MAX3319CAE+T [MAXIM]
Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, CMOS, PDSO16, SSOP-16;
| 型号： | MAX3319CAE+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, CMOS, PDSO16, SSOP-16 驱动 光电二极管 接口集成电路 驱动器 |
| 文件： | 总15页 (文件大小：214K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1751; Rev 0; 6/00
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
General Description
Features
o AutoShutdown Plus (MAX3318/MAX3319)
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.
o 300µA Operating Supply Current
o 1µA Low-Power Shutdown with Receivers Active
o Guaranteed 460kbps Data Rate
o Guaranteed 4V/µs Slew Rate
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.
o RS-232 Compatible Down to 2.25V
Ordering Information
PART
TEMP. RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
20 TSSOP
16 SSOP
MAX3316CUP
MAX3316CAE
MAX3316EUP
MAX3316EAE
20 TSSOP
16 SSOP
Ordering Information continued at end of data sheet.
Typical Application Circuits
+2.5V
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).
15
0.1 F
C
BYPASS
V
CC
3
7
2
C1+
V+
V-
C1
0.1 F
C3
0.1 F
4
5
6
C1-
C2+
MAX3319
C4
0.1 F
C2
0.1 F
C2-
RS-232-
COMPATIBLE
OUTPUT
11
T1IN
T1OUT 13
CMOS
INPUT
________________________Applications
RS-232-
COMPATIBLE
INPUT
Palmtop Computers
Hand-Held Instruments
Pagers
9
R1OUT
R1IN
5k
8
CMOS
OUTPUT
Cellular Phones
GPS
TO POWER-
MANAGEMENT
UNIT
READY
INVALID 10
1
AutoShutdown
Plus
Handy Terminals
Hand-Held Electronic Books
FORCEOFF
FORCEON
16
12
V
CC
GND
14
AutoShutdown Plus is a trademark of Maxim Integrated Products.
Typical Application Circuits continued at end of data sheet.
Pin Configurations appear at end of data sheet.
Selector Guide
NO. OF DRIVERS/
RECEIVERS
GUARANTEED
DATA RATE (kbps)
AutoShutdown
PART
READY OUTPUT
SHUTDOWN
Plus
MAX3316
MAX3317
MAX3318
MAX3319
2/2
2/2
2/2
1/1
460
460
460
460
—
—
ꢀ
—
—
—
ꢀ
ꢀ
—
—
ꢀ
ꢀ
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND..............................................................-0.3V to +6V
Short-Circuit Duration, T_OUT to GND.......................Continuous
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
Continuous Power Dissipation (T = +70°C)
A
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
T_IN, EN, SHDN, FORCEON,
FORCEOFF to GND ..................................................-0.3V to +6V
R_IN to GND ..................................................................... 25V
Output Voltages
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
T_OUT to GND............................................................... 13.2V
R_OUT, INVALID, READY to GND ..........-0.3V to (V
+ 0.3V)
CC
Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
= +2.25V to +3.0V, C1–C4 = 0.1µF, T = T
to T
, unless otherwise noted. Typical values are at V = +2.5V,
CC
CC
A
MIN
MAX
T
A
= +25°C.)
PARAMETER
SYMBOL
= +2.5V, T = +25°C)
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS (V
CC
A
FORCEON = GND, FORCEOFF = V
all R_IN idle, all T_IN idle
(MAX3318/MAX3319)
,
CC
AutoShutdown Plus Supply
Current
1
1
10
10
1
µA
µA
SHDN = GND (MAX3317), FORCEOFF = GND
(MAX3318/MAX3319)
Shutdown Supply Current
Supply Current
SHDN = V , no load (MAX3317),
CC
0.3
mA
FORCEON = FORCEOFF = V , no load
CC
(MAX3318/MAX3319)
LOGIC INPUTS
0.3 ✕ V
CC
Input Logic Threshold Low
Input Logic Threshold High
V
V
T_IN, EN, SHDN, FORCEON, FORCEOFF
T_IN, EN, SHDN, FORCEON, FORCEOFF
0.7 ✕ V
CC
Transmitter Input Hysteresis
Input Leakage Current
RECEIVER OUTPUTS
Output Leakage Current
Output Voltage Low
Output Voltage High
RECEIVER INPUTS
Input Voltage Range
Input Threshold Low
Input Threshold High
Input Hysteresis
0.3
V
0.01
1
µA
T_IN, EN, SHDN, FORCEON, FORCEOFF
0.05
10
µA
V
EN = V
(MAX3317), receivers disabled
CC
0.1 ✕ V
I
= 0.5mA
= -0.5mA
CC
OUT
OUT
0.9 ✕ V
-25
I
V
CC
+25
V
V
V
V
k
0.3 ✕ V
T
T
= +25°C
= +25°C
CC
A
0.7 ✕ V
3
CC
A
0.3
5
Input Resistance
T
A
= +25°C
7
TRANSMITTER OUTPUTS
All transmitter outputs loaded with 3k to
ground
Output Voltage Swing
3.7
4
V
2
_______________________________________________________________________________________
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
ELECTRICAL CHARACTERISTICS (continued)
(V
= +2.25V to +3.0V, C1–C4 = 0.1µF, T = T
= +25°C.)
