PE-1008CM272GTT PULSE ELECTRONICS CORPORATION, PE-1008CM272GTT Datasheet - Page 29
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PE-1008CM272GTT
Manufacturer Part Number
PE-1008CM272GTT
Description
INDUCTOR WW 2700NH 10MHZ 1008
Manufacturer
PULSE ELECTRONICS CORPORATION
Series
1008CMr
Type
Ceramic Core, Wirewoundr
Datasheet
1.PE-0805CM561JTT.pdf
(30 pages)
Specifications of PE-1008CM272GTT
Inductance
2.7µH
Current
150mA
Tolerance
±2%
Dc Resistance (dcr)
7.7 Ohm Max
Q @ Freq
30 @ 25MHz
Self Resonant Freq
90MHz
Package / Case
1008 (2520 Metric)
Mounting Type
Surface Mount
Operating Temperature
-40°C ~ 125°C
Frequency - Test
10MHz
Material - Core
Ceramic
Applications
General Purpose
Maximum Dc Current
150 mAmps
Maximum Dc Resistance
7.7 Ohms
Self Resonant Frequency
90 MHz
Q Minimum
30
Termination Style
SMD/SMT
Dimensions
2.79 mm W x 2.92 mm L x 2.290 mm H
Shielding
Unshielded
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Shielding
-
Current - Saturation
-
Current - Temperature Rise
-
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
PE-1008CM272GTT
Manufacturer:
PULSE
Quantity:
3 200
WIRE-WOUND
RF CHIP INDUCTORS
Application Notes
www.pulseeng.com
Q factor / SRF
The ratio of an inductor's reactance (XL) to its series resistance (Rs) is often used as measure of the quality factor of
the inductor. The larger the ratio, the better the inductor. The quality factor of an inductor is often referred to as the Q
of the inductor. If the inductor were constructed from a perfect conductor (zero loss), its Q would be infinite. Of course
this is impossible, and so the Q of an inductor will always have some finite value.
The Q factor, Fr and SRF of an inductor are directly linked to one another. If the test frequency is near Fr or SRF, the
inductor results may be misleading by very wide margins, since the result is dominated by distributed capacitance
reactance. To overcome this problem, the test frequency of the inductor is normally located at a point on the inductor's
curve where the reactance of the inductor approaches that of an ideal inductor, so that component to component
variations are kept to a minimum since the parasitic contribution is also at a minimum. To overcome this problem, RF
engineers should select an inductor with the highest test frequency possible to guarantee the quality of the inductor.
At low frequencies, the Q of an inductor is very good because the only resistance in the winding is the dc resistance of
the wire which is very small (Fig. 2.0). As mentioned earlier, as the frequency increases, the skin effect increases to
degrade the Q of the inductor. At low frequencies, the Q increases directly inline with the reactance (XL) since the skin
effect has not become noticeable. The Q continues to rise, but as the frequency approaches Fr, the skin effect starts to
become a dominant, reducing the rate of increase. At Fr, the series resistance and reactance are increasing at the
same rate. Above Fr, the distributed capacitance Cd and skin effect of the winding combine together to decrease the
Q of the inductor to zero at SRF.
Understanding Inductor Curves
RF design engineers require inductors to meet the following requirements:
Distributed Capacitance
Determining the Inductor Equivalent Circuit
To determine the inductor equivalent circuit, an RF engineer must deduce the value of Rs and Cd from the curves sup-
plied by the inductor manufacturer. To do this, the following equations can be used. Of course, the values deduced
only apply at one specific frequency. The recommended frequency at which the inductor is used within the application
should be an order of magnitude (÷ 10) below the SRF, and preferably not near than ½ Fr.
USA 858 674 8100
1. Low cost
2. Compatibility to the competition
3. Component to component variation small
4. Performance approachs that of an ideal inductor
Series resistor
• Q, SRF and useable frequency range => competition
• High Q (low series resistance)
• High SRF (low distributed capacitance)
Equation 1: Fc<
Equation 2: Rs = XL = 2 *
Equation 3: Cd
• •
Germany 49 7032 7806 0
SRF and/or < FR
10
Q
=
3.0 Characteristics of a Real World Inductor Vs Ideal Inductor
Cd = 0
Rs = 0
(2 *
• •
π
Singapore 65 6287 8998
π
Q
* Fc * L
* SRF)2 * L
1
2
Ideal Inductor
Infinite SRF
Infinite Q
27
• •
Shanghai 86 21 62787060
Where:
Fc
SRF = Series resonant or self resonant frequency of the inductor
π π
L
= Centre frequency of application / intended operation
= 3.14159
= Inductor value
• •
China 86 755 33966678
Cd = Min
Rs = Min
Real World Inductor
• •
Taiwan 886 3 4356768
High SRF
WC701.L (4/10)
High Fr
High Fr
High Q