Datasheet MAX3245EEWI, MAX3245EEAI, MAX3245ECWI, MAX3245ECAI, MAX3244EEWI Datasheet (Maxim)

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone] ext. 3468.

________________General Description

The MAX3224E/MAX3225E/MAX3226E/MAX3227E/
MAX3244E/MAX3245E are 3V-powered EIA/TIA-232
and V.28/V.24 communications interfaces with automat­ic shutdown/wakeup features, high data-rate capabili­ties, and enhanced electrostatic discharge (ESD)
protection. 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.

All devices achieve a 1µA supply current using Maxim’s
revolutionary AutoShutdown Plus™ feature. These
devices automatically enter a low-power shutdown
mode when the RS-232 cable is disconnected or the
transmitters of the connected peripherals are inactive,
and the UART driving the transmitter inputs is inactive
for more than 30 seconds. They turn on again when
they sense a valid transition at any transmitter or receiv­er input. AutoShutdown Plus saves power without
changes to the existing BIOS or operating system.

The MAX3225E/MAX3227E/MAX3245E also feature
MegaBaud™ operation, guaranteeing 1Mbps for high­speed applications such as communicating with ISDN
modems. The MAX3224E/MAX3226E/MAX3244E guar­antee 250kbps operation. The transceivers have a pro­prietary low-dropout transmitter output stage enabling
true RS-232 performance from a +3.0V to +5.5V supply
with a dual charge pump. The charge pump requires
only four small 0.1µF capacitors for operation from a

3.3V supply. The MAX3224E–MAX3227E feature a logic­level output (READY) that asserts when the charge
pump is regulating and the device is ready to begin
transmitting.

All devices are available in a space-saving SSOP pack­age.

________________________Applications

Notebook, Subnotebook, and Palmtop Computers
Cellular Phones
Battery-Powered Equipment
Hand-Held Equipment
Peripherals
Printers

____________________________Features

♦ ESD Protection for RS-232 I/O Pins:

±15kV—Human Body Model
±8kV—IEC1000-4-2, Contact Discharge
±15kV—IEC1000-4-2, Air-Gap Discharge

♦ Latchup Free
♦ 1µA Supply Current
♦ AutoShutdown Plus—EDN Innovation of the Year
♦ Guaranteed Data Rate:

250kbps (MAX3224E/3226E/3244E)
1Mbps (MAX3225E/3227E/3245E)

♦ Guaranteed Slew Rate:

6V/µs (MAX3224E/3226E/3244E)
24V/µs (MAX3225E/3227E/3245E)

♦ Meets EIA/TIA-232 Specifications Down to 3.0V
♦ Guaranteed Mouse Driveability

(MAX3244E/3245E)

♦ Ready-to-Transmit Logic-Level Output

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

________________________________________________________________

Maxim Integrated Products

1

19-1339; Rev 0; 1/98

PART

MAX3224E
MAX3225E
MAX3226E

1/1

2/2

2/2

NO. OF

DRIVERS/

RECEIVERS

READY

OUTPUT

✔
✔
✔

AUTO-

SHUTDOWN

PLUS

✔
✔
✔

250k

1M

250k

GUARANTEED

DATA RATE

(bps)

MAX3227E
MAX3244E
MAX3245E

3/5

3/5

1/1

✔

—
—

✔
✔
✔

1M

250k

1M

PART

MAX3224ECPP

MAX3224ECAP
MAX3224EEPP -40°C to +85°C

0°C to +70°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

20 Plastic DIP
20 SSOP

20 Plastic DIP
MAX3224EEAP
MAX3225ECPP
MAX3225ECAP 0°C to +70°C

0°C to +70°C

-40°C to +85°C 20 SSOP
20 Plastic DIP
20 SSOP

MAX3225EEPP -40°C to +85°C 20 Plastic DIP
MAX3225EEAP -40°C to +85°C 20 SSOP

Ordering Information continued at end of data sheet.

AutoShutdown Plus and MegaBaud are trademarks of
Maxim Integrated Products.

†

Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577;
4,797,899; 4,809,152; 4,897,774; 4,999,761; 5,649,210; and other
patents pending.

_____________________ Selector Guide

_______________Ordering Information

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3V to +5.5V, C1–C4 = 0.1µF, tested at 3.3V ±10%; CL= 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%; TA= T

MIN

to T

MAX

,

unless otherwise noted. Typical values are at T

A

= +25°C.)

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.

VCCto GND..............................................................-0.3V to +6V

V+ to GND (Note 1)..................................................-0.3V to +7V

V- to GND (Note 1)...................................................+0.3V to -7V

V+ +

V-(Note 1) ................................................................+13V

Input Voltages

T_IN, FORCEON,

FORCEOFF to GND................ -0.3V to +6V

R_IN to GND....................................................................±25V

Output Voltages

T_OUT to GND.............................................................±13.2V

R_OUT, INVALID, READY to GND .........-0.3V to (V

CC

+ 0.3V)

Short-Circuit Duration

T_OUT to GND.......................................................Continuous

Continuous Power Dissipation (T

A

= +70°C)

16-Pin SSOP (derate 7.14mW/°C above +70°C) .........571mW

20-Pin Plastic DIP (derate 11.11mW/°C above +70°C) ...889mW

20-Pin SSOP (derate 8.00mW/°C above +70°C) .........640mW

28-Pin Wide SO (derate 12.5mW/°C above +70°C)........... 1W

28-Pin SSOP (derate 9.52mW/°C above +70°C) .........762mW

Operating Temperature Ranges

MAX32_ _EC_ _ .................................................0°C to +70°C

MAX32_ _EE_ _................................................-40°C to +85°C

Storage Temperature Range.............................-65°C to +160°C

Lead Temperature (soldering, 10sec).............................+300°C

Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.

