Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

AC ELECTRICAL CHARACTERISTICS

1,2

SYMBOL

PARAMETER

TEST CONDITIONS

LIMITS

UNITS

SYMBOL

PARAMETER

TEST CONDITIONS

TYP

UNITS

LNA (V

= V

CCMX

= +5V, T

= 25

C; Enable = Hi, Test Figure 1, unless otherwise stated.)

Amplifier gain

900MHz

14.9

17.1

Amplifier gain in thru mode

Enable = LO, 900MHz

9.0

-7.5

6.0

Gain temperature sensitivity enabled

900MHz

-0.008

dB/

Gain temperature sensitivity in thru mode

Enable = LO, 900MHz

-0.014

dB/

Gain frequency variation

800MHz - 1.2GHz

-0.014

dB/MHz

Amplifier reverse isolation

900MHz

-42

Amplifier input match

900MHz

-10

Amplifier output match

900MHz

16.8

-15

13.2

-1dB

Amplifier input 1dB gain compression

900MHz

21.2

-20

18.8

dBm

Amp input 3rd-order intercept

Test Fig. 2, 900MHz

11.6

-10

8.6

dBm

Amp input 3rd-order intercept (thru mode)

Test Fig. 2, 900MHz, Enable = LO

+26

dBm

Amplifier noise figure

900MHz

1.9

2.2

2.5

Amp noise figure w/shunt 15nH inductor
at input

900MHz

1.7

2.0

2.3

Amplifier turn-on time

Coupling = 100pF

Coupling = 0.01

Enable Lo

OFF

Amplifier turn-off time

Coupling = 100pF

Coupling = 0.01

Enable Hi

Mixer (V

= V

CCMX

= +5V, T

= 25

C, Enable = Hi, f

= 1GHz @ 0dBm, f

= 900MHz, f

= 100MHz, Test Fig. 1, unless otherwise stated)

Mixer voltage conversion gain

= R

= 1k

9.5

10.4

11.3

Mixer power conversion gain

= R

= 1k

3.05

2.6

2.15

11RF

Mixer input match

900MHz

-20

Mixer SSB noise figure

Test Fig. 3, 900MHz, f

= 80MHz

12.2

15.8

-1dB

Mixer input 1dB gain compression

900MHz

5.3

-4

2.7

dBm

3INT

Mixer input third order intercept

900MHz

dBm

2INT

Mixer input second order intercept

900MHz

+18

+20

+22

dBm

RFM-IF

Mixer RF feedthrough

900MHz, C

= 3pF

LO-IF

Mixer LO feedthrough

900MHz, C

= 3pF

-10

LO-RFM

Local oscillator to mixer input feedthrough

900MHz

-33

11LO

LO input match

900MHz

LO-RF

Local oscillator to RF input feedthrough

900MHz

-46

RFO-RFM

Filter feedthrough

900MHz

-39

LNA + Mixer (V

CCMX

=+5V, T

=25

C, Enable=Hi, f

=1GHz @ 0dBm, f

= 900MHz, f

= 100MHz, Test Fig. 1, unless otherwise

stated)

Overall power conversion gain

13.4

Overall noise figure

3.5

Overall input 3rd-order intercept

dBm

NOTE:
1. All meausrements include the effects of the NE/SA600 Evaluation Board (see Figure ) unless otherwise noted. Measurement system

impedance is 50

2. Standard deviations are estimated from design simulations to represent manufacturing variations over the life of the product.

3. With a shunt 15nH inductor at the input of the LNA, the value of S

is typically 15dB.

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

NE/SA600

IMAGE

REJECTION

FILTER

POWER-DOWN

CONTROL

LO INPUT

0dBm

1.0GHz

BYPASS

INPUT

900MHz

+5V

0.01

100pF

0.1

RF IN MX

RF OUT A

IF OUT

RFC

100pF

NOTES:
RATIO OF BYPASS TO SIGNAL COUPLING CAPS FOR LNA SHOULD BE 100:1
OR GREATER.
IF FILTER SHOULD BE AC COUPLED.

