Datasheet

SPI/MICROWIRE-Compatible UART and ±15kV ESD-
Protected RS-232 Transceivers with Internal Capacitors
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.
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. Of course, all pins require this protec-
tion 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
Crystals, Oscillators, and
Ceramic Resonators
The MAX3110E/MAX3111E include an oscillator circuit
derived from an external crystal oscillator for baud-rate
generation. For standard baud rates, use a 1.8432MHz
or 3.6864MHz crystal. The 1.8432MHz crystal results
in lower operating current; however, the 3.6864MHz
crystal may be more readily available in surface
mount.
CHARGE-CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
C
s
100pF
R
C
1M
R
D
1500Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
Figure 8a. Human Body ESD Test Model
I
P
100%
90%
36.8%
t
RL
TIME
t
DL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
I
r
10%
0
0
AMPERES
Figure 8b. Human Body Model Current Waveform
CHARGE-CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
C
s
150pF
R
C
50M to 100M
R
D
330Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
t
r
= 0.7ns to 1ns
30ns
60ns
t
100%
90%
10%
I
PEAK
I
Figure 9a. IEC 1000-4-2 ESD Test Model
Figure 9b. IEC 1000-4-2 ESD Generator Current Waveform
Maxim Integrated
23
MAX3110E/MAX3111E