VCC= 5.0V

FORCEON = GND, FORCEOFF = VCC,
all R_IN idle, all T_IN idle

TA= +25°C

VCC= 3.3V

T_IN, FORCEON,

FORCEOFF

CONDITIONS

kΩ3 5 7Input Resistance

V0.5Input Hysteresis

1.8 2.4

V

1.5 2.4

Input Threshold High

0.8 1.5

V

0.6 1.2

Input Threshold Low

V-25 +25Input Voltage Range

V

VCC- 0.6 VCC- 0.1

Output Voltage High

V0.4Output Voltage Low

µA1 10Supply Current, Shutdown

µA1 10

Supply Current,
AutoShutDown Plus

µA±0.05 ±10Output Leakage Current

µA±0.01 ±1

Transmitter Input Hysteresis V0.5

V

2.4

Input Logic Threshold High

mA0.3 1

Supply Current,
AutoShutDown Plus Disabled

V0.8Input Logic Threshold Low

2

UNITSMIN TYP MAXSYMBOLPARAMETER

FORCEOFF = GND

TA= +25°C

VCC= 5.0V

VCC= 3.3V

TA= +25°C

R_OUT (MAX3244E/MAX3245E), receivers
disabled

T_IN, FORCEON, FORCEOFF

VCC= 5.0V

FORCEON = FORCEOFF = VCC, no load

T_IN, FORCEON, FORCEOFF

I

OUT

= -1.0mA

VCC= 3.3V

I

OUT

= 1.6mA

DC CHARACTERISTICS (VCC= 3.3V or 5.0V, TA= +25°C)

LOGIC INPUTS AND RECEIVER OUTPUTS

RECEIVER INPUTS

Input Leakage Current

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3V to +5.5V, C1–C4 = 0.1µF, tested at 3.3V ±10%; CL= 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%; TA= T

MIN

to T

MAX

,

unless otherwise noted. Typical values are at T

A

= +25°C.)

CONDITIONS

Ω300 10MOutput Resistance

V±5 ±5.4Output Voltage Swing

UNITSMIN TYP MAXSYMBOLPARAMETER

Figure 4a

T1IN = T2IN = GND, T3IN = VCC,
T3OUT loaded with 3kΩ to GND,
T1OUT and T2OUT loaded with

2.5mA each

sec15 30 60t

AUTOSHDN

Receiver or Transmitter Edge to
Transmitters Shutdown

µs100t

WU

Receiver or Transmitter Edge to
Transmitters Enabled

µs30t

INVL

Receiver Positive or Negative
Threshold to INVALID Low

µs1t

INVH

Receiver Positive or Negative
Threshold to INVALID High

V

V

CC

- 0.6

INVALID, READY
Output Voltage High
(MAX3224E–MAX3227E)

V0.4

INVALID, READY
Output Voltage Low
(MAX3224E–MAX3227E)

V-0.3 0.3

Receiver Input Threshold to
INVALID Output Low

-2.7

V

2.7

Receiver Input Threshold to
INVALID Output High

±15

±8R_IN, T_OUT kV

±15

V±5Transmitter Output Voltage

µA±25Output Leakage Current

±60 mAOutput Short-Circuit Current

VCC= V+ = V- = 0, transmitter outputs = ±2V

All transmitter outputs loaded with 3kΩ to
ground

VCC= 5V, Figure 5b (Note 2)

VCC= 5V, Figure 5b (Note 2)

VCC= 5V, Figure 4b

VCC= 5V, Figure 4b

I

OUT

= -1.0mA

I

OUT

= -1.6mA

Figure 4a

Negative threshold

Positive threshold

Human Body Model

VCC= 0 or 3V to 5.5V, V

OUT

= ±12V,

Transmitters disabled

IEC1000-4-2 Contact Discharge

IEC1000-4-2 Air Discharge

TRANSMITTER OUTPUTS

MOUSE DRIVEABILITY (MAX3244E/MAX3245E)

ESD PROTECTION

AUTOSHUTDOWN PLUS (FORCEON = GND, FORCEOFF = VCC)

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus

4 _______________________________________________________________________________________

TIMING CHARACTERISTICS—MAX3224E/MAX3226E/MAX3244E

(VCC= +3V to +5.5V, C1–C4 = 0.1µF, tested at 3.3V ±10%; CL= 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%; TA= T

MIN

to T

MAX

,

unless otherwise noted. Typical values are at T

A

= +25°C.)

TIMING CHARACTERISTICS—MAX3225E/MAX3227E/MAX3245E

(VCC= +3V to +5.5V, C1–C4 = 0.1µF, tested at 3.3V ±10%; CL= 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%; TA= T

MIN

to T

MAX

,

unless otherwise noted. Typical values are at T

A

= +25°C.)

Note 2: A transmitter/receiver edge is defined as a transition through the transmitter/receiver input logic thresholds.
Note 3: Transmitter skew is measured at the transmitter zero cross points.

CL= 150pF
to 2500pF

CL= 150pF
to 1000pF

R_IN to R_OUT, CL= 150pF

RL= 3kΩ, CL= 1000pF,
one transmitter switching

VCC= 3.3V, TA= +25°C,
RL= 3kΩ to 7kΩ,
measured from +3V to -3V
or -3V to +3V

Normal operation (MAX3244E only)
Normal operation (MAX3244E only)
(Note 3)

CONDITIONS

0.15t

PLH

µs

0.15t

PHL

kbps250Maximum Data Rate

Receiver Propagation Delay

V/µs

4 30

6 30

Transition-Region Slew Rate

ns200Receiver Output Enable Time
ns200Receiver Output Disable Time
ns100



t

PHL

- t

PLH 

Transmitter Skew

ns50



t

PHL

- t

PLH 

Receiver Skew

UNITSMIN TYP MAXSYMBOLPARAMETER

VCC= 4.5V to 5.5V, RL= 3kΩ,
CL= 1000pF, one transmitter switching

VCC= 3.0V to 4.5V, RL= 3kΩ,
CL= 250pF, one transmitter switching

RL= 3kΩ, CL= 1000pF,
one transmitter switching

VCC= 3.3V, TA= +25°C,
RL= 3kΩ to 7kΩ, CL= 150pF to 1000pF,
measured from +3V to -3V or -3V to +3V

