MAX3320LCAP-T
更新时间：2024-09-18 13:07:53
品牌：MAXIM
描述：Line Transceiver, 1 Func, 2 Driver, 2 Rcvr, PDSO20, 0.200 INCH, 0.65 MM PITCH, SSOP-20
概述
规格参数
数据手册
替代型号MAX3320LCAP-T 概述
Line Transceiver, 1 Func, 2 Driver, 2 Rcvr, PDSO20, 0.200 INCH, 0.65 MM PITCH, SSOP-20 线路驱动器或接收器
MAX3320LCAP-T 规格参数
| 是否无铅： | 含铅 | 是否Rohs认证： | 不符合 |
| 生命周期： | Obsolete | 零件包装代码： | SSOP |
| 包装说明： | 0.200 INCH, 0.65 MM PITCH, SSOP-20 | 针数： | 20 |
| Reach Compliance Code： | not_compliant | ECCN代码： | EAR99 |
| HTS代码： | 8542.39.00.01 | 风险等级： | 5.26 |
| Is Samacsys： | N | 差分输出： | NO |
| 驱动器位数： | 2 | 输入特性： | SCHMITT TRIGGER |
| 接口集成电路类型： | LINE TRANSCEIVER | 接口标准： | EIA-232 |
| JESD-30 代码： | R-PDSO-G20 | JESD-609代码： | e0 |
| 长度： | 7.2 mm | 湿度敏感等级： | 1 |
| 功能数量： | 1 | 端子数量： | 20 |
| 最高工作温度： | 70 °C | 最低工作温度： | |
| 封装主体材料： | PLASTIC/EPOXY | 封装代码： | SSOP |
| 封装形状： | RECTANGULAR | 封装形式： | SMALL OUTLINE, SHRINK PITCH |
| 峰值回流温度（摄氏度）： | 245 | 认证状态： | Not Qualified |
| 接收器位数： | 2 | 座面最大高度： | 1.99 mm |
| 最大供电电压： | 5.5 V | 最小供电电压： | 3 V |
| 标称供电电压： | 3.3 V | 表面贴装： | YES |
| 温度等级： | COMMERCIAL | 端子面层： | Tin/Lead (Sn85Pb15) |
| 端子形式： | GULL WING | 端子节距： | 0.65 mm |
| 端子位置： | DUAL | 处于峰值回流温度下的最长时间： | NOT SPECIFIED |
| 宽度： | 5.29 mm | Base Number Matches： | 1 |
MAX3320LCAP-T 数据手册
通过下载MAX3320LCAP-T数据手册来全面了解它。这个PDF文档包含了所有必要的细节，如产品概述、功能特性、引脚定义、引脚排列图等信息。
PDF下载19-1253; Rev 0; 8/97
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
MX320ABL/T
_______________Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
The MAX3320 combines a microprocessor (µP) super-
visory circuit with an RS-232 transceiver. The power-on
reset performs a single function: it asserts a reset signal
♦ Precise Monitoring of 5V and 3.3V Power-
Supply Voltages:
— 100ms (min) Power-On RESET Pulse Width
— Power-Supply Transient Immunity
whenever the V supply voltage declines below a pre-
CC
set threshold, staying asserted for at least 100ms after
— Guaranteed RESET Valid to V = 1V
CC
V
CC
rises above the reset threshold. The MAX3320 has
an active-low RESET output, which is guaranteed to be in
♦ 4µA Supply Current Achieved with
the correct state for V down to 1V. The reset compara-
CC
AutoShutdown Plus
tor is designed to ignore fast transients on V . Reset
CC
♦ Receivers Always Active
thresholds suitable for operation with a variety of supply
voltages are available.
♦ Power-On Reset Always Active
♦ 4µA Low-Power Shutdown
♦ 250kbps Guaranteed Data Rate
The MAX3320 tra nsc e ive rs ha ve a p roprie ta ry low-
dropout transmitter output stage, enabling true RS-232
performance with a dual charge pump powered from a
+3V to +5.5V supply. The device requires only four
small 0.1µF external charge-pump capacitors, and is
guaranteed to run at data rates of up to 250kbps. It
comes in the space-saving 20-pin SSOP package.
