General Description
The MAX3316–MAX3319 transceivers have a proprietary
low-dropout transmitter output stage enabling RS-232-
compatible performance from +2.25V to +3.0V with a
dual-charge pump. These devices require only four
0.1µF capacitors, and are guaranteed to operate at data
rates up to 460kbps.
The MAX3318/MAX3319 achieve a 1µA supply current
using Maxim’s revolutionary AutoShutdown Plus™ fea-
ture. These devices automatically enter a low-power
shutdown mode when the RS-232 cable is disconnected
or the transmitters of the connected peripherals are inac-
tive 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 MAX3318
is a 2-Tx/2-Rx device while the MAX3319 is a 1-Tx/1-Rx
device. These devices also feature a logic-level output
(READY) that asserts when the charge pump is regulat-
ing and the device is ready to begin transmitting.
The MAX3316/MAX3317 are 2-Tx/2-Rx transceivers. The
MAX3317 features a 1µA shutdown mode that can be
entered by driving SHDN low. The MAX3317’s receivers
remain active while in shutdown mode, allowing external
devices such as modems to be monitored using only
1µA supply current.
These devices are available in space-saving packages:
MAX3316 (16-pin SSOP and 20-pin TSSOP), MAX3317/
MAX3318 (20-pin SSOP and 20-pin TSSOP), and
MAX3319 (16-pin SSOP).
________________________Applications
Palmtop Computers
Hand-Held Instruments
Pagers
Cellular Phones
GPS
Handy Terminals
Hand-Held Electronic Books
Features
♦AutoShutdown Plus (MAX3318/MAX3319)
♦300µA Operating Supply Current
♦1µA Low-Power Shutdown with Receivers Active
♦Guaranteed 460kbps Data Rate
♦Guaranteed 4V/µs Slew Rate
♦RS-232 Compatible Down to 2.25V
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
________________________________________________________________ Maxim Integrated Products 1
MAX3319
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
VCC
VCC
C4
0.1µF
C3
0.1µF
0.1µF 15
C1
0.1µF
C2
0.1µF
CBYPASS
+2.5V
TO POWER-
MANAGEMENT
UNIT
5k
CMOS
INPUT
RS-232-
COMPATIBLE
OUTPUT
RS-232-
COMPATIBLE
INPUT
CMOS
OUTPUT
Typical Application Circuits
19-1751; Rev 0; 6/00
Ordering Information
AutoShutdown Plus is a trademark of Maxim Integrated Products.
Pin Configurations appear at end of data sheet.
Typical Application Circuits continued at end of data sheet.
PIN-PACKAGETEMP. RANGEPART
MAX3316CUP 0°C to +70°C 20 TSSOP
16 SSOP0°C to +70°CMAX3316CAE
MAX3316EUP -40°C to +85°C 20 TSSOP
16 SSOP-40°C to +85°CMAX3316EAE
PART NO. OF DRIVERS/
RECEIVERS
GUARANTEED
DATA RATE (kbps) READY OUTPUT SHUTDOWN
——460
460 —✓
—
—
✓
✓
460
460
2/2
2/2
2/2
1/1
MAX3316
MAX3317
MAX3318
MAX3319
AutoShutdown
Plus
—
—
✓
✓
Selector Guide
Ordering Information continued at end of data sheet.
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.
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = +2.25V to +3.0V, C1–C4 = 0.1µF, TA= TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +2.5V,
TA= +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.
