LM5009AMM/NOPB National Semiconductor, LM5009AMM/NOPB Datasheet - Page 8

IC BUCK ADJ .15A 8MSOP

LM5009AMM/NOPB

Manufacturer Part Number
LM5009AMM/NOPB
Description
IC BUCK ADJ .15A 8MSOP
Manufacturer
National Semiconductor
Series
PowerWise®r
Type
Step-Down (Buck)r
Datasheet

Specifications of LM5009AMM/NOPB

Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
2.5 ~ 85 V
Current - Output
150mA
Frequency - Switching
50kHz ~ 1.1MHz
Voltage - Input
6 ~ 95 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-
Other names
LM5009AMMTR

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LM5009AMM/NOPB
Manufacturer:
TI/德州仪器
Quantity:
20 000
Part Number:
LM5009AMM/NOPB
0
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Regulation Comparator
The feedback voltage at FB is compared to an internal 2.5V
reference. In normal operation (the output voltage is regulat-
ed), an on-time period is initiated when the voltage at FB falls
below 2.5V. The buck switch will stay on for the on-time,
causing the FB voltage to rise above 2.5V. After the on-time
period, the buck switch will stay off until the FB voltage again
falls below 2.5V. During start-up, the FB voltage will be below
2.5V at the end of each on-time, resulting in the minimum off-
time of 300 ns. Bias current at the FB pin is nominally 100 nA.
Over-Voltage Comparator
The feedback voltage at FB is compared to an internal 2.875V
reference. If the voltage at FB rises above 2.875V the on-time
pulse is immediately terminated. This condition can occur if
the input voltage, or the output load, change suddenly. The
buck switch will not turn on again until the voltage at FB falls
below 2.5V.
FIGURE 2. Startup Sequence
8
On-Time Generator and Shutdown
The on-time for the LM5009A is determined by the R
and is inversely proportional to the input voltage (Vin), result-
ing in a nearly constant frequency as Vin is varied over its
range. The on-time equation for the LM5009A is:
R
V
This requirement limits the maximum frequency for each ap-
plication, depending on V
The LM5009A can be remotely disabled by taking the R
pin to ground. See
between 1.5 and 3.0 volts, depending on Vin and the value of
the R
IN
T
) greater than 400 ns, for proper current limit operation.
should be selected for a minimum on-time (at maximum
T
resistor.
T
ON
= 1.385 x 10
Figure
IN
3. The voltage at the R
and V
-10
x R
OUT
T
.
/ V
IN
30087114
T
/SD pin is
T
resistor,
T
/SD
(2)

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