322_E with Transmitters Enabled Using
AutoShutdown
MAX3228E/MAX3229E maintain the outputs in regulation until the battery voltage drops below +3.1V. Then
the output regulation points change to ±4.0V
When VCC is rising, the charge pump will generate an
output voltage of ±4.0V, while VCC is between +2.5V
and +3.5V. When VCC rises above the switchover voltage of +3.5V, the charge pump switches modes to
generate an output of ±5.5V.
Table 1 shows different supply schemes and their
operating voltage ranges.
The transmitter inputs do not have pullup resistors.
Connect unused inputs to GND or VL.
RS-232 Transmitters
The transmitters are inverting level translators that convert CMOS-logic levels to RS-232 levels. The
MAX3228E/MAX3229E will automatically reduce the
RS-232 compliant levels (±5.5V) to RS-232 compatible
levels (±4.0V) when V CC falls below approximately
+3.1V. The reduced levels also reduce supply current
requirements, extending battery life. Built-in hysteresis
of approximately 400mV for VCC ensures that the RS232 output levels do not change if VCC is noisy or has a
sudden current draw causing the supply voltage to
drop slightly. The outputs will return to RS-232 compliant levels (±5.5V) when VCC rises above approximately
+3.5V.
The MAX3228E/MAX3229E transmitters guarantee a
250kbps data rate with worst-case loads of 3kΩ in parallel with 1000pF.
When FORCEOFF is driven to ground, the transmitters
and receivers are disabled and the outputs become
high impedance. When the AutoShutdown circuitry
senses that all receiver and transmitter inputs are inactive for more than 30µs, the transmitters are disabled
and the outputs go to a high-impedance state. When
the power is off, the MAX3228E/MAX3229E permit the
transmitter outputs to be driven up to ±12V.
RS-232 Receivers
The MAX3228E/MAX3229E receivers convert RS-232
signals to logic output levels. All receivers have inverting three-state outputs and can be active or inactive. In
shutdown (FORCEOFF = low) or in AutoShutdown, the
MAX3228E/MAX3229E receivers are in a high-impedance state (Table 3).
The MAX3228E/MAX3229E feature an INVALID output
that is enabled low when no valid RS-232 signal levels
have been detected on any receiver inputs. INVALID is
functional in any mode (Figures 2 and 3).
VL
FORCEOFF
POWER DOWN
VL
VCC
FORCEON
INVALID
INVALID IS AN INTERNALLY GENERATED SIGNAL
THAT IS USED BY THE AUTOSHUTDOWN LOGIC
AND APPEARS AS AN OUTPUT OF THE DEVICE.
POWER DOWN IS ONLY AN INTERNAL SIGNAL.
IT CONTROLS THE OPERATIONAL STATUS OF
THE TRANSMITTERS AND THE POWER SUPPLIES.
Figure 2c. MAX322_E AutoShutdown Logic
_______________________________________________________________________________________
7
MAX3228E/MAX3229E
+2.7V
+0.3V
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
MAX3228E/MAX3229E
AutoShutdown
The MAX3228E/MAX3229E achieve a 1µA supply current with Maxim’s AutoShutdown feature, which operates 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
and drivers are shut off, reducing VCC supply current to
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 any RS-232 receiver input. As a result, the system
saves power without changes to the existing BIOS or
operating system.
RECEIVER INPUT LEVELS
TRANSMITTERS ENABLED, INVALID HIGH
+2.7V
INDETERMINATE
+0.3V
0
AUTOSHUTDOWN, TRANSMITTERS DISABLED,
1µA SUPPLY CURRENT, INVALID LOW
-0.3V
INDETERMINATE
-2.7V
TRANSMITTERS ENABLED, INVALID HIGH
a)
RECEIVER
INPUT
VOLTAGE
(V)
INVALID
REGION
VCC
INVALID
OUTPUT
(V)
0
tINVL
tINVH
tWU
V+
VCC
0
V-
Table 3 and Figure 2c summarize the MAX3228E/
MAX3229E operating modes. FORCEON and FORCEOFF override AutoShutdown. When neither control is
asserted, the IC selects between these states automatically, 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 timing diagram for AutoShutdown operation.