VCC to GND..............................................................-0.3V to +6V
V+ to GND (Note 1) ..................................................-0.3V to +7V
V- to GND (Note 1) ...................................................-7V to +0.3V
V+ + |V-| (Note 1) .................................................................+13V
Input Voltages
T_IN, EN, SHDN, 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 (VCC + 0.3V)
Short-Circuit Duration, T_OUT to GND.......................Continuous
Continuous Power Dissipation (TA= +70°C)
16-Pin SSOP (derate 7.14mW/°C above +70°C).........571mW
20-Pin SSOP (derate 8.00mW/°C above +70°C).........640mW
20-Pin TSSOP (derate 7.00mW/°C above +70°C).......559mW
Operating Temperature Ranges
MAX331_C_ _.....................................................0°C to +70°C
MAX331_E_ _..................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Die Temperature ..............................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
MAX3316–MAX3319
TRANSMITTER OUTPUTS
PARAMETER
RECEIVER INPUTS
RECEIVER OUTPUTS
LOGIC INPUTS
SYMBOL MIN TYP MAX UNITS
Input Logic Threshold High 0.7 ✕VCC V
Input Logic Threshold Low 0.3 ✕VCC V
Supply Current 0.3 1 mA
Transmitter Input Hysteresis 0.3 V
Input Leakage Current ±0.01 ±1 µA
Output Leakage Current ±0.05 ±10 µA
AutoShutdown Plus Supply
Current 110
µA
Shutdown Supply Current 110
µA
Output Voltage Low 0.1 ✕VCC V
Output Voltage High 0.9 ✕VCC V
Input Voltage Range -25 +25 V
Input Threshold Low 0.3 ✕VCC V
Input Threshold High 0.7 ✕VCC V
Input Hysteresis 0.3 V
Input Resistance 357
kΩ
Output Voltage Swing ±3.7 ±4 V
CONDITIONS
IOUT = 0.5mA
T_IN, EN, SHDN, FORCEON, FORCEOFF
IOUT = -0.5mA
T_IN, EN, SHDN, FORCEON, FORCEOFF
SHDN = VCC, no load (MAX3317),
FORCEON = FORCEOFF = VCC, no load
(MAX3318/MAX3319)
T_IN, EN, SHDN, FORCEON, FORCEOFF
EN = VCC (MAX3317), receivers disabled
TA= +25°C
TA= +25°C
TA= +25°C
FORCEON = GND, FORCEOFF = VCC,
all R_IN idle, all T_IN idle
(MAX3318/MAX3319)
All transmitter outputs loaded with 3kΩto
ground
SHDN = GND (MAX3317), FORCEOFF = GND
(MAX3318/MAX3319)
DC CHARACTERISTICS (VCC = +2.5V, TA= +25°C)
LOGIC INPUTS
RECEIVER OUTPUTS
RECEIVER INPUTS
TRANSMITTER OUTPUTS
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +2.25V to +3.0V, C1–C4 = 0.1µF, TA= TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +2.5V,
TA= +25°C.)
TIMING CHARACTERISTICS
(VCC = +2.25V to +3.0V, C1–C4 = 0.1µF, TA= TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +2.5V,
TA= +25°C.)
R_IN to R_OUT, CL= 150pF
RL= 3kΩ, CL= 1000pF, one transmitter
switching
Normal operation (MAX3317)
Normal operation (MAX3317)
(Note 3)
CONDITIONS
0.175
tPLH
µs
0.175
tPHL
kbps
460
Maximum Data Rate
Receiver Propagation Delay
ns
250
Receiver Output Enable Time
ns
250
Receiver Output Disable Time
ns
100
|tPHL - tPLH|
Transmitter Skew
ns
50
|tPHL - tPLH|
Receiver Skew
UNITSMIN TYP MAXSYMBOLPARAMETER
Receiver Positive or Negative
Threshold to INVALID Low tINVL 30 µs
Receiver or Transmitter Edge to
Transmitters Enabled tWU 100 µs
Receiver or Transmitter Edge to
Transmitters Shutdown
tAUTO-
SHDN 15 30 60 s
Negative threshold
Figure 4b
Figure 4b (Note 2)
VCC = 2.5V, Figure 4b (Note 2)
Positive threshold
Receiver Input Threshold to
INVALID Output High
2.7 V
-2.7
Receiver Input Threshold to
INVALID Output Low -0.3 0.3 V
INVALID, READY Output
Voltage Low 0.1 ✕VCC V
INVALID, READY Output
Voltage High 0.9 ✕VCC V
Receiver Positive or Negative
Threshold to INVALID High tINVH 1µs
Figure 4a
Figure 4a
IOUT = 0.5mA
IOUT = -0.5mA
Figure 4b
PARAMETER SYMBOL MIN TYP MAX UNITS
Output Resistance 300 10M Ω
Output Short-Circuit Current ±25 ±60 mA
Output Leakage Current ±25 µA
CONDITIONS
VCC = 0, transmitter output = ±2V
VCC = 0 or 2.25V to 3.0V, VOUT = ±12V,
transmitters disabled
AutoShutdown Plus (FORCEON = GND, FORCEOFF = VCC) (MAX3318/MAX3319)
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VCC = +2.5V, C1–C4 = 0.1µF, 460kbps data rate, all transmitters loaded with 3kΩ, TA= +25°C, unless otherwise noted.)