______________Ord e rin g In fo rm a t io n
________________________Ap p lic a t io n s
Palmtop Computers
PART*
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
20 SSOP
Portable/Battery-Powered Equipment
Hand-Held Equipment
MAX3320_CAP
MAX3320_EAP
-40°C to +85°C
20 SSOP
Peripherals
* This part offers a choice of reset threshold voltage. From the
table below, select the suffix corresponding to the desired
threshold and insert it into the blank to complete the part
number.
Printers
__________________P in Co n fig u ra t io n
RESET THRESHOLD
SUFFIX
(V)
A
B
L
T
4.25
2.85
4.63
3.08
TOP VIEW
V+
C2+
1
2
3
4
5
6
7
8
9
20 C1+
19
V
CC
C2-
18 C1-
V-
17 GND
MAX3320
T1IN
16 T1OUT
15 T2OUT
14 R1IN
T2IN
Typical Operating Circuit appears at end of data sheet.
R1OUT
R2OUT
INVALID
13 R2IN
12 FORCEON
11 FORCEOFF
RESET 10
SSOP
AutoShutdown Plus is a trademark of Maxim Integrated Products.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
ABSOLUTE MAXIMUM RATINGS
V
CC
.............................................................................-0.3V to 6V
Short-Circuit Duration
V+ (Note 1) .................................................................-0.3V to 7V
V- (Note 1)...................................................................0.3V to -7V
T_OUT....................................................................Continuous
Continuous Power Dissipation (T = +70°C)
A
V+ + V- (Note 1) ...................................................................13V
Input Voltages
SSOP (derate 8.00mW/°C above +70°C) ....................640mW
Operating Temperature Ranges
|
|
T_IN, FORCEOFF, FORCEON................................-0.3V to 6V
R_IN.................................................................................±25V
Output Voltages
MAX3320_CAP ...................................................0°C to +70°C
MAX3320_EAP ................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
T_OUT ..........................................................................±13.2V
R_OUT, INVALID, RESET.......................-0.3V to (V + 0.3V)
CC
Note 1: V+ and V- can have a magnitude of +7V (max), 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 = 3V to 5.5V, C1–C4 = 0.1µF (tested at 3.3V ±10%), C1 = 0.047µF, C2–C4 = 0.33µF (tested at 5V ±10%), T = T
CC
MX320ABL/T
to T
,
A
MIN
MAX
unless otherwise noted. Typical values are at T = +25°C.)
A
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
Power-Supply Current
No load, V = 3.3V or 5V, T = +25°C
0.45
4.0
1.0
10
mA
µA
CC
A
Shutdown Supply Current
FORCEOFF = GND, T = +25°C
A
All R_IN unconnected, FORCEON = GND,
AutoShutdown Plus
Supply Current
4.0
10
µA
FORCEOFF = V , all T_IN = V or GND, T = +25°C
CC
CC
A
LOGIC INPUTS AND RECEIVER OUTPUTS
Input Logic Threshold Low
0.8
V
V
T_IN, FORCEON, FORCEOFF
V
= 3.3V
= 5V
2.0
2.4
T_IN, FORCEON,
FORCEOFF
CC
Input Logic Threshold High
V
CC
Input Leakage Current
Input Hysteresis
±0.01
250
±1.0
0.4
µA
mV
V
T_IN, FORCEON, FORCEOFF
T_IN, FORCEON, FORCEOFF
Output Voltage Low
I
= 1.6mA
OUT
V
0.6
-
V
CC -
0.1
CC
Output Voltage High
I
= -1mA
V
OUT
RECEIVER INPUTS
Input Voltage Range
-25
0.6
0.8
25
V
V
V
= 3.3V
= 5V
1.2
1.5
1.5
1.8
0.3
5
CC
Input Threshold Low
Input Threshold High
V
CC
V
CC
= 3.3V
= 5V
2.4
2.4
V
V
CC
Input Hysteresis
Input Resistance
INVALID OUTPUT
V
kΩ
T
A
= +25°C
3
7
Figure 3, positive threshold
Figure 3, negative threshold
2.7
Receiver Input Threshold to
INVALID Output High
V
-2.7
-0.3
Receiver Input Threshold to
INVALID Output Low
Figure 3
0.3
0.4
V
V
I
= 1.6mA
INVALID Output Voltage Low
OUT
2
_______________________________________________________________________________________
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
MX320ABL/T
ELECTRICAL CHARACTERISTICS (continued)
(V = 3V to 5.5V, C1–C4 = 0.1µF (tested at 3.3V ±10%), C1 = 0.047µF, C2–C4 = 0.33µF (tested at 5V ±10%), T = T
CC
to T
,
A
MIN
MAX
unless otherwise noted. Typical values are at T = +25°C.)
