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

LP5951

SNVS345G – JUNE 2006 – REVISED DECEMBER 2014

www.ti.com

Figure 11. 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 1 µF 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 1-µF to 4.7-µF 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.

Table 2. Suggested Capacitors and Their Suppliers

CAPACITANCE / µF

MODEL

VENDOR

TYPE

CASE SIZE / INCH (mm)

1

C1608X5R1A105K

TDK

Ceramic, X5R

0603 (1608)

1

C1005X5R1A105K

TDK

Ceramic, X5R

0402 (1005)

12

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