MAX338CSE-T [MAXIM]
Single-Ended Multiplexer, 1 Func, 8 Channel, CMOS, PDSO16, 0.150 INCH, SOIC-16;
| 型号： | MAX338CSE-T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Single-Ended Multiplexer, 1 Func, 8 Channel, CMOS, PDSO16, 0.150 INCH, SOIC-16 |
| 文件： | 总12页 (文件大小：183K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1437; Rev 1; 10/99
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
________________General Description
____________________________Features
The MAX3385E is a 3V-powered EIA/TIA-232 and
V.28/V.24 communications interface with low power
requirements, high data-rate capabilities, and en-
hanced electrostatic discharge (ESD) protection. All
transmitter outputs and receiver inputs are protected to
±±5ꢀV using IEꢁ ±111-4-2 Air-ꢂap Discharge, ±8ꢀV
using IEꢁ ±111-4-2 ꢁontact Discharge, and ±±5ꢀV
using the Human Body Model.
ꢀ ESD Protection for RS-232 I/O Pins
±±15kV—Humn ꢀoꢁd ꢂoꢁeꢃ
±ꢄ5kVIEꢅ ±ꢆꢆꢆ-ꢇ-2ꢈ ꢅontmct Discꢉmrꢊe
±±15kVIEꢅ ±ꢆꢆꢆ-ꢇ-2ꢈ ꢋir-ꢌma Discꢉmrꢊe
ꢀ LmtcꢉHa Free
ꢀ 3ꢆꢆµꢋ SHaaꢃd ꢅHrrent
ꢀ ±µꢋ Low-Power SꢉHtꢁown witꢉ Receivers ꢋctive
ꢀ 21ꢆ5bas ꢌHmrmnteeꢁ Dmtm Rmte
ꢀ 21ꢆµs Tiue to Exit SꢉHtꢁown witꢉ 35Ω Lomꢁ on k+
ꢀ 6k/µs ꢌHmrmnteeꢁ Sꢃew Rmte
The transceiver has a proprietary low-dropout transmit-
ter output stage, delivering true RS-232 performance
from a +3.1V to +5.5V supply with a dual charge pump.
The charge pump requires only four small 1.±µF capac-
itors for operation from a +3.3V supply. Each device is
guaranteed to run at data rates of 251ꢀbps while main-
taining RS-232 output levels.
ꢀ ꢂeets EIꢋ/TIꢋ-232 Saecificmtions Down to 3.ꢆk
Ordering Information
The MAX3385E has two receivers and two drivers. It
features a ±µA shutdown mode that reduces power con-
sumption and extends battery life in portable systems.
Its receivers can remain active in shutdown mode,
allowing external devices such as modems to be moni-
tored using only ±µA supply current.
PART
TEMP. RANGE
1°ꢁ to +71°ꢁ
1°ꢁ to +71°ꢁ
-41°ꢁ to +85°ꢁ
PIN-PACKAGE
21 SSOP
MAX3385EꢁAP
MAX3385EꢁWN
MAX3385EEAP
±8 SO
21 SSOP
The MAX3385E is available in a space-saving SSOP
pacꢀage in either the commercial (1°ꢁ to +71°ꢁ) or
extended-industrial (-41°ꢁ to +85°ꢁ) temperature range.
Typical Operating Circuit
+3.3V
________________________Applications
C
BYPASS
V
CC
Hand-Held Equipment
Peripherals
Battery-Powered
Equipment
C1+
V+
C1
0.1µF
C3*
0.1µF
C1-
C2+
Printers
MAX3385E
V-
C2
0.1µF
C4
-in Configurations
0.1µF
C2-
T1OUT
T1IN
TOP VIEW
N.C.
C1+
V+
1
2
SHDN
20
19
18
17
16
15
14
13
12
11
TTL/CMOS
INPUTS
RS-232
OUTPUTS
V
CC
T2IN
T2OUT
R1IN
GND
3
T1OUT
R1IN
C1-
4
R1OUT
R2OUT
MAX3385E
C2+
C2-
5
TTL/CMOS
OUTPUTS
RS-232
INPUTS
5k
R1OUT
T1IN
6
R2IN
V-
7
T2OUT
5k
T2IN
8
R2OUT
N.C.
R2IN
N.C.