A
PARAMETER
CONDITIONS
MIN
- 0.6
CC
TYP
MAX
UNITS
I
= -1mA
V
V
INVALID Output Voltage High
OUT
Receiver Positive or Negative
Threshold to INVALID High
Figure 3
Figure 3
0.1
90
µs
µs
Receiver Positive or Negative
Threshold to INVALID Low
AUTOSHUTDOWN PLUS (FORCEON = GND, FORCEOFF = V
)
CC
Receiver or Transmitter Edge
Figure 5
25
30
µs
to Transmitters Enabled
Receiver or Transmitter Edge
Figure 3
15
60
sec
to Shutdown
TRANSMITTER OUTPUTS
All transmitter outputs loaded with 3kΩ to ground
= V+ = V- = GND, V = ±2V
Output Voltage Swing
Output Resistance
±5.0
300
±5.4
10M
±35
V
Ω
V
CC
T_OUT
Output Short-Circuit Current
Output Leakage Current
RESET OUTPUT
T_OUT = GND, T_IN = V or GND
±60
±25
mA
µA
CC
V
T_OUT
= ±12V, V = 0 to 5.5V, transmitters disabled
CC
MAX3320_C
MAX3320_E
MAX3320A
MAX3320B
MAX3320L
MAX3320T
1.0
1.2
5.5
5.5
RESET Operating Voltage
Range
V
V
4.00
2.70
4.50
3.00
4.25
2.85
4.63
3.08
4.50
3.00
4.75
3.15
0.3
RESET Threshold
I
= 1.2mA, V = reset threshold, MAX3320B/T
CC
SINK
I
= 3.2mA, V = reset threshold, MAX3320A/L
0.4
SINK
CC
V
RESET Output Voltage
I
= 50µA, V > 1V, MAX3320_C
0.3
SINK
CC
I
= 100µA, V > 1.2V, MAX3320_E
0.4
SINK
CC
_______________________________________________________________________________________
3
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
TIMING CHARACTERISTICS
(V
CC
= 3V to 5.5V, C1–C4 = 0.1µF, C1–C4 = 0.1µF (for 3.3V ±10%), C1 = 0.047µF, C2–C4 = 0.33µF (tested at 5V ±10%),
T
A
= T
to T
, unless otherwise noted. Typical values are at T = +25°C.)
MIN
MAX
A
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
R
= 3kΩ, C = 1000pF, one transmitter switching
Maximum Data Rate
250
kbps
L
L
t
t
0.3
0.3
PHL
PLH
Receiver Propagation Delay
R_IN to R_OUT, C = 150pF
µs
L
Transmitter Skew
Receiver Skew
100
200
ns
ns
t
t
- t
PHL PLH
|
|
|
|
- t
PHL PLH
C
= 150pF to
L
6
4
30
30
V
= 3.3V, R = 3kΩ to 7kΩ,
L
CC
1000pf
Transition-Region Slew Rate
V/µs
measured from +3V to -3V or -3V to
+3V, T = +25°C
A
C
= 150pF to
L
2500pf
MX320ABL/T
100mV overdrive from reset threshold
40
µs
V
CC
to RESET Delay
V
CC
= reset threshold
100
280
ms
RESET Active Timeout Period
__________________________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(V
CC
= 3.3V, 250kbps data rate, C1–C4 = 0.1µF, all transmitters loaded with 3kΩ. Typical values are at T = +25°C, unless
A
otherwise noted.)
