MAX3388EEUG+ Maxim Integrated Products, MAX3388EEUG+ Datasheet - Page 8

• Manufacturer Part Number: MAX3388EEUG+
• Description: IC TXRX RS232 250KBPS 24-TSSOP
• Manufacturer: Maxim Integrated Products
• Type: Transceiverr

Specifications of MAX3388EEUG+

• Number Of Drivers/receivers: 3/3
• Protocol: RS232
• Voltage - Supply: 3 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 24-TSSOP
• Propagation Delay Time Ns: 0.15 us
• Operating Supply Voltage: 2.35 V to 3 V
• Supply Current: 0.3 mA
• Operating Temperature Range: - 40 C to + 85 C
• Data Rate: 460 Kbps
• Mounting Style: SMD/SMT
• Number Of I/os: 3 / 2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2.5V, ±15kV ESD-Protected RS-232
Transceivers for PDAs and Cell Phones
Figure 4a. IEC 1000-4-2 ESD Test Model
Figure 4b. IEC 1000-4-2 ESD Generator Current Waveform
Table 2. Minimum Required Capacitor
Values
8
t R = 0.7ns to 1ns
VOLTAGE
SOURCE
HIGH-
_______________________________________________________________________________________
DC
2.5 to 3.0
100%
CHARGE-CURRENT
50MΩ to 100MΩ
90%
10%
LIMIT RESISTOR
V
I
(V)
CC
R
C
150pF
C s
30ns
STORAGE
CAPACITOR
RESISTANCE
DISCHARGE
330Ω
R
D
60ns
C1–C4
(µF)
0.1
DEVICE
UNDER
TEST
t
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.
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.
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 capacitors
for 2.5V operation (Table 2). Do not use values 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 con-
sumption. 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, and C4 to
maintain the proper ratios (C1 to the other capacitors).
When using the minimum required capacitor values,
make sure the capacitor value does not degrade
excessively with temperature. If in doubt, use capacitors
with a larger 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-.
In most circumstances, a 0.1µF bypass capacitor is
adequate. In applications that are sensitive to power-
supply noise, decouple V
the same value as charge-pump capacitor C1. Connect
bypass capacitors as close to the IC as possible.
Figure 2 shows two transmitter outputs when exiting
shutdown mode. As they become active, the two
transmitter outputs are shown going to opposite RS-232
levels (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
undesirable transients as they come out of shutdown.
Note that the transmitters are enabled only when the
magnitude of V- exceeds approximately 2.5V.
__________Applications Information
Transmitter Outputs when
Power-Supply Decoupling
CC
to ground with a capacitor of
Capacitor Selection
Exiting Shutdown
Machine Model