9
SHDN
GND
10
SSOP
* C3 CAN BE RETURNED TO EITHER V OR GROUND.
CC
Pin Configurations continued at end of data sheet.
NOTE: SEE TABLE 2 FOR CAPACITOR SELECTION
†
Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577; 4,797,899; 4,809,152; 4,897,774; 4,999,761; and other patents pending.
________________________________________________________________ Maxim Integrated Products
±
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
ABSOLUTE MAXIMUM RATINGS
ꢁꢁ
V
to ꢂND..............................................................-1.3V to +6V
ꢁontinuous Power Dissipation (T = +71°ꢁ)
A
V+ to ꢂND (Note ±)..................................................-1.3V to +7V
V- to ꢂND (Note ±) ...................................................+1.3V to -7V
V+ + |V-| (Note ±).................................................................+±3V
Input Voltages
T_IN, SHDN to ꢂND ..............................................-1.3V to +6V
R_IN to ꢂND .....................................................................±25V
Output Voltages
21-Pin SSOP (derate 8.11mW/°ꢁ above +71°ꢁ) ..........641mW
±8-Pin SO (derate 9.52mW/°ꢁ above +71°ꢁ)...............762mW
Operating Temperature Ranges
MAX3385EꢁAP....................................................1°ꢁ to +71°ꢁ
MAX3385EꢁWN...................................................1°ꢁ to +71°ꢁ
MAX3385EEAP .................................................-41°ꢁ to +85°ꢁ
Storage Temperature Range.............................-65°ꢁ to +±51°ꢁ
Lead Temperature (soldering, ±1sec) .............................+311°ꢁ
T_OUT to ꢂND...............................................................±±3.2V
R_OUT.....................................................-1.3V to (V
+ 1.3V)
ꢁꢁ
Short-ꢁircuit Duration, T_OUT to ꢂND.......................ꢁontinuous
Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed ±3V.
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
= +3V to +5.5V, ꢁ±–ꢁ4 = 1.±µF, tested at 3.3V ±±10% ꢁ± = 1.147µF, ꢁ2–ꢁ4 = 1.33µF, tested at 5.1V ±±10% T = T
to T
,
MAX
A
MIN
unless otherwise noted. Typical values are at T = +25°ꢁ.)
A
PARAMETER
DC CHARACTERISTICS (V
Supply ꢁurrent
CONDITIONS
= +3.3V or +5V, T = +25°ꢁ)
MIN
TYP
MAX
UNITS
ꢁꢁ
A
1.3
±
±
mA
µA
SHDN = V , no load
ꢁꢁ
Shutdown Supply ꢁurrent
LOGIC INPUTS
±1
SHDN = ꢂND
Input Logic Threshold Low
1.8
V
V
T_IN, SHDN
T_IN, SHDN
V
V
= 3.3V
= 5.1V
2.1
2.4
ꢁꢁ
Input Logic Threshold High
ꢁꢁ
Transmitter Input Hysteresis
Input Leaꢀage ꢁurrent
RECEIVER OUTPUTS
Output Leaꢀage ꢁurrent
Output Voltage Low
1.5
V
±1.1±
±±
µA
T_IN, SHDN
R_OUT, receivers disabled
±1.15
±±1
1.4
µA
V
I
= ±.6mA
OUT
V
1.6
-
V
1.±
-
ꢁꢁ
ꢁꢁ
Output Voltage High
I
= -±.1mA
V
OUT
RECEIVER INPUTS
Input Voltage Range
-25
1.6
1.8
+25
V
V
V
ꢁꢁ
V
ꢁꢁ
V
ꢁꢁ
V
ꢁꢁ
= 3.3V
= 5.1V
= 3.3V
= 5.1V
±.2
±.5
±.5
±.8
1.5
5
Input Threshold Low
Input Threshold High
T = +25°ꢁ
A
2.4
2.4
T = +25°ꢁ
A
V
Input Hysteresis
Input Resistance
V
T = +25°ꢁ
A
3
7
ꢀΩ
2
_______________________________________________________________________________________
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
ELECTRICAL CHARACTERISTICS (continued)
ꢁꢁ
(V
= +3V to +5.5V, ꢁ±–ꢁ4 = 1.±µF, tested at 3.3V ±±10% ꢁ± = 1.147µF, ꢁ2–ꢁ4 = 1.33µF, tested at 5.1V ±±10% T = T
to T
,
MAX
A
MIN
unless otherwise noted. Typical values are at T = +25°ꢁ.)