SUPPLY CURRENT
vs. LOAD CAPACITANCE WHEN
TRANSMITTING DATA
SLEW RATE
vs. LOAD CAPACITANCE
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
12
10
45
40
35
7.5
5.0
2.5
0
ONE TRANSMITTER AT
FULL DATA RATE INDICATED
V
T_OUT+
NEGATIVE
SLEW
ONE TRANSMITTER AT 250kbps
ONE TRANSMITTER AT 15.6kbps
ONE TRANSMITTER AT
1/16 DATA RATE INDICATED
250kbps
8
6
4
30
25
20
15
10
5
LOAD = 3kΩ + C
L
POSITIVE
SLEW
120kbps
20kbps
-2.5
-5.0
-7.5
ONE TRANSMITTER AT 250kbps
ONE TRANSMITTER AT 15.6kbps
2
0
V
T_OUT-
LOAD = 3kΩ + C
L
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)
4
_______________________________________________________________________________________
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
MX320ABL/T
____________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
(V
CC
= 3.3V, 250kbps data rate, C1–C4 = 0.1µF, all transmitters loaded with 3kΩ. Typical values are at T = +25°C, unless
A
otherwise noted.)
NORMALIZED POWER-UP RESET
DELAY vs. TEMPERATURE
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
1.040
1.030
1.020
1.010
300
250
200
150
100
50
SHUTDOWN MODE
1.000
0.990
0.980
NOT IN
SHUTDOWN
MODE
0.970
0.960
C
BYPASS
= 0.1µF
0
-40
-20
0
20
40
60
80
10
100
RESET COMPARATOR OVERDRIVE (mV)
1000
TEMPERATURE (°C)
______________________________________________________________P in De s c rip t io n
PIN
1
NAME
V+
FUNCTION
5.5V generated by the charge pump
2
C2+
C2-
Positive terminal of inverting charge-pump capacitor
Negative terminal of inverting charge-pump capacitor
-5.5V generated by the charge pump
3
4
V-
5, 6
7, 8
T_IN
R_OUT
TTL/CMOS Transmitter Inputs (T1IN and T2IN)
TTL/CMOS Receiver Outputs (R1OUT and R2OUT)
Output of the Valid Signal Detector. Asserts when no valid RS-232 levels are present on any of
the receiver inputs for 90µs.
9
INVALID
RESET
RESET Output. RESET remains low while V is below the reset threshold, and for 280ms (max)
CC
10
after V rises above the reset threshold.
CC
Force-Off Input. Drive FORCEOFF low to shut down transmitters and on-board power supply.
This overrides AutoShutdown Plus and FORCEON (Table 1).
11
12
FORCEOFF
Force-On Input. Drive FORCEON high to override AutoShutdown Plus, keeping transmitters on
(FORCEOFF must be high) (Table 1).
