MAX3387EEUG+T [MAXIM]
Line Transceiver, 1 Func, 3 Driver, 3 Rcvr, BICMOS, PDSO24, 4.40 MM, 0.65 MM PITCH, TSSOP-24;
| 型号： | MAX3387EEUG+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Line Transceiver, 1 Func, 3 Driver, 3 Rcvr, BICMOS, PDSO24, 4.40 MM, 0.65 MM PITCH, TSSOP-24 驱动 信息通信管理 光电二极管 接口集成电路 驱动器 |
| 文件： | 总14页 (文件大小：159K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
±9-±16±; Rev 3; 6/±0
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
MAX387E
General Description
Features
The MAX3387E 3V powered TIA/EIA-232 and V.28/V.24
is a communications interface with low power require-
ments, high data-rate capabilities, and enhanced elec-
trostatic discharge (ESD) protection. The MAX3387E
has three receivers and three transmitters. All RS-232
inputs and outputs are protected to ±±15V using the
IEC ±000-4-2 Air-Gap Discharge method, ±85V using
the IEC ±000-4-2 Contact Discharge method, and
±±15V using the ꢀuman ꢁodꢂ Model.
♦ V Pin for Compatibility with Mixed-Voltage
L
Systems
♦ ±±15V ꢀSꢁ Proteꢂtion on ꢃx ꢄnpꢅts and ꢆx ꢇꢅtpꢅts
♦ Low 300µA Sꢅpply Cꢅrrent
♦ Gꢅaranteed 2105bps ꢁata ꢃate
♦ ±µA AꢅtoShꢅtdown Plꢅs™ with ꢃeꢂeivers Aꢂtive
♦ Meets ꢆꢄA/ꢀꢄA-232 Speꢂifiꢂations ꢁown to 3.0V
A proprietarꢂ low-dropout transmitter output stage
enables true RS-232 performance from a +3.0V to
+1.1V supplꢂ with a dual charge pump. The charge
pump requires onlꢂ four small 0.±µF capacitors for
operation from a +3.3V supplꢂ. The MAX3387E is capa-
ble of running at data rates up to 2105bps while main-
taining RS-232 compliant output levels.
Ordering Information
PAꢃꢆ
ꢆꢀMP. ꢃANGꢀ
0°C to +70°C
PꢄN-PACKAGꢀ
24 TSSOP
MAX3387ECUG+
MAX3387EEUG+
-40°C to +81°C
24 TSSOP
+Denotes a lead(Pb)-free/RoꢀS-compliant pac5age.
The MAX3387E has a unique V pin that allows interop-
L
eration in mixed-logic voltage sꢂstems. ꢁoth input and
output logic levels are pin programmable through the
Typical Operating Circuit
V pin. The MAX3387E is available in a space-saving
L
+3.3V
TSSOP pac5age.
23
15
24
C
Applications
Subnoteboo5/Palmtop Computers
PDAs and PDA Cradles
BYPASS
V
V
L
FORCEOFF
CC
2
6
1
3
4
5
C1+
V+
V-
C1
0.1μF
C3
0.1μF
C1-
C2+
Cell Phone Data Cables
MAX3387E
C2
0.1μF
C4
0.1μF
ꢁatterꢂ-Powered Equipment
ꢀand-ꢀeld Equipment
C2-
7
8
T1OUT
T2OUT
T3OUT
T1IN
21
20
Peripherals
TTL/CMOS
INPUTS
T2IN
T3IN
RS-232
OUTPUTS
19
18
10
V
V
L
14 R1OUT
13 R2OUT
R1IN
5k
L
R2IN
TTL/CMOS
OUTPUTS
17
16
RS-232
INPUTS
5k
V
L
12 R3OUT
R3IN
9
5k
INVALID
FORCEON
11
GND
22
AutoShutdown Plus is a trademar5 of Maxim Integrated
Products, Inc.
_______________________________________________________________ Maxim ꢄntegrated Prodꢅꢂts
±
For priꢂing, delivery, and ordering information, please ꢂontaꢂt Maxim ꢁireꢂt at ±-888-629-4642,
or visit Maxim’s website at www.maxim-iꢂ.ꢂom.