A
PARAMETER
TRANSMITTER OUTPUTS
Output Voltage Swing
Output Resistance
CONDITIONS
MIN
TYP
MAX
UNITS
All transmitter outputs loaded with 3ꢀΩ to ground
±5
±5.4
±1M
V
Ω
V
V
= V+ = V- = 1, transmitter output = ±2V
311
ꢁꢁ
Output Short-ꢁircuit ꢁurrent
Output Leaꢀage ꢁurrent
ESD PROTECTION
±61
±25
mA
µA
= 1 or 3V to 5.5V, V
= ±±2V, transmitters disabled
ꢁꢁ
OUT
Human Body Model
IEꢁ±111-4-2 Air Discharge
IEꢁ±111-4-2 ꢁontact Discharge
±±5
±±5
±8
R_IN, T_OUT
ꢀV
TIMING CHARACTERISTICS
ꢁꢁ
(V
= +3V to +5.5V, ꢁ±–ꢁ4 = 1.±µF, tested at 3.3V ±±10% ꢁ± = 1.147µF, ꢁ2–ꢁ4 = 1.33µF, tested at 5.1V ±±10% T = T
to T
,
MAX
A
MIN
unless otherwise noted. Typical values are at T = +25°ꢁ.)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
R = 3ꢀΩ, ꢁ = ±111pF,
L
L
Maximum Data Rate
251
ꢀbps
one transmitter switching
t
t
1.±5
1.±5
251
±11
51
PHL
Receiver input to receiver output,
ꢁ = ±51pF
L
Receiver Propagation Delay
µs
PLH
Time to Exit Shutdown
Transmitter Sꢀew
Receiver Sꢀew
V
OUT
≥ +3.7V, R
at V+ = 3ꢀΩ
µs
ns
ns
LOAD
t
t
- t
(Note 2)
PHL PLH
- t
PHL PLH
V
= 3.3V,
= +25°ꢁ,
ꢁꢁ
ꢁ = ±51pF to
L
±111pF
6
4
31
31
T
A
Transition-Region Slew Rate
R = 3ꢀΩ to 7ꢀΩ,
measured from +3V
to -3V or -3V to +3V
V/µs
L
ꢁ = ±51pF to
L
2511pF
Note 2: Transmitter sꢀew is measured at the transmitter zero cross points.
_______________________________________________________________________________________
3
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
__________________________________________Typical Operating Characteristics
(V
= +3.3V, 251ꢀbps data rate, 1.±µF capacitors, all transmitters loaded with 3ꢀΩ and ꢁ , T = +25°ꢁ, unless otherwise noted.)
ꢁꢁ
L
A
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
SLEW RATE vs. LOAD CAPACITANCE
6
5
16
14
12
10
8
45
40
35
30
25
20
T1 TRANSMITTING AT 250kbps
T2 TRANSMITTING AT 15.6kbps
V
OUT+
4
-SLEW
+SLEW
3
250kbps
120kbps
T1 TRANSMITTING AT 250kbps
T2 TRANSMITTING AT 15.6kbps
2
1
0
-1
-2
-3
-4
-5
-6
6
20kbps
15
10
5
4
V
2
OUT-
FOR DATA RATES UP TO 250kbps
0
0
0
1000
2000
3000
4000
5000
0
1000
2000
3000
4000
5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
______________________________________________________________ -in Description
PIN
NAME
FUNCTION
No ꢁonnection. Not internally connected.
SO
±
SSOP
±, ±1, ±±
N.ꢁ.
ꢁ±+
V+
2
2
3
4
5
6
Positive terminal of the voltage-doubler charge-pump capacitor.
+5.5V generated by the charge pump.
3
4
ꢁ±-
ꢁ2+
ꢁ2-
Negative terminal of the voltage-doubler charge-pump capacitor.
Positive terminal of inverting charge-pump capacitor.
Negative terminal of inverting charge-pump capacitor.
5
6
7
7
V-
-5.5V generated by the charge pump.