to T
, unless otherwise noted. Typical values are at V = +2.5V,
CC
CC
A
MIN
MAX
T
A
PARAMETER
SYMBOL
CONDITIONS
= 0, transmitter output = 2V
MIN
TYP
10M
25
MAX
UNITS
Output Resistance
V
V
300
CC
Output Short-Circuit Current
60
25
mA
µA
= 0 or 2.25V to 3.0V, V
= 12V,
CC
OUT
Output Leakage Current
transmitters disabled
AutoShutdown Plus (FORCEON = GND, FORCEOFF = V ) (MAX3318/MAX3319)
CC
Positive threshold
Negative threshold
2.7
0.3
Receiver Input Threshold to
INVALID Output High
Figure 4a
Figure 4a
V
V
-2.7
-0.3
Receiver Input Threshold to
INVALID Output Low
INVALID, READY Output
Voltage Low
0.1 ✕ V
CC
I
= 0.5mA
V
OUT
OUT
INVALID, READY Output
Voltage High
0.9 ✕ V
I
= -0.5mA
V
CC
Receiver Positive or Negative
Threshold to INVALID High
t
Figure 4b
1
µs
µs
µs
s
INVH
Receiver Positive or Negative
Threshold to INVALID Low
t
Figure 4b
30
INVL
Receiver or Transmitter Edge to
Transmitters Enabled
t
Figure 4b (Note 2)
100
30
WU
Receiver or Transmitter Edge to
Transmitters Shutdown
t
AUTO-
SHDN
V
CC
= 2.5V, Figure 4b (Note 2)
15
60
TIMING CHARACTERISTICS
CC
(V
= +2.25V to +3.0V, C1–C4 = 0.1µF, T = T
to T
, unless otherwise noted. Typical values are at V = +2.5V,
CC
A
MIN
MAX
T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
R = 3k , C = 1000pF, one transmitter
switching
L
L
Maximum Data Rate
460
kbps
t
t
0.175
0.175
250
PHL
Receiver Propagation Delay
R_IN to R_OUT, C = 150pF
L
µs
PLH
Receiver Output Enable Time
Receiver Output Disable Time
Transmitter Skew
Normal operation (MAX3317)
Normal operation (MAX3317)
(Note 3)
ns
ns
ns
ns
250
t
- t
100
PHL PLH
Receiver Skew
t
- t
50
PHL PLH
_______________________________________________________________________________________
3
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
TIMING CHARACTERISTICS (continued)
(V
= +2.25V to +3.0V, C1–C4 = 0.1µF, T = T
to T
, unless otherwise noted. Typical values are at V = +2.5V,
CC
CC
A
MIN
MAX
T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
= 2.5V, T = +25°C, R = 3k to 7k ,
MIN
TYP
MAX
UNITS
V
CC
A
L
Transition-Region Slew Rate
one transmitter switching, measured from +3V
to -3V or -3V to +3V, C = 150pF to 2500pF
4
30
V/µs
L
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.
Typical Operating Characteristics
(V
= +2.5V, C1–C4 = 0.1µF, 460kbps data rate, all transmitters loaded with 3k , T = +25°C, unless otherwise noted.)