IF FILTER

100MHz

RL2

RL1

NE/SA600

POWER-DOWN

CONTROL

LO INPUT

0dBm

1.0GHz

BYPASS

INPUT

900MHz

+5V

RFC

0.01

0.1

RF IN MX

RF OUT A

IF OUT

0.01

NE/SA600

POWER-DOWN

CONTROL

LO INPUT

0dBm

1.0GHz

BYPASS

INPUT

900MHz

+5V

RFC

0.01

100pF

0.1

RF IN MX

RF OUT A

IF OUT

100pF

RL1

4.7pF

470nH

NE/SA600

IMAGE

REJECTION

FILTER

POWER-DOWN

CONTROL

LO INPUT

0dBm

1.0GHz

BYPASS

INPUT

900MHz

+5V

RFC

0.1

RF IN MX

RF OUT A

RL1

0.01

IF OUT

4.7pF

470nH

TYPICAL APPLICATION

TEST FIGURE 1

TEST FIGURE 2

TEST FIGURE 3

0.01

SR00084

Figure 3. Test Application and Test Figures 1, 2 and 3

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

NOTE: All performance curves include the effects of the NE/SA600 evaluation board.

LNA S21 CHARACTERISTICS

4.5V

= V

CCMX

5.5V, Test Figure 1, unless otherwise specified.

LNA S21 vs Frequency

10

20

100

1000

2000

FREQUENCY (MHz)

S21 MAGNITUDE (dB)

ENABLE=HI

ENABLE=LO

LNA S21 vs Frequency

10

800

900

1000

1100

1200

S21 MAGNITUDE (dB)

FREQUENCY (MHz)

ENABLE=HI

ENABLE=LO

LNA S21 Phase vs Frequency

800

S21 PHASE (Deg)

FREQUENCY (MHz)

900

1000

1100

1200

20

40

60

80

100

120

S21 MAGNITUDE (dB)

FREQUENCY (MHz)

LNA S21 vs Frequency and V

800

900

1000

17.5

16.5

15.5

VCC = 4.5V
VCC = 5.0V
VCC = 5.5V

40

800

FREQUENCY (MHz)

LNA S21 vs Frequency and Temperature

S21 MAGNITUDE (dB)

900

1000

1100

1200

40

800

FREQUENCY (MHz)

LNA Thru S21 vs Frequency and Temperature

S21 MAGNITUDE (dB)

900

1000

1100

1200

10

12

SR00085

Figure 4. LNA S21 Performance Characteristics

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

LNA S11/S12/S22 CHARACTERISTICS

4.5V

= V

CCMX

5.5V, Test Figure 1, unless otherwise specified.

40

800

FREQUENCY (MHz)

LNA S11 vs Frequency and Temperature

1 MAGNITUDE (dB)

900

1000

1100

1200

10

12

14

16

18

20

LNA S12 vs Frequency

100

1000

2000

FREQUENCY (MHz)

S12 MAGNITUDE (dB)

ENABLE=HI

10

20

30

40

50

60

70

80

40

800

FREQUENCY (MHz)

LNA S22 vs Frequency and Temperature

S22 MAGNITUDE (dB)

900

1000

1100

1200

10

12

14

16

18

20

S22

800

FREQUENCY (MHz)

LNA Thru S11 and S22 vs Frequency

Sii MAGNITUDE (dB)

900

1000

1100

1200

10

12

14

16

18

20

S11

SR00086

Figure 5. LNA S11/S12/S22 Performance Characteristics

Table 1.