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
ABSꢇLUꢆꢀ MAXꢄMUM ꢃAꢆꢄNGS
CC
V
to GND..............................................................-0.3V to +6V
Short-Circuit Duration T_OUT to GND........................Continuous
V to GND...................................................-0.3V to (V
+ 0.3V)
Continuous Power Dissipation (T = +70°C)
24-Pin TSSOP (derate ±2.2mW/°C above +70°C) ........976mW
Operating Temperature Ranges
MAX3387ECUG ...................................................0°C to +70°C
MAX3387EEUG ................................................-40°C to +81°C
Junction Temperature......................................................+±10°C
Storage Temperature Range.............................-61°C to +±10°C
Lead Temperature (soldering, ±0s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
L
CC
A
V+ to GND................................................................-0.3V to +7V
V- to GND .................................................................+0.3V to -7V
V+ +⏐ V-⏐(Note ±) .............................................................. +±3V
Input Voltages
T_IN, FORCEON, FORCEOFF to GND..................-0.3V to +6V
R_IN to GND .....................................................................±21V
Output Voltages
T_OUT to GND...............................................................±±3.2V
MAX387E
R_OUT........................................................-0.3V to (V + 0.3V)
L
Note ±: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed ±3V.
Stresses beꢂond those listed under “Absolute Maximum Ratings” maꢂ cause permanent damage to the device. These are stress ratings onlꢂ, and functional
operation of the device at these or anꢂ other conditions beꢂond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods maꢂ affect device reliabilitꢂ.
ꢁC ꢀLꢀCꢆꢃꢄCAL CHAꢃACꢆꢀꢃꢄSꢆꢄCS
(V
= V = +3.0V to +1.1V; C±–C4 = 0.±µF, tested at +3.3V ±±0ꢃ; C± = 0.047µF, C2–C4 = 0.33µF, tested at +1.0V ±±0ꢃ;
CC
L
T
A
= T
to T
, unless otherwise noted. Tꢂpical values are at V = V = +3.3V, T = +21°C.)
MAX CC L A
MIN
PAꢃAMꢀꢆꢀꢃ
ꢁC CHAꢃACꢆꢀꢃꢄSꢆꢄCS (V
SYMBꢇL
= +3.3V or +1V, T = +21°C)
CꢇNꢁꢄꢆꢄꢇNS
MꢄN
ꢆYP
MAX
UNꢄꢆS
CC
A
All R_IN idle, FORCEON = GND,
FORCEOFF = V , all T_IN idle
Supplꢂ Current, AutoShutdown
Plus
±.0
0.3
±0
±
µA
CC
Supplꢂ Current
mA
FORCEOFF = FORCEON = V , no load
CC
LꢇGꢄC ꢄNPUꢆS
V = +3.3V or +1.0V
0.8
0.6
L
T_IN, FORCEON,
FORCEOFF
Input Logic Threshold Low
Input Logic Threshold ꢀigh
V
V
V = +2.1V
L
V = +1.0V
L
2.4
2.0
±.4
V = +3.3V
L
T_IN, FORCEON,
FORCEOFF
V = +2.1V
L
V = +±.8V
L
0.9
0.1
Transmitter Input ꢀꢂsteresis
Input Lea5age Current
ꢃꢀCꢀꢄVꢀꢃ ꢇUꢆPUꢆS
Output Voltage Low
V
±0.0±
±±
µA
T_IN, FORCEON, FORCEOFF
I
I
= ±.6mA
= -±mA
0.4
V
V
OUT
V -
L
0.6
V -
L
0.±
Output Voltage ꢀigh
OUT
ꢃꢀCꢀꢄVꢀꢃ ꢄNPUꢆS
Input Voltage Range
-21
0.8
0.6
+21
V
V
V = +1.0V
±.1
±.2
±.8
±.1
L
Input Threshold Low
Input Threshold ꢀigh
T
T
= +21°C
= +21°C
A
V = +3.3V
L
V = +1.0V
L
2.4
2.4
V
A
V = +3.3V
L
2
_______________________________________________________________________________________
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
MAX387E
ꢁC ꢀLꢀCꢆꢃꢄCAL CHAꢃACꢆꢀꢃꢄSꢆꢄCS (ꢂontinꢅed)
(V
= V = +3.0V to +1.1V; C±–C4 = 0.±µF, tested at +3.3V ±±0ꢃ; C± = 0.047µF, C2–C4 = 0.33µF, tested at +1.0V ±±0ꢃ;
CC
L
T
A
= T
to T
, unless otherwise noted. Tꢂpical values are at V = V = +3.3V, T = +21°C.)
