LM5010 EVAL/NOPB National Semiconductor, LM5010 EVAL/NOPB Datasheet - Page 9

• Manufacturer Part Number: LM5010 EVAL/NOPB
• Manufacturer: National Semiconductor

Specifications of LM5010 EVAL/NOPB

• Lead Free Status / Rohs Status: Compliant

Typical Performance Characteristics
Functional Description
The LM5010 Step Down Switching Regulator features all the
functions needed to implement a low cost, efficient buck bias
power converter capable of supplying in excess of 1A to the
load. This high voltage regulator contains an N-Channel
buck switch, is easy to implement, and is available in the
thermally enhanced LLP-10 and TSSOP-14EP packages.
The regulator’s operation is based on a hysteretic control
scheme, and uses an on-time which varies inversely with
V
ing relatively constant with load and input voltage variations.
The switching frequency can range from 100 kHz to
MHz. The hysteretic control requires no loop compensation
resulting in very fast load transient response. The valley
current limit detection circuit, internally set at 1.25A, holds
the buck switch off until the high current level subsides.
Figure 1 shows the functional block diagram. The LM5010
can be applied in numerous applications to efficiently regu-
late down higher voltages. This regulator is well suited for
IN
. This feature results in the operating frequency remain-
FIGURE 8. Startup Sequence
>
1.0
9
(Continued)
48V telecom applications, as well as the new 42V automo-
tive power bus. Implemented as a Point-of-Load regulator
following a highly efficient intermediate bus converter can
result in high overall system efficiency. Features include:
Thermal shutdown, V
under-voltage lockout, and maximum duty cycle limit.
Hysteretic Control Circuit
Overview
The LM5010 buck DC-DC regulator employs a control
scheme based on a comparator and a one-shot on-timer,
with the output voltage feedback (FB) compared to an inter-
nal reference (2.5V). If the FB voltage is below the reference
the buck switch is turned on for a time period determined by
the input voltage and a programming resistor (R
ing the on-time the switch remains off for 265 ns, or until the
FB voltage falls below the reference, whichever is longer.
The buck switch then turns on for another on-time period.
CC
under-voltage lockout, gate drive
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