S-Parameters

Freq. MHz

800

-9.5

-160

-46

17.9

125

-18.0

151

900

-9.5

-172

-43

16.4

105

-15.8

122

1000

-9.4

-173

-40

15.1

-14.0

1100

-9.1

-200

-37

13.8

-12.4

1200

-8.9

-216

-35

12.9

-11.1

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

LNA OVERLOAD/NOISE/DISTORTION CHARACTERISTICS

4.5V

= V

CCMX

5.5V, Test Fig. 1, unless otherwise specified.

800

FREQUENCY (MHz)

LNA Input 1dB Gain Compression Point vs Frequency

P1 (dBm)

900

1000

1100

1200

10

15

20

25

30

40

TEMPERATURE (

LNA Input 1dB Gain Compression Point vs Temperature

P1 (dBm)

10

15

20

25

30

20

100

800

FREQUENCY (MHz)

LNA 50

Noise Figure vs Frequency

NF (dB)

900

1000

1100

1200

2.5

1.5

0.5

LNA 50

Noise Figure vs Temperature

NF (dB)

2.5

1.5

0.5

40

TEMPERATURE (

20

100

F = 900MHz

800

FREQUENCY (MHz)

LNA Input Third-Order Intercept vs Frequency

IP3 (dBm)

900

1000

1100

1200

10

12

14

16

18

20

F2 = F1 + 100kHz

LNA Input Third-Order Intercept vs Temperature

IP3 (dBm)

10

12

14

16

18

20

F1 = 900MHz

40

TEMPERATURE (

20

100

F2 = 900.1MHz

TEST FIGURE 2

SR00087

Figure 6. LNA Overload/Noise/Distortion Performance Characteristics

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

MIXER GAIN/NOISE CHARACTERISTICS

4.5V

= V

CCMX

5.5V, Test Figure 1, unless otherwise specified.

Mixer Voltage Conversion Gain vs LO Power

VOL

AGE CONVERSION GAIN (dB)

Frf = 900MHz

10

LO POWER (dBm)

Flo = 1GHz
Fif = 100MHz
Scaled to RL1 = RL2 = 1k

Mixer Voltage Conversion Gain vs IF Frequency

VOL

AGE CONVERSION GAIN (dB)

Frf = 900MHz

IF FREQUENCY (MHz)

Flo > Frf
Plo = 0dBm

100

150

200

250

300

Mixer Voltage Conversion Gain vs Temperature

VOL

AGE CONVERSION GAIN (dB)

Frf = 900MHz

40

Flo = 1GHz
Fif = 100MHz
Plo = 0dBm

20

100

TEMPERATURE (

Mixer 50

Noise Figure vs LO Power

NOISE FIGURE (dB)

12

Frf = 881MHz
Plo = 981MHz

LO POWER (dBm)

Fif = 100MHz

10

Frf = 881MHz

IF FREQUENCY (MHz)

Flo > Frf
Plo = 0dBm
IF Tuned to 81MHz

Mixer Noise Figure vs IF Frequency

100

110

120

NOISE FIGURE (dB)

Mixer Noise Figure vs Temperature

Frf = 881MHz

40

Flo = 981MHz
Fif = 100MHz
Plo = 0dBm

20

100

TEMPERATURE (

NOISE FIGURE (dB)

TEST FIGURE 3

Scaled to RL1 = RL2 = 1k

SR00088

Figure 7. Mixer Gain/Noise Performance Characteristics

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

MIXER OVERLOAD/DISTORTION CHARACTERISTICS

4.5

= V

CCMX

5.5V, Test Fig. 1, unless otherwise specified

Frf = 900MHz
Plo = 1GHz

LO POWER (dBm)

Fif = 100MHz

10

P1 (dBm)

Mixer Input 1dB Gain Compression Point vs LO Power

10

P1 (dBm)

Mixer Input 1dB Gain Compression Point vs Temperature

Frf = 900MHz

40

Flo = 1GHz
Fif = 100MHz
Plo = 0dBm

20

100

TEMPERATURE (

IP3 (dBm)

