MAX14514 Datasheet, PDF (11/14 Pages) Maxim Integrated Products – Dual Electroluminescent Lamp Driver

Dual Electroluminescent Lamp Driver
The MAX14514 boost converter frequency uses an
internal switch oscillator to set the desired frequency of
the boost converter. The boost converter frequency is
adjusted by either 1) the combination of a resistor from
SLEW to GND and an external capacitor from SW to
GND, or 2) by driving a PWM signal directly into the SW
input. When SW is driven with an external PWM signal
at a suggested 90% duty cycle, the boost converter fre-
quency is changed to the frequency of the external
PWM signal. (See the C_SW Capacitor Selection section
for choosing the C_SW capacitor value.)
Shutdown
The MAX14514 features a shutdown mode to disable
the device and reduce supply current. Entering and
exiting shutdown mode depends on if slow turn-on/turn-
off is enabled or disabled.
When slow turn-on/turn-off is enabled, shut down the
device by driving EN low. Enable the device by driving
EN high.
When slow turn-on/turn-off is disabled, shut down the
device by driving EN low and both DIM1 and DIM2
below V_{IL_DIM_}. Enable the device by driving EN high
and either DIM1 or DIM2 above V_{LPD_}.
Undervoltage Lockout (UVLO)
The MAX14514 has a UVLO threshold of +2.1V (typ).
When V_DD falls below this threshold, the device enters
a nonoperative mode.
Thermal Short-Circuit Protection
The MAX14514 enters a nonoperative mode if the
internal die temperature of the device reaches or
exceeds +158°C (typ). The device turns back on when
the internal die temperature cools to +150°C (typ).
±15kV ESD Protection
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 EL lamp driver outputs of the MAX14514
(V₁, V₂, and COM) have extra protection against static
electricity. Maxim’s engineers have developed state-of-
the-art structures to protect these pins against ESD of
±15kV without damage. The ESD structures withstand
high ESD in all states: normal operation, shutdown, and
powered down. After an ESD event, the MAX14514
keeps working without latchup or damage.
ESD protection can be tested in various ways. The
transmitter EL lamp outputs of the MAX14514 are char-
acterized for protection to the following limits:
• ±15kV using the Human Body Model
• ±4kV IEC 61000-4-2 Contact Discharge
• ±4kV IEC 61000-4-2 Air-Gap Discharge
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test setup, test methodology, and test results.
Human Body Model
Figure 1a shows the Human Body Model, and Figure
1b shows the current waveform it generates when dis-
charged into a low impedance. This model consists of a
100pF capacitor charged to the ESD voltage of interest,
which is then discharged into the test device through a
1.5kΩ resistor.
IEC 61000-4-2
The IEC 61000-4-2 standard covers ESD testing and
performance of finished equipment. However, it does
not specifically refer to integrated circuits. The
MAX14514 assists in designing equipment to meet IEC
61000-4-2 without the need for additional ESD-protec-
tion components.
The major difference between tests done using the
Human Body Model and IEC 61000-4-2 is higher peak
current in IEC 61000-4-2 because series resistance is
lower in the IEC 61000-4-2 model. Hence, the ESD with-
stand voltage measured to IEC 61000-4-2 is generally
lower than that measured using the Human Body
Model. Figure 1c shows the IEC 61000-4-2 model, and
Figure 1d shows the current waveform for IEC 61000-4-2
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
energized.
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