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PDF MAX3380E Data sheet ( Hoja de datos )
| Número de pieza | MAX3380E | |
| Descripción | +2.35V to +5.5V / 1A / 2Tx/2Rx RS-232 Transceivers with 15kV ESD-Protected I/O and Logic Pins | |
| Fabricantes | Maxim Integrated | |
| Logotipo |  |
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19-2128; Rev 0; 8/01
+2.35V to +5.5V, 1µA, 2Tx/2Rx RS-232 Transceivers
with ±15kV ESD-Protected I/O and Logic Pins
General Description
The MAX3380E/MAX3381E are +2.35V to +5.5V-pow-
ered EIA/TIA-232 and V.28/V.24 communication inter-
faces with low power requirements, high data-rate
capabilities, and enhanced electrostatic discharge
(ESD) protection on both the TTL and RS-232 sides.
The MAX3380E/MAX3381E have two receivers and two
transmitters. All RS-232 inputs, outputs, and logic input
pins are protected to ±15kV using IEC 1000-4-2 Air-
Gap Discharge method and the Human Body Model,
and ±8kV using IEC 1000-4-2 Contact Discharge
method.
The proprietary low-dropout transmitter output stage
enables true RS-232 performance from a +3.1V to
+5.5V supply with a dual charge pump. The parts
reduce the transmitter output levels to RS-232-compati-
ble levels with no increase in supply current for sup-
plies less than +3.1V and greater than +2.35V. The
+2.35V to +5.5V operating range is fully compatible
with lithium-ion (Li+) batteries. The charge pump
requires only four small 0.1µF capacitors for operation.
The MAX3380E/MAX3381E transceivers use Maxim’s
revolutionary AutoShutdown Plus™ feature to auto-
matically enter a 1µA shutdown mode. These
devices shut down the on-board power supply and
drivers when they do not sense a valid signal transi-
tion for 30 seconds on either the receiver or trans-
mitter inputs.
The MAX3380E is capable of transmitting data at
rates of 460kbps while maintaining RS-232 output
levels, and the MAX3381E operates at data rates up
to 250kbps. The MAX3381E offers a slower slew rate
for applications where noise and EMI are issues. The
MAX3380E/MAX3381E have a unique VL pin that
allows interoperation in mixed-logic voltage systems
down to +1.65V. Both input and output logic levels
are referenced to the VL pin. The MAX3380E/MAX3381E
are available in a space-saving TSSOP package.
Applications
Cell Phone Data Lump Cables
PDA Data Lump Cables
GPS Receivers
Digital Cameras
AutoShutdown Plus is a trademark of Maxim Integrated Products
Pin Configuration appears at end of data sheet.
Features
o ±15kV ESD Protection on All CMOS and RS-232
Inputs and Outputs (Except INVALID)
±15kV Human Body Model
±15kV IEC 1000-4-2 Air-Gap Discharge
±8kV IEC 1000-4-2 Contact Discharge
o Operates Over Entire Li+ Battery Range
o Low Logic Threshold Down to +1.65V for
Compatibility with Cell Phone Logic Supply Voltages
o 1µA Low-Power AutoShutdown Plus Mode
o Compatible with Next-Generation GSM Data Rates
o 20-Pin TSSOP Package
Ordering Information
PART
MAX3380ECUP
MAX3380EEUP
MAX3381ECUP
MAX3381EEUP
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
20 TSSOP
20 TSSOP
20 TSSOP
20 TSSOP
Typical Operating Circuit
+3.3V
C5
0.1µF
VCC VL
C1
0.1µF
C2
0.1µF
TTL/CMOS
INPUTS
TTL/CMOS
OUTPUTS
C1+
C1-
MAX3380E/
C2+ MAX3381E
V+
V-
C2-
T1IN T1OUT
T2IN
R1OUT
R2OUT
VL
VL
GND
T2OUT
R1IN
5kΩ
R2IN
5kΩ
C3
0.1µF
C4
0.1µF
RS-232
OUTPUTS
RS-232
INPUTS
________________________________________________________________ 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.
1 page  
+2.35V to +5.5V, 1µA, 2Tx/2Rx RS-232 Transceivers
with ±15kV ESD-Protected I/O and Logic Pins
Typical Operating Characteristics (continued)
(VCC = VL = +4.2V, C1 = 0.22µF, C2 = C3 = C4 = 1µF, C5 = 0.1µF parallel with 47µF, RL = 3kΩ, CL = 1000pF, data rate is 250kbps,
TA = +25°C, unless otherwise noted.)