FORCEON
13, 14
15, 16
17
R_IN
T_OUT
GND
C1-
RS-232 Receiver Inputs (R2IN and R1IN)
RS-232 Transmitter Outputs (T2OUT and T1OUT)
Ground
18
Negative terminal of voltage-doubler charge-pump capacitor
+3V to +5.5V Supply Voltage
19
V
CC
20
C1+
Positive terminal of voltage-doubler charge-pump capacitor
_______________________________________________________________________________________
5
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
Table 1. MAX3320 Output Control Truth Table
AUTOSHUTDOWN
PLUS*
OPERATION
STATUS
FORCEON
T_OUT
High-Z
Active
R_OUT
Active
Active
Active
Active
FORCEOFF
Shutdown
(forced off)
X
0
1
1
1
X
Normal operation
(forced on)
1
X
Normal operation
(AutoShutdown Plus)
0
0
<30sec*
>30sec*
Active
Shutdown
(AutoShutdown Plus)
High-Z
X = Don’t Care
*Time since last receiver or transmitter input activity
MX320ABL/T
______________ De t a ile d De s c rip t io n
POWER-
MANAGEMENT
UNIT OR
KEYBOARD
CONTROLLER
FORCEOFF
FORCEON
INVALID
Du a l Ch a rg e -P u m p Vo lt a g e Co n ve rt e r
The MAX3320’s internal power supply consists of a reg-
ulated dual charge pump that provides output voltages
of +5.5V (doubling charge pump) and -5.5V (inverting
charge pump) while V
remains in the 3V to 5.5V
CC
range. The charge pumps operate in discontinuous
mode; they are enabled if the output voltages are less
than 5.5V, and disabled if output voltages exceed 5.5V.
Each charge pump requires a flying capacitor (C1, C2)
and a reservoir capacitor (C3, C4) to generate the V+
and V- supplies.
MAX3320
T1
T2
I/O
RS -2 3 2 Tra n s m it t e rs
The transmitters are inverting level translators that con-
vert CMOS-logic levels to 5V EIA/TIA-232 levels. The
MAX3320 transmitters guarantee a 250kbps data rate
with worst-case loads of 3kΩ in parallel with 1000pF,
providing compatibility with PC-to-PC communication
software (such as LapLink™). Transmitters can be par-
alleled to drive multiple receivers. Figure 1 shows a
complete system connection.
RS-232
CHIP
WITH
UART
R1
R2
CPU
When FORCEOFF is driven to ground, the transmitter’s
Figure 1. Interface Under Control of PMU
outp uts b e c ome hig h imp e d a nc e . Whe n the
AutoShutdown Plus circuitry senses that all receiver
and transmitter inputs are inactive for more than 30sec,
the transmitters turn off and the outputs go into a high-
imp e d a nc e s ta te , b ut the re c e ive rs re ma in a c tive .
When the power is off or the MAX3320 is shut down,
outputs may be driven up to ±12V.
RS -2 3 2 Re c e ive rs
The receivers convert RS-232 signals to CMOS-logic out-
put levels. All receivers have inverting outputs and are
active in shutdown FORCEOFF (Table 1).
Au t o S h u t d o w n P lu s Mo d e
Maxim’s AutoShutdown Plus feature, which operates
when FORCEOFF is high and FORCEON is low, achieves
a 4µA supply current. When the MAX3320 senses no
valid signal levels on all receiver and transmitter inputs for
30sec, the on-board power supply and drivers shut off,
The transmitter inputs do not have pull-up resistors.
Connect unused inputs to GND or V
.
CC
Laplink is a trademark of Traveling Software.
6
_______________________________________________________________________________________
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
BL/TMAX320
reducing supply current to 4µA. This occurs if the RS-232
cable is disconnected or the connected peripheral trans-
+0.3V
mitters turn off. The system turns on again when a valid
transition occurs at any RS-232 receiver or transmitter
input. As a re sult, the syste m sa ve s p owe r without
changes to the existing BIOS or operating system. The
INVALID output is high when the receivers are active.
Since INVALID indicates the receiver inputs’ condition, it
can be used in any mode (Figure 2).
R_IN
90µs
TIMER
R
INVALID
-0.3V
INVALID ASSERTED IF BOTH RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR
AT LEAST 90µs.
Tables 1 and 2 and Figure 2 summarize the MAX3320’
s
Figure 2a. INVALID Functional Diagram, INVALID Low
operating modes. FORCEON and FORCEOFF override
the automatic circuitry and force the transceiver into its
normal operating state or into its low-power standby
state. When neither control is asserted, the IC enters
AutoShutdown Plus mode and selects between these
s ta te s a utoma tic a lly, b a s e d on the la s t re c e ive r or
transmitter input edge received.