(Note 3)

R_IN to R_OUT, CL= 150pF
Normal operation (MAX3245E only)

Normal operation (MAX3245E only)

CONDITIONS

1000

1000 kbps

250

Maximum Data Rate

V/µs24 150Transition-Region Slew Rate

ns50



t

PHL

- t

PLH 

Receiver Skew

ns25



t

PHL

- t

PLH 

Transmitter Skew

µs

0.15t

PHL

Receiver Propagation Delay

0.15t

PLH

ns200Receiver Output Enable Time
ns200Receiver Output Disable Time

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

_______________________________________________________________________________________

5

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

0 1000 2000 3000 4000 5000

MAX3224E/MAX3226E

TRANSMITTER OUTPUT VOLTAGE

vs. LOAD CAPACITANCE

MAX3224-7/44/45E-01

LOAD CAPACITANCE (pF)

TRANSMITTER OUTPUT VOLTAGE (V)

T1 TRANSMITTING AT 250kbps
T2 (MAX3224E) TRANSMITTING AT 15.6kbps

V

OUT+

V

OUT-

0

2

4

6

8

10

12

14

16

0 1000 2000 3000 4000 5000

MAX3224E/MAX3226E

SLEW RATE vs. LOAD CAPACITANCE

MAX3224-7/44/45E-02

LOAD CAPACITANCE (pF)

SLEW RATE (V/µs)

-SLEW

+SLEW

FOR DATA RATES UP TO 250kbps

0

5

10

15

20

25

30

35

40

45

0 20001000 3000 4000 5000

MAX3224E/MAX3226E

OPERATING SUPPLY CURRENT

vs. LOAD CAPACITANCE

MAX3224-7/44/45E-03

LOAD CAPACITANCE (pF)

SUPPLY CURRENT (mA)

250kbps

120kbps

20kbps

T1 TRANSMITTING AT 250kbps
T2 (MAX3224E) TRANSMITTING AT 15.6kbps

-7.5

0

-2.5

-5.0

2.5

5.0

7.5

0 1000500 1500 2000 2500

MAX3225E/MAX3227E

TRANSMITTER OUTPUT VOLTAGE

vs. LOAD CAPACITANCE

MAX3224-7/44/45E-04

LOAD CAPACITANCE (pF)

TRANSMITTER OUTPUT VOLTAGE (V)

2Mbps

2Mbps

1.5Mbps

1.5Mbps

1Mbps

1Mbps

1 TRANSMITTER AT FULL DATA RATE
1 TRANSMITTER AT 1/16 DATA RATE

(MAX3225E)
LOAD = 3kΩ + C

L

0

15
10

5

20

25

30

35

40

45

50

0 1000500 1500 2000 2500 3000

MAX3225E/MAX3227E

TRANSMITTER SKEW vs.

LOAD CAPACITANCE

MAX3224-7/44/45E-07

LOAD CAPACITANCE (pF)

TRANSMITTER SKEW (ns)

AVERAGE; 10 PARTS

1 TRANSMITTER AT 512kbps
1 TRANSMITTER AT 30kbps

(MAX3225E)
LOAD = 3kΩ + C

L

0

80
70
60
50
40
30
20
10

0 500 1000 1500 2000 2500

MAX3225E/MAX3227E

SLEW RATE vs. LOAD CAPACITANCE

MAX3224-7/44/45E-05

LOAD CAPACITANCE (pF)

SLEW RATE (V/µs)

1 TRANSMITTER AT 1Mbps
1 TRANSMITTER AT 62.5kbps (MAX3225E)

-SLEW

+SLEW

0

20
10

40
30

60
50

70

90
80

100

0 500 1000 1500 2000 2500

MAX3225E/MAX3227E

OPERATING SUPPLY CURRENT

vs. LOAD CAPACITANCE

MAX3224-7/44/45E-06

LOAD CAPACITANCE (pF)

SUPPLY CURRENT (mA)

2Mbps

1.5Mbps

1Mbps

1 TRANSMITTER AT FULL DATA RATE
1 TRANSMITTER AT 1/16 DATA RATE

(MAX3225E)
LOAD = 3kΩ + C

L

20

24
22

30
28
26

36
34
32

38

-40 0 20-20 40 60 80 100

MAX3224E–MAX3227E
READY TURN-ON TIME

vs. TEMPERATURE

MAX3224-7/44/45E-08

TEMPERATURE (°C)

READY TURN-ON TIME (µs)

0

200
180
160
140
120
100

80
60
40
20

-40 0 20-20 40 60 80 100

MAX3224E–MAX3227E
READY TURN-OFF TIME

vs. TEMPERATURE

MAX3224-7/44/45E-09

TEMPERATURE (°C)

READY TURN-OFF TIME (ns)

__________________________________________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.)

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus

6 _______________________________________________________________________________________

_____________________________Typical Operating Characteristics (continued)

(V

CC

= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and CL, TA= +25°C, unless otherwise noted.)

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

0 1000 2000 3000 4000 5000

MAX3244E

TRANSMITTER OUTPUT VOLTAGE

vs. LOAD CAPACITANCE

MAX3224-7/44/45E-10

LOAD CAPACITANCE (pF)

TRANSMITTER OUTPUT VOLTAGE (V)

1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps

V

OUT+

V

OUT-

0

4

2

8

6

12

10

14

0 1000 2000 3000 4000 5000

MAX3244E

SLEW RATE vs. LOAD CAPACITANCE

MAX3224-7/44/45E-11

LOAD CAPACITANCE (pF)

SLEW RATE (V/µs)

0

30

20

10

40

50

60

0 20001000 3000 4000 5000

MAX3244E

OPERATING SUPPLY CURRENT

vs. LOAD CAPACITANCE

MAX3224-7/44/45E-12

LOAD CAPACITANCE (pF)

SUPPLY CURRENT (mA)