Mixer Input Third-Order Intercept Point vs LO Power

Frf1 = 900MHz

10

Frf2 = 901MHz
Flo = 1GHz
Fif = 100MHz

LO POWER (dBm)

IP3 (dBm)

Mixer Input Third-Order Intercept Point vs IF Frequency

100

125

150

175

200

Frf1 = 900MHz
Frf2 = 901MHz
Flo > Frf

IF FREQUENCY (MHz)

IP3 (dBm)

Mixer Input Third-Order Intercept Point vs RF Frequency

800

Frf1 = X00MHz
Frf2 = X01MHz

Flo > Frf

FREQUENCY (MHz)

X = 8, 9, 10, 11, 12

Fif = 100MHz

900

1000

1100

1200

IP3 (dBm)

Mixer Input Third-Order Intercept Point vs Temperature

Frf1 = 900MHz
Frf2 = 901MHz

Plo = 0dBm

Flo = 1GHz

Fif = 100MHz

40

20

100

TEMPERATURE (

TEST FIGURE 2

SR00089

Figure 8. Mixer Overload/Distortion Characteristics

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

MIXER S11/ISOLATION/INTERFERENCE CHARACTERISTICS

4.5

= V

CCMX

5.5V, Test Fig. 1, unless otherwise specified

1 MAGNITUDE (dB)

Mixer S11 at RF Port

vs Frequency and Temperature

800

FREQUENCY (MHz)

10

15

20

25

30

35

40

900

1000

1100

1200

40

800

900

1000

1100

1200

FREQUENCY (MHz)

1 MAGNITUDE (dB)

10

15

20

25

Mixer S11 at LO Port

vs Frequency and Temperature

OUTPUT

INTERF

. SIGNAL

REL. T

OUTPUT

SIGNAL

(dB)

Mixer Output Interferring Signal vs

Input Interferring Signal Strength

Frf = 900MHz
Frfinterf = 901MHz

Plo = 0dBm

Flo = 1GHz

Fif = 100MHz

INPUT INTERFERRING SIGNAL (dBm)

10

20

30

40

50

60

70

30

25

20

15

10

Fifinterf = 98MHz

CHANGE IN CONVERSION GAIN

10

15

20

25

30

35

20

15

10

Frf = 900MHz

Plo = 0dBm

Flo = 1GHz

Fif = 100MHz

Conversion Gain Variation vs

RF Signal Overdrive

RF SIGNAL POWER

SR00090

Figure 9. Mixer S11/Isolation/Interference Characteristics

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

OVERALL PERFORMANCE: ISOLATION CHARACTERISTICS

4.5

= V

CCMX

5.5V, Test Fig. 1, unless otherwise specified

Isolation From LNA Output to Mixer

RF Input vs Frequency

800

FREQUENCY (MHz)

ISOLA

TION MAGNITUDE (dB)

ENABLE=HI

ENABLE=LO

10

20

30

40

50

60

900

1000

1100

1200

Isolation From LO vs Frequency

800

FREQUENCY (MHz)

ISOLA

TION MAGNITUDE (dB)

At LNA input ENABLE = LO

10

20

30

40

50

60

900

1000

1100

1200

At LNA input ENABLE = HI

At Mixer RF input

SR00091

Figure 10. Overall Performance: Isolation Characteristics

SPECIFICATIONS

The goal of the Specifications section of the datasheet is to provide
information on the NE/SA600 in such a way that the designer can
estimate statistical variations, and can reproduce the
measurements. To this end the high frequency measurements are
specified with a particular PC board layout. Variations in board
layout will cause parameter variations (sensitive parameters are
discussed in the sections on the LNA and mixer below). For many
RF parameters the

3 sigma limits are specified. Statistically only

0.26% of the units will be outside these limits.

The LNA + mixer conversion gain is measured with an incident
900MHz signal and a 83MHZ SAW filter at the IF output. This
measurement along with a gain measurement of the LNA ensure the
correct operation of the chip and also allows a calculation of mixer
conversion gain.