0
2
6
4
8
10
2.25 2.652.45 2.85 3.05 3.25 3.45 3.65
MAX3316/MAX3317
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX3316 TOC01
V
CC
(V)
SUPPLY CURRENT (mA)
T1 TRANSMITTING AT SPECIFIED
DATA RATE
T2 TRANSMITTING AT 20kbps
C
L
= 1000pF
460kbps
230kbps
20kbps
-6
-2
-4
2
0
4
6
2.25 2.85 3.052.45 2.65 3.25 3.45 3.65
MAX3316/MAX3317
TRANSMITTER OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
MAX3316 TOC02
V
CC
(V)
TRANSMITTER OUTPUT VOLTAGE (V)
T_OUT+
T_OUT-
T1 TRANSMITTING AT 460kbps
T2 TRANSMITTING AT 20kbps
CL = 1000pF
-5
-2
-3
-4
-1
0
1
2
3
4
5
0 1000 2000 3000
MAX3316/MAX3317
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3316 TOC03
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
T_OUT+
T_OUT-
T1 TRANSMITTING AT 460kbps
T2 TRANSMITTING AT 20kbps
0
2
6
4
8
10
MAX3316/MAX3317
SLEW RATE vs. LOAD CAPACITANCE
MAX3316 TOC04
LOAD CAPACITANCE (pF)
SLEW RATE (V/µs)
0 20001000 3000
-SLEW
+SLEW
FOR DATA RATES UP TO 460kbps
TIMING CHARACTERISTICS (continued)
(VCC = +2.25V to +3.0V, C1–C4 = 0.1µF, TA= TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +2.5V,
TA= +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 crosspoints.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V/µs
430
VCC = 2.5V, TA= +25°C, RL= 3kΩto 7kΩ,
one transmitter switching, measured from +3V
to -3V or -3V to +3V, CL= 150pF to 2500pF
Transition-Region Slew Rate
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
_______________________________________________________________________________________ 5
0
3
9
6
12
15
2.25 2.652.45 2.85 3.05 3.25 3.45 3.65
MAX3318/MAX3319
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX3316 TOC06
V
CC
(V)
SUPPLY CURRENT (mA)
460kbps
230kbps
20kbps
T1 TRANSMITTING AT SPECIFIED
DATA RATE
T2 TRANSMITTING AT 20kbps
C
L
= 1000pF
-6
-2
-4
2
0
4
6
2.25 2.85 3.052.45 2.65 3.25 3.45 3.65
MAX3318/MAX3319
TRANSMITTER OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
MAX3316 TOC07
V
CC
(V)
TRANSMITTER OUTPUT VOLTAGE (V)
T1 TRANSMITTING AT 460kbps
T2 TRANSMITTING AT 20kbps
C
L
= 1000pF
T_OUT+
T_OUT-
-5
-2
-3
-4
-1
0
1
2
3
4
5
0 1000 2000 3000
MAX3318/MAX3319
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3316 TOC08
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
T_OUT+
T_OUT-
T1 TRANSMITTING AT 460kbps
T2 TRANSMITTING AT 20kbps
0
2
6
4
8
10
MAX3318/MAX3319
SLEW RATE vs. LOAD CAPACITANCE
MAX3316 TOC09
LOAD CAPACITANCE (pF)
SLEW RATE (V/µs)
0 20001000 3000
-SLEW
+SLEW
FOR DATA RATES UP TO 460kbps 0
10
5
20
15
30
25
35
MAX3318/MAX3319
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3316 TOC10
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
0 1000 2000 3000
460kbps
230kbps
20kbps
T1 TRANSMITTING AT SPECIFIED
DATA RATE
T2 TRANSMITTING AT 20kbps
Typical Operating Characteristics (continued)
(VCC = +2.5V, C1–C4 = 0.1µF, 460kbps data rate, all transmitters loaded with 3kΩ, TA= +25°C, unless otherwise noted.)