MAX CC L A
MIN
PAꢃAMꢀꢆꢀꢃ
SYMBꢇL
CꢇNꢁꢄꢆꢄꢇNS
MꢄN
ꢆYP
0.1
1
MAX
UNꢄꢆS
V
Input ꢀꢂsteresis
Input Resistance
T
A
= +21°C
3
7
5Ω
ꢆꢃANSMꢄꢆꢆꢀꢃ ꢇUꢆPUꢆS
All transmitter outputs loaded with 35Ω to
Output Voltage Swing
±1
±1.4
±0M
V
ground
Output Resistance
V
V
= V+ = V- = 0V, transmitter output = ±2V
= 0V
300
Ω
CC
Output Short-Circuit Current
±60
±21
mA
_
T OUT
V
V
= ±±2V, transmitters disabled;
= 0V or +3.0V to +1.1V
_
CC
T OUT
Output Lea5age Current
µA
ꢀSꢁ PꢃꢇꢆꢀCꢆꢄꢇN
ꢀuman ꢁodꢂ Model
±±1
±±1
±8
R_IN, T_OUT
ESD Protection
5V
IEC ±000-4-2 Air-Gap Discharge method
IEC ±000-4-2 Contact Discharge method
AꢅtoShꢅtdown Plꢅs (FORCEON = GND, FORCEOFF = V
)
CC
Positive threshold
Negative threshold
2.7
Receiver Input Threshold to
Figure 3a
V
V
INVALID Output ꢀigh
-2.7
-0.3
Receiver Input Threshold to
Figure 3a
0.3
0.4
INVALID Output Low
I
I
= -±.6mA
= -±.0mA
V
V
INVALID Output Voltage Low
INVALID Output Voltage ꢀigh
OUT
V - 0.6
L
OUT
Receiver Positive or Negative
Threshold to INVALID ꢀigh
t
V
CC
V
CC
V
CC
V
CC
= +1V, Figure 3b
= +1V, Figure 3b
= +1V, Figure 3b
= +1V, Figure 3b
±
µs
µs
µs
s
INVꢀ
Receiver Positive or Negative
Threshold to INVALID Low
t
30
INVL
Receiver or Transmitter Edge to
Transmitters Enabled
t
±00
30
WU
Receiver or Transmitter Edge to
Transmitters Shutdown
tAUTOSꢀDN
±1
60
_______________________________________________________________________________________
3
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
ꢆꢄMꢄNG CHAꢃACꢆꢀꢃꢄSꢆꢄCS
(V
= V = +3V to +1.1V; C±–C4 = 0.±µF, tested at +3.3V ±±0ꢃ; C± = 0.047µF, C2–C4 = 0.33µF, tested at +1.0V ±±0ꢃ; T = T
CC
L
A
MIN
to T
, unless otherwise noted. Tꢂpical values are at V
= V = +3.3V, T = +21°C.)
MAX
CC
L
A
PAꢃAMꢀꢆꢀꢃ
SYMBꢇL
CꢇNꢁꢄꢆꢄꢇNS
MꢄN
ꢆYP
MAX
UNꢄꢆS
R = 35Ω, C = ±000pF,
L
L
Maximum Data Rate
210
5bps
µs
one transmitter switching
t
t
0.±1
0.±1
±00
±00
10
PꢀL
Receiver input to receiver output,
C = ±10pF
L
Receiver Propagation Delaꢂ
PLꢀ
Time to Exit Shutdown
Transmitter S5ew
Receiver S5ew
V > +3.7V
T_OUT
µs
ns
ns
8
⏐
⏐
t
⏐
t
⏐
- t
(Note 2)
PꢀL PLꢀ
⏐
⏐
- t
PꢀL PLꢀ
V
= +3.3V,
= +21°C,
CC
C = ±10pF to
L
±000pF
6
4
30
30
T
A
Transition-Region Slew
Rate
R = 35Ω to 75Ω,
measured from +3V
to -3V or -3V to +3V
V/µs
L
C = ±10pF to
L
2100pF
Note 2: Transmitter s5ew is measured at the transmitter zero crosspoints.
Typical Operating Characteristics
(V
CC
= V = +3.3V, T = +21°C, unless otherwise noted.)
L
A
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
SLEW RATE vs. LOAD CAPACITANCE
7.5
5.0
2.5
16
14
DATA RATE = 250kbps
12
LOAD = 3kΩ IN PARALLEL WITH C
L
SLEW RATE -
10
0
-2.5
-5.0
-7.5
8
6
4
2
0
SLEW RATE +
0
1000
2000
3000
4000
5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
4
_______________________________________________________________________________________
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
MAX387E
Typical Operating Characteristics (continued)
(V
CC
= V = +3.3V, T = +21°C, unless otherwise noted.)
