19-1901; Rev 0; 2/01
460kbps, 1µA Supply Current,
RS-232-Compatible Transceivers in µMAX
General Description
The MAX3311/MAX3313 are low-power, +5V EIA/TIA-
232-compatible transceivers. Both devices have one
transmitter and one receiver. The transceivers have a
proprietary low-dropout transmitter output stage
enabling RS-232-compatible operation from a +5V sup-
ply with a single inverting charge pump. These devices
require only three 0.1µF capacitors and will run at data
rates up to 460kbps while maintaining RS-232-compati-
ble output levels.
The MAX3311 features a 1µA shutdown mode. In shut-
down the device turns off the charge pump, pulls V- to
ground, and the transmitter output is disabled. The
MAX3313 features an
INVALID
output that asserts high
when an active RS-232 cable signal is connected, sig-
naling to the host that a peripheral is connected to the
communication port.
o
INVALID
Output (MAX3313)
o
Receiver Active in Shutdown (MAX3311)
o
Single Transceiver (1Tx/1Rx) in 10-Pin µMAX
o
RS-232-Compatible Operation
Features
o
1µA Low-Power Shutdown (MAX3311)
MAX3311/MAX3313
Ordering Information
________________________Applications
Digital Cameras
PDAs
GPS
POS
Telecommunications
Handy Terminals
Set-Top Boxes
+5V
C
BYPASS
0.1µF
9
C1
0.1µF
C1+
1
V
CC
V-
8
C2
0.1µF
C1-
PART
MAX3311CUB
MAX3311EUB
MAX3313CUB
MAX3313EUB
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
10 µMAX
10 µMAX
10 µMAX
10 µMAX
Typical Operating Circuit
Pin Configurations
2
TOP VIEW
V
CC
1
C1-
SHDN
TIN
ROUT
2
3
4
5
10
GND
9
C1+
MAX3311
MAX3313
TOUT 7
4 TIN
MAX3311
5 ROUT
RIN 6
5kΩ
8
7
6
V-
TOUT
RIN
SHDN (MAX3311) 3
INVALID (MAX3313)
GND
10
CAPACITORS MAY BE POLARIZED OR NONPOLARIZED.
µMAX
Pin Configurations continued at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
460kbps, 1µA Supply Current,
RS-232-Compatible Transceivers in µMAX
MAX3311/MAX3313
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ..............................................................-0.3V to +6V
V- to GND .................................................................+0.3V to -7V
V
CC
+
|
V-
|
.............................................................................+13V
Input Voltages
TIN,
SHDN
to GND .................................................-0.3V to +6V
RIN to GND ........................................................................±25V
Output Voltages
TOUT to GND..................................................................±13.2V
ROUT,
INVALID
to GND .......................…-0.3V to (V
CC
+ 0.3V)
Short-Circuit Duration
TOUT to GND ...........................................................Continuous
Continuous Power Dissipation
10-Pin µMAX (derate 5.6mW/°C above +70°C) .............444mW
Operating Temperature Ranges
MAX331_CUB .......................................................0°C to +70°C
MAX331_EUB ....................................................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°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.
ELECTRICAL CHARACTERISTICS
(V
CC
= +5V, C1 and C2 = 0.1µF, T
A
= T
MIN
to T
MAX
. Typical values are at T
A
= +25°C.)