0
10
5
20
15
30
25
35
MAX3316/MAX3317
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3316 TOC05
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
0 1000 2000 3000
T1 TRANSMITTING AT SPECIFIED DATA RATE
T2 TRANSMITTING AT 20kbps
460kbps
230kbps
20kbps
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
6 _______________________________________________________________________________________
0
100
300
200
400
500
0 1000500 1500 2000 2500 3000
TRANSMITTER SKEW vs.
LOAD CAPACITANCE (tPLH - tPHL
)
MAX3316E TOC11
LOAD CAPACITANCE (pF)
TRANSMITTER SKEW (ns)
MAX3316/MAX3317
MAX3318/MAX3319
T1 TRANSMITTING AT 460kbps
T2 TRANSMITTING AT 20kbps
0
10
5
20
15
25
30
-40 0 20-20 40 60 80
MAX3318/MAX3319
READY TURN-ON TIME
vs. TEMPERATURE
MAX3316E TOC12
TEMPERATURE (°C)
READY TURN-ON TIME (µs)
0
40
120
80
160
200
-40 0-20 20 40 60 80
MAX3318/MAX3319
READY TURN-OFF TIME
vs. TEMPERATURE
MAX3316E TOC13
TEMPERATURE (°C)
READY TURN-OFF TIME (ns)
Typical Operating Characteristics (continued)
(VCC = +2.5V, C1–C4 = 0.1µF, 460kbps data rate, all transmitters loaded with 3kΩ, TA= +25°C, unless otherwise noted.)
Pin Description
—
—
MAX3318
SSOP/
TSSOP
2
3
4
8, 17
7
6
5
19
18
12, 13
10, 15
9, 16
No Connection
Receiver Enable, Active Low
FUNCTION
Positive Terminal of Voltage-Doubler Charge-
Pump Capacitor
+2 ✕VCC Generated by the Charge Pump
Negative Terminal of Voltage-Doubler Charge-
Pump Capacitor
RS-232 Transmitter Outputs
-2 ✕VCC Generated by the Charge Pump
Negative Terminal of Inverting Charge-Pump
Capacitor
Positive Terminal of Inverting Charge-Pump
Capacitor
+2.25V to +3.0V Single-Supply Voltage
Ground
CMOS Transmitter Inputs
CMOS Receiver Outputs
RS-232 Receiver Inputs
—
—
MAX3319
SSOP
2
3
4
13
7
6
5
15
14
11
9
8
N.C.
EN
NAME
C1+
V+
C1-
T_OUT
V-
C2-
C2+
VCC
GND
T_IN
R_OUT
R_IN
—1, 10, 11, 20 11, 14
— — 1
MAX3316 MAX3317
SSOP/
TSSOP
1 2 2
PIN
2 3 3
3 4 4
7, 14 8, 17 8, 17
6 7 7
5 6 6
4 5 5
16 19 19
15 18 18
10, 11 13, 14 12, 13
9, 12 12, 15 10, 15
8, 13 9, 16 9, 16
SSOP TSSOP
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
_______________________________________________________________________________________ 7
Pin Description (continued)
Detailed Description
Dual Charge-Pump Voltage Converter
The MAX3316–MAX3319s’ internal power supply con-
sists of a regulated dual charge pump that provides
output voltages of +4.4V (doubling charge pump) and
-4.3V (inverting charge pump), over the +2.25V to
+3.0V input voltage range. The charge pump operates
in discontinuous mode: if the output voltages are less
than 4.4V, the charge pump is enabled; if the output
voltages exceed 4.4V, 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 (MAX3318/MAX3319) is low when
the charge pumps are disabled in shutdown mode. The
READY signal asserts high when V- goes below -2.75V.