A system with AutoShutdown may need time to wake
up. Figure 4 shows a circuit that forces the transmitters
on for 100ms, allowing enough time for the other system to realize that the MAX3228E/MAX3229E are
active. If the other system transmits valid RS-232 signals within that time, the RS-232 ports on both systems
remain enabled.
When shut down, the device’s charge pumps are off,
V+ is pulled to VCC, V- is pulled to ground, and the
transmitter outputs are high-impedance. The time
required to exit shutdown is typically 100µs (Figure 3b).
FORCEON and FORCEOFF
b)
Figure 3. AutoShutdown Trip Levels
POWERMANAGEMENT
UNIT
MASTER SHDN LINE
0.1µF
1MΩ
In case FORCEON and FORCEOFF are inaccessible,
these pins have 60kΩ (typ) pullup resistors connected to
VL (Table 2). Therefore, if FORCEON and FORCEOFF
are not connected, the MAX3228E and MAX3229E will
always be active. Pulling these pins to ground will draw
current from the VL supply. This current can be calculated from the voltage supplied at VL and the 60kΩ (typ)
pullup resistor.
FORCEOFF FORCEON
MAX3228E
MAX3229E
VL Logic Supply Input
Unlike other RS-232 interface devices, where the
receiver outputs swing between 0 and V CC , the
Table 2. Power-On Default States
Figure 4. AutoShutdown with Initial Turn-On to Wake Up a
Mouse or Another System
8
PIN NAME
POWER-ON DEFAULT
FORCEON
High
Internal pullup
FORCEOFF
High
Internal pullup
_______________________________________________________________________________________
MECHANISM
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
MAX3228E/MAX3229E
Table 3. Output Control Truth Table
FORCEON
FORCEOFF
RECEIVER STATUS
Low
High
High-Z
L
X
Low
High-Z
†
Normal Operation (Forced On)
High
High
Active
†
Normal Operation (AutoShutdown)
Low
High
Active
H
TRANSCEIVER STATUS
Shutdown (AutoShutdown)
Shutdown (Forced Off)
INVALID
X = Don’t care.
† = INVALID output state is determined by R_IN input levels.
MAX3228E/MAX3229E feature a separate logic supply
input (VL) that sets VOH for the receiver and INVALID
outputs. The transmitter inputs (T_IN), FORCEON and
FORCEOFF, are also referred to VL. This feature allows
maximum flexibility in interfacing to different systems
and logic levels. Connect VL to the system’s logic supply voltage (+1.65V to +5.5V), and bypass it with a
0.1µF capacitor to GND. If the logic supply is the same
as VCC, connect VL to VCC. Always enable VCC before
enabling the VL supply. VCC must be greater than or
equal to the VL supply.
Software-Controlled Shutdown
If direct software control is desired, connect FORCEOFF and FORCEON together to disable AutoShutdown.
The microcontroller then drives FORCEOFF and
FORCEON like a SHDN input, INVALID can be used to
alert the microcontroller to indicate serial data activity.
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electrostatic discharges encountered during handling and
assembly. The driver outputs and receiver inputs of the
MAX3228E/MAX3229E have extra protection against
static electricity. 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, shutdown, and powered 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.
ESD protection can be tested in various ways; the transmitter outputs and receiver inputs of this product family
are characterized for protection to the following limits:
1) ±15kV using the Human Body Model.
2) ±8kV using the Contact Discharge method specified
in IEC 1000-4-2.
3) ±15kV using the IEC 1000-4-2 Air-Gap method.
RC 1MΩ
CHARGE-CURRENT
LIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
100pF
RD 1500Ω
DISCHARGE
RESISTANCE
DEVICE
UNDER
TEST
STORAGE
CAPACITOR
Figure 5a. Human Body ESD Test Models
IP 100%
90%
Ir
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
AMPERES
36.8%
10%
0
0
tRL
TIME
tDL
CURRENT WAVEFORM
Figure 5b. Human Body Model Current Waveform
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test setup, test methodology, and test results.
Human Body Model
Figure 5a shows the Human Body Model, and Figure 5b
shows the current waveform it generates when discharged into a low impedance. This model consists of a
100pF capacitor charged to the ESD voltage of interest,
which is then discharged into the test device through a
1.5kΩ resistor.