250kbps

120kbps

20kbps

1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps

-7.5

0

-2.5

-5.0

2.5

5.0

7.5

0 800400 1200 1600 2000

MAX3245E

TRANSMITTER OUTPUT VOLTAGE

vs. LOAD CAPACITANCE

MAX3224-7/44/45E-13

LOAD CAPACITANCE (pF)

TRANSMITTER OUTPUT VOLTAGE (V)

2Mbps

2Mbps

1.5Mbps

1.5Mbps

1Mbps

1Mbps

1 TRANSMITTER AT FULL DATA RATE
2 TRANSMITTERS AT 1/16 DATA RATE

0

20
10

40
30

60
50

70

90
80

100

0 400 800 1200 1600 2000

MAX3245E

OPERATING SUPPLY CURRENT

vs. LOAD CAPACITANCE

MAX3224-7/44/45E-15

LOAD CAPACITANCE (pF)

SUPPLY CURRENT (mA)

2Mbps

1.5Mbps

1Mbps

1 TRANSMITTER AT FULL DATA RATE
2 TRANSMITTERS AT 1/16 DATA RATE

0

20

10

40

30

60

50

70

0 400 800 1200 1600 2000

MAX3245E

SLEW RATE vs. LOAD CAPACITANCE

MAX3224-7/44/45E-14

LOAD CAPACITANCE (pF)

SLEW RATE (V/µs)

1 TRANSMITTER AT 1Mbps
2 TRANSMITTERS AT 62.5kbps

0

15
10

5

20

25

30

35

40

45

50

0 1000 2000 3000

MAX3245E

TRANSMITTER SKEW vs.

LOAD CAPACITANCE

MAX3224-7/44/45E-16

LOAD CAPACITANCE (pF)

TRANSMITTER SKEW (ns)

_______________Detailed Description

Dual Charge-Pump Voltage Converter

The MAX3224E–MAX3227E/MAX3244E/MAX3245E’s
internal power supply consists of a regulated dual
charge pump that provides output voltages of +5.5V
(doubling charge pump) and -5.5V (inverting charge
pump), over the +3.0V to +5.5V range. The charge
pump operates in discontinuous mode: if the output
voltages are less than 5.5V, the charge pump is
enabled; if the output voltages exceed 5.5V, the
charge-pump is disabled. Each charge pump requires
a flying capacitor (C1, C2) and a reservoir capacitor
(C3, C4) to generate the V+ and V- supplies.

The READY output (MAX3224E–MAX3227E) is low
when the charge pumps are disabled in shutdown
mode. The READY signal asserts high when V- goes
below -4V.

RS-232 Transmitters

The transmitters are inverting level translators that
convert CMOS-logic levels to 5.0V EIA/TIA-232 levels.
The MAX3224E/MAX3226E/MAX3244E guarantee a
250kbps data rate (1Mbps, for the
MAX3225E/MAX3227E/
MAX3245E) with worst-case loads of 3kΩ in parallel with
1000pF, providing compatibility with PC-to-PC com-

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

_______________________________________________________________________________________ 7

PIN

NAME

MAX3224E
MAX3225E

MAX3226E
MAX3227E

MAX3244E
MAX3245E

1 1 — READY

2 2 28 C1+ Positive Terminal of Voltage-Doubler Charge-Pump Capacitor
3 3 27 V+ +5.5V generated by the charge pump
4 4 24 C1- Negative Terminal of Voltage-Doubler Charge-Pump Capacitor
5 5 1 C2+ Positive Terminal of Inverting Charge-Pump Capacitor
6 6 2 C2- Negative Terminal of Inverting Charge-Pump Capacitor

7 7 3 V- -5.5V generated by the charge pump
8, 17 13 9–11 T_OUT RS-232 Transmitter Outputs
9, 16 8 4–8 R_IN RS-232 Receiver Inputs

10, 15 9 15–19 R_OUT TTL/CMOS Receiver Outputs

11 10 21

INVALID

Valid Signal Detector Output, active low. A logic high indicates that a valid
RS-232 level is present on a receiver input.

12, 13 11 12–14 T_IN TTL/CMOS Transmitter Inputs

14 12 23 FORCEON

Force-On Input, active high. Drive high to override AutoShutdown Plus,

keeping transmitters and receivers on (FORCEOFF must be high) (Table 1).
18 14 25 GND Ground
19 15 26 V

CC

+3.0V to +5.5V Single Supply Voltage

20 16 22

FORCEOFF

Force-Off Input, active low. Drive low to shut down transmitters, receivers

(except R2OUTB), and charge pump. This overrides AutoShutdown Plus

and FORCEON (Table 1).

— — 20 R2OUTB TTL/CMOS Noninverting Complementary Receiver Outputs. Always active.

Ready to Transmit Output, active-high. READY is enabled high when

V- goes below -4V and the device is ready to transmit.

FUNCTION

______________________________________________________________Pin Description

LapLink is a trademark of Traveling Software.

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

munication software (such as LapLink™). Transmitters
can be paralleled to drive multiple receivers. Figure 1
shows a complete system connection.

When FORCEOFF is driven to ground or when the Auto­Shutdown Plus circuitry senses that all receiver and
transmitter inputs are inactive for more than 30sec, the
transmitters are disabled and the outputs go into a high­impedance state. When powered off or shut down, the
outputs can be driven to ±12V. The transmitter inputs
do not have pull-up resistors. Connect unused inputs to
GND or VCC.

