Philips Semiconductors RF Communications Products
Product specification
Low voltage LNA, mixer and VCO — 1GHz
SA620
DESCRIPTION
The SA620 is a combined RF amplifier, VCO
with tracking bandpass filter and mixer
designed for high-performance low-power
communication systems from 800-1200MHz.
The low-noise preamplifier has a 1.6dB noise
figure at 900MHz with 11.5dB gain and an
IP3 intercept of -3dBm at the input. The gain
is stabilized by on-chip compensation to vary
less than
±0.2dB
over -40 to +85°C
temperature range. The wide-dynamic-range
mixer has an 9dB noise figure and IP3 of
–6dBm at the input at 900MHz. An external
LO can be used in place of the internal VCO
for improved mixer input IP3 and a 3mA
reduction in current. The chip incorporates a
through-mode option so the RF amplifier can
be disabled and replaced by an attenuator
(S
21
= –7.5dB). This is useful for improving
the overall dynamic range of the receiver
when in an overload situation. The nominal
current drawn from a single 3V supply is
10.4mA and 7.2mA in the thru-mode.
Additionally, the VCO and Mixer can be
powered down to further reduce the supply
current to 1.2mA.
FEATURES
•
Low current consumption: 10.4mA nominal,
7.2mA with thru-mode activated
PIN CONFIGURATION
DK Package
LNA ENABLE 1
LNA GND 2
LNA IN 3
LNA GND 4
LNA GND
5
20 V
CC
19 LNA GND
18 LNA OUT
17 LNA BIAS
16 MIXER IN
15 MIXER GND
14 MIXER BYPASS
13 MIXER OUT
12 OSC GND
11 VCO OUT
•
Outstanding noise figure: 1.6dB for the
amplifier and 9dB for the mixer at 900MHz
•
Excellent gain stability versus temperature
and supply voltage
•
Switchable overload capability
•
Independent LNA, mixer and VCO power
down capability
OSC GND 6
MIXER PWRDN
OSC PWRDN
7
8
•
Internal VCO automatic leveling loop
•
Monotonic VCO frequency vs control
voltage
OSC1 9
OSC2 10
APPLICATIONS
•
900MHz cellular front-end
•
900MHz cordless front-end
•
Spread spectrum receivers
•
RF data links
•
UHF frequency conversion
•
Portable radio
TEMPERATURE RANGE
-40 to +85
°
C
ORDER CODE
SA620DK
DWG #
1563
ORDERING INFORMATION
DESCRIPTION
20-Pin Plastic Shrink Small Outline Package (Surface-mount, SSOP)
BLOCK DIAGRAM
V
CC
LNA
GND
LNA
OUT
LNA
BIAS
MIXER
IN
MIXER
GND
MIXER
BYPASS
MIXER
OUT
OSC
GND
VCO
OUT
20
19
18
17
16
15
14
13
12
11
RF
IF
LO
TRACKING
BANDPASS
FILTER
LNA
AUTOMATIC
LEVELING
LOOP
VCO
1
LNA
ENABLE
2
LNA
GND
3
LNA IN
4
LNA
GND
5
LNA
GND
6
OSC
GND
7
MIXER
PWRDN
8
OSC
PWRDN
9
OSC1
10
OSC2
December 15, 1993
2
853-1725 11658
Philips Semiconductors RF Communications Products
Product specification
Low voltage LNA, mixer and VCO — 1GHz
SA620
ABSOLUTE MAXIMUM RATINGS
SYMBOL
V
CC
V
IN
P
D
T
JMAX
P
MAX
T
STG
Supply voltage
1
Voltage applied to any other pin
Power dissipation, T
A
= 25°C (still air)
2
20-Pin Plastic SSOP
Maximum operating junction temperature
Maximum power input/output
Storage temperature range
PARAMETER
RATING
-0.3 to +6
-0.3 to (V
CC
+ 0.3)
980
150
+20
–65 to +150
UNITS
V
V
mW
°C
dBm
°C
NOTE:
1. Transients exceeding 8V on V
CC
pin may damage product.
2. Maximum dissipation is determined by the operating ambient temperature and the thermal resistance,
θ
JA
: 20-Pin SSOP = 110°C/W
RECOMMENDED OPERATING CONDITIONS
SYMBOL
V
CC
T
A
T
J
Supply voltage
Operating ambient temperature range
Operating junction temperature
PARAMETER
RATING
2.7 to 5.5
-40 to +85
-40 to +105
UNITS
V
°C
°C
DC ELECTRICAL CHARACTERISTICS
V
CC
= +3V, T
A
= 25
°
C; unless otherwise stated.