_______________________________________________________________________________________
9
IEC 1000-4-2
The IEC 1000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically
refer to integrated circuits. The MAX3228E/MAX3229E
help you design equipment that meets Level 4 (the highest level) of IED 1000-4-2, without the need for additional ESD-protection components.
The major difference between tests done using the
Human Body 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. Hence, the ESD withstand voltage measured to IEC 1000-4-2 is generally
lower than that measured using the Human Body 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.
The air-gap test involves approaching the device with a
charged probe. The Contact Discharge method connects the probe to the device before the probe is energized.
RC 50MΩ to 100MΩ
CHARGE-CURRENT
LIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
150pF
RD 330Ω
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
DEVICE
UNDER
TEST
Figure 6a. IEC 1000-4-2 ESD Test Model
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 by contact that
occurs with handling and assembly during manufacturing. Of course, all pins require this protection during
manufacturing, not just RS-232 inputs and outputs.
Therefore, after PC board assembly, the Machine Model
is less relevant to I/O ports.
Applications Information
Capacitor Selection
The capacitor type used for C1–C4 is not critical for
proper operation; either polarized or non polarized
capacitors may be used. However, ceramic chip
capacitors with an X7R or X5R dielectric work best. The
charge pump requires 0.1µF capacitors for 3.3V operation. For other supply voltages, refer to Table 4 for
required capacitor values. Do not use values smaller
than those listed in Table 4. Increasing the capacitor
values (e.g., by a factor of 2) reduces ripple on the
transmitter outputs and slightly reduces power consumption. C2, C3, and C4 can be increased without
changing C1’s value. However, do not increase C1
without also increasing the values of C2, C3, and C4
to maintain the proper ratios (C1 to the other capacitors).
When using the minimum required capacitor values,
make sure the capacitor value does 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 influences the amount of ripple on
V+ and V-.
Power-Supply Decoupling
I
100%
In most circumstances, a 0.1µF VCC bypass capacitor
is adequate. In applications that are sensitive to powersupply noise, use a capacitor of the same value as the
charge-pump capacitor C1. Connect bypass capacitors as close to the IC as possible.
90%
I PEAK
MAX3228E/MAX3229E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
Table 4. Required Capacitor Values
10%
t r = 0.7ns to 1ns
t
30ns
60ns
VCC (V)
C1, CBYPASS (µF)
C2, C3, C4 (µF)
2.5 to 3.0
0.22
0.22
3.0 to 3.6
0.1
0.1
4.5 to 5.5
0.047
0.33
3.0 to 5.5
0.22
1
Figure 6b. IEC 1000-4-2 ESD Generator Current Waveform
10
_____________________________________________________________________________________
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
Figure 7 shows a transmitter output when exiting shutdown mode. The transmitter is loaded with 3kΩ in parallel with 1000pF. The transmitter output displays no
ringing or undesirable transients as it comes out of
shutdown, and is enabled only when the magnitude of
V- exceeds approximately -3V.
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.