PIN DESCRIPTIONS AND OPERATIONAL LIMITS

INA

Input of LNA, AC coupling required, DC = 0.78V, frequency range
from DC to 2GHz, gain at low frequencies is 40dB -- so be careful
of overload, impedance below 50

, shunt 15-18nH inductor helps

input match and noise figure.

OUTA

Output of LNA, AC coupling required, DC = 1.27V, frequency range
from DC to 2GHz, impedance above 50

BYPASS
Bypass capacitor should be 100 times larger than the largest signal
coupling capacitor for the LNA, DC = 1.05V.

INMX

Mixer RF port, AC coupling required, DC = 1.43V, frequency range
from 100MHz to 2.5GHz, impedance close to 50

resistive.

Mixer LO port, AC coupling required, DC=3.35V, frequency range
from 100MHz to 2.5GHz, impedance close to 50

resistive.

OUT

Mixer IF port, open-collector output with 1.6mA DC, frequency range
DC to 1GHz, impedance approximately 1pF capacitive.

Enable
TTL/CMOS compatible input. Bias current approximately zero.

CONVERSION GAIN DEFINITIONS

Referring to the figure above, we define the ratio of V

(at the IF

frequency) to V

(at the RF frequency) to be the Available Voltage

Conversion Gain, or more simply Voltage Conversion Gain,

RL1

IF FILTER

RL2

SR00092

Figure 11.

20 log

where V

and V

are expressed in similar voltage units (such as

peak-to-peak). The voltage output V

is decreased by the IF Filter

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

loss (and any other matching required). Typically, VG

is 10.4dB for

the NE/SA600 mixer with the net IF impedance equal to 500

It is more common to express the conversion gain in terms of power,
so we have the Power Conversion Gain,

10 log

3dB

where P

= V

/ R

and P

= V

/ R

. R

is the net resistance at

the IF frequency at the IF port, and R

is the input impedance at

the mixer RF port. With a 500

IF impedance and a 50

RF input

impedance, the conversion gain works out to 2.6dB typically. The
power delivered to the load is down 3dB with respect to the available
power because of loss in R

THEORY OF OPERATION

The NE/SA600 is fabricated on the Philips Semiconductors
advanced QUBiC technology that features 1

m channel length

MOSFETs and 13GHz FT bipolar transistors.

LNA
The Low Noise Amplifier (LNA) is a two stage design incorporating
feedback to stablize the amplifier. An external bypass capacitor of
(typically) 0.01

F is used. The inputs and outputs are matched to

. The amplifier has two gain states: when the ENABLE pin is

taken high, the amplifier draws 9mA of current and has 16dB of gain
at 900MHz. When the ENABLE pin is low, the amplifier current goes
to zero, and the amplifier is replaced by a thru. Typical loss for the
thru is 7dB. This dual-gain state approach can be used in
bang-bang control systems to achieve a low gain, high overload
front-end as well as the more usual high gain, low overload
front-end.

The amplifier has gain to frequencies past 2GHz, but a practical
upper end is 1.6-1.7GHz. Both the input match and the noise figure
(NF) can be improved with a shunt 15-18nH inductor at the input.
Typically, the gain increases 0.4dB, the match improves to 13-16dB,
and the noise figure drops to 1.95-2dB. Variations of any of the RF
parameters with V

is negliglible, and variation with temperature is

minimal.

Mixer
The mixer is a single-balanced topology designed to draw very low
current, typically 4mA, and provide a very high input third-order
intermodulation intercept point , typically IP3=+6dBm. The RF and
LO ports impedances are nearly 50

resistive, and the IF output is

an open collector. The open-collector output allows direct
interfacing with high impedance IF filters, such as surface acoustic
wave (SAW) filters without the need for external step-up
transformers (which are needed for 50

output mixers).