RS-232 Transmitter Outputs
RS-232 Receiver Inputs
8, ±5
9, ±4
8, ±7
9, ±6
T_OUT
R_IN
±1, ±3
±±, ±2
±6
±2, ±5
±3, ±4
±8
R_OUT
T_IN
TTL/ꢁMOS Receiver Outputs
TTL/ꢁMOS Transmitter Inputs
ꢂND
ꢂround
±7
±9
V
ꢁꢁ
+3.1V to +5.5V Supply Voltage
±8
21
Active-Low Shutdown-ꢁontrol Input. Drive low to shut down transmitters and charge
SHDN
4
_______________________________________________________________________________________
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
V
V
CC
CC
0.1µF
0.1µF
V
V
CC
CC
C1+
C1+
V+
V-
V+
V-
C1
C2
C1
C2
3k
3k
C3
C3
C1-
C2+
C1-
C2+
MAX3385E
MAX3385E
C4
C4
C2-
C2-
T_ OUT
R_ IN
T_ OUT
R_ IN
T_ IN
T_ IN
R_ OUT
SHDN
R_ OUT
SHDN
5k
5k
V
V
CC
CC
2500pF
150pF
3k
7k
GND
GND
MINIMUM SLEW-RATE TEST CIRCUIT
Figure 1. Slew-Rate Test Circuits
MAXIMUM SLEW-RATE TEST CIRCUIT
The MAX3385E’s transmitters are disabled and the out-
puts are forced into a high-impedance state when the
device is in shutdown (SHDN = ꢂND). The MAX3385E
permits the outputs to be driven up to ±±2V in shut-
down.
_______________Detailed Description
Dual Chargeꢂ-ump koltage Converter
The MAX3385E’s internal power supply consists of a
regulated dual charge pump that provides output volt-
ages of +5.5V (doubling charge pump) and -5.5V
The transmitter inputs do not have pull-up resistors.
(inverting charge pump), over the 3.1V to 5.5V V
ꢁꢁ
ꢁonnect unused inputs to ꢂND or V
.
ꢁꢁ
range. The charge pump operates in discontinuous
mode% if the output voltages are less than 5.5V, the
charge pump is enabled, and if the output voltages
exceed 5.5V, the charge pump is disabled. Each
charge pump requires a flying capacitor (ꢁ±, ꢁ2) and a
reservoir capacitor (ꢁ3, ꢁ4) to generate the V+ and V-
supplies (Figure ±).
Rꢁꢂ232 Receivers
The receivers convert RS-232 signals to ꢁMOS-logic
output levels (Table ±).
ꢁhutdown Mode
Supply current falls to less than ±µA in shutdown mode
(SHDN = low). When shut down, the device’s charge
pumps are shut off, V+ is pulled down to V , V- is
ꢁꢁ
pulled to ground, and the transmitter outputs are dis-
abled (high impedance). The time required to exit shut-
Rꢁꢂ232 Transmitters
The transmitters are inverting level translators that con-
vert ꢁMOS-logic levels to ±5.1V EIA/TIA-232 levels.
The MAX3385E transmitters guarantee a 251ꢀbps data
rate with worst-case loads of 3ꢀΩ in parallel with ±111pF,
providing compatibility with Pꢁ-to-Pꢁ communication
software (such as LapLinꢀ™). Transmitters can be paral-
leled to drive multiple receivers or mice.
Table 1. Shutdown Truth Table
T_OUT
High-Z
Active
R_OUT
Active
Active
SHDN
1
±
Laplink is a trademark of Traveling Software.
_______________________________________________________________________________________
5
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
charged into a low impedance. This model consists of a
±11pF capacitor charged to the ESD voltage of interest,
5V/div
0
SHDN
which is then discharged into the test device through a
T2OUT
±.5ꢀΩ resistor.
IEC 1000-4-2
The IEꢁ ±111-4-2 standard covers ESD testing and per-
formance of finished equipment% it does not specifically
refer to integrated circuits. The MAX3385E helps you
design equipment that meets Level 4 (the highest level) of
IEꢁ ±111-4-2, without the need for additional ESD-pro-
tection components.
