0

1.0

2.0

_

3.0

_

4.0

_

5.0

_

DC BIAS (V)

100%

80%

60%

40%

_

20%

_

0402, 6.3V, X5R

0603, 10V, X5R

LP3990

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SNVS251I – MAY 2004 – REVISED MAY 2013

in the capacitance value falling below the minimum value given in the recommended capacitor specifications

table (0.7µF in this case). Note that the graph shows the capacitance out of spec for the 0402 case size

capacitor at higher bias voltages. It is therefore recommended that the capacitor manufacturers’ specifications for

the nominal value capacitor are consulted for all conditions, as some capacitor sizes (e.g. 0402) may not be

suitable in the actual application.

Figure 1. Graph Showing a Typical Variation in Capacitance vs DC Bias

The ceramic capacitor’s capacitance can vary with temperature. The capacitor type X7R, which operates over a

temperature range of -55°C to +125°C, will only vary the capacitance to within ±15%. The capacitor type X5R

has a similar tolerance over a reduced temperature range of -55°C to +85°C. Many large value ceramic

capacitors, larger than 1µF are manufactured with Z5U or Y5V temperature characteristics. Their capacitance

can drop by more than 50% as the temperature varies from 25°C to 85°C. Therefore X7R is recommended over

Z5U and Y5V in applications where the ambient temperature will change significantly above or below 25°C.

Tantalum capacitors are less desirable than ceramic for use as output capacitors because they are more

expensive when comparing equivalent capacitance and voltage ratings in the 0.47µF to 4.7µF range.

Another important consideration is that tantalum capacitors have higher ESR values than equivalent size

ceramics. This means that while it may be possible to find a tantalum capacitor with an ESR value within the

stable range, it would have to be larger in capacitance (which means bigger and more costly) than a ceramic

capacitor with the same ESR value. It should also be noted that the ESR of a typical tantalum will increase about

2:1 as the temperature goes from 25°C down to -40°C, so some guard band must be allowed.

ENABLE CONTROL

enabled the regulator output is off and the device typically consumes 2nA.

regulator output permanently on.

DSBGA MOUNTING

The DSBGA package requires specific mounting techniques, which are detailed in Application Note AN1112.

For best results during assembly, alignment ordinals on the PC board may be used to facilitate placement of the

DSBGA device.

Copyright © 2004–2013, Texas Instruments Incorporated

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