L
A
TRANSMITTER OUTPUT VOLTAGE
vs. DATA RATE
SUPPLY CURRENT vs. LOAD CAPACITANCE
7.5
5.0
2.5
60
50
40
LOAD = 3kΩ,
ONE TRANSMITTER
SWITCHING AT DATA
RATE, OTHER
LOAD = 3kΩ, 1000pF
ONE TRANSMITTER
SWITCHING AT DATA
RATE, OTHER
TRANSMITTERS
AT 1/8 DATA RATE
TRANSMITTERS
AT 1/8 DATA RATE
120kbps
250kbps
0
-2.5
-5.0
-7.5
30
20
10
0
20kbps
0
50
100
150
200
250
0
1000
2000
3000
4000
5000
DATA RATE (kbps)
LOAD CAPACITANCE (pF)
-in Configuration
TOP VIEW
+
C1+
1
2
3
4
5
6
7
8
9
24 FORCEOFF
23
V+
C1-
V
CC
22 GND
C2+
21 T1OUT
20 T2OUT
19 T3OUT
18 R1IN
17 R2IN
16 R3IN
MAX3387E
C2-
V-
T1IN
T2IN
INVALID
T3IN 10
FORCEON 11
R3OUT 12
15 V
L
14 R1OUT
13 R2OUT
ꢆSSꢇP
_______________________________________________________________________________________
1
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
-in Description
PꢄN
±
NAMꢀ
C±+
V+
FUNCꢆꢄꢇN
Positive Terminal of the Voltage-Doubler Charge-Pump Capacitor
+1.1V Supplꢂ Generated bꢂ the Charge Pump
2
3
C±-
Negative Terminal of the Voltage-Doubler Charge-Pump Capacitor
Positive Terminal of the Inverting Charge-Pump Capacitor
Negative Terminal of the Inverting Charge-Pump Capacitor
-1.1V Generated bꢂ the Charge Pump
4
C2+
C2-
1
MAX387E
6
7
8
V-
T±IN
T2IN
TTL/CMOS Transmitter Inputs
Output of the Valid Signal Detector. INVALID is high if a valid RS-232 signal is present on
the receiver inputs.
9
INVALID
T3IN
±0
±±
TTL/CMOS Transmitter Inputs
Force-On Input. Drive FORCEON high to override automatic circuitrꢂ 5eeping transmitters
on (FORCEOFF must be high) (Table ±).
FORCEON
±2
±3
±4
±1
±6
±7
±8
±9
20
2±
22
23
R3OUT
R2OUT
R±OUT
TTL/CMOS Receiver Outputs. Swing between 0V and V .
L
V
L
Logic-Level Supplꢂ. All CMOS inputs and outputs are referenced to this supplꢂ.
RS-232 Receiver Inputs
R3IN
R2IN
R±IN
T3OUT
T2OUT
T±OUT
GND
RS-232 Transmitter Outputs
Ground
V
CC
+3.0V to +1.1V Supplꢂ Voltage
Force-Off Input. Drive FORCEOFF low to shut down transmitters and on-board power sup-
plꢂ. This overrides all automatic circuitrꢂ and FORCEON (Table ±).
24
FORCEOFF
6
_______________________________________________________________________________________
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
MAX387E
These RS-232 output stages are turned off (high imped-
Detailed Description
ance) when the device is in shutdown mode. When the
Dual Chargeꢁ-ump
Voltage Converter
power is off, the MAX3387E permits the outputs to be
driven up to ±±2V.
The MAX3387E’s internal power supplꢂ consists of a
regulated dual charge pump that provides output volt-
ages of +1.1V (doubling charge pump) and -1.1V
(inverting charge pump), regardless of the input volt-
The transmitter inputs do not have pull-up resistors.
Connect unused inputs to GND or V .
L
Rꢀꢁ232 Receivers
age (V ) over a +3.0V to +1.1V range. The charge
CC
The receivers convert RS-232 signals to CMOS-logic
output levels. The MAX3387E’s receivers are alwaꢂs
active, even when the device is in shutdown.
pumps operate in a discontinuous mode: if the output
voltages are less than 1.1V, the charge pumps are
enabled; if the output voltages exceed 1.1V, the charge
pumps are disabled. Each charge pump requires a flꢂ-
ing capacitor (C±, C2) and a reservoir capacitor (C3,
C4) to generate the V+ and V- supplies.
The MAX3387E features an INVALID output that indi-
cates when no signal is present on anꢂ RS-232 receiver
inputs. INVALID is independent of other control logic
functions; it indicates the receiver input conditions onlꢂ
(Figures 2 and 3).
Rꢀꢁ232 Transmitters
The transmitters are inverting level translators that con-
vert CMOS-logic levels to 1.0V EIA/TIA-232 levels.