SYMBOL
PARAMETER
TEST CONDITIONS
MIN
LNA enable input high
LNA enable input low
I
CC
Supply current
VCO power-down input low
Mixer power-down input low
Full chip power-down
V
T
V
IH
V
IL
I
IL
I
IH
V
LNA–IN
V
LNA–OU
T
LIMITS
TYP
10.4
7.2
7.4
7.4
1.2
1.2
1.5
1.8
V
CC
0.8
0
0
0.78
2.1
2.1
0.94
1
1
MAX
UNITS
mA
mA
mA
mA
mA
V
V
V
µA
µA
V
V
V
V
Enable logic threshold voltage
NO TAG
Logic 1 level
Logic 0 level
Enable input current
Enable input current
LNA input bias voltage
LNA output bias voltage
LNA bias voltage
Mixer RF input bias voltage
RF amp on
RF amp off
Enable = 0.4V
Enable = 2.4V
Enable = 2.4V
Enable = 2.4V
Enable = 2.4V
2.0
–0.3
-1
-1
V
B
V
MX–IN
NOTE:
1. The ENABLE input must be connected to a valid logic level for proper operation of the SA620 LNA.
December 15, 1993
3
Philips Semiconductors RF Communications Products
Product specification
Low voltage LNA, mixer and VCO — 1GHz
SA620
AC ELECTRICAL CHARACTERISTICS
V
CC
= +3V, T
A
= 25
°
C; Enable = +3V; unless otherwise stated.
SYMBOL
PARAMETER
TEST CONDITIONS
-3σ
S
21
S
21
∆S
21
/∆T
∆S
21
/∆T
∆S
21
/∆f
S
12
S
11
S
22
P
-1dB
IP3
NF
t
ON
t
OFF
VG
C
PG
C
S
11M
NF
M
P
-1dB
IP3
M
IP
2INT
P
RFM-IF
P
LO-IF
P
LO-RFM
P
LO-RF
P
VCO
Amplifier gain
Amplifier gain in through mode
Gain temperature sensitivity in pwr-dwn mode
Gain temperature sensitivity enabled
Gain frequency variation
Amplifier reverse isolation
Amplifier input match
1
Amplifier output match
1
Amplifier input 1dB gain compression
Amplifier input third order intercept
Amplifier noise figure
Amplifier turn-on time (Enable Lo
→
Hi)
Amplifier turn-off time (Enable Hi
→
Lo)
Mixer voltage conversion gain: R
P
= R
L
= 1kΩ,
Mixer power conversion gain: R
P
= R
L
= 1kΩ,
Mixer input match
1
Mixer SSB noise figure
Mixer input 1dB gain compression
Mixer input third order intercept
Mixer input second order intercept
Mixer RF feedthrough
LO feedthrough to IF
LO to mixer input feedthrough
LO to LNA input feedthrough
VCO buffer out
VCO frequency range
VCO phase noise
NOTE:
1. Simple L/C elements are needed to achieve specified return loss.
Offset = 60kHz
900MHz
Enable = 0.4V, 900MHz
900MHz
900MHz
800MHz - 1.2GHz
900MHz
900MHz
900MHz
900MHz
900MHz
900MHz
See Figure 1
See Figure 1
f
S
= 0.9GHz, f
LO
= 0.8GHz,
f
IF
= 100MHz
f
S
= 0.9GHz, f
LO
= 0.8GHz,
f
IF
= 100MHz
900MHz
900MHz
900MHz
f
2
–f
1
= 1MHz, 900MHz
900MHz
900MHz
900MHz
900MHz
900MHz
900MHz
300
(min)
-105
-7.5
7.5
14.5
1.5
-4.5
1.3
10
-9
LIMITS
TYP
11.5
-7.5
-0.014
0.003
0.01
-20
-10
-12
-16
-3
1.6
50
5
16
3
-10
9
-13
-6
12
-20
-25
-30
-45
-16
1200
(max)
-4.5
10.5
17.5
4.5
-1.5
1.9
+3σ
13
-6
dB
dB
dB/°C
dB/°C
dB/MHz
dB
dB
dB
dBm
dBm
dB
µs
µs
dB
dB
dB
dB
dBm
dBm
dBm
dB
dBm
dBm
dBm
dBm
MHz
dBc/Hz
UNITS
December 15, 1993
4
Philips Semiconductors RF Communications Products
Product specification
Low voltage LNA, mixer and VCO — 1GHz
SA620
LNA ENABLE
C23
1µF
LNA IN
C1
100pF
4.7nH
535 mils
C22
0.44µF/(V
CC
–1)
L1
56nH
R6
R = 9k x (V
CC
– 1)
V
CC
C19
100pF
C21
0.1µF
C20
100pF
1
2
3
4
5
6
7
8
9
10
LNA ENABLE
LNA GND
LNA IN
LNA GND
LNA GND
OSC GND
MIXER PD
OSC PD
OSC1
OSC2
SA620
VCO OUT
(50Ω)
Vcc
LNA GND
LNA OUT
LNA BIAS
MIXER IN
MIXER GND
MIXER BYPASS
MIXER OUT
OSC GND
VCO OUT
20
19
18
17
16
15
14
13
12
11
C16
5.6pF
w = 15 mils
L = 160 mils
4.7nH
535 mils
w = 15 mils
L = 260 mils
4.7nH
535 mils
C18
2.2pF
C17
100pF
MIXER IN
LNA OUT
C2
1.8pF
w = 15 mils
L = 260 mils
C3
0.1µF
C4
10µF
C5
3.9pF
C13
12pF
L2
2.7nH
C14
1-5pF
V
CC
C15
0.1µF
V
CC
C6
GND
100pF
L3
2.7nH
D1
SMV 1204 - 099
Alpha Industries
C7
3.3pF
C9
100pF
4.7nH
535 mils
C10
100pF
V
CC
R3
22Ω
MIXER OUT
(1kΩ, 83MHz)
C11
1000pF
L4
150nH
C12
10pF
MIXER OUT
(50Ω, 83MHz)
R2
10kΩ
V_CONTROL
(0 to V
CC
)
R1
10kΩ
C8
0.1µF
R4
1kΩ
R5
51Ω
Figure 1. A Complete LNA, Mixer and VCO
CIRCUIT TECHNOLOGY
LNA
Impedance Match:
Intrinsic return loss at the
input and output ports is 7dB and 9dB,
respectively. With no external matching, the
associated LNA gain is
≈10dB
and the noise
figure is
≈1.4dB.