PARAMETER
DC CHARACTERISTICS
Supply Operation Range
Supply Current
Shutdown Supply Current
LOGIC INPUTS (TIN,
SHDN)
Input Logic Threshold Low
Input Logic Threshold High
Transmitter Input Hysteresis
Input Leakage Current
RECEIVER OUTPUT
Output Voltage Low
Output Voltage High
INVALID
OUTPUT (MAX3313 ONLY)
Receiver Input Threshold to
INVALID
Output High
Receiver Input Threshold to
INVALID
Output Low
INVALID
Output Low
INVALID
Output High
Receiver Positive or Negative
Threshold to
INVALID
High
Receiver Positive or Negative
Threshold to
INVALID
Low
V
OL
V
OH
Figure 5, positive threshold
Figure 5, negative threshold
Figure 5
I
OUT
= 1.6mA
I
OUT
= -1.0mA
Figure 5
Figure 5
V
CC
- 0.6
0.1
30
-2.7
-0.3
0.3
0.4
2.7
V
V
V
V
µs
µs
V
OL
V
OH
I
OUT
= 1.6mA
I
OUT
= -1.0mA
V
CC
-
0.6
V
CC
-
0.1
0.4
V
V
V
IL
V
IH
0.5
±0.01
±1
0.8
2.4
V
V
V
µA
V
CC
SHDN
= V
CC
, no load
SHDN
= GND (MAX3311 only)
4.5
5
100
1
5.5
250
10
V
µA
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2 _________________________________________________________________________________________
460kbps, 1µA Supply Current,
RS-232-Compatible Transceivers in µMAX
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +5V, C1 and C2 = 0.1µF, T
A
= T
MIN
to T
MAX
. Typical values are at T
A
= +25°C.)
PARAMETER
RECEIVER INPUT
Input Threshold Low
Input Threshold High
Input Hysteresis
Input Resistance
TRANSMITTER OUTPUT
Output Voltage Swing
Output Resistance (Note 1)
Output Short-Circuit Current
Output Leakage Current
V
OUT
=
±12V,
transmitter disabled
Transmitter output loaded with 3kΩ to
ground
V
CC
= 0, transmitter output =
±2V
±3.7
300
±60
±25
V
Ω
mA
µA
V
IL
V
IH
0.5
5
0.8
2.4
V
V
V
kΩ
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX3311/MAX3313
Note 1:
Not tested—guaranteed by design.
TIMING CHARACTERISTICS
(V
CC
= +5V, C1 and C2 = 0.1µF, T
A
= T
MIN
to T
MAX
. Typical values are at T
A
= +25°C.)
PARAMETER
Maximum Data Rate
Receiver Propagation Delay
Transmitter Skew
Receiver Skew
Transition Region Slew Rate
RL = 3kΩ to 7kΩ, CL = 150pF to 1000pF,
measured from +3V to -3V or from -3V to +3V
t
PLH
,
t
PHL
SYMBOL
CONDITIONS
RL = 3kΩ, CL = 1000pF
Receiver input to receiver output
CL = 150pF
MIN
460
0.15
100
50
11
TYP
MAX
UNITS
kbps
µs
ns
ns
V/µs
_______________________________________________________________________________________
3
460kbps, 1µA Supply Current,
RS-232-Compatible Transceivers in µMAX
MAX3311/MAX3313
Typical Operating Characteristics
(V
CC
= +5V, 0.1µF capacitors, transmitter loaded with 3kΩ and C
L
, T
A
= +25°C, unless otherwise noted.)
SLEW RATE
vs. LOAD CAPACITANCE
MAX3311/13 toc01
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3311/13 toc02
SUPPLY CURRENT
vs. LOAD CAPACITANCE
460kbps
250kbps
10
8
6
4
2
0
20kbps
120kbps
MAX3311/13 toc03
14
250 kbps DATA RATE
12
SLEW RATE (V/µs)
10
8
6
4
2
0
0
500
1000
1500
2000
2500
-SLEW
+SLEW
6
TRANSMITTER OUTPUT VOLTAGE (V)
5
4
3
2
1
0
-1
-2
-3
-4
-5
460kbps/250kbps/120kbps
460kbps/250kbps/120kbps
14
12
SUPPLY CURRENT (mA)
3000
0
500
1000
1500
2000
2500
3000
0
500
1000
1500
2000
2500
3000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
Pin Description
PIN
MAX3311
1
2
3
—
4
5
6
7
8
9
10
MAX3313
1
2
—
3
4
5
6
7
8
9
10
NAME
V
CC
C1-
SHDN
INVALID
TIN
ROUT
RIN
TOUT
V-
C1+
GND
FUNCTION
+5V External Power Supply. Decouple with a 0.1µF capacitor to ground.