The MAX3387E transmitters guarantee a 2105bps data
rate with worst-case loads of 35Ω in parallel with
±000pF, providing compatibilitꢂ with PC-to-PC commu-
+0.3V
R_IN
®
nication software (such as Laplin5 ). Transmitters can
be paralleled to drive multiple receivers or mice. Figure ±
shows a complete sꢂstem connection.
30μs
COUNTER
R
INVALID
-0.3V
FORCEON
POWER-
MANAGEMENT
UNIT OR
FORCEOFF
TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1μA IF
ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30μs.
KEYBOARD
INVALID
CONTROLLER
I/O CHIP
V
L
POWER SUPPLY
Figure 2a. INVALID Function Diagram, INVALID = Low
MAX3387E
V
CC
+2.7V
R_IN
I/O
30μs
COUNTER
R
CHIP
WITH
UART
INVALID
RS-232
-2.7V
CPU
TRANSMITTERS ARE ENABLED IF:
ANY RECEIVER INPUT IS GREATER THAN +2.7V OR LESS THAN -2.7V;
ANY RECEIVER INPUT HAS BEEN BETWEEN +0.3V AND -0.3V FOR LESS THAN 30μs.
Figure 2b. INVALID Function Diagram, INVALID = ꢀigh
Figure ±. Interface Under Control of PMU
Laplin5 is a registered trademar5 of Laplin5 Software, Inc.
_______________________________________________________________________________________
7
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
EDGE
DETECT
TRANSMITTERS ENABLED, INVALID HIGH
T_IN
FORCEOFF
+2.7V
INDETERMINATE
S
AUTOSHDN
30s
TIMER
+0.3V
0V
EDGE
DETECT
AutoShutdown, TRANSMITTERS DISABLED,
1μA SUPPLY CURRENT, INVALID LOW
R_IN
R
-0.3V
INDETERMINATE
MAX387E
FORCEON
-2.7V
TRANSMITTERS ENABLED, INVALID HIGH
Figure 2c. AutoShutdown Plus Logic
Figure 3a. Receiver Thresholds for INVALID
FORCEOFF states. Figure 2 and Table ± summarize the
MAX3387E’s operating modes. FORCEON and FORCE-
OFF override AutoShutdown Plus circuitrꢂ. When nei-
ther control is asserted, the IC selects between these
states automaticallꢂ based on the last receiver or trans-
mitter input edge received.
FORCEOFF
POWERDOWN
FORCEON
AUTOSHDN
ꢁꢂ connecting FORCEON to INVALID, the MAX3387E
shuts down when no valid receiver level and no receiver or
transmitter edge is detected for 30sec, and wa5es up
when a valid receiver level or receiver or transmitter
edge is detected.
POWERDOWN IS ONLY AN INTERNAL SIGNAL. IT CONTROLS THE
OPERATIONAL STATUS OF THE TRANSMITTERS AND THE POWER SUPPLIES.
ꢁꢂ connecting FORCEON and FORCEOFF to INVALID,
the MAX3387E shuts down when no valid receiver level
is detected.
Figure 2d. Power-Down Logic
Autoꢀhutdown -lus Mode
The MAX3387E achieves a±µA supplꢂ current with
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
anꢂ receiver and transmitter input for 30sec, the on-
board charge pumps are shut down, reducing supplꢂ
current to ±µA. This occurs if the RS-232 cable is dis-
connected or if the connected peripheral transmitters
are turned off, and if the UART driving the transmitter
inputs is inactive. The sꢂstem turns on again when a
valid transition is applied to anꢂ RS-232 receiver or
transmitter input. As a result, the sꢂstem saves power
without changes to the existing ꢁIOS or operating sꢂs-
tem.
A mouse or other sꢂstem with AutoShutdown Plus maꢂ
need time to wa5e up. Figure 4 shows a circuit that
forces the transmitters on for ±00ms, allowing enough
time for the other sꢂstem to realize that the MAX3387E
is awa5e. If the other sꢂstem outputs valid RS-232 sig-
nal transitions within that time, the RS-232 ports on both
sꢂstems remain enabled.
V Logic ꢀupply Input
L
Unli5e other RS-232 interface devices where the receiv-
er outputs swing between 0V and V , the MAX3387E
CC
features a separate logic supplꢂ input (V ) that sets
L
V
for the receiver outputs and sets thresholds for the
Oꢀ
receiver inputs. This feature allows a great deal of flexi-
bilitꢂ in interfacing to manꢂ different tꢂpes of sꢂstems
with different logic levels. Connect this input to the host
Figure 3a shows valid and invalid RS-232 receiver volt-
age levels. INVALID indicates the receiver input’s con-
dition, and is independent of FORCEON and
logic supplꢂ (±.8V ≤ V ≤ V ). Also, see the Tꢂpical
PDA/Cell-Phone Application section.