2V/div
0
T1OUT
V
= 3.3V
CC
C1–C4 = 0.1µF
The major difference between tests done using the
Human Body Model and IEꢁ ±111-4-2 is higher peaꢀ
current in IEꢁ ±111-4-2, because series resistance is
lower in the IEꢁ ±111-4-2 model. Hence, the ESD with-
stand voltage measured to IEꢁ ±111-4-2 is generally
lower than that measured using the Human Body
Model. Figure 4a shows the IEꢁ ±111-4-2 model, and
Figure 4b shows the current waveform for the 8ꢀV IEꢁ
±111-4-2 Level 4 ESD contact-discharge test.
40µs/div
Figure 2. Transmitter Outputs Exiting Shutdown or
Powering Up
down is typically ±11µs, as shown in Figure 2. ꢁonnect
SHDN to V if the shutdown mode is not used.
ꢁꢁ
±±5ꢀk EꢁD -rotection
The air-gap test involves approaching the device with a
charged probe. The contact-discharge method con-
nects the probe to the device before the probe is ener-
gized.
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro-
static discharges encountered during handling and
assembly. The driver outputs and receiver inputs of the
MAX3385E have extra protection against static electric-
ity. Maxim’s engineers have developed state-of-the-art
structures to protect these pins against ESD of ±±5ꢀV
without damage. The ESD structures withstand high
ESD in all states: normal operation, shutdown, and
powered down. After an ESD event, Maxim’s “E” ver-
sions ꢀeep worꢀing without latchup, whereas compet-
ing RS-232 products can latch and must be powered
down to remove latchup.
Machine Model
The Machine Model for ESD tests all pins using a
211pF storage capacitor and zero discharge resis-
tance. Its objective is to emulate the stress caused by
contact that occurs with handling and assembly during
manufacturing. Of course, all pins require this protec-
tion during manufacturing, not just RS-232 inputs and
outputs. Therefore, after Pꢁ board assembly, the
Machine Model is less relevant to I/O ports.
ESD protection can be tested in various ways% the
transmitter outputs and receiver inputs of this product
family are characterized for protection to the following
limits:
Applications Information
Capacitor ꢁelection
The capacitor type used for ꢁ±–ꢁ4 is not critical for
proper operation% polarized or nonpolarized capacitors
can be used. The charge pump requires 1.±µF capaci-
tors for 3.3V operation. For other supply voltages, refer
to Table 2 for required capacitor values. Do not use val-
±) ±±5ꢀV using the Human Body Model
2) ±8ꢀV using the contact-discharge method specified
in IEꢁ ±111-4-2
3) ±±5ꢀV using IEꢁ ±111-4-2’s air-gap method.
Table 2. Required Minimum Capacitance
Values
ESD Test Conditions
ESD performance depends on a variety of conditions.
ꢁontact Maxim for a reliability report that documents
test setup, test methodology, and test results.
V
CC
C1, C
C2, C3, C4
(µF)
BYPASS
(V)
(µF)
Human Body Model
Figure 3a shows the Human Body Model, and Figure
3b shows the current waveform it generates when dis-
3.1 to 3.6
4.5 to 5.5
3.1 to 5.5
1.±
1.147
1.±
1.±
1.33
1.47
6
_______________________________________________________________________________________
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
R
R
C
1M
D
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
C
STORAGE
CAPACITOR
s
36.8%
100pF
SOURCE
10%
0
TIME
0
t
RL
t
DL
CURRENT WAVEFORM
Figure 3a. Human Body ESD Test Model
Figure 3b. Human Body Model Current Waveform
I
100%
90%
R
R
D
330Ω
C
50M to 100M
DISCHARGE
RESISTANCE
CHARGE-CURRENT
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
C
s
150pF
STORAGE
CAPACITOR
SOURCE
10%
t
t = 0.7ns to 1ns
r
30ns
60ns
Figure 4b. IEC 10000-4-2 ESD Generator Current Waveform
Figure 4a. IEC 1000-4-2 ESD Test Model
ues smaller than those listed in Table 2. Increasing the
capacitor values (e.g., by a factor of 2) reduces ripple
on the transmitter outputs and slightly reduces power
consumption. ꢁ2, ꢁ3, and ꢁ4 can be increased without
changing ꢁ±’s value. However, do not increase C1
without also increasing the values of C2, C3, C4,
-owerꢂꢁupply Decoupling
In most circumstances, a 1.±µF V
bypass capacitor
ꢁꢁ
is adequate. In applications that are sensitive to power-
supply noise, use a capacitor of the same value as
charge-pump capacitor ꢁ±. ꢁonnect bypass capaci-
tors as close to the Iꢁ as possible.
and C
to maintain the proper ratios (C1 to
BYPASS
the other capacitors).
