LMX2216M National Semiconductor, LMX2216M Datasheet - Page 10

• Manufacturer Part Number: LMX2216M
• Description: IC AMP/MIXER LO NOISE 16-SOIC
• Manufacturer: National Semiconductor

Specifications of LMX2216M

• Current - Supply: 6.5mA ~ 8mA
• Frequency: 100MHz ~ 2GHz
• Gain: 9dB ~ 10dB
• Noise Figure: 4.8dB ~ 6dB
• P1db: -5dBm ~ -3dBm
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Rf Type: Cellular, WLAN, PCS, PHS, Cordless Phones
• Test Frequency: 2GHz
• Voltage - Supply: 2.85V ~ 3.15V
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LMX2216M

Figures of Merit
GAIN (G)
Many different types of gain are specified in RF engineering
The type referred to here is called transducer gain and is
defined as the ratio of the power delivered to the load to the
available power from the source
where V
generator voltage with internal resistance R
scattering parameters transducer gain is defined as
where S
be measured using a network analyzer
1 dB COMPRESSION POINT (P
A measure of amplitude Iinearity 1 dB compression point is
the point at which the actual gain is 1dB below the ideal
linear gain For a memoryless two-port with weak nonlineari-
ty the output can be represented by a power series of the
input as
For a sinusoidal input
the output is
assuming that all of the fourth and higher order terms are
negligible For an amplifier the fundamental component is
the desired output and it can be rewritten as
This fundamental component is larger than k
linear gain) if k
cal devices k
tude A of the input signal gets larger The 1 dB compression
point can be expressed in terms of either the input power or
the output power Measurement of P
increasing the input power while observing the output power
until the gain is compressed by 1 dB
THIRD ORDER INTERCEPT (OIP
Third order intercept is another figure of merit used to char-
acterize the linearity of a two-port It is defined as the point
at which the third order intermodulation product equals the
ideal linear uncompressed output Unlike the P
involves two input signals However it can be shown mathe-
matically (similar derivation as above) that the two are
closely related and OIP
figures of merit are illustrated in Figure 6
v
o
e
OUT
21
1
2
a
is the forward transmission parameter which can
k
G
2
v
is the voltage across the load R
2
1
A
e
o
3 k
3 l
2
e
k
P
k
2
a
P
1
OUT
0 and the gain compresses as the ampli-
k
A
IN
A 1
0 and smaller if k
1
2
G
v
k
cos 2
i
e
1
v
e
a
i
A
3
a
e
V
20 log (
k
V
a
2
OUT
2
Acos
2
IN
3
4
1
v
3
4
2
i
t
P
(k
R
R
a
a
1dB
k
1dB
3
S
L
3
l
S
3
k
k
A
1
4
)
e
1
21
)
3
1
t
3
a
3 k
) A
v
k
l
4
)
1dB
3
3
i
2
R
cos
10 dB Theses two
A
a
R
0 For most practi-
S
3
L
can be made by
V
cos 3
V
L
2
OUT
1
S
2
1
IN
and V
A (the ideally
t
In terms of
1dB
1
IN
t
is the
OIP
3
10
NOISE FIGURE (NF)
Noise figure is defined as the input signal to noise ratio di-
vided by the output signal to noise ratio For an amplifier it
can also be interpreted as the amount of noise introduced
by the amplifier itself seen at the output Mathematically
where S
available at the input to the amplifier S
and noise power levels available at the output G
able gain and Na the noise added by the amplifier Noise
figure is an important figure of merit used to characterize the
performance of not only a single component but also the
entire system It is one of the factors which determine the
system sensitivity
IMAGE FREQUENCY DSB SSB NF
Image frequency refers to that frequency which is also
down-converted by the mixer along with the desired RF
component to the intermediate frequency This image fre-
quency is located at the same distance away from the LO
but on the opposite side of the RF For most mixers it must
be filtered out before the signal is down-converted other-
wise an image-reject mixer must be used Figure 7 illus-
trates the concept
FIGURE 7 Input and Output Spectrum of Mixers
F
FIGURE 6 Typical P
e
i
and N
S
S
o
i
N
N
i
i
o
represent the signal and noise power levels
e
G
a
NF
S
i
e
(N
S
OUT
10 log (F)
i
a
N
a
–P
i
G
IN
a
N
Characteristics
i
)
o
e
and N
N
a
G
a
TL W 11814 – 16
TL W 11814 – 17
a
o
a
G
N
the signal
the avail-
a
i
N
i