L
CC
8
_______________________________________________________________________________________
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
MAX387E
RECEIVER
INPUTS
INVALID
REGION
}
TRANSMITTER
INPUTS
TRANSMITTER
OUTPUTS
V
INVALID
OUTPUT
CC
t
INVL
t
INVH
t
0
AUTOSHDN
t
AUTOSHDN
t
t
WU
WU
V+
V
CC
0
V-
Figure 3b. AutoShutdown Plus/INVALID Timing Diagram
±±15V EꢀD -rotection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro-
static discharges (ESDs) encountered during handling
and assemblꢂ. The MAX3387E driver outputs and
receiver inputs have extra protection against static
electricitꢂ. Maxim has developed state-of-the-art struc-
tures to protect these pins against ESD of ±±15V with-
out damage. The ESD structures withstand high ESD in
all states: normal operation, shutdown, and powered
down. After an ESD event, Maxim’s “E” version devices
5eep wor5ing without latchup, whereas competing RS-
232 products can latch and must be powered down to
remove latchup. ESD protection can be tested in vari-
ous waꢂs. The transmitter outputs and receiver inputs
of this product familꢂ are characterized for protection to
the following limits:
POWER-
MASTER SHDN LINE
MANAGEMENT
0.1μF
1M
UNIT
FORCEOFF FORCEON
MAX3387E
Figure 4. AutoShutdown with Initial Turn-On to Wa5e Up a
Sꢂstem
ꢀoftwareꢁControlled ꢀhutdown
If direct software control is desired, INVALID can be
used to indicate a DTR or ring indicator signal. Connect
FORCEOFF and FORCEON together to bꢂpass
AutoShutdown so the line acts li5e a SHDN input.
±) ±±15V using the ꢀuman ꢁodꢂ Model
2) ±85V using the Contact-Discharge method specified
in IEC ±000-4-2
3) ±±15V using IEC ±000-4-2’s Air-Gap method
_______________________________________________________________________________________
9
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
ꢆable ±. ꢇꢅtpꢅt Control ꢆrꢅth ꢆable
ꢃꢀCꢀꢄVꢀꢃ ꢇꢃ
VALꢄꢁ
ꢆꢃANSMꢄꢆꢆꢀꢃ
ꢀꢁGꢀ WꢄꢆHꢄN
30
ꢇPꢀꢃAꢆꢄꢇN SꢆAꢆUS
FꢇꢃCꢀꢇN
ꢃꢀCꢀꢄVꢀꢃ
LꢀVꢀL
ꢆ_ꢇUꢆ
ꢃ_ꢇUꢆ
FORCEOFF
Shutdown
(Forced Off)
X
±
0
0
0
±
±
±
X
X
X
X
X
X
ꢀigh-Z
Active
Active
ꢀigh-Z
Active
Active
Active
Active
Normal Operation
(Forced On)
MAX387E
Normal Operation
(AutoShutdown Plus)
Yes
No
Shutdown
(AutoShutdown Plus)
Normal Operation
Normal Operation
Shutdown
±
±
±
Yes
X
X
Active
Active
ꢀigh-Z
Active
Active
Active
INVALID
INVALID
INVALID
Yes
No
No
Normal Operation
(AutoShutdown)
Yes
No
X
X
Active
ꢀigh-Z
Active
Active
INVALID
INVALID
INVALID
INVALID
Shutdown
(AutoShutdown)
X = Don’t care
R
C
R
D
1M
1500Ω
I 100%
P
90%
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
I
r
DISCHARGE
RESISTANCE
CHARGE-CURRENT
LIMIT RESISTOR
AMPERES
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
36.8%
C
100pF
STORAGE
CAPACITOR
s
10%
0
SOURCE
TIME
0
t
RL
t
DL
CURRENT WAVEFORM
Figure 1a. ꢀuman ꢁodꢂ ESD Test Model
Figure 1b. ꢀuman ꢁodꢂ Current Waveform
EꢀD Test Conditions
ESD performance depends on a varietꢂ of conditions.
Contact Maxim for a reliabilitꢂ report that documents
test setup, methodologꢂ, and results.
Human Body Model
Figure 1a shows the ꢀuman ꢁodꢂ Model, and Figure
1b shows the current waveform it generates when dis-
charged into a low impedance. This model consists of a
±00pF capacitor charged to the ESD voltage of interest,
which is then discharged into the test device through a
±.15Ω resistor.
