MIC2025_10 Datasheet, PDF (10/14 Pages) Micrel Semiconductor – Single-Channel Power Distribution Switch MM8®

MIC2025/2075
Short-Circuit Applied to Enabled Output
When a heavy load or short-circuit is applied, a large transient
current may flow until the current-limit circuitry responds. Once
this occurs the device limits current to less than the short-cir-
cuit current limit specification. See the Short-Circuit Transient
Response graph under Functional Characteristics.
Current-Limit Response—Ramped Load
The MIC2025/75 current-limit profile exhibits a small foldback
effect of about 200mA. Once this current-limit threshold is
exceeded the device switches into a constant current mode.
It is important to note that the device will supply current until
the current-limit threshold is exceeded. See the Current-Limit
Response graph under Functional Characteristics.
Micrel, Inc.
Fault Flag
The FLG signal is an N-channel open-drain MOSFET output.
FLG is asserted (active-low) when either an overcurrent
or thermal shutdown condition occurs. In the case where
an overcurrent condition occurs, FLG will be asserted only
after the flag response delay time, t_D, has elapsed. This
ensures that FLG is asserted only upon valid overcurrent
conditions and that erroneous error reporting is eliminated.
For example, false overcurrent conditions can occur during
hot-plug events when a highly capacitive load is connected
and causes a high transient inrush current that exceeds the
current-limit threshold. The FLG response delay time t_D is
typically 3ms.
Undervoltage Lockout
Undervoltage lockout (UVLO) prevents the output MOS-
FET from turning on until V_IN exceeds approximately 2.5V.
Undervoltage detection functions only when the switch is
enabled.
V_{E N}
V_{O U T}
I_LIMIT
I_{D C}
I_{O U T}
V_{F L G}
Short-Circuit Fautl
Thermal Shutdown
Reached
t_D
Load Removed
(Output Reset)
Figure 1.  MIC2075-2 Timing: Output Reset by Removing Load
V_{E N}
V_{O U T}
I_LIMIT
I_{D C}
I_{O U T}
V_{F L G}
Short-Circuit Fautl
Load/Fault
Removed
Thermal Shutdown
Reached
t_D
Figure 2.  MIC2025-2 Timing
MIC2025/2075
10
June 2010