+2.7V
R_IN
90µs
TIMER
R
INVALID
When shut down, the device’s charge pumps turn off,
-2.7V
V+ decays to V , V- decays to ground, and the trans-
CC
mitte r outp uts turn off (hig h imp e d a nc e ). The time
required to exit shutdown is typically 25µs (Figure 3a).
INVALID DEASSERTED IF EITHER RECEIVER INPUT HAS BEEN BETWEEN +2.7V
AND -2.7V FOR LESS THAN 90µs.
S o ft w a re -Co n t ro lle d S h u t d o w n
If direct software control is desired, use INVALID to indi-
cate DTR or Ring Indicator signal. Connect FORCEOFF
and FORCEON together to bypass the AutoShutdown
Plus feature so the line acts like a SHDN input.
Figure 2b. INVALID Functional Diagram, INVALID High
EDGE
T_IN
FORCEOFF
DETECT
S
P o w e r-On Re s e t
In addition to issuing a reset to the microprocessor (µP)
during power-up, power-down, and brownout condi-
tions , the MAX3320 is re la tive ly immune to s hort-
AUTOSHDN
30sec
TIMER
EDGE
DETECT
R
R_IN
duration, negative-going V
transitions (glitches).
CC
FORCEON
Typically, a V
transient that goes 100mV below the
CC
reset threshold and lasts 20µs or less does not cause a
reset pulse (see Typical Operating Characteristics).
Additional bypass capacitance mounted as close as
Figure 2c. AutoShutdown Plus Logic
possible to the V
immunity.
pin provides additional transient
CC
FORCEOFF
POWERDOWN*
FORCEON
Table 2. INVALID Truth Table
AUTOSHDN
RS-232 SIGNAL PRESENT AT
RECEIVER INPUT
INVALID
OUTPUT
* POWERDOWN IS ONLY AN INTERNAL SIGNAL.
IT CONTROLS THE OPERATIONAL STATUS OF
THE TRANSMITTERS AND THE POWER SUPPLIES.
Yes
No
H
L
Figure 2d. Power-Down Logic
_______________________________________________________________________________________
7
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
INVALID
REGION
*
**
RECEIVER
INPUTS
VOLTAGE
TRANSMITTER
INPUTS
VOLTAGE
TRANSMITTER
OUTPUTS
VOLTAGE
V
INVALID
OUTPUT
CC
t
0
AUTOSHDN
MX320ABL/T
I
t
AUTOSHDN
NVL
t
t
WU
WU
V+
V
CC
0
V-
* ALL RECEIVER/TRANSMITTER INPUTS INACTIVE
** ANY ONE RECEIVER/TRANSMITTER INPUT BECOMES ACTIVE
FORCEON = GND, FORCEOFF = V
CC
Figure 3a. AutoShutdown Plus and INVALID Timing Diagram
can drift to undefined voltages. This presents no prob-
lem in most applications, since most µPs and other cir-
INVALID HIGH
2.7V
cuitry is inoperative with V
below 1V. However, in
CC
applications where RESET must be valid down to 0V,
add a pull-down resistor to ground, holding RESET low
(Figure 4). R1’s value is not critical; 100kΩ is large
enough not to load RESET, and small enough to pull it
to ground.
INDETERMINATE
0.3V
0V
INVALID LOW
INDETERMINATE
INVALID HIGH
-0.3V
Ca p a c it o r S e le c t io n
The capacitor type used for C1–C4 is not critical for
proper operation; use either polarized or nonpolarized
capacitors. The charge pump requires 0.1µF capaci-
tors for 3.3V operation. For other supply voltages, refer
to Table 3 for required capacitor values. Do not use val-
ues smaller than those listed in Table 3. 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 C2, C3, C4,
-2.7V
Figure 3b. Receiver Positive/Negative Thresholds for INVALID
__________Ap p lic a t io n s In fo rm a t io n
En s u rin g a Va lid Re s e t Ou t p u t
Do w n t o V
= 0 V
CC
falls below 1V, RESET no longer sinks cur-
and C
, to maintain the proper ratios (C1 to
BYPASS
When V
CC
the other capacitors).