RS-232 Receivers

The receivers convert RS-232 signals to CMOS-logic
output levels. The MAX3224E–MAX3227E feature
inverting outputs that always remain active (Table 1).
The MAX3244E/MAX3245E have inverting three-state

±15kV ESD-Pr otected, 1µA, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus

8 _______________________________________________________________________________________

MAX3244E
MAX3245E

I/O
CHIP
WITH
UART

CPU

RS-232

POWER­MANAGEMENT
UNIT OR
KEYBOARD
CONTROLLER

FORCEOFF
FORCEON

INVALID

Figure 1. Interface Under Control of PMU

MAX3244E
MAX3245E

T1OUT

R2OUTB

Tx

5k

UART

V

CC

T1IN

THREE-STATED

LOGIC

TRANSITION

DETECTOR

R2IN

PROTECTION
DIODE

R2OUT

FORCEOFF = GND

V

CC

TO
µP

Rx

PREVIOUS

RS-232

Tx

UART

SHDN = GND

V

CC

V

CC

GND

Rx

5k

a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE

RECEIVER OUTPUT IN SHUTDOWN.

b) NEW MAX3244E/MAX3245E: IN SHUTDOWN, R2OUTB IS USED TO MONITOR

EXTERNAL DEVICES AND R2OUT IS THREE STATED, ELIMINATING A CURRENT
PATH THROUGH THE UART'S PROTECTION DIODE.

GND

PROTECTION
DIODE

I

I

Figure 2. The MAX3244E/MAX3245E detect RS-232 activity
when the UART and interface are shut down.

outputs that are high impedance when shut down
(FORCEOFF = GND) (Table 1).

The MAX3244E/MAX3245E feature an extra, always
active, noninverting output, R2OUTB. R2OUTB output
monitors receiver activity while the other receivers are
high impedance, allowing Ring Indicator applications to
be monitored without forward biasing other devices
connected to the receiver outputs. This is ideal for sys­tems where VCCis set to ground in shutdown to
accommodate peripherals such as UARTs (Figure 2).

The MAX3224E–MAX3227E/MAX3244E/MAX3245E fea­ture an INVALID output that is enabled low when no
valid RS-232 voltage levels have been detected on all
receiver inputs. Because INVALID indicates the receiv-

er input’s condition, it is independent of FORCEON and
FORCEOFF states (Figures 3 and 4).

AutoShutdown Plus Mode

The MAX3224E–MAX3227E/MAX3244E/MAX3245E
achieve a1µAsupplycurrentwith Maxim’s AutoShutdown
Plus feature, which operates when FORCEOFF is high
and a FORCEON is low. When these devices do not
sense a valid signal transition on any receiver and trans­mitter input for 30sec, the on-board charge pumps are
shut down, reducing supply current to 1µA. This occurs
if the RS-232 cable is disconnected or if the connected
peripheral transmitters are turned off, and the UART dri­ving the transmitter inputs is inactive. The system turns
on again when a valid transition is applied to any
RS-232 receiver or transmitter input. As a result, the sys-

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

_______________________________________________________________________________________ 9

Table 1. Output Control Truth Table

OPERATION

STATUS

FORCEON

FORCEOFF

VALID

RECEIVER

LEVEL

RECEIVER OR

TRANSMITTER

EDGE WITHIN

30sec

T_OUT

R_OUT

(MAX3224E/

MAX3225E/
MAX3226E/
MAX3227E)

R_OUT

(MAX3244E/

MAX3245E)

R2OUTB

(MAX3244E/

MAX3245E)

Shutdown
(Forced Off)

X 0 X X High-Z Active High-Z Active

Normal
Operation
(Forced On)

1 1 X X Active Active Active Active

Normal
Operation
(AutoShutdown
Plus)

0 1 X Yes Active Active Active Active

Shutdown (Auto­Shutdown Plus)

0 1 X No High-Z Active Active Active

Normal
Operation

INVALID*

1 Yes X Active Active Active Active

Normal
Operation

INVALID*

1 X Yes Active Active Active Active

Shutdown

INVALID*

1 No No High-Z Active Active Active

Normal
Operation
(AutoShutdown)

INVALID* INVALID**

Yes X Active Active Active Active

Shutdown
(AutoShutdown)

INVALID* INVALID**

No X High-Z Active High-Z Active

X = Don’t care

*

INVALID connected to FORCEON

**

INVALID connected to FORCEON and FORCEOFF

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

tem saves power without changes to the existing BIOS
or operating system.

Figures 3a and 3b depict valid and invalid RS-232
receiver voltage levels. INVALID indicates the receiver
input’s condition, and is independent of FORCEON and
FORCEOFF states. Figure 3 and Tables 1 and 2 sum­marize the operating modes of the MAX3224E–
MAX3227E/MAX3244E/MAX3245E. FORCEON and
FORCEOFF override AutoShutdown Plus circuitry.
When neither control is asserted, the IC selects
between these states automatically based on the last
receiver or transmitter input edge received.

When shut down, the device’s charge pumps turn off,
V+ is pulled to VCC, V- is pulled to ground, the transmit­ter outputs are high impedance, and READY

(MAX3224E– MAX3227E) is driven low. The time
required to exit shutdown is typically 100µs (Figure 8).

By connecting FORCEON to INVALID, the MAX3224E–
MAX3227E/MAX3244E/MAX3245E shut down when no
valid receiver level and no receiver or transmitter edge is
detected for 30sec, and wake up when a valid receiver
level or receiver or transmitter edge is detected.

By connecting FORCEON and FORCEOFF to INVALID,
the MAX3224E–MAX3227E/MAX3244E/MAX3245E shut
down when no valid receiver level is detected and

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus

10 ______________________________________________________________________________________

+0.3V

-0.3V

INVALID

R_IN

INVALID ASSERTED IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR
AT LEAST 30µs.

30µs

TIMER

R

+2.7V

-2.7V

INVALID

R_IN

INVALID DEASSERTED IF ANY RECEIVER INPUT HAS BEEN BETWEEN +2.7V AND -2.7V
FOR LESS THAN 30µs.

30µs

TIMER

R

AUTOSHDN

R_IN

T_IN

R

S
30sec
TIMER

EDGE

DETECT

EDGE

DETECT

FORCEOFF

FORCEON

Figure 3a. INVALID Functional Diagram, INVALID Low

Figure 3b. INVALID Functional Diagram, INVALID High

Figure 3c. AutoShutdown Plus Logic

POWERDOWN*

AUTOSHDN

FORCEOFF

FORCEON

* POWERDOWN IS ONLY AN INTERNAL SIGNAL.
IT CONTROLS THE OPERATIONAL STATUS OF
THE TRANSMITTERS AND THE POWER SUPPLIES.