A
CC
MAX3316/MAX3317
TRANSMITTER OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
MAX3316/MAX3317
SUPPLY CURRENT vs. SUPPLY VOLTAGE
10
8
6
4
T_OUT+
460kbps
230kbps
2
T1 TRANSMITTING AT 460kbps
T2 TRANSMITTING AT 20kbps
6
C = 1000pF
L
0
4
20kbps
-2
-4
-6
T1 TRANSMITTING AT SPECIFIED
DATA RATE
T_OUT-
2
T2 TRANSMITTING AT 20kbps
C = 1000pF
L
0
2.25 2.45 2.65 2.85 3.05 3.25 3.45 3.65
2.25 2.45 2.65 2.85 3.05 3.25 3.45 3.65
(V)
V
(V)
V
CC
CC
MAX3316/MAX3317
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3316/MAX3317
SLEW RATE vs. LOAD CAPACITANCE
5
4
10
8
FOR DATA RATES UP TO 460kbps
T_OUT+
3
-SLEW
T1 TRANSMITTING AT 460kbps
T2 TRANSMITTING AT 20kbps
2
1
6
+SLEW
0
-1
-2
-3
-4
-5
4
2
T_OUT-
0
0
1000
2000
3000
0
1000
2000
3000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
4
_______________________________________________________________________________________
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
Typical Operating Characteristics (continued)
(V
= +2.5V, C1–C4 = 0.1µF, 460kbps data rate, all transmitters loaded with 3k , T = +25°C, unless otherwise noted.)
A
CC
MAX3316/MAX3317
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3318/MAX3319
TRANSMITTER OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
MAX3318/MAX3319
SUPPLY CURRENT vs. SUPPLY VOLTAGE
35
15
12
9
6
4
T1 TRANSMITTING AT SPECIFIED DATA RATE
T2 TRANSMITTING AT 20kbps
T_OUT+
460kbps
30
25
20
15
10
5
2
460kbps
230kbps
230kbps
20kbps
T1 TRANSMITTING AT 460kbps
T2 TRANSMITTING AT 20kbps
C = 1000pF
L
0
6
-2
-4
-6
20kbps
T1 TRANSMITTING AT SPECIFIED
DATA RATE
T2 TRANSMITTING AT 20kbps
T_OUT-
3
C = 1000pF
L
0
0
0
1000
2000
3000
2.25 2.45 2.65 2.85 3.05 3.25 3.45 3.65
(V)
2.25 2.45 2.65 2.85 3.05 3.25 3.45 3.65
LOAD CAPACITANCE (pF)
V
V
(V)
CC
CC
MAX3318/MAX3319
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3318/MAX3319
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3318/MAX3319
SLEW RATE vs. LOAD CAPACITANCE
5
4
35
30
25
20
15
10
5
10
T1 TRANSMITTING AT SPECIFIED
DATA RATE
T2 TRANSMITTING AT 20kbps
T_OUT+
3
8
6
4
2
0
-SLEW
+SLEW
2
T1 TRANSMITTING AT 460kbps
T2 TRANSMITTING AT 20kbps
460kbps
230kbps
1
0
-1
-2
-3
-4
-5
20kbps
T_OUT-
FOR DATA RATES UP TO 460kbps
0
0
1000
2000
3000
0
1000
2000
3000
0
1000
2000
3000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
_______________________________________________________________________________________
5
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
Typical Operating Characteristics (continued)
(V
= +2.5V, C1–C4 = 0.1µF, 460kbps data rate, all transmitters loaded with 3k , T = +25°C, unless otherwise noted.)
A
CC
MAX3318/MAX3319
READY TURN-ON TIME
vs. TEMPERATURE
MAX3318/MAX3319
READY TURN-OFF TIME
vs. TEMPERATURE
TRANSMITTER SKEW vs.
