Datasheet

LM340-N, LM78xx
www.ti.com SNOSBT0I –FEBRUARY 2000–REVISED MARCH 2013
LM340-N/LM78XX Series 3-Terminal Positive Regulators
Check for Samples: LM340-N, LM78xx
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FEATURES
DESCRIPTION
The LM140/LM340A/LM340-N/LM78XXC monolithic
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• Complete Specifications at 1A Load
3-terminal positive voltage regulators employ internal
• Output Voltage Tolerances of ±2% at T
j
= 25°C
current-limiting, thermal shutdown and safe-area
and ±4% Over the Temperature Range
compensation, making them essentially indestructible.
(LM340A)
If adequate heat sinking is provided, they can deliver
over 1.0A output current. They are intended as fixed
• Line Regulation of 0.01% of V
OUT
/V of ΔV
IN
at
voltage regulators in a wide range of applications
1A Load (LM340A)
including local (on-card) regulation for elimination of
• Load Regulation of 0.3% of V
OUT
/A (LM340A)
noise and distribution problems associated with
• Internal Thermal Overload Protection
single-point regulation. In addition to use as fixed
voltage regulators, these devices can be used with
• Internal Short-circuit Current Limit
external components to obtain adjustable output
• Output Transistor Safe Area Protection
voltages and currents.
• P
+
Product Enhancement Tested
Considerable effort was expended to make the entire
series of regulators easy to use and minimize the
number of external components. It is not necessary to
bypass the output, although this does improve
transient response. Input bypassing is needed only if
the regulator is located far from the filter capacitor of
the power supply.
The 5V, 12V, and 15V regulator options are available
in the steel TO-3 power package. The
LM340A/LM340-N/LM78XXC series is available in the
TO-220 plastic power package, and the LM340-N-5.0
is available in the SOT-223 package, as well as the
LM340-5.0 and LM340-12 in the surface-mount
DDPAK/TO-263 package.
Typical Applications
*Required if the regulator is located far from the power supply filter.
**Although no output capacitor is needed for stability, it does help
transient response. (If needed, use 0.1 μF, ceramic disc).
V
OUT
= 5V + (5V/R1 + I
Q
) R2 5V/R1 > 3 I
Q
,
load regulation (L
r
) ≈ [(R1 + R2)/R1] (L
r
of LM340-5).
Figure 1. Fixed Output Regulator Figure 2. Adjustable Output Regulator
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Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.