Figure 3d. Power-Down Logic

RECEIVER INPUT LEVELS

-2.7V

-0.3V

+2.7V

+0.3V

0

INDETERMINATE

INVALID HIGH

INVALID LOW

INVALID HIGH

INDETERMINATE

Figure 4a. Receiver Positive/Negative Thresholds for INVALID

RS-232 SIGNAL

PRESENT AT ANY

RECEIVER INPUT

INVALID OUTPUT

Yes High

No Low

Table 2. INVALID Truth Table

wake up when a valid receiver level is detected (same
functionality as AutoShutdown feature on MAX3221E/
MAX3223E/MAX3243E).

A mouse or other system with AutoShutdown Plus may
need time to wake up. Figure 5 shows a circuit that
forces the transmitters on for 100ms, allowing enough
time for the other system to realize that the MAX3244E/
MAX3245E is awake. If the other system outputs valid
RS-232 signal transitions within that time, the RS-232
ports on both systems remain enabled.

Software-Controlled Shutdown

If direct software control is desired, use INVALID to
indicate DTR or Ring Indicator signal. Tie FORCEOFF
and FORCEON together to bypass the AutoShutdown
Plus so the line acts like a SHDN input.

±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
MAX3224E–MAX3227E/MAX3244E/MAX3245E 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.

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

______________________________________________________________________________________ 11

V

CC

0

0

V+

V-

V

CC

0

INVALID

OUTPUT

OUTPUT

TRANSMITTER

INPUTS

RECEIVER

INPUTS

}

INVALID
REGION

*MAX3224E–MAX3227E

TRANSMITTER

OUTPUTS

*V

CC

t

AUTOSHDN

t

WU

t

WU

t

INVL

t

INVH

t

AUTOSHDN

Figure 4b. AutoShutdown Plus, INVALID, and READY Timing Diagram

FORCEON

MASTER SHDN LINE

0.1µF 1M

FORCEOFF

MAX3224E
MAX3225E
MAX3226E
MAX3227E
MAX3244E
MAX3245E

POWER-

MANAGEMENT

UNIT

Figure 5. AutoShutdown Plus Initial Turn-On to Wake Up a
Mouse or Another System

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

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 IEC1000-4-2

3) ±15kV using IEC1000-4-2’s air-gap method.

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 6a shows the Human Body Model and Figure 6b
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.

IEC1000-4-2

The IEC1000-4-2 standard covers ESD testing and per­formance of finished equipment; it does not specifically
refer to integrated circuits. The MAX3224E–MAX3227E,
MAX3244E/MAX3245E help you design equipment that
meets Level 4 (the highest level) of IEC1000-4-2, with­out the need for additional ESD-protection components.

The major difference between tests done using the
Human Body Model and IEC1000-4-2 is higher peak
current in IEC1000-4-2, because series resistance is

±15kV ESD-Pr otected, 1µA, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus

12 ______________________________________________________________________________________

IP 100%

90%

36.8%

t

RL

TIME

t

DL

CURRENT WAVEFORM

PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)

I

r

10%

0

0

AMPERES

Figure 6b. Human Body Current Waveform

tr = 0.7ns to 1ns

30ns

60ns

t

100%

90%

10%

I

PEAK

I

Figure 7b. IEC1000-4-2 ESD Generator Current Waveform

CHARGE-CURRENT

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE
CAPACITOR

C

s

100pF

R

C

1M RD 1500Ω

HIGH-

VOLTAGE

DC

SOURCE

DEVICE
UNDER

TEST

Figure 6a. Human Body ESD Test Model Figure 7a. IEC1000-4-2 ESD Test Model

CHARGE CURRENT

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE
CAPACITOR

C

s

150pF

R

C

50M to 100M RD 330Ω

HIGH-

VOLTAGE

DC

SOURCE

DEVICE
UNDER

TEST

lower in the IEC1000-4-2 model. Hence, the ESD with­stand voltage measured to IEC1000-4-2 is generally
lower than that measured using the Human Body
Model. Figure 7a shows the IEC1000-4-2 model and
Figure 7b shows the current waveform for the 8kV,
IEC1000-4-2, 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.

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; polarized or nonpolarized capacitors
can be used. The charge pump requires 0.1µF capaci­tors for 3.3V operation. For other supply voltages, see
Table 3 for required capacitor values. Do not use val­ues smaller than those listed in Table 3. 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, C4,
and C

BYPASS

, 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), which usually rises at low
temperatures, influences the amount of ripple on V+
and V-.

Power-Supply Decoupling

In most circumstances, a 0.1µF VCCbypass capacitor
is adequate. In applications that are sensitive to power­supply noise, use a capacitor of the same value as
charge-pump capacitor C1. Connect bypass capaci­tors as close to the IC as possible.

Transmitter Outputs

when Exiting Shutdown

Figure 8 shows two transmitter outputs when exiting
shutdown mode. As they become active, the two trans­mitter outputs are shown going to opposite RS-232 lev­els (one transmitter input is high, the other is low). Each
transmitter is loaded with 3kΩ in parallel with 1000pF.
The transmitter outputs display no ringing or undesir­able transients as they come out of shutdown. Note that
the transmitters are enabled only when the magnitude
of V- exceeds approximately -3V.