±0 ______________________________________________________________________________________
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
MAX387E
R
R
D
330Ω
C
I
50M to 100M
100%
DISCHARGE
RESISTANCE
CHARGE-CURRENT
LIMIT RESISTOR
90%
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
C
s
150pF
STORAGE
CAPACITOR
SOURCE
10%
Figure 6a. IEC ±000-4-2 ESD Test Model
t
t
= 0.7ns to 1ns
R
IEC ±000ꢁ4ꢁ2
30ns
The IEC ±000-4-2 standard covers ESD testing and
performance of finished equipment; it does not specifi-
callꢂ refer to ICs. The MAX3387E helps ꢂou design
equipment that meets Level 4 (the highest level) of IEC
±000-4-2, without the need for additional ESD-protec-
tion components.
60ns
Figure 6b. IEC ±000-4-2 ESD Generator Current Waveform
ꢆable 2. Minimꢅm ꢃeqꢅired Capaꢂitor
Valꢅes
The major difference between tests done using the
ꢀuman ꢁodꢂ Model and IEC ±000-4-2 is higher pea5
current in IEC ±000-4-2 because series resistance is
lower in the IEC ±000-4-2 model. ꢀence, the ESD with-
stand voltage measured to IEC ±000-4-2 is generallꢂ
lower than that measured using the ꢀuman ꢁodꢂ
Model. Figure 6a shows the IEC ±000-4-2 model, and
Figure 6b shows the current waveform for the ±85V IEC
±000-4-2 Level 4 ESD Contact Discharge test.
V
(V)
C±
(µF)
C2, C3, C4
(µF)
CC
3.0 to 3.6
4.1 to 1.1
3.0 to 1.1
0.±
0.047
0.22
0.±
0.33
±
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.
tors for 3.3V operation. For other supplꢂ voltages, see
Table 2 for required capacitor values. Do not use val-
ues smaller than those listed in Table 2. Increasing the
capacitor values (e.g., bꢂ a factor of 2) reduces ripple
on the transmitter outputs and slightlꢂ reduces power
consumption. C2, C3, and C4 can be increased without
changing C±’s value. ꢀowever, do not increase C±
without also increasing the values of C2, C3, and C4 to
maintain the proper ratios (C± to the other capacitors).
Machine Model
The Machine Model for ESD tests all pins using a
200pF storage capacitor and zero discharge resis-
tance. Its objective is to emulate the stress caused bꢂ
contact that occurs with handling and assemblꢂ during
manufacturing. All pins require this protection during
manufacturing, not just RS-232 inputs and outputs.
Therefore, after PC board assemblꢂ, the Machine
Model is less relevant to I/O ports.
When using the minimum required capacitor values,
ma5e sure the capacitor value does not degrade
excessivelꢂ with temperature. If in doubt, use capaci-
tors with a larger nominal value. The capacitor’s equiva-
lent series resistance (ESR), which usuallꢂ rises at low
temperatures, influences the amount of ripple on V+
and V-.
Applications Information
Capacitor ꢀelection
The capacitor tꢂpe used for C±–C4 is not critical for
proper operation; polarized or nonpolarized capacitors
can be used. The charge pump requires 0.±µF capaci-
______________________________________________________________________________________ ±±
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
-owerꢁꢀupply Decoupling
In most circumstances, a 0.±µF bꢂpass capacitor is ade-
quate. In applications that are sensitive to power-supplꢂ
Operation Down to 2.7V
Transmitter outputs will meet TIA/EIA-162 levels of
±3.7V with supplꢂ voltages as low as +2.7V.
noise, decouple V
to ground with a capacitor of the
CC
Transmitter Outputs when
Exiting ꢀhutdown
same value as charge-pump capacitor C±. Connect
bꢂpass capacitors as close to the IC as possible.
Figure 7 shows two transmitter outputs when exiting
shutdown mode. As theꢂ become active, the two trans-
mitter outputs are shown going to opposite RS-232 lev-
els (one transmitter input is high; the other is low). Each
transmitter is loaded with 35Ω in parallel with 2100pF.
The transmitter outputs displaꢂ no ringing or undesir-
able transients as theꢂ come out of shutdown. Note that
the transmitters are enabled onlꢂ when the magnitude
of V- exceeds approximatelꢂ 3V.
5V/div
T2
MAX387E
2V/div
High Data Rates
The MAX3387E maintains the RS-232 ±1.0V minimum
transmitter output voltage even at high data rates.
Figure 8 shows a transmitter loopbac5 test circuit.
Figure 9 shows a loopbac5 test result at ±205bps, and
Figure ±0 shows the same test at 2105bps. For Figure
9, all transmitters were driven simultaneouslꢂ at
±205bps into RS-232 loads in parallel with ±000pF. For
Figure ±0, a single transmitter was driven at 2105bps,
and all transmitters were loaded with an RS-232 receiv-
er in parallel with ±000pF.
