MAX14588 Datasheet, PDF (12/15 Pages) Maxim Integrated Products – 1A Adjustable Overcurrent and Overvoltage Protector with High Accuracy

MAX14588
1A Adjustable Overcurrent and Overvoltage
Protector with High Accuracy
Thermal Shutdown Protection
The MAX14588 has a thermal-shutdown feature to pro-
tect the device from overheating. The device turns off and
the FLAG asserts when the junction temperature exceeds
+150ºC (typ). The devices exit thermal shutdown and
resume normal operation after the junction temperature
cools by 30ºC (typ), except when in latch off mode, the
device remains latched off.
The thermal limit behaves similar to the current limit. For
autoretry mode, the thermal limit works with auto retry
timer. When the device comes out of the thermal limit, it
starts after the retry time. For latch off mode, the device
latches off until power or EN cycle. For continuous mode,
the device only disables while the temperature is over the
limit. There is no blanking time for thermal protection.
Overvoltage Lockout (OVLO)
The MAX14588 has a 33V (typ) preset OVLO threshold
when the voltage at OVLO is set below the external
OVLO select voltage (V_SEL). Connect OVLO to GND to
activate the preset OVLO threshold. Connect the external
resistors to OVLO pin as shown in the Typical Operating
Circuit to externally adjust the OVLO threshold. Use the
following equation to adjust the OVLO threshold. The rec-
ommended value for R3 is 2.2MΩ.
V_OVLO=
V_BG
×
₁
+
R3
R4^
Undervoltage Lockout (UVLO)
The MAX14588 has a 19V (typ) preset UVLO threshold
when the voltage at UVLO is set below the external OVLO
select voltage (V_SEL). Connect UVLO to GND to activate
the preset UVLO threshold. Connect the external resistors
to UVLO pin as shown in the Typical Operating Circuit to
externally adjust the UVLO threshold. Use the following
equation to adjust the UVLO threshold. The recommend-
ed value for R1 is 2.2MΩ.
V_UVLO=
V_BG
×
₁
+
R1
R2^
Switch Control
There are two independent enable inputs (HVEN and
EN) for MAX14588. HVEN is a high-voltage capable
input. Toggle HVEN or EN to reset the fault condition
once short-circuit is detected and the device shuts down
(Table 2).
Input Debounce Protection
The MAX14588 features input debounce protection.
When the input voltage is higher than the UVLO thresh-
old voltage for a period greater than the debounce time
(t_DEB), the internal FETs are turned on. This feature is
intended for applications where the EN or HVEN signal
is present when the power supply ramps up (Figure 3).
Applications Information
Setting the Current Limit / Threshold
A resistor from SETI to ground programs the current-limit/
threshold value for the MAX14588. Leaving SETI uncon-
nected selects a 0A current limit/threshold. Connecting
SETI to ground asserts FLAG.
Use the following formula to calculate the current limit:
R
SETI
(kΩ)
= ⁶¹⁰⁰
ILIM (mA)
IN Bypass Capacitor
Connect a minimum of 0.47µF capacitor from IN to GND
to limit the input voltage drop during momentary output
short-circuit conditions. Larger capacitor values further
reduce the voltage undershoot at the input.
Hot Plug IN
In many system powering applications, an input filter-
ing capacitor is required to lower the radiated emission,
enhance the ESD capability, etc. In hot plug applications,
parasitic cable inductance along with the input capacitor
causes overshoot and ringing when the powered cable is
connected to the input terminal.
This effect causes the protection device to see almost
twice the applied voltage. An input voltage of 24V can
easily exceed the absolute maximum rating of 40V, which
may permanently damage the device. A transient voltage
suppressor (TVS) is often used for industrial applications
to protect the system from these conditions. We recom-
mend using a TVS that is capable of limiting the input
surge to 40V placed close to the input terminal.
Table 2. Enable Inputs
HVEN
EN
0
0
0
1
1
0
1
1
SWITCH STATUS
ON
ON
OFF
ON
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