lm25066apsqx National Semiconductor Corporation, lm25066apsqx Datasheet - Page 13

• Manufacturer Part Number: lm25066apsqx
• Description: Lm25066a System Power Management And Protection Ic With Pmbus
• Manufacturer: National Semiconductor Corporation

Block Diagram
Functional Description
The inline protection functionality of the LM25066A is de-
signed to control the in-rush current to the load upon insertion
of a circuit card into a live backplane or other “hot” power
source, thereby limiting the voltage sag on the backplane’s
supply voltage, and the dV/dt of the voltage applied to the
load. Effects on other circuits in the system are minimized,
preventing possible unintended resets. A controlled shutdown
when the circuit card is removed can also be implemented
using the LM25066A.
In addition to a programmable current limit, the LM25066A
monitors and limits the maximum power dissipation in the se-
ries pass device to maintain operation within the device Safe
Operating Area (SOA). Either current limiting or power limiting
for an extended period of time results in the shutdown of the
series pass device. In this event, the LM25066A can latch off
or repetitively retry based on the hardware setting of the
13
RETRY pin. Once started, the number of retries can be set to
none, 1, 2, 4, 8, 16, or infinite. The circuit breaker function
quickly switches off the series pass device upon detection of
a severe over-current condition. Programmable under-volt-
age lock-out (UVLO) and over-voltage lock-out (OVLO) cir-
cuits shut down the LM25066A when the system input voltage
is outside the desired operating range.
The telemetry capability of the LM25066A provides intelligent
monitoring of the input voltage, output voltage, input current,
input power, temperature, and an auxiliary input. The
LM25066A also provides a peak capture of the input power
and programmable hardware averaging of the input voltage,
current, power, and output voltage. Warning thresholds which
trigger the SMBA pin may be programmed for input and output
voltage, current, power and temperature via the PMBus in-
terface. Additionally, the LM25066A is capable of detecting
damage to the external MOSFET, Q
1
.
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