The basic mixer is functional from DC to well over 2.5GHz, but RF
and LO return losses degrade below 100MHz. The IF output can be
used from DC to 500MHz or more, although typically the
intermediate frequency is in the range 45-120MHz in many 900MHz
receivers. To achieve the lowest noise, the LO drive level should be
increased as high as possible, consistent with power dissipation
limitations.

POWER SUPPLY ISSUES

bypassing is important, but not extremely critical because of

the internal supply regulation of the NE/SA600. The Pin 1 V

supplies the LNA and powers overhead circuitry. Typical current

draw is 9.8mA while enable is high (1mA powered down). The Pin
14 V

CCMX

powers the mixer and typically has 3.2mA of current

(assuming an inductor biasing the IFout back to V

CCMX

). Care must

be taken to avoid bringing any IC pin above V

by more than 0.3V,

or below any ground by more than 0.3V. For example, this can
occur if the enable pin is fed from a microcontroller that is powered
up quicker than the NE/SA600. In this condition the internal
electrostatic discharge (ESD) protection network may turn-on,
possibly causing a part misfunction. Generally this condition is
reversible, so long as the source creating the overstress is current
limited to less than 100mA. To avoid the problem, make sure both
V

pins are tied together near the IC, and install a 1k

resistor in

series with the enable pin if it is likely to go above V

BOARD LAYOUT CONSIDERATIONS

The LNA is sensitive to mutual inductance from the input to ground.
Therefore long narrow input traces will degrade the input match.
Ideally, a top side ground-plane should be employed to maximize
LNA gain and minimize stray coupling (such as LO to antenna). To
avoid amplifier peaking, the output and input grounds should not be
run together. Attach both grounds to a solid ground plane. A solid
ground plane beneath the package will maximize gain. Top side to
back side ground through holes are highly recommended.

The mixer is relatively insensitive to grounding. Care should be
taken to minimize the capacitance on the RF port (Pin 11) for best
noise figure. Also, the capacitance on the IFout pin must be kept
small to avoid conversion gain rolloff when using high IF
frequencies. The purpose of the inductor from IFout to V

is to set

the midpoint of the IF swing to be V

. Without this inductor the

part is sensitive to output overload under low V

= 4.5V) and

hot temperature conditions. The V

CCMX

pin must be kept at the

same potential as the V

pin.

APPLICATIONS INFORMATION

The NE/SA600 is a high performance, wide-band, low power, low
noise amplifier (LNA) and mixer circuit integrated in a BiCMOS
technology. It is ideally suited for RF receiver front-ends for both
analog and digital communications systems.

There are several advantages to using the NE/SA600 as a high
frequency front-end block instead of a discrete implementation. First
is the simplicity of use. The NE/SA600 does not need any external
biasing components. Due to the higher level of integration and
small footprint (SO14) package it occupies less space on the printed
circuit board and reduces the manufacturing cost of the system.
Also the higher level of integration improves the reliability of the LNA
and mixer over a discrete implementation with several components.

The LNA thru mode in NE/SA600 helps reduce power consumption
in applications where the amplifiers can be disabled due to higher
received signal strength (RSSI). Other advantages of this feature
are described later in this section.

The mixer is an active mixer with excellent conversion gain at low
LO input levels, so LO levels as low as -5dBm to -10dBm can be
used depending on the applications requirement for mixer gain,
mixer noise figure and mixer third order intercept point. This
reduces the LO drive requirements from the VCO buffer, thus
reducing its current consumption. Also, due to lower LO levels, the
shielding requirements can be minimized or eliminated, resulting in
substantial cost savings and weight and space reduction.

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

And last but not least, is the impedance matching at LNA inputs and
outputs and mixer RF and LO input ports. Only those who have
toiled through discrete transistor implementations for 50

input and

output impedance matching can truly appreciate the elegance and
simplicity of the NE/SA600 input and output impedance matching to
50

. Also, the mixer output impedance is high, so matching to a

crystal or SAW IF filter becomes extremely easy without the need for
additional IF impedance transformers (tapped-C networks with
inductors or baluns).