Operation Down to 2.7k
Transmitter outputs will meet EIA/TIA-562 levels of
±3.7V with supply voltages as low as 2.7V.
When using the minimum required capacitor values,
maꢀe sure the capacitor value does not degrade
excessively with temperature. If in doubt, use capaci-
tors with a larger nominal value. The capacitor’s equiva-
lent series resistance (ESR), which usually rises at low
temperatures, influences the amount of ripple on V+
and V-.
Transmitter Outputs when
Exiting ꢁhutdown
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 lev-
_______________________________________________________________________________________
7
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
els (one transmitter input is high, the other is low). Each
transmitter is loaded with 3ꢀΩ in parallel with 2511pF.
The transmitter outputs display no ringing or undesir-
able transients as they come out of shutdown. Note that
the transmitters are enabled only when the magnitude
of V- exceeds approximately -3V.
Figure 8 shows the same test at 251ꢀbps. For Figure 7,
all transmitters were driven simultaneously at ±21ꢀbps
into RS-232 loads in parallel with ±111pF. For Figure 8,
a single transmitter was driven at 251ꢀbps, and all
transmitters were loaded with an RS-232 receiver in
parallel with ±111pF.
High Data Rates
The MAX3385E maintains the RS-232 ±5.1V minimum
transmitter output voltage even at high data rates.
Figure 6 shows a transmitter loopbacꢀ test circuit.
Figure 7 shows a loopbacꢀ test result at ±21ꢀbps, and
Interconnection with 3k and 5k Logic
The MAX3385E can directly interface with various 5V
logic families, including AꢁT and HꢁT ꢁMOS. See
Table 3 for more information on possible combinations
of interconnections.
V
CC
0.1µF
5V/div
5V/div
5V/div
T1IN
V
CC
C1+
V+
V-
C3
C4
C1
C1-
C2+
T1OUT
R1OUT
MAX3385E
C2
C2-
V
= 3.3V
CC
C1–C4 = 0.1µF
T_ OUT
T_ IN
2µs/div
R_ IN
5k
R_ OUT
SHDN
Figure 7. MAX3385E Loopback Test Result at 120kbps
1000pF
V
CC
GND
5V/div
T1IN
T1OUT
R1OUT
Figure 6. Loopback Test Circuit
5V/div
5V/div
V
= 3.3V
CC
C1–C4 = 0.1µF
2µs/div
Figure 8. MAX3385E Loopback Test Result at 250kbps
8
_______________________________________________________________________________________
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
-in Configurations (continued)
Table 3. Logic-Family Compatibility with
Various Supply Voltages
TOP VIEW
SYSTEM
V
SUPPLY
VOLTAGE
(V)
CC
POWER-SUPPLY
VOLTAGE
(V)
COMPATIBILITY
18
17
16
N.C.
C1+
V+
1
2
3
4
5
6
7
8
9
SHDN
V
CC
ꢁompatible with all
ꢁMOS families
GND
3.3
5
3.3
5
15 T1OUT
14 R1IN
C1-
ꢁompatible with all TTL
and ꢁMOS families
MAX3385E
C2+
C2-
13
12
11
R1OUT
T1IN
ꢁompatible with AꢁT
and HꢁT ꢁMOS, and
with Aꢁ, Hꢁ, or
V-
5
3.3
T2OUT
T2IN
ꢁD4111 ꢁMOS
10 R2OUT
R2IN
SO
___________________Chip Information
TRANSISTOR ꢁOUNT: ±±29
_______________________________________________________________________________________
9
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
________________________________________________________-acꢀage Information
10 ______________________________________________________________________________________
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
-acꢀage Information (continued)
______________________________________________________________________________________ 11
±±5ꢀk EꢁDꢂ-rotected, 3.0k to 5.5k, Lowꢂ-ower,
up to 250ꢀbps, True Rꢁꢂ232 Transceiver
NOTES
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.
12 ____________________Maxim Integrated -roducts, ±20 ꢁan Gabriel Drive, ꢁunnyvale, CA 94086 408ꢂ737ꢂ7600
© 1999 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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