RS-232-Compatible Transmitters
The MAX3316–MAX3319s’ transmitters are inverting
level translators that convert CMOS-logic levels to
RS-232-compatible voltage levels. They guarantee a
460kbps data rate with worst-case loads of 3kΩin parallel
with 1000pF, providing compatibility with PC-to-PC
communication software (such as LapLink™).
The MAX3317’s transmitters are turned off (high imped-
ance) when SHDN is asserted low, putting the device in
shutdown mode. The MAX3318/MAX3319s’ transmitters
are turned off (high impedance) when FORCEOFF is
asserted low, or when the AutoShutdown Plus circuitry
senses that all receiver and transmitter inputs are inac-
tive for more than 30 seconds.
The transmitter outputs can be driven to ±12V when
power is off. The transmitter inputs do not have internal
pullup resistors. Connect unused inputs to GND or VCC.
Figure 1a shows an RS-232-compatibility circuit and
Figure 1b shows MAX3316–MAX3319 transmitter output
compatibility with an RS-232 receiver.
RS-232 Receivers
The MAX3316–MAX3319s’ receivers convert RS-232
signal levels into CMOS-logic output levels. The
receivers are rated to receive signals up to ±25V. The
MAX3316/MAX3318/MAX3319s’ receivers feature
inverting outputs that always remain active (Table 1).
The MAX3317’s receivers have inverting, three-state
outputs. In shutdown, the receivers can be active or
inactive (Table 2).
The MAX3318/MAX3319 feature an INVALID output that
is asserted low when no valid RS-232 voltage levels
have been detected on all receiver inputs. Because
INVALID indicates the receiver’s input condition, it
is independent of the states of FORCEON and
FORCEOFF.
LapLink is a trademark of Traveling Software.
PIN
MAX3316 MAX3317
SSOP/
TSSOP
MAX3318
SSOP/
TSSOP
MAX3319
SSOP
NAME FUNCTION
Shutdown Control, Active Low
Ready to Transmit Output, Active High. READY is
enabled high when V- goes below -2.75V and the
device is ready to transmit.
Valid Signal Detector Output, Active Low. A logic
high indicates that a valid RS-232 level is present
on a receiver input.
Force-On Input, Active High. Drive high to override
AutoShutdown Plus, keeping transmitters and
receivers on (FORCEOFF must be high) (Table 1).
Force-Off Input, Active Low. Drive low to shut
down transmitters, receivers, and charge pump.
This overrides AutoShutdown Plus and FORCEON
(Table 1).
FORCEOFF
FORCEON
INVALID
READY
SHDN
—
1
10
12
1620
14
11
1
—20
—
—
—
——
—
—
—
——
—
—
—
—
SSOP TSSOP
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
8 _______________________________________________________________________________________
MAX3317 Shutdown Mode
Supply current falls to less than 1µA in shutdown mode
(SHDN = low). When shut down, the device’s charge
pumps are turned off, V+ is pulled down to VCC, V- is
pulled to ground, and the transmitter outputs are disabled
(high impedance). The time required to exit shutdown is
typically 30µs, as shown in Figure 2. Connect SHDN to
VCC if the shutdown mode is not used; SHDN has no
effect on R_OUT.
MAX3318/MAX3319
AutoShutdown Plus Mode
Maxim’s AutoShutdown Plus feature on the MAX3318/
MAX3319 allows the supply current to fall to 1µA. These
devices will enter the AutoShutdown Plus mode if
FORCEOFF is high, FORCEON is low, and they do not
sense a valid signal transition on any receiver or trans-
mitter input for 30 seconds. This may occur if the RS-232
cable is disconnected or if the 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 system saves power
without changes to the existing BIOS or operating system.