LOAD CAPACITANCE ( t - t
)
PLH PHL
30
25
20
15
10
5
500
200
160
120
80
T1 TRANSMITTING AT 460kbps
T2 TRANSMITTING AT 20kbps
400
300
200
100
0
MAX3316/MAX3317
MAX3318/MAX3319
40
0
0
-40
-20
0
20
40
60
80
0
500 1000 1500 2000 2500 3000
LOAD CAPACITANCE (pF)
-40
-20
0
20
40
60
80
TEMPERATURE ( C)
TEMPERATURE ( C)
Pin Description
PIN
NAME
FUNCTION
MAX3317 MAX3318
MAX3316
MAX3319
SSOP
SSOP/
SSOP/
SSOP
TSSOP
TSSOP
TSSOP
Positive Terminal of Voltage-Doubler Charge-
Pump Capacitor
1
2
3
2
3
4
2
3
4
2
3
4
2
3
4
C1+
V+
+2 ✕ V
CC
Generated by the Charge Pump
Negative Terminal of Voltage-Doubler Charge-
Pump Capacitor
C1-
Positive Terminal of Inverting Charge-Pump
Capacitor
4
5
5
6
5
6
5
6
5
6
C2+
C2-
Negative Terminal of Inverting Charge-Pump
Capacitor
6
7, 14
8, 13
9, 12
10, 11
15
7
8, 17
9, 16
12, 15
13, 14
18
7
7
8, 17
9, 16
10, 15
12, 13
18
7
V-
-2 ✕ V Generated by the Charge Pump
CC
8, 17
9, 16
10, 15
12, 13
18
13
8
T_OUT
R_IN
RS-232 Transmitter Outputs
RS-232 Receiver Inputs
CMOS Receiver Outputs
CMOS Transmitter Inputs
Ground
9
R_OUT
T_IN
11
14
15
—
—
GND
16
19
19
19
V
CC
+2.25V to +3.0V Single-Supply Voltage
Receiver Enable, Active Low
No Connection
—
—
1
—
EN
—
1, 10, 11, 20
11, 14
—
N.C.
6
_______________________________________________________________________________________
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
Pin Description (continued)
PIN
NAME
FUNCTION
MAX3317 MAX3318
MAX3316
MAX3319
SSOP
SSOP/
SSOP/
SSOP
TSSOP
TSSOP
TSSOP
—
—
20
—
—
Shutdown Control, Active Low
SHDN
Ready to Transmit Output, Active High. READY is
enabled high when V- goes below -2.75V and the
device is ready to transmit.
—
—
—
—
—
1
1
READY
Valid Signal Detector Output, Active Low. A logic
high indicates that a valid RS-232 level is present
on a receiver input.
—
—
—
—
11
14
10
12
INVALID
Force-On Input, Active High. Drive high to override
AutoShutdown Plus, keeping transmitters and
receivers on (FORCEOFF must be high) (Table 1).
FORCEON
Force-Off Input, Active Low. Drive low to shut
down transmitters, receivers, and charge pump.
This overrides AutoShutdown Plus and FORCEON
(Table 1).
—
—
—
20
16
FORCEOFF
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.
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 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 V
.
CC
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 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 3k in parallel
with 1000pF, providing compatibility with PC-to-PC
communication software (such as LapLink™).
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.
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
LapLink is a trademark of Traveling Software.
_______________________________________________________________________________________
7
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
Table 1. Output Control Truth Table (MAX3318/MAX3319)
RECEIVER OR
VALID RECEIVER TRANSMITTER
OPERATION
STATUS
FORCEON
T_OUT
R_OUT
FORCEOFF
LEVEL
EDGE WITHIN
30s
Shutdown (Forced
Off)
X
0
X
X
X
X
High-Z
Active
Active
High-Z
Active
Active
High-Z
Active
High-Z
Active
Active
Active
Active
Normal Operation
(Forced On)
1
1
Normal Operation
(AutoShutdown Plus)
0
1
X
Yes
No
X
Shutdown
(AutoShutdown Plus)
0
1
X
Normal Operation
Normal Operation
Shutdown
1
Yes
X
Active
Active
Active
Active
Active
INVALID*
INVALID*
INVALID*
INVALID**
INVALID**
1
Yes
No
X
1
No
Yes
No
Normal Operation
(AutoShutdown)
INVALID**
INVALID**
Shutdown
(AutoShutdown)
X
X = Don’t care
*INVALID connected to FORCEON
MAX3318/MAX3319
AutoShutdown Plus Mode
**INVALID connected to FORCEON and FORCEOFF
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.
Table 2. Shutdown and Enable Control
Truth Table (MAX3317)
T_OUT
High-Z
High-Z
Active
Active
R_OUT
Active
High-Z
Active
High-Z
SHDN
0
EN
0
0
1
1
1
0
1
MAX3317 Shutdown Mode
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.
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 V , V- is
CC
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
V
if the shutdown mode is not used; SHDN has no
CC
effect on R_OUT.