re nt: it b e c ome s a n op e n c irc uit. The re fore , hig h-
impedance CMOS logic inputs connected to RESET
8
_______________________________________________________________________________________
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
MX320ABL/T
FORCEON =
FORCEOFF
V
CC
2V/div
T2OUT
MAX3320
V
CC
GND
RESET
2V/div
100k
T1OUT
V
= 3.3V
5µs/div
CC
Figure 4. Ensuring RESET Valid to V = 0V
CC
C1 - C4 = 0.1µF
When using the minimum required capacitor values,
ma ke s ure the c a p a c itor va lue d oe s not d e g ra d e
excessively with temperatures outside the 0°C to +70°C
range. If in doubt, use capacitors with a larger nominal
va lue . The c a p a c itor's e q uiva le nt se rie s re sista nc e
(ESR), which usually rises at low temperatures, influ-
ences the amount of ripple on V+ and V-.
Figure 5. Transmitter Outputs when Exiting Shutdown or
Powering Up
V
CC
V
CC
C1+
V+
V-
C3*
C4
Tra n s m it t e r Ou t p u t s
w h e n Ex it in g S h u t d o w n
C1
C1-
Figure 5 shows two transmitter outputs when exiting
shutdown mode. As they become active, the two trans-
mitter outputs go to opposite RS-232 levels (one trans-
mitter input is high; the other is low). Each transmitter is
loaded with 3kΩ in parallel with 2500pF. The transmitter
outputs display no ringing or undesirable transients as
the y e xit s hutd own. Note tha t the tra ns mitte rs a re
e na b le d only whe n the ma g nitud e of V- e xc e e d s
approximately 3V.
C2+
MAX3320
C2
C2-
T_ OUT
T_ IN
R_ IN
5k
R_ OUT
FORCEON
FORCEOFF
1000pF
Hig h Da t a Ra t e s
The MAX3320 ma inta ins the RS-232 ± 5V minimum
tra ns mitte r outp ut volta g e e ve n a t hig h d a ta ra te s .
Figure 6 shows a transmitter loop-back test circuit.
Figure 7 shows a loop-back test result at 120kbps, and
Figure 8 shows the same test at 250kbps. For Figure 7,
b oth tra ns mitte rs we re d rive n s imulta ne ous ly a t
120kbps into RS-232 loads in parallel with 1000pF. For
Figure 8, a single transmitter was driven at 250kbps,
a nd b oth tra ns mitte rs we re loa d e d with a n RS-232
receiver in parallel with 1000pF.
V
CC
GND
*C3 CAN BE RETURNED TO
OR GND.
V
CC
Figure 6. Loop-Back Test Circuit
Table 3. Required Minimum
Capacitance Values
In t e rc o n n e c t io n w it h 3 V a n d 5 V Lo g ic
The MAX3320 can directly interface with various 5V
logic fa milie s, inc lud ing ACT a nd HCT CMOS. Se e
Table 4 for more information on possible combinations
of interconnections.