Figure 4a depicts valid and invalid RS-232 receiver volt-
age levels. INVALID indicates the receiver input’s condi-
tion and is independent of FORCEON and FORCEOFF
states. Figure 3 and Table 1 summarize the operating
modes of the MAX3318/MAX3319. 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 trans-
mitter edge received.
X
X
X
X
VALID RECEIVER
LEVEL
Active
Active
Active
Active
R_OUT
No
Yes
X
X
RECEIVER OR
TRANSMITTER
EDGE WITHIN
30s
High-Z
Active
Active
High-Z
T_OUT
Shutdown
(AutoShutdown Plus) 0 1
Normal Operation
(AutoShutdown Plus) 0 1
Normal Operation
(Forced On) 1 1
Shutdown (Forced
Off) X 0
OPERATION
STATUS FORCEON FORCEOFF
No
Yes
No
X
Yes
Active
Active
Active
Active
Active
X
X
No
Yes
X
High-Z
Active
High-Z
Active
Active
Shutdown
(AutoShutdown) INVALID** INVALID**
Normal Operation
(AutoShutdown) INVALID** INVALID**
Shutdown INVALID*1
Normal Operation INVALID*1
Normal Operation INVALID*1
Table 1. Output Control Truth Table (MAX3318/MAX3319)
Table 2. Shutdown and Enable Control
Truth Table (MAX3317)
X = Don’t care
*
INVALID
connected to FORCEON
**
INVALID
connected to FORCEON and
FORCEOFF
SHDN EN T_OUT R_OUT
0 0 High-Z Active
0 1 High-Z High-Z
1 0 Active Active
1 1 Active High-Z
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
_______________________________________________________________________________________ 9
MAX3316
MAX3317
MAX3318
MAX3319
R_ IN
R_ OUT
C2-
C2+
C1-
C1+
V-
V+
VCC
C2
0.1µF
C1
0.1µF
CBYPASS
T_ OUT
T_ IN
GND
0.1µF
C3
0.1µF
C4
0.1µF
CL
1000pF
+2.5V
RS-232-
COMPLIANT
TRANSCEIVER
+5V
RX
TX
Figure 1a. RS-232-Compatibility Circuit
5V/div
5V/div
5V/div
T1 IN
MAX3316–MAX3319
T1 OUT
MAX3316–MAX3319
RS-232-COMPLIANT
RECEIVER OUTPUT
2V/div
2V/div
10µs/div
VCC OR SHDN
(MAX3317)
FORCEOFF
(MAX3318/MAX3319)
T1
T2
Figure 1b. MAX3316–MAX3319 Transmitter Output
Compatibility with an RS-232 Receiver
Figure 2. Transmitter Outputs when Exiting Shutdown or
Powering Up
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
10 ______________________________________________________________________________________
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 is driven low.
The time required to exit shutdown is typically 30µs
(Figure 2).
By connecting FORCEON to INVALID, the MAX3318/
MAX3319 shut down when no valid receiver level is
detected and wake up when a valid receiver level is
detected.
A system with AutoShutdown Plus may need time to
wake up. Figure 5 shows a circuit that forces the trans-
mitters on for 100ms, allowing enough time for the other
system to realize that the MAX3318/MAX3319 is awake.
If the other system outputs valid RS-232 signal transi-
tions within that time, the RS-232 ports on both systems
remain enabled.
Connecting to the PC
(MAX3318/MAX3319)
If direct software control is desired, use INVALID to
indicate DTR or ring indicator (RI) signal. This can be
used to connect a hand-held device to a PC. One
example is using the hot sync function on a personal
digital assistant (PDA). The transmitter and receiver
signals (T_OUT and R_IN) are used for communication,
while INVALID causes a change of state on RI. The
change of state on RI will trigger an interrupt on the PC
and allow communication to begin between the device
and the PC. This eliminates the need for the PC to poll
constantly the receiver or transmitter lines to determine
if the device is connected.
