LM25066APSQE/NOPB National Semiconductor, LM25066APSQE/NOPB Datasheet - Page 25

• Manufacturer Part Number: LM25066APSQE/NOPB
• Description: IC CTLR PM HOTSWAP 24-LLP
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM25066APSQE/NOPB

• Applications: Base Station-Networking Line Cards, Servers
• Current - Supply: 5.8mA
• Voltage - Supply: 2.9 V ~ 17 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: *
• Package / Case: *
• Input Voltage: 17V
• Internal Switch: No
• Supply Voltage Range: 2.9V To 5.5V
• Rohs Compliant: Yes
• Digital Ic Case Style: LLP
• No. Of Pins: 24
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM25066APSQE/NOPBTR

SYSTEM CONSIDERATIONS
A) Continued proper operation of the LM25066A hot swap
circuit normally dictates that capacitance be present on the
supply side of the connector into which the hot swap circuit is
plugged in, as depicted in
“LIVE POWER SOURCE” section is necessary to absorb the
voltage transient generated whenever the hot swap circuit
shuts off the load current. If the capacitance is not present,
parasitic inductance of the supply lines will generate a voltage
transient at shut-off which may exceed the absolute maximum
rating of the LM25066A, resulting in its destruction. A TVS
device with appropriate voltage and power ratings can also
be connected from VIN to GND to clamp the voltage spike
(see application note AN-2100).
PC BOARD GUIDELINES
The following guidelines should be followed when designing
the PC board for the LM25066A:
- Place the LM25066A close to the board’s input connector to
minimize trace inductance from the connector to the MOS-
FET.
- Place a small capacitor, C
VIN and GND pins of the LM25066A to help minimize tran-
sients which may occur on the input supply line. Transients of
several volts can easily occur when the load current is shut
off. ASIDE: note that if the current drawn by such capacitor
following a hot-plug event is deemed unacceptable, input
Figure
IN
(1nF), directly adjacent to the
FIGURE 15. Adding Delay to the Power Good Output Pin
FIGURE 16. Output Diode Required for Inductive Loads
16. The capacitor in the
25
B) If the load powered by the LM25066A hot swap circuit has
inductive characteristics, a Schottky diode is required across
the LM25066A’s output along with some load capacitance.
The capacitance and the diode are necessary to limit the
negative excursion at the OUT pin when the load current is
shut off. If the OUT pin transitions more than 0.3V negative,
the LM25066A will internally reset, erasing the volatile setting
for retries and warning thresholds. See
slew rates on VOUT can couple into the LM25066A's GATE
pin and create negative voltage excursions at this pin. To al-
leviate this, a small gate resistance (e.g. 10Ω) can be used.
This resistor has the added benefit of reducing very high fre-
quency gate voltage oscillations, particularly in paralleled
FET arrangements.
voltage spike transients can be appropriately minimized by
proper placement of a TVS device and operation without this
C
- Place a 1 µF ceramic capacitor as close as possible to VREF
pin.
- Place a 1 µF ceramic capacitor as close as possible to VDD
pin.
- The sense resistor (R
LM25066A. In particular, the trace to the VIN pin should be
made as low resistance as practical to ensure maximum cur-
rent and power measurement accuracy. Connect R
Kelvin techniques shown in
IN
capacitor becomes feasible.
S
) should be placed close to the
Figure
7.
Figure
30146054
16. Also, rapid
www.national.com
30146052
S
using the