High Data Rates
The MAX3228E/MAX3229E maintain the RS-232 ±5.0V
minimum transmitter output voltage even at high data
rates. Figure 8 shows a transmitter loopback test circuit. Figure 9 shows a loopback test result at 120kbps,
and Figure 10 shows the same test at 250kbps. For
5V/div
FORCEON =
FORCEOFF
0
5V
T_IN
0
5V
0
T_OUT
-5V
5V
2V/div
TOUT
R_OUT
0
4µs/div
4µs/div
Figure 7. Transmitter Outputs Exiting Shutdown or Powering Up
VCC
0
Figure 9. Loopback Test Result at 120kbps
VL
5V
0.1µF
0.1µF
T_IN
C1+
VCC
VL
0
V+
5V
C3
C1
C1-
T_OUT
MAX3229E
C2+
0
V-
C2
-5V
C4
VL
C2-
5V
T1OUT
T1IN
R_OUT
4µs/div
R1IN
R1OUT
Figure 10. Loopback Test Result at 250kbps
5kΩ
INVALID
FORCEON
GND
0
1000pF
VL
FORCEOFF
TO POWERMANAGEMENT UNIT
VL
Figure 8. Transmitter Loopback Test Circuit
______________________________________________________________________________________
11
MAX3228E/MAX3229E
Transmitter Outputs when
Exiting Shutdown
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
MAX3228E/MAX3229E
Typical Operating Circuits
(continued)
2.5V TO 5.5V 1.65V TO 5.5V
CBYPASS
0.1µF
A1
C1
C1
0.1µF
D1
A2
C2
0.1µF
A3
VCC
C1+
C1-
0.1µF
A5
VL
V+
MAX3229E
C2+
V-
B1
C3
0.1µF
A4
C4
0.1µF
VL
C2-
T1OUT
A6 T1IN
E3
VL
TTL/CMOS
RS-232
R1IN E5
C6 R1OUT
5kΩ
VL
VL
INVALID
20µA
E2
20µA
FORCEOFF C5
B5 FORCEON
TO POWERMANAGEMENT
UNIT
UCSP Reliability
The UCSP represents a unique packaging form factor
that may not perform equally to a packaged product
through traditional mechanical reliability tests. CSP reliability is integrally linked to the user’s assembly methods,
circuit board material, and usage environment. The user
should closely review these areas when considering use
of a CSP package. Performance through Operating Life
Test and Moisture Resistance remains uncompromised
as it is primarily determined by the wafer-fabrication
process.
Mechanical stress performance is a greater consideration for a CSP package. CSPs are attached through
direct solder contact to the user’s PC board, foregoing
the inherent stress relief of a packaged product lead
frame. Solder joint contact integrity must be considered.
Table 2 shows the testing done to characterize the CSP
reliability performance. In conclusion, the UCSP is capable of performing reliably through environmental stresses
as indicated by the results in the table. Additional usage
data and recommendations are detailed in the UCSP
application note, which can be found on Maxim’s website at www.maxim-ic.com.
Chip Information
VL
TRANSISTOR COUNT: 698
PROCESS TECHNOLOGY: CMOS
GND
E1
Table 2. Reliability Test Data
TEST
Temperature Cycle
CONDITIONS
-35°C to +85°C,
-40°C to +100°C
DURATION
NO. OF FAILURES PER
SAMPLE SIZE
150 cycles,
900 cycles
0/10,
0/200
Operating Life
TA = +70°C
240hr
0/10
Moisture Resistance
+20°C to +60°C, 90% RH
240hr
0/10
Low-Temperature Storage
Low-Temperature
Operational
Solderability
-20°C
240hr
0/10
-10°C
24hr
0/10
8hr steam age
—
0/15
ESD
±2000V, Human Body Model
—
0/5
High-Temperature Operating
Life
TJ = +150°C
168hr
0/45
12
______________________________________________________________________________________
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
TOP VIEW
A
VCC
C2+
C2-
V-
VL
T1IN
B
V+
N.C.
N.C.
N.C.
FON
T2IN
C
C1+
N.C.
N.C.
N.C.
FOFF
R2OUT
D
C1-
N.C.
N.C.
N.C.
N.C.
R1OUT
E
GND
INV
T1OUT
T2OUT
R2IN
R1IN
1
2
3
4
5
MAX3228E
6
FON = FORCEON
FOFF = FORCEOFF
INV = INVALID
______________________________________________________________________________________
13
MAX3228E/MAX3229E
Pin Configurations
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
MAX3228E/MAX3229E
Pin Configurations (continued)
TOP VIEW
A
VCC
C2+
C2-
V-
VL
T1IN
B
V+
N.C.
N.C.
N.C.
FON
N.C.
C
C1+
N.C.
N.C.
N.C.
FOFF
R1OUT
D
C1-
N.C.
N.C.
N.C.
N.C.
N.C.
E
GND
INV
T1OUT
N.C.
R1IN
N.C.
1
2
3
4
5
MAX3229E
14
6
FON = FORCEON
FOFF = FORCEOFF
INV = INVALID
______________________________________________________________________________________
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
30L, UCSP 6x5 .EPS
PACKAGE OUTLINE, 6x5 UCSP
21-0123
G
1
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 Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15
© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX3228E/MAX3229E
Package Information