8
_______________________________________________________________________________________
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
+2.5V
0.1 F
C
BYPASS
V
CC
C1+
V+
V-
C3
0.1 F
C1
0.1 F
C1-
C2+
MAX3316
MAX3317
MAX3318
MAX3319
+5V
C4
0.1 F
C2
0.1 F
C2-
T_ OUT
R_ IN
T_ IN
RX
TX
RS-232-
COMPLIANT
TRANSCEIVER
C
L
1000pF
R_ OUT
GND
Figure 1a. RS-232-Compatibility Circuit
V
OR SHDN
CC
(MAX3317)
T1 IN
MAX3316–MAX3319
FORCEOFF
(MAX3318/MAX3319)
5V/div
5V/div
2V/div
T1
T2
T1 OUT
MAX3316–MAX3319
2V/div
RS-232-COMPLIANT
RECEIVER OUTPUT
5V/div
10 s/div
Figure 1b. MAX3316–MAX3319 Transmitter Output
Compatibility with an RS-232 Receiver
Figure 2. Transmitter Outputs when Exiting Shutdown or
Powering Up
_______________________________________________________________________________________
9
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
When shut down, the device’s charge pumps turn off,
V+ is pulled to V , V- is pulled to ground, the transmitter
CC
+0.3V
outputs are high impedance, and READY is driven low.
The time required to exit shutdown is typically 30µs
(Figure 2).
R_IN
-0.3V
30µs
TIMER
R
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.
INVALID
INVALID ASSERTED IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR
AT LEAST 30 s.
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.
Figure 3a. INVALID Functional Diagram, INVALID Low
+2.7V
Connecting to the PC
(MAX3318/MAX3319)
R_IN
30µs
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.
TIMER
R
INVALID
-2.7V
INVALID DEASSERTED IF ANY RECEIVER INPUT HAS BEEN BETWEEN +2.7V AND -2.7V
FOR LESS THAN 30 s.
Figure 3b. INVALID Functional Diagram, INVALID High
INVALID HIGH
+2.7V
Applications Information
INDETERMINATE
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 3k and 2500pF.
+0.3V
0
INVALID LOW
INDETERMINATE
INVALID HIGH
-0.3V
The receiver inputs are fully EIA-232 compliant.
-2.7V
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.
Figure 4a. Receiver Positive/Negative Thresholds for INVALID
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
10 ______________________________________________________________________________________
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
RECEIVER
INPUTS
INVALID
REGION
}
TRANSMITTER
INPUTS
TRANSMITTER
OUTPUTS
V
INVALID
OUTPUT
CC
0
t
INVL
t
INVH
t
AUTOSHDN
t
AUTOSHDN
t
t
WU
WU
READY
OUTPUT
*V
CC
0
V+
V
CC
0
V-
*MAX3318/MAX3319
Figure 4b. AutoShutdown Plus, INVALID, and READY Timing Diagram
C2, C3, C4, and C
to maintain proper ratios
BYPASS
(C1 to other capacitors).
POWER-
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-.
MASTER SHDN LINE
MANAGEMENT
0.1 F
1M
UNIT
FORCEOFF FORCEON
MAX3318
MAX3319
Power-Supply Decoupling
In most circumstances, a 0.1µF bypass capacitor is
adequate. In applications that are sensitive to power-
supply noise, decouple V
to ground with a capacitor
CC
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 3k in par-
Figure 5. AutoShutdown Plus Initial Turn-On to Wake Up a
Mouse or Another System
______________________________________________________________________________________ 11
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
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
2V/div
when the magnitude of V- exceeds approximately -3V.
T1 IN
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.
5V/div
T1 OUT
R1 OUT
2V/div
Figure 7. Loopback Test Result at 230kbps
V
CC
C
BYPASS
Ordering Information (continued)
V
CC
PART
TEMP. RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
20 TSSOP
20 SSOP
C1+
V+
V-
MAX3317CUP
MAX3317CAP
MAX3317EUP
MAX3317EAP
MAX3318CUP
MAX3318CAP
MAX3318EUP
MAX3318EAP
MAX3319CAE
MAX3319EAE
C3*
C4
C1
MAX3316
MAX3317
MAX3318
MAX3319
C1-
C2+
20 TSSOP
20 SSOP
C2
20 TSSOP
20 SSOP
C2-
20 TSSOP
20 SSOP
T_ OUT
T_ IN
16 SSOP
R_ IN
5k
R_ OUT
16 SSOP
C
L
1000pF
FORCEON**
FORCEOFF**
Chip Information
V
CC
TRANSISTOR COUNT: 1130
PROCESS: CMOS
GND
*C3 CAN BE RETURNED TO V OR GND.