The NE/SA600 applications and demo board features standard low
cost 62mil FR-4 board. A top-side ground plane is used and 50

coplanar transmission lines are used. LO and RF

INA

traces are

perpendicular. Provisions for the image reject filter between RF

OUTA

and RF

INMX

are provided. A simple LC match for 80MHz IF is used

so that 50

measurements can be made on the demo board.

The NE/SA600 applications evaluation board schematic is shown in
Figure 1. The V

(Pin 1) and V

CCMX

(Pin 14) are tied together and

the power supply is bypassed with capacitors C5 and C6. These
capacitors should be placed as close to the device as practically
possible.

C1 is the DC blocking capacitor to the input of the LNA. L1 provides
additional input matching to the LNA for an improved return loss
(S11). This inductor can be a surface-mount component or can be
easily drawn on the printed circuit board (small spiral or serpentine).
This additional match improves the gain of the LNA by 0.4dB and
lowers the noise figure to 2dB or less. If the typical gain of the LNA
of 16dB is acceptable with 2.2dB of noise figure, then L1 can be
eliminated. If the LNA input is fed from a duplexer or selectivity
filter after the antenna, C1 can also be eliminated since the filter will
also provide DC blocking. The LNA bypass capacitor C3 should be
at least 100 times C1 or C9 for low frequency stability. Switch S1
toggles the LNA gain/through function. R1 is used only to limit the
maximum current into the enable pin and only necessary if enable
may power up before the V

C4 is a DC blocking capacitor for the LO input pin and may not be
needed in actual applications if the VCO output is isolated and will
not upset the internal DC biasing of the mixer. The image reject
filter goes between the output of the LNA and the RF input to the
mixer. Since the LO input, RF output and mixer input are all 50

matched impedances internally, there is no need for any external
components. C8 and C9 are DC blocking capacitors to the
connectors and will not be needed in an actual application.

R2 and L2 are the load to the mixer output which is typical of the IF
crystal or SAW filters. C2 and L3 provide a match from the high
impedance mixer output to a 50

test set-up (spectrum analyzer,

etc.) and C7 is a DC blocking capacitor for the mixer output.

The printed circuit board layout for the schematic of Figure 1 is
shown in Figure 14. It is a very simple printed circuit board layout
with all the components on a single side. The layout also
accomodates a two pole image reject filter between the LNA outupt
and mixer input. All the input and output traces to the LNA and
mixer should be 50

tracks with the exception of mixer output,

which can be very narrow due to the higher impedances of the filter.

The NE/SA600 internal supply is very well regulated. This is seen
from Figure 15 which shows the I

vs. V

for the NE/SA600.

Table NO TAG shows the S11, S21, S22 and S21 for the LNA from
800-1200MHz. Typical measurements at 900MHz for the critical
parameters such as gain, noise figure, IP

, 1dB compression point,

etc. as measured on an applications evaluation board are as follows
:

LNA gain = 16.5dB
LNA through = 7dB
Mixer gain =3dB (into a 50

load)

LNA noise figure = 2dB
Mixer noise figure = 14dB
LNA IP

= 10dBm (in gain mode)

LNA IP

= +26dBm (in through mode)

LNA 1dB compression point = 20dBm
Mixer 1dB compression point = 4dBm

The shunt inductor L1 for input match is optional. Figure 16 shows
the effect of the inductor value from 8.2nH to 15nH on gain, noise
figure and input match.

