LP2980AIM5-5.0 National Semiconductor, LP2980AIM5-5.0 Datasheet - Page 11

• Manufacturer Part Number: LP2980AIM5-5.0
• Description: IC, LDO VOLT REG, 5V, 50mA, 5-SOT-23
• Manufacturer: National Semiconductor

Specifications of LP2980AIM5-5.0

• Primary Input Voltage: 16V
• Output Voltage Fixed: 5V
• Dropout Voltage Vdo: 120mV
• No. Of Pins: 5
• Output Current: 50mA
• Operating Temperature Range: -40°C To +125°C
• Termination Type: SMD
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Application Hints
OUTPUT CAPACITOR
Like any low-dropout regulator, the LP2980 requires an out-
put capacitor to maintain regulator loop stability. This capac-
itor must be selected to meet the requirements of minimum
capacitance and equivalent series resistance (ESR) range. It
is not difficult to find capacitors which meet the criteria of the
LP2980, as the acceptable capacitance and ESR ranges are
wider than for most other LDOs.
In general, the capacitor value must be at least 1 μF (over the
actual ambient operating temperature), and the ESR must be
within the range indicated in Figures 1, 2 and Figure 3. It
should be noted that, although a maximum ESR is shown in
these Figures, it is very unlikely to find a capacitor with ESR
that high.
Tantalum Capacitors
Surface-mountable solid tantalum capacitors offer a good
combination of small physical size for the capacitance value,
and ESR in the range needed by the LP2980.
The results of testing the LP2980 stability with surface-mount
solid tantalum capacitors show good stability with values of at
least 1 μF. The value can be increased to 2.2 μF (or more) for
even better performance, including transient response and
noise.
Small value tantalum capacitors that have been verified as
suitable for use with the LP2980 are shown in Table 2. Ca-
pacitance values can be increased without limit.
Aluminum Electrolytic Capacitors
Although probably not a good choice for a production design,
because of relatively large physical size, an aluminum elec-
trolytic capacitor can be used in the design prototype for an
LP2980 regulator. A value of at least 1 μF should be used,
and the ESR must meet the conditions of Figures 1, 2 and
Figure 3. If the operating temperature drops below 0°C, the
regulator may not remain stable, as the ESR of the aluminum
electrolytic capacitor will increase, and may exceed the limits
indicated in the Figures.
Multilayer Ceramic Capacitors
Surface-mountable multilayer ceramic capacitors may be an
attractive choice because of their relatively small physical size
and excellent RF characteristics. However, they sometimes
Kemet
NEC
Siemens
Nichicon
Sprague
Kemet
NEC
Siemens
Nichicon
Sprague
TABLE 2. Surface-Mount Tantalum Capacitor
Manufacturer
Manufacturer
2.2 μF Surface-Mount Tantalums
1 μF Surface-Mount Tantalums
Selection Guide
T491A105M010AS
NRU105M10
B45196-E3105-K
F931C105MA
293D105X0016A2T
T491A225M010AS
NRU225M06
B45196/2.2/10/10
F930J225MA
293D225X0010A2T
Part Number
Part Number
11
have ESR values lower than the minimum required by the
LP2980, and relatively large capacitance change with tem-
perature. The manufacturer's datasheet for the capacitor
should be consulted before selecting a value.
Test results of LP2980 stability using multilayer ceramic ca-
pacitors show that a minimum value of 2.2 μF is usually
needed for the 5V regulator. For the lower output voltages, or
for better performance, a higher value should be used, such
as 4.7 μF.
Multilayer ceramic capacitors that have been verified as suit-
able for use with the LP2980 are shown in Table 3.
Tokin
Murata
Tokin
TABLE 3. Surface-Mount Multilayer Ceramic Capacitor
Manufacturer
Manufacturer
2.2 μF Surface-Mount Ceramic
4.7 μF Surface-Mount Ceramic
FIGURE 2. 2.2 μF ESR Range
FIGURE 1. 1 μF ESR Range
Selection Guide
1E225ZY5U-C203
GRM42-6Y5V225Z16
1E475ZY5U-C304
Part Number
Part Number
1207848
1207849
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