LM2931M ETC [List of Unclassifed Manufacturers], LM2931M Datasheet - Page 3

• Manufacturer Part Number: LM2931M
• Description: 100mA Low Dropout Voltage Regulator
• Manufacturer: ETC [List of Unclassifed Manufacturers]

Note 1: Output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range.
Note 2: Unless otherwise specified all limits guaranteed for T
pin versions are feedback tied to –XX Voltage tap and output tied to output Sense pin ( V
Note 2: Regulation is measured at constant junction temperature , using pulse testing with a low duty cycle. Changes in output voltage due to
heating effects are covered under specification for thermal regulation.
Note 3: Line regulation for is tested at 150 C for I
B2931-15 16V V
Note 4: Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at
1V differential.
Note 5: Ground pin Current is the regulator quiescent current. The total current drawn from the source is the sum of the ground pin current and
output load current.
Note 6: Thermal regulation is the change in output voltage at a time T after a change in power dissipation, excluding load or line regulation
effects. Specifications are for a 50 mA load pulse (1.25W) for T = 10ms.
Note 7: V
Note 8: V
Application Hints
The LM2931 requires an output capacitor for device
stability.
depending upon the application circuit and other
factors.
electrolytic capacitors depend greatly on the type and
also on the manufacturer. Sometimes only bench
testing is the only means to determine the proper
capacitor type and value. The high quality 100 F
aluminum electrolytic covers all general application
circuits, this stability can be obtained with a tantalum
electrolytic value of 47 F.
Another critical point of electrolytic characteristics is
its performance over temperature. The LM2931 is
designed to operate starting at -40 C which may not
be true in the case of electrolytic.
temperatures generally no problem. The electrolytic.
type in aluminum will freeze around -30 C. This
could cause an oscillation at output of regulator. At a
lower temperature requirement by many applications
the capacitor should maintain its performance. So as
a result, for an application which regulator junction
temperature does not exceed 25 C, the output
capacitor can be reduced by the
Bay Linear, Inc
REF
SHUTDOWN
The high frequency characteristics of
V
The value required varies greatly
OUT
IN
2V, V
(V
26V.
2478 Armstrong Street, Livermore, CA 94550 Tel: [phone], Fax: [phone]
IN
IN
–1V), 2.3V
26V, V
OUT
V
= 0
IN
26V, 100 A
L
= 1mA. For I
Higher
J
= 25 C, V
I
L
L
= 100 A and T
100mA, T
IN
= V
J
factor of two over the value needed for the entire
temperature range.
Other points with linear regulators are that the twitch
higher output current stability decreases.
applications the LM2931 is operating at few
milliamps. In these applications the output capacitance
can be further reduced.
regulator is running at 10mA output current the output
capacitance value is half compared to the same
regulator that is running at 100 mA.
With the LM2931 adjustable regulator, the minimum
value of output capacitance is a function of the output
voltage. The value decreases with higher output
voltages, since the internal loop gain is reduced.
The worst case occurs at the lower temperature and
maximum operating currents, the entire circuit and the
electrolytic, should be cooled down to the minimum
temperature. The minimum of 0.6 volts required at
the input of regulator above the output to keep the
power dissipation and die heating to its minimum.
After the value for the capacitor has been determined
for actual use, the value should be doubled.
O
T
+1V, I
J
JMAX
= 125 C, line regulation is guaranteed by design to 0.2%. for
L
= 100 A and C
OUT
= XX V) and V
L
= 1 F. Additional conditions for the 8-
SHUTDOWN
For example, when the
0.8V
LM2931
www.baylinear.com
In most