The total power gain for the LNA and mixer (excluding the image
reject filter) in a system where the output of the mixer is loaded with
50

is about 14dB. In an actual system the output impedance of

the mixer is usually much higher than 50

(more like 1k

or higher)

and so it is more important to consider the voltage gain from the
input at the LNA to the mixer output. The voltage gain in this case
will be about 29.85V/V. The total noise figure for the LNA and mixer
combination is be about 3.27dB. The input third order intercept
point for the LNA and mixer is about -11dBm. In the LNA through
mode, the intercept point for the combination is higher than
+19dBm. This LNA through feature provides an additional boost to
the total dynamic range of the system.

The NE/SA600 finds applications in many areas of RF
communications. It is an ideal down converter block for high
performance, low cost, low power RF communications transceivers.
The front-end of a typical AMPS/TACS/NMT/TDMA/CDMA cellular
phone is shown in Figure 13. This could also be the front-end of a
VHF/UHF handheld transceiver, UHF cordless telephone or a
spread spectrum system.

The antenna is connected to the duplexer input. The receiver output
of the duplexer is connected to the RF input of the LNA. If the
additional improvement in noise figure and gain are not needed to
meet the system specifications then L1 and C1 can be eliminated.
In TDMA systems, the NE/SA600 can be totally powered down by
Q1 and the two resistors. In this mode the current consumption will
be zero mA. Care should be taken in the software of the system to
insure that the enable pin on NE/SA600 tied to the LNA gain control
port is held low while the device is in total power down mode. L2
and C2 can be tuned to the IF frequency and to match to the IF filter
impedance.

A complete analysis of the front-end shows that the total voltage
gain from the antenna input to the mixer output is about 9.5V/V. This
value includes a 3.2dB loss for the duplexer and a 1.8dB loss for the
bandpass filter. The noise figure as referred to the antenna is 7dB
and the input third order intercept point is about -7.5dBm. In LNA
through mode the input third order intercept point increases to about
+24dBm.

During normal operation of a handheld RF receiver the received
signal strength (RSSI) is nominally greater than -100dBm. The
signal only drops below this level due to severe multipath fading,
shadow effect or when the receiver is at extreme fringes of cell
coverage. The LNA through mode can be used here as a two step
gain control such that when RSSI is below a certain threshold level
(e.g. -90dBm), the LNA has a -7dB loss and the total current
consumption of the NE/SA600 is only 4.3mA. The sensitivity of the
system will not suffer because the received RF signal is much higher
than the noise floor of the system. When the RSSI falls below a
certain threshold (e.g. -95dBm) the LNA is enabled to give the full

Philips Semiconductors

Product specification

NE/SA600

1GHz LNA and mixer

1993 Dec 15

16.5dB of gain with 2dB of noise figure. In this mode the current
consumption is increased to 13mA. But for hand-held equipment,
the average current consumption will be closer to 5-6mA. The other
advantage of the LNA through mode besides power savings is the
input overload characteristics. Due to the much higher input third
order intercept point of the LNA (+26dBm), the receiver is immune to
strong adjacent channel interference. Implementing this feature with
an FM/IF device such as the NE625/7 with fast RSSI response and
a window comparator toggling the LNA mode of NE/SA600, a fast
two-step AGC with response time less than 10

s can be achieved.

This is a very useful feature to equalize multipath fading effects in a
mobile radio system.

In conclusion, the NE/SA600 offers higher level of integration, higher
reliability, higher level of performance, ease of use, simpler system
design at a cost lower than the discrete multi-transistor
implementations. In addition, the NE/SA600 provides unique
features to enhance receiver performance which are almost
unattainable with discrete implementations.

NE/SA600

BANDPASS

FILTER

LO INPUT

BYPASS

INPUT

900MHz

10nF

100pF

0.1

MIXER IN

RF OUT

IF OUT

470nH

100pF

10nF

4.7pF

10nF

OUT

VC
C
GNDB

RF INA

GNDA1

VCCMX

GNDMX

IFOUT

RF INMX

BYPASS

GNDLO

LOIN

GNDA2

ENABLE

RF OUTA

15nH

VCC

SR00093

Figure 12.

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ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: NE600D