Applications Information
RS-232-Compatible Operation
The MAX3316–MAX3319 do not meet EIA-232 require-
ments for transmitter output voltage levels. EIA-232 com-
pliance specifies transmitter output voltage swings of
±5V when loaded with 3kΩand 2500pF.
The receiver inputs are fully EIA-232 compliant.
The MAX3316–MAX3319 will function properly with most
modern RS-232 interfaces. This allows RS-232-compati-
ble communication in low-voltage systems without the
added expense of a voltage tripler or switched-mode
power supply.
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 capaci-
tors. 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
+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
Figure 3a.
INVALID
Functional Diagram,
INVALID
Low
+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
Figure 3b.
INVALID
Functional Diagram,
INVALID
High
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
C2, C3, C4, and CBYPASS to maintain proper ratios
(C1 to other capacitors).
When using the minimum-required capacitor values,
make sure the capacitor value does not degrade exces-
sively with temperature. If in doubt, use capacitors with
a higher nominal value. The capacitor’s equivalent
series resistance (ESR), which usually rises at low tem-
peratures, influences the amount of ripple on V+ and V-.
Power-Supply Decoupling
In most circumstances, a 0.1µF bypass capacitor is
adequate. In applications that are sensitive to power-
supply noise, decouple VCC to ground with 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 2 shows two transmitter outputs when exiting
shutdown mode. As they become active, the two trans-
mitter outputs are shown going to opposite RS-232-
compatible levels (one transmitter input is high, the
other is low). Each transmitter is loaded with 3kΩin par-
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
______________________________________________________________________________________ 11
FORCEON
MASTER SHDN LINE
0.1µF1MΩ
FORCEOFF
MAX3318
MAX3319
POWER-
MANAGEMENT
UNIT
Figure 5. AutoShutdown Plus Initial Turn-On to Wake Up a
Mouse or Another System
VCC
0
0
V+
V-
VCC
0
INVALID
OUTPUT
READY
OUTPUT
TRANSMITTER
INPUTS
RECEIVER
INPUTS }INVALID
REGION
*MAX3318/MAX3319
TRANSMITTER
OUTPUTS
*VCC
tAUTOSHDN tWU tWU
tINVL tINVH tAUTOSHDN
Figure 4b. AutoShutdown Plus,
INVALID
, and READY Timing Diagram
allel with 2500pF. 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.
High Data Rates
The MAX3316–MAX3319 maintain RS-232-compatible
±3.7V minimum transmitter output voltage even at high
data rates. Figure 6 shows a transmitter loopback test
circuit. Figure 7 shows a loopback test result at
230kbps. For Figure 7, all transmitters were driven
simultaneously at 230kbps into EIA/TIA-562 loads in
parallel with 1000pF.
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
12 ______________________________________________________________________________________
2V/div
5V/div
2V/div
T1 IN
T1 OUT
R1 OUT
Figure 7. Loopback Test Result at 230kbps
MAX3316
MAX3317
MAX3318
MAX3319
5k
R_ IN
R_ OUT
FORCEON**
C2-
C2+
C1-
C1+
V-
V+
VCC
C4
C3*
C1
C2
CBYPASS
VCC
FORCEOFF**
*C3 CAN BE RETURNED TO VCC OR GND.