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

______________________________________________________________________________________ 13

V

CC

(V)

C2, C3, C4

(µF)

3.0 to 3.6 0.22

3.15 to 3.6 0.1

C1, C

BYPASS

(µF)

0.22

0.1

4.5 to 5.5 0.33

3.0 to 5.5 1

0.047

0.22

Table 3. Required Minimum Capacitance
Values

5µs/div

T1OUT

FORCEON = FORCEOFF

T2OUT
READY

5V/div

0

2V/div

0

5V/div

0

VCC = 3.3V
C1–C4 = 0.1µF

Figure 8. Transmitter Outputs when Exiting Shutdown or
Powering Up

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

High Data Rates

The MAX3224E/MAX3226E/MAX3244E maintain the
RS-232 ±5.0V minimum transmitter output voltage even
at high data rates. Figure 9 shows a transmitter loop­back test circuit. Figure 10 shows a loopback test result
at 120kbps, and Figure 11 shows the same test at
250kbps. For Figure 10, all transmitters were driven
simultaneously at 120kbps into RS-232 loads in parallel
with 1000pF. For Figure 11, a single transmitter was dri­ven at 250kbps, and all transmitters were loaded with
an RS-232 receiver in parallel with 250pF.

The MAX3225E/MAX3227E/MAX3245E maintain the
RS-232 ±5.0V minimum transmitter output voltage at
data rates up to 1Mbps (MegaBaud). Figure 12 shows
a loopback test result with a single transmitter driven at
1Mbps and all transmitters loaded with an RS-232
receiver in parallel with 250pF.

Mouse Driveability

The MAX3244E/MAX3245E are specifically designed to
power serial mice while operating from low-voltage
power supplies. They have been tested with leading
mouse brands from manufacturers such as Microsoft
and Logitech. The MAX3244E/MAX3245E successfully
drove all serial mice tested and met their respective
current and voltage requirements. The MAX3244E/

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus

14 ______________________________________________________________________________________

MAX3224E
MAX3225E
MAX3226E
MAX3227E
MAX3244E
MAX3245E

5k

R_ IN

R_ OUT

FORCEON

C2-

C2+

C1-

C1+

V-

V+

V

CC

C4

C3*

C1

C2

C

BYPASS

V

CC

FORCEOFF

*C3 CAN BE RETURNED TO V

CC

OR GND.

T_ OUT

T_ IN

GND

V

CC

1000pF

Figure 9. Loopback Test Circuit

Figure 10. MAX3224E/MAX3226E/MAX3244E Loopback Test
Result at 120kbps

2µs/div

T1IN

T1OUT

R1OUT

5V/div

5V/div

5V/div

VCC = 3.3V

Figure 11. MAX3224E/MAX3226E/MAX3244E Loopback Test
Result at 250kbps

2µs/div

T1IN

T1OUT

R1OUT

5V/div

5V/div

5V/div

VCC = 3.3V

Figure 12. MAX3225E/MAX3227E/MAX3245E Loopback Test
Result at 1Mbps

200ns/div

T1IN

T1OUT

R1OUT

5V/div

5V/div

5V/div

VCC = 3.3V

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

______________________________________________________________________________________ 15

Figure 13a. Mouse Driver Test Circuit

+V

COMPUTER SERIAL PORT

+V

-V

GND

Tx

SERIAL
MOUSE

MAX3244E
MAX3245E

FORCEOFF

23

R5OUT

15

R4OUT

16

R3OUT

17

R2OUT

18

R1OUT

19

R2OUTB

20

LOGIC

OUTPUTS

5k

5k

5k

5k

5k

R5IN 8

R4IN

7

R3IN

6

R2IN 5

R1IN

4

RS-232
INPUTS

GND

25

LOGIC

INPUTS

T3IN

12

T2IN

13

T1IN

14

C2-

2

C2+

1

C1-

24

C1+

28

T3OUT

11

T2OUT 10

T1OUT 9

V-

3

V+

27

V

CC

V

CC

C4

0.1µF

C3

0.1µF

0.1µF

26

C1

0.1µF

C2

0.1µF

FORCEON

INVALID

22

21

TO POWER-

MANAGEMENT

UNIT

+3.3V

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

MAX3245E dual charge pump ensures the transmitters
will supply at least ±5V during worst-case conditions.
Figure 13b shows the transmitter output voltages under
increasing load current. Figure 13a shows a typical
mouse connection.

Interconnection with 3V and 5V Logic

The MAX3224E–MAX3227E/MAX3244E/MAX3245E can
directly interface with various 5V logic families, includ­ing ACT and HCT CMOS. See Table 4 for more infor­mation on possible combinations of interconnections.

Table 5 lists other Maxim ESD-powered transceivers.

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus

16 ______________________________________________________________________________________

SYSTEM

POWER-SUPPLY

VOLTAGE (V)

COMPATIBILITY

3.3 Compatible with all CMOS families
5 Compatible with all TTL and CMOS families

VCCSUPPLY

VOLTAGE

(V)

3.3
5

5 Compatible with ACT and HCT CMOS, and with AC, HC, or CD4000 CMOS3.3

Part

Supply

Voltage

Range

(V)

No.

of

Tx/Rx

Guaranteed

Data Rate

(kbps)

MAX3241E +3.0 to +5.5 3/5 250
MAX3243E +3.0 to +5.5 3/5 250
MAX3244E +3.0 to +5.5 3/5 250
MAX3245E +3.0 to +5.5 3/5 1Mbps
MAX3232E +3.0 to +5.5 2/2 250
MAX3222E +3.0 to +5.5 2/2 250
MAX3223E +3.0 to +5.5 2/2 250
MAX3224E +3.0 to +5.5 2/2 250
MAX3225E +3.0 to +5.5 2/2 1Mbps
MAX3221E +3.0 to +5.5 1/1 250

MAX3227E +3.0 to +5.5 1/1 1Mbps

MAX3226E +3.0 to +5.5 1/1 250

Supply

Current

(µA)

300

1
1

1
300
300

1

1

1

1

1

1

Auto-

Shutdown

Plus

—

—
Yes
Yes

—

—

—
Yes
Yes

—

Yes

Yes

Auto-

Shutdown

—

Yes

—
—
—
—

Yes

—
—

Yes

—

—

Human

Body

Model

(kV)

±15
±15
±15
±15
±15
±15
±15
±15
±15
±15

±15

±15

IEC 1000-4-2

Contact

Discharge

(kV)