CC
**MAX3318/MAX3319
Figure 6. Loopback Test Circuit
12 ______________________________________________________________________________________
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
Pin Configurations (continued)
TOP VIEW
C1+
V+
1
2
3
4
5
6
7
8
16 V
CC
READY
1
2
3
4
5
6
7
8
9
20 FORCEOFF
19
N.C.
C1+
V+
1
2
3
4
5
6
7
8
9
20 N.C.
19
C1+
V+
V
CC
V
CC
15 GND
14 T1OUT
13 R1IN
12 R1OUT
11 T1IN
10 T2IN
18 GND
C1-
18 GND
C1-
17 T1OUT
16 R1IN
C2+
C2-
MAX3316
C1-
17 T1OUT
16 R1IN
MAX3318
MAX3316
C2+
C2-
C2+
C2-
15 R1OUT
15 R1OUT
V-
V-
14
T2OUT
R2IN
V-
14
T1IN
FORCEON
T2OUT
R2IN
13 T1IN
9
R2OUT
T2OUT
R2IN
13 T2IN
12 R2OUT
11 N.C.
12 T2IN
SSOP
R2OUT 10
11 INVALID
N.C. 10
SSOP/TSSOP
TSSOP
READY
C1+
V+
1
2
3
4
5
6
7
8
16 FORCEOFF
EN
C1+
V+
1
2
3
4
5
6
7
8
9
20 SHDN
19
V
CC
15
V
CC
18 GND
14 GND
C1-
C2+
C2-
V-
17 T1OUT
16 R1IN
C1-
C2+
C2-
V-
MAX3319
13 T1OUT
12 FORCEON
11 T1IN
MAX3317
15 R1OUT
14
10 INVALID
N.C.
T2OUT
R2IN
13 T1IN
12 T2IN
11 N.C.
R1IN
9
R1OUT
SSOP
R2OUT 10
SSOP/TSSOP
______________________________________________________________________________________ 13
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
Typical Application Circuits (continued)
+2.5V
+2.5V
19
16
0.1 F
0.1 F
0.1 F
V
V
CC
CC
3
7
2
4
5
6
2
6
1
3
4
5
C1+
C1+
V+
V+
C1
0.1 F
C3*
C3*
0.1 F
0.1 F
C1-
C2+
C1-
C2+
MAX3317
MAX3316
V-
V-
C2
0.1 F
C4
0.1 F
C4
0.1 F
0.1 F
C2-
C2-
13
T1OUT
T1IN
17
8
11
T1OUT
T1IN
14
7
RS-232-
COMPATIBLE
OUTPUTS
RS-232-
COMPATIBLE
OUTPUTS
CMOS
INPUTS
CMOS
INPUTS
T2IN
T2OUT
R1IN
12
T2IN
T2OUT
R1IN
10
16
9
15 R1OUT
10 R2OUT
13
8
12 R1OUT
RS-232-
RS-232-
COMPATIBLE
INPUTS
CMOS
CMOS
OUTPUTS
5k
5k
COMPATIBLE
INPUTS
OUTPUTS
R2IN
9
R2OUT
R2IN
5k
5k
EN
1
20
SHDN
GND
18
GND
15
*C3 CAN BE RETURNED TO EITHER V OR GROUND.
CIRCUIT SHOWN IS FOR THE 16-PIN SSOP.
CC
14 ______________________________________________________________________________________
2.5V, 1µA, 460kbps,
RS-232-Compatible Transceivers
Typical Application Circuits (continued)
+2.5V
19
C
0.1 F
2
BYPASS
V
CC
3
7
C1+
V+
V-
C1
0.1 F
C3
4
5
6
0.1 F
C1-
C2+
MAX3318
C4
0.1 F
C2
0.1 F
C2-
13
T1IN
T1OUT 17
CMOS
INPUTS
RS-232-COMPATIBLE
OUTPUTS
8
T2IN
T2OUT
12
16
15 R1OUT
10 R2OUT
R1IN
CMOS
OUTPUTS
RS-232-COMPATIBLE
INPUTS
5k
R2IN
9
5k
TO POWER-
MANAGEMENT
UNIT
AutoShutdown
Plus
READY
INVALID 11
1
FORCEOFF
FORCEON
20
14
V
CC
GND
18
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.
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Printed USA
is a registered trademark of Maxim Integrated Products.
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