MAX3381E
SLEW RATE vs. LOAD CAPACITANCE
14
13
12 VCC = +4.2V
11
10
9 VCC = +2.5V
8
7
SUPPLY CURRENT vs. LOAD CAPACITANCE
WHEN TRANSMITTING DATA
80
1 TRANSMITTER SWITCHING
70
460kbps
60
50 250kbps
40
30
20 20kbps
10
TRANSMITTER OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE (VCC FALLING)
8
6
VOUT+
4
2
0
-2
-4 VOUT-
6
0 500 1000 1500 2000 2500 3000
LOAD CAPACITANCE (pF)
0
0 500 1000 1500 2000 2500 3000
LOAD CAPACITANCE (pF)
-6
2.5
3.5 4.5
SUPPLY VOLTAGE (V)
5.5
TRANSMITTER OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE (VCC RISING)
8
6
VOUT+
4
2
SUPPLY CURRENT
vs. SUPPLY VOLTAGE (VCC FALLING)
25
1 TRANSMITTER SWITCHING
20
15
0
-2
-4 VOUT-
10
5
-6
2.5
T_IN
5V/div
3.5 4.5
SUPPLY VOLTAGE (V)
5.5
MAX3380E
DATASTREAM VCC = +4.2V
MAX3380E toc09
5V
0
0
2.5
T_IN
5V/div
3.5 4.5
SUPPLY VOLTAGE (V)
5.5
MAX3380E
DATASTREAM VCC = +2.5V
MAX3380E toc10
5V
0
T_OUT
5V/div
1µs/div
5V
T_OUT
0 5V/div
-5V
VCC = VL = +2.5V
1µs/div
5V
0
-5V
_______________________________________________________________________________________ 5
5 Page 
+2.35V to +5.5V, 1µA, 2Tx/2Rx RS-232 Transceivers
with ±15kV ESD-Protected I/O and Logic Pins
to IEC 1000-4-2 are generally lower than that measured
using the Human Body Model. Figure 6a shows the IEC
1000-4-2 model, and Figure 6b shows the current
waveform for the ±8kV IEC 1000-4-2 Level 4 ESD
Contact Discharge test.
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.
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 by
contact that occurs with handling and assembly during
manufacturing. All pins require this protection during
manufacturing, not just RS-232 inputs and outputs.
Therefore, after PC board assembly, the Machine
Model is less relevant to I/O ports.
Applications Information
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 for +3.3V operation. For other supply 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., 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, and
C5 to maintain the proper ratios (C1 to the other capac-
itors).
When using the minimum required capacitor values,
make sure the capacitor value does not degrade
excessively with temperature. If in doubt, use capaci-
tors with a large nominal value. The capacitor’s equiva-
lent series resistance (ESR) usually rises at low
temperatures and influences the amount of ripple on
V+ and V-.
Table 2. Minimum Required Capacitor
Values
VCC (V)
+2.35 to +3.6
+4.5 to +5.5
+2.35 to +5.5
C1, C5 (µF)
0.1
0.047
0.22
C2, C3, C4 (µF)
0.1
0.33
1
Power-Supply Decoupling
In most circumstances, connect a 0.1µF capacitor from
VCC to GND. This capacitor is for noise reduction. If the
MAX3380E/MAX3381E are used in a data cable appli-
cation, add a 47µF capacitor from VCC to ground. The
47µF capacitor is used to ensure that the current need-
ed during power-up is supplied to the device. In appli-
cations that are sensitive to power-supply noise,
decouple VCC to ground with a capacitor of the same
value as charge-pump capacitor C1. Connect bypass
capacitors as close to the IC as possible.
Transmitter Outputs when Recovering
from Shutdown
Figure 7 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-
els (one transmitter input is high, the other is low). Each
transmitter is loaded with 3kΩ in parallel with 1000pF.
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.
High Data Rates
The MAX3380E/MAX3381E maintain the RS-232 ±5.0V
minimum transmitter output voltage even at high data
rates. Figure 8 shows a transmitter loopback test cir-
cuit. Figure 9 shows a loopback test result for the
MAX3380E at 460kbps with true RS-232 output voltage
levels (VCC = +4.2V). Figure 10 shows the same test
with RS-232-compatible levels (VCC = +2.5V). With
data rates as high as 460kbps, the MAX3380E is com-
patible with 2.5-Generation GSM standards.
5V/div
5V FORCEON =
0 FORCEOFF
6V T2OUT
2V/div
0
4µs/div
VCC = 3.3V, C1–C4 = 0.1µF, CLOAD = 1000pF
T1OUT
6V
Figure 7. Transmitter Outputs when Recovering from Shutdown
or Powering Up
______________________________________________________________________________________ 11
11 Page | ||
| Páginas | Total 14 Páginas | |
| PDF Descargar | [ Datasheet MAX3380E.PDF ] | |
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