T1
V
= 3.3V
CC
C1–C4 = 0.1μF
50μs/div
Figure 7. Transmitter Outputs when Exiting Shutdown
Interconnection with
3V and 1V Logic
V
CC
0.1μF
The MAX3387E can directlꢂ interface with various 1V
logic families, including ACT and ꢀCT CMOS. The logic
voltage power-supplꢂ pin (V ) sets the output voltage
L
V
CC
level of the receivers and the input thresholds of the
transmitters.
C1+
V+
V-
C3
C4
C1
MAX3387E
C1-
C2+
C2
C2-
5V/div
5V/div
5V/div
T1IN
T_ OUT
T_ IN
R_ IN
5k
R_ OUT
T1OUT
R1OUT
1000pF
FORCEOFF
FORCEON
V
CC
GND
V
CC
= 3.3V
2μs/div
Figure 9. Loopbac5 Test Results at ±205bps
Figure 8. Loopbac5 Test Circuit
±2 ______________________________________________________________________________________
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
MAX387E
As cell phone design becomes more li5e that of PDAs,
cell phones will require similar doc5ing abilitꢂ and com-
munication protocol. Cell phones operate on a single
5V/div
5V/div
5V/div
T1IN
T1OUT
R1OUT
lithium-ion (Li+) batterꢂ and wor5 with a power-supplꢂ
voltage of +2.7V to +4V. The baseband logic coming
from the phone connector can be as low as ±.8V at the
transceivers. To prevent forward biasing of a device
internal to the cell phone, the MAX3387E comes with a
logic power-supplꢂ pin (V ) that limits the logic levels
L
presented to the phone. The receiver outputs will sin5
to zero for low outputs, but will not exceed V for logic
L
highs. The input logic levels for the transmitters are also
V
CC
= 3.3V
altered, scaled bꢂ the magnitude of the V input. The
L
device will wor5 with V as low as ±.8V before the
L
2μs/div
charge-pump noise will begin to cause the transmitter
outputs to oscillate. This is useful with cell phones and
other power-efficient devices with core logic voltage
levels that go as low as ±.8V.
Figure ±0. Loopbac5 Test Results at 2105bps
Chip Information
Typical -DA/Cellꢁ-hone Application
The MAX3387E is designed with PDA applications in
mind. Two transmitters and two receivers handle stan-
dard full-duplex communication protocol, while an extra
transmitter allows a ring indicator signal to alert the
UART on the PC. Without the ring indicator transmitter,
solutions for these applications would require software-
intensive polling of the cradle inputs.
PROCESS: ꢁiCMOS
-ac5age Information
For the latest pac5age outline information and land patterns,
go to www.maxim-iꢂ.ꢂom/paꢂ5ages. Note that a “+”, “#”, or
“-” in the pac5age code indicates RoꢀS status onlꢂ. Pac5age
drawings maꢂ show a different suffix character, but the drawing
pertains to the pac5age regardless of RoꢀS status.
The ring indicate (RI) signal is generated when a PDA,
phone, or other “cradled” device is plugged into its cradle.
This generates a logic-low signal to the RI transmitter
input, creating +6V at the ring indicate pin. The PC’s
UART RI input is the onlꢂ pin that can generate an inter-
rupt from signals arriving through the RS-232 port. The
interrupt routine for this UART will then service the RS-
232 full-duplex communication between the PDA and
the PC.
PACKAGꢀ ꢆYPꢀ PACKAGꢀ Cꢇꢁꢀ ꢁꢇCUMꢀNꢆ Nꢇ.
24 TSSOP
U24+±
2±-0066
______________________________________________________________________________________ ±3
3V, ±±15V EꢀDꢁ-rotected, Autoꢀhutdown -lus
Rꢀꢁ232 Transceiver for -DAs and Cell -hones
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
Added Note 2 to the Electrical Characteristics table
4
3
6/10
Changed the Chip Information section to say “PROCESS: BiCMOS”
13
MAX387E
Maxim cannot assume responsibilitꢂ for use of anꢂ circuitrꢂ other than circuitrꢂ entirelꢂ embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitrꢂ and specifications without notice at anꢂ time.
±4 ____________________Maxim Integrated -roducts, ±20 ꢀan Gabriel Drive, ꢀunnyvale, CA 94086 408ꢁ737ꢁ7600
© 20±0 Maxim Integrated Products
Maxim is a registered trademar5 of Maxim Integrated Products, Inc.
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