Negative Terminal of the Voltage Inverter Charge-Pump Capacitor
Shutdown Active-Low (0 = off, 1 = on)
Valid Signal Detector Output, Active-Low. A logic high indicates that a valid
RS-232 level is present on the receiver input.
TTL/CMOS Transmitter Input
TTL/CMOS Receiver Output
RS-232 Receiver Input
RS-232-Compatible Transmitter Output
-4.3V generated by the charge pump. Connect a 0.1µF capacitor to ground.
Positive Terminal of the Voltage Inverter Charge-Pump Capacitor
Ground
4
_______________________________________________________________________________________
460kbps, 1µA Supply Current,
RS-232-Compatible Transceivers in µMAX
Detailed Description
Single Charge-Pump Voltage Converter
The MAX3311/MAX3313 internal power supply has a
single inverting charge pump that provides a negative
voltage from a single +5V supply. The charge pump
operates in a discontinuous mode and requires a flying
capacitor (C1) and a reservoir capacitor (C2) to gener-
ate the V- supply.
factor of 2) reduces power consumption. C2 can be
increased without changing C1’s value. However, do
not increase C1’s value without also increasing the
value of C2 and C
BYPASS
to maintain the proper ratios
(C1 to the other capacitors).
When using the minimum 0.1µF capacitors, make sure
the capacitance does not degrade excessively with
temperature. If in doubt, use capacitors with a larger
nominal value. The capacitor’s equivalent series resis-
tance (ESR) usually rises at low temperatures and influ-
ences the amount of ripple on V-.
To reduce the output impedance at V-, use larger
capacitors (up to 10µF).
Bypass V
CC
to ground with at least 0.1µF. In applica-
tions sensitive to power-supply noise generated by the
charge pump, decouple V
CC
to ground with a capaci-
tor the same size as (or larger than) charge-pump
capacitors C1 and C2.
MAX3311/MAX3313
RS-232-Compatible Driver
The transmitter is an inverting level translator that con-
verts CMOS-logic levels to EIA/TIA-232-compatible lev-
els. It guarantees data rates up to 460kbps with
worst-case loads of 3kΩ in parallel with 1000pF. When
SHDN
is driven low, the transmitter is disabled and put
into three state. The transmitter input does not have an
internal pullup resistor.
RS-232 Receiver
The MAX3311/MAX3313 receiver converts RS-232 sig-
nals to CMOS-logic output levels. The MAX3311 receiv-
er will remain active during shutdown mode. The
MAX3313
INVALID
indicates when an RS-232 signal is
present at the receiver input, and therefore when the
port is in use.
The MAX3313
INVALID
output is pulled low when no
valid RS-232 signal level is detected on the receiver
input.
Transmitter Output when Exiting
Shutdown
Figure 1 shows the 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 the MAX3311
comes out of shutdown. Note that the transmitter is
enabled only when the magnitude of V- exceeds
approximately -3V.
MAX3311 Shutdown Mode
In shutdown mode, the charge pump is turned off, V- is
pulled to ground, and the transmitter output is disabled
(Table 1). This reduces supply current typically to 1µA.
The time required to exit shutdown is typically less than
100µs.
Applications Information
Capacitor Selection
The capacitor type used for C1 and C2 is not critical for
proper operation; either polarized or nonpolarized
capacitors are acceptable. If polarized capacitors are
used, connect polarity as shown in the
Typical
Operating Circuit.
The charge pump requires 0.1µF
capacitors. Increasing the capacitor values (e.g., by a
5V/div
0
TIN = GND
SHDN
1.5V/div
0
TOUT
TIN = V
CC
Table 1. MAX3311 Shutdown Logic Truth
Table
SHDN
L
H
TRANSMITTER
OUTPUT
High Z
Active
RECEIVER
OUTPUT
Active
Active
CHARGE
PUMP
Inactive
Active
10µs/div
Figure 1. Transmitter Output when Exiting Shutdown or
Powering Up
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