±8
±8
±8
±8
±8
±8
±8
±8
±8
±8

±8

±8

IEC 1000-4-2

Air-Gap

Discharge

(kV)

±15
±15
±15
±15
±15
±15
±15
±15
±15
±15

±15

±15

Figure 13b. MAX324_E Transmitter Output Voltage vs. Load
Current per Transmitter

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

0 1 2 3 4 5 6 7 8 9 10

MAX2343E-FIG15

LOAD CURRENT PER TRANSMITTER (mA)

TRANSMITTER OUTPUT VOLTAGE (V)

V

OUT+

V

OUT-

V

OUT+

V

OUT-

V

CC

VCC = 3.0V

Table 5. ±15kV ESD-Protected, 3.0V to 5.5V Powered RS-232 Transceivers from Maxim

Table 4. Logic Family Compatibility with Various Supply Voltages

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

______________________________________________________________________________________ 17

MAX3244E
MAX3245E

FORCEON

23

R5OUT

15

R4OUT

16

R3OUT

17

R2OUT

18

R1OUT

19

R2OUTB

20

FORCEOFF

22

R5IN 8

R4IN

7

R3IN

6

R2IN 5

R1IN

4

GND

25

T3IN

12

T2IN

13

T1IN

14

C2-

2

C2+

1

C1-

24

C1+

28

T3OUT

11

T2OUT 10

T1OUT 9

V-

3

V+

27

V

CC

C4

0.1µF

C3

0.1µF

C1

0.1µF

C

BYPASS

0.1µF

C2

0.1µF

+3.3V

26

INVALID

21

AUTOSHUTDOWN

PLUS

MAX3226E
MAX3227E

FORCEON

READY

AUTOSHUTDOWN

PLUS

12

1

R1OUT9

FORCEOFF

16

INVALID 10

GND

14

T1IN

11

C2-

6

C2+

5

C1-

4

C1+

2

R1IN 8

T1OUT 13

V-

7

V+

3

V

CC

V

CC

C4

0.1µF

C3

0.1µF

0.1µF

15

C1

0.1µF

C2

0.1µF

C

BYPASS

C

BYPASS

+3.3V

TO POWER­MANAGEMENT
UNIT

5k

MAX3224E
MAX3225E

FORCEON

READY

14

1

R2OUT10

R1OUT15

FORCEOFF

20

INVALID 11

R2IN

9

GND

18

RS-232
OUTPUTS

TTL/CMOS

INPUTS

T2IN

12

T1IN

13

C2-

6

C2+

5

C1-

4

C1+

2

R1IN

16

T2OUT

8

T1OUT 17

V-

7

V+

3

V

CC

V

CC

C4

0.1µF

C3

0.1µF

0.1µF

19

C1

0.1µF

C2

0.1µF

+3.3V

RS-232
INPUTS

TO POWER­MANAGEMENT
UNIT

TTL/CMOS

OUTPUTS

5k

5k

AUTOSHUTDOWN

PLUS

___________________________________________________Typical Operating Circuits

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus

18 ______________________________________________________________________________________

16
15
14
13
12
11
10

9

1
2
3
4
5
6
7
8

READY

C1+

V+

C1-

C2+

C2-

V-

R1IN

FORCEOFF
V

CC

GND
T1OUT
FORCEON
T1IN
INVALID
R1OUT

MAX3226E
MAX3227E

SSOP

28
27
26
25
24
23
22
21
20
19
18
17
16
15

1
2
3
4
5
6
7
8

9
10
11
12
13
14

C1+
V+
V

CC

GND
C1­FORCEON
FORCEOFF
INVALID
R2OUTB
R1OUT
R2OUT
R3OUT
R4OUT
R5OUT

C2+

C2-

V­R1IN
R2IN
R3IN
R4IN
R5IN

T1OUT
T2OUT
T3OUT

T3IN
T2IN
T1IN

SO/SSOP

MAX3244E
MAX3245E

20
19
18
17
16
15
14
13

1
2
3
4
5
6
7
8

FORCEOFF
V

CC

GND
T1OUT

C1-

V+

C1+

READY

R1IN
R1OUT
FORCEON
T1IN

T2OUT

V-

C2-

C2+

12
11

9

10

T2IN
INVALIDR2OUT

R2IN

DIP/SSOP

MAX3224E
MAX3225E

___________________________________________________________Pin Configurations

___________________Chip Information

MAX3224E

TRANSISTOR COUNT: 1129

MAX3225E

TRANSISTOR COUNT: 1129

MAX3226E

TRANSISTOR COUNT: 1129

MAX3227E

TRANSISTOR COUNT: 1129

MAX3244E/MAX3245E

TRANSISTOR COUNT: 1335

_Ordering Information (continued)

PART

MAX3227ECAE*

MAX3227EEAE* -40°C to +85°C

0°C to +70°C 16 SSOP

16 SSOP

TEMP. RANGE PIN-PACKAGE

MAX3226ECAE*

MAX3226EEAE*

MAX3244ECWI

0°C to +70°C

-40°C to +85°C

0°C to +70°C 16 SSOP

16 SSOP

28 Wide SO
MAX3244ECAI
MAX3244EEWI
MAX3244EEAI -40°C to +85°C

-40°C to +85°C

0°C to +70°C 28 SSOP

28 Wide SO

28 SSOP
MAX3245ECWI

0°C to +70°C 28 Wide SO
MAX3245ECAI
MAX3245EEWI
MAX3245EEAI -40°C to +85°C

-40°C to +85°C

0°C to +70°C 28 SSOP

28 Wide SO
28 SSOP

*

Future product. Contact factory for availability.

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

______________________________________________________________________________________ 19

________________________________________________________Package Information

SOICW.EPS

SSOP.EPS

MAX3224E–MAX3227E/MAX3244E/MAX3245E

†

±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus

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.

20

____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

___________________________________________Package Information (continued)

PDIPN.EPS