**MAX3318/MAX3319
T_ OUT
T_ IN
GND
VCC
CL
1000pF
Figure 6. Loopback Test Circuit
Chip Information
TRANSISTOR COUNT: 1130
PROCESS: CMOS
Ordering Information (continued)
PIN-PACKAGETEMP. RANGEPART
MAX3317CUP 0°C to +70°C 20 TSSOP
20 SSOP0°C to +70°CMAX3317CAP
MAX3317EUP -40°C to +85°C 20 TSSOP
20 SSOP-40°C to +85°CMAX3317EAP
MAX3318CUP 0°C to +70°C 20 TSSOP
20 SSOP0°C to +70°CMAX3318CAP
20 TSSOP-40°C to +85°CMAX3318EUP
MAX3318EAP -40°C to +85°C 20 SSOP
16 SSOP0°C to +70°C
MAX3319CAE
16 SSOP-40°C to +85°CMAX3319EAE
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
______________________________________________________________________________________ 13
Pin Configurations (continued)
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
READY FORCEOFF
VCC
GND
T1OUT
FORCEON
T1IN
INVALID
R1OUT
MAX3319
SSOP
C1+
V+
C2-
C1-
C2+
V-
R1IN
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
SHDN
VCC
GND
T1OUTC1-
V+
C1+
EN
R1IN
R1OUT
N.C.
T1INT2OUT
V-
C2-
C2+
12
11
9
10
T2IN
N.C.R2OUT
R2IN
MAX3317
SSOP/TSSOP
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
N.C.
VCC
GND
T1OUTC1-
V+
C1+
N.C.
R1IN
R1OUT
T1IN
T2INT2OUT
V-
C2-
C2+
12
11
9
10
R2OUT
N.C.N.C.
R2IN
MAX3316
TSSOP
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
C1+ VCC
GND
T1OUT
R1IN
R1OUT
T1IN
T2IN
R2OUT
MAX3316
SSOP
V+
C1-
V-
C2+
C2-
T2OUT
R2IN
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
FORCEOFF
VCC
GND
T1OUTC1-
V+
C1+
READY
R1IN
R1OUT
FORCEON
T1INT2OUT
V-
C2-
C2+
12
11
9
10
T2IN
INVALIDR2OUT
R2IN
MAX3318
SSOP/TSSOP
TOP VIEW
MAX3317
R2OUT10
1
R1OUT15
R2IN 9
20
GND
18
RS-232-
COMPATIBLE
OUTPUTS
CMOS
INPUTS
T2IN
12
T1IN
13
C2-
6
C2+
5
C1-
4
C1+
2
R1IN 16
T2OUT 8
T1OUT 17
V- 7
V+ 3
VCC
19
C1
0.1µF
C2
0.1µF
0.1µF
+2.5V
RS-232-
COMPATIBLE
INPUTS
CMOS
OUTPUTS 5k
5k
EN
SHDN
C3*
0.1µF
C4
0.1µF
*C3 CAN BE RETURNED TO EITHER VCC OR GROUND.
MAX3316
R2OUT9
R1OUT12
R2IN 8
GND
15
RS-232-
COMPATIBLE
OUTPUTS
CMOS
INPUTS
T2IN
10
T1IN
11
C2-
5
C2+
4
C1-
3
C1+
1
R1IN 13
T2OUT 7
T1OUT 14
V- 6
V+ 2
VCC
C4
0.1µF
16
0.1µF
0.1µF
0.1µF
+2.5V
RS-232-
COMPATIBLE
INPUTS
CMOS
OUTPUTS
C3*
0.1µF
5k
5k
CIRCUIT SHOWN IS FOR THE 16-PIN SSOP.
Typical Application Circuits (continued)
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
14 ______________________________________________________________________________________
MAX3316–MAX3319
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
Typical Application Circuits (continued)
CBYPASS
MAX3318
FORCEON
READY
14
1
R2OUT10
R1OUT15
FORCEOFF 20
INVALID 11
R2IN 9
GND
18
RS-232-COMPATIBLE
OUTPUTS
CMOS
INPUTS T2IN
12
T1IN
13
C2-
6
C2+
5
C1-
4
C1+
2
R1IN 16
T2OUT 8
T1OUT 17
V- 7
V+ 3
VCC
VCC
C4
0.1µF
C3
0.1µF
0.1µF 19
C1
0.1µF
C2
0.1µF
+2.5V
RS-232-COMPATIBLE
INPUTS
TO POWER-
MANAGEMENT
UNIT
CMOS
OUTPUTS 5k
5k
AutoShutdown
Plus
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implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
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