V
(V)
C1
(µF)
C2, C3, C4, C
(µF)
CC
BYPASS
3 to 3.6
4.5 to 5.5
3 to 5.5
0.1
0.047
0.1
0.1
0.33
0.47
_______________________________________________________________________________________
9
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
5V
0V
5V
0V
T1IN
T1IN
5V
0V
-5V
5V
0V
-5V
T1OUT
R1IN
T1OUT
R1IN
5V
0V
5V
0V
R1OUT
R1OUT
2µs/div
2µs/div
V
CC
= 3.3V
V = 3.3V
CC
MX320ABL/T
C1 - C4 = 0.1µF
= 1000pF
C1 - C4 = 0.1µF
= 1000pF
C
C
LOAD
LOAD
Figure 8. Loop-Back Test Result at 250kbps
Figure 7. Loop-Back Test Result at 120kbps
Table 4. Logic-Family Compatibility
with Various Supply Voltages
___________________Ch ip In fo rm a t io n
TRANSISTOR COUNT: 1577
SYSTEM
V
SUPPLY
VOLTAGE
(V)
CC
POWER-SUPPLY
VOLTAGE
(V)
COMPATIBILITY
Compatible with all
CMOS families
3.3
5
3.3
5
Compatible with all
TTL and CMOS
families
Compatible with ACT
and HCT CMOS, and
with AC, HC, or
5
3.3
CD4000 CMOS
10 ______________________________________________________________________________________
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
MX320ABL/T
___________________________________________________Typ ic a l Op e ra t in g Circ u it
+3.3V
V
CC
0.1µF
V
CC
C1+
C1-
V+
V-
C1
0.1µF
C3*
0.1µF
MAX3320
C2+
C2
C4
0.1µF
0.1µF
C2-
V
CC
T1IN
T1OUT
T1
T2
RS-232
OUTPUTS
T2IN
T2OUT
FORCEOFF
AUTOSHUTDOWN
PLUS
FORCEON
R1OUT
µP
SYSTEM
R1IN
R1
5k
RS-232
INPUTS
R2OUT
R2IN
R2
5k
RESET
INPUT
RESET
GND
INVALID
*C3 MAY BE RETURNED TO EITHER V OR GND.
CC
______________________________________________________________________________________ 11
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
________________________________________________________P a c k a g e In fo rm a t io n
MX320ABL/T
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 ____________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 4 0 8 -7 3 7 -7 6 0 0
© 1997 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX3320LCAP-T 替代型号
| 型号 | 制造商 | 描述 | 替代类型 | 文档 |
| MAX3320LEAP+ | MAXIM | Line Transceiver, 1 Func, 2 Driver, 2 Rcvr, PDSO20, 0.200 INCH, 0.65 MM PITCH, SSOP-20 | 功能相似 |
|
MAX3320LCAP-T 相关器件
| 型号 | 制造商 | 描述 | 价格 | 文档 |
| MAX3320LEAP | MAXIM | Transceiver | 获取价格 |
|
| MAX3320LEAP+ | MAXIM | Line Transceiver, 1 Func, 2 Driver, 2 Rcvr, PDSO20, 0.200 INCH, 0.65 MM PITCH, SSOP-20 | 获取价格 |
|
| MAX3320LEAP+T | MAXIM | Line Transceiver, 1 Func, 2 Driver, 2 Rcvr, PDSO20, 0.200 INCH, 0.65 MM PITCH, SSOP-20 | 获取价格 |
|
| MAX3320LEAP-T | MAXIM | Line Transceiver, 1 Func, 2 Driver, 2 Rcvr, PDSO20, 0.200 INCH, 0.65 MM PITCH, SSOP-20 | 获取价格 |
|
| MAX3320T | MAXIM | 3V to 5.5V, up to 250kbps True RS-232 Transceiver with 4レA AutoShutdown Plus and Power-On Reset | 获取价格 |
|
| MAX3320TCAP | MAXIM | Transceiver | 获取价格 |
|
| MAX3320TCAP+ | MAXIM | Line Transceiver, 1 Func, 2 Driver, 2 Rcvr, BICMOS, PDSO20, 0.200 INCH, 0.65 MM PITCH, SSOP-20 | 获取价格 |
|
| MAX3320TCAP+T | MAXIM | Line Transceiver, 1 Func, 2 Driver, 2 Rcvr, PDSO20, 0.200 INCH, 0.65 MM PITCH, SSOP-20 | 获取价格 |
|
| MAX3320TCAP-T | MAXIM | Line Transceiver, 1 Func, 2 Driver, 2 Rcvr, PDSO20, 0.200 INCH, 0.65 MM PITCH, SSOP-20 | 获取价格 |
|
| MAX3320TEAP | MAXIM | Transceiver | 获取价格 |
|
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