However, the return loss
can be improved at 900MHz using suggested
L/C elements (Figure NO TAG) as the LNA is
unconditionally stable.
Noise Match:
The LNA achieves 1.6dB
noise figure at 900MHz when S
11
= -10dB.
Further improvements in S
11
will slightly
increase the NF and S
21
.
Thru-Mode:
A series switch can be activated
to feed RF signals from LNA input to output
with an attenuator (S
21
= –7.5dB). As a
result, the power handling is greatly improved
and current consumption is decreased by
3.2mA as well. However, if this mode is not
required, C23 and R6 can be deleted.
Temperature Compensation:
The LNA has
a built-in temperature compensation scheme
to reduce the gain drift to 0.003dB/°C from
–40°C to +85°C.
Supply Voltage Compensation:
Unique
circuitry provides gain stabilization over wide
supply voltage range. The gain changes no
more than 0.5dB when V
CC
increases from
3V to 5V.
Mixer
Input Match:
The mixer is configured for
maximum gain and best noise figure. The
user needs to supply L/C elements to
achieve this performance.
Mixer Bypass:
To optimize the IP3 of the
mixer input, one must adjust the value of C14
for the given board layout. The value
typically lies between 1 and 5pF. Once a
value if selected, a fixed capacitor can be
used. Further improvements in mixer IP3 can
be achieved by inserting a resistive loss at
the mixer input, at the expense of system
gain and noise figure.
Tracking Bandpass Filter:
At the LO input
port of the mixer there is a second-order
bandpass filter (approx. 50MHz bandwidth)
which will track the VCO center frequency.
The result is the elimination of low frequency
noise injected into the mixer LO port without
the need for an external LO filter.
Power Down:
The mixer can be disabled by
connecting Pin 7 to ground. If a Schottky
diode is connected between Pin 1 (cathode)
and Pin 7 (anode), the LNA disable signal will
control both LNA and mixer simultaneously
When the mixer is disabled, 3mA is saved.
Test Port:
Resistor R5 can be substituted
with an external test port of 50Ω input
impedance. Since R5 and MIXER OUT have
the same output power, the result is a direct
power gain measurement.
VCO
Automatic Leveling Loop:
An on-chip
detector and loop amplifier will adjust VCO
bias current to regulate the VCO amplitude
regardless of the Q-factor (>10) of the
resonator and varactor diode. However, the
real current reduction will not occur until the
VCO frequency falls below 500MHz. For a
typical resonator the steady-state current is
3mA at 800MHz.
Buffered VCO Output:
The VCO OUT (Pin
11) signal can drive an external prescaler
directly (see also the Philips SA7025 low
voltage, fractional-N synthesizer). The
extracted signal levels need to be limited to
–16dBm or less to maintain mixer IIP3.
Phase Noise:
If close-in phase noise is not
critical, or if an external synthesizer is used,
C4 (Pin 8) can be decreased to a lower
value.
Power-Down:
The VCO can be disabled by
connecting Pin 8 to ground. If a Schottky
diode is connected between Pin 1 (cathode)
and Pin 8 (anode), the LNA disable signal will
control both LNA and VCO simultaneously.
When the VCO is disabled, 3mA is saved.
December 15, 1993
5
Philips Semiconductors RF Communications Products
Product specification
Low voltage LNA, mixer and VCO — 1GHz
SA620
TYPICAL PERFORMANCE CHARACTERISTICS
CH1
S
11
1
U
FS
4:
30.707
Ω
-24.89
Ω
5.86 pF
1100.000 000 MHz
1:
33.184
Ω
-39.105
Ω
800 MHz
31.879
Ω
-33.66
Ω
900 MHz
30.594
Ω
-28.695
Ω
1 GHz
2:
3:
START
800.000 000
MHz
STOP
1200.000 000
MHz
CH1
S
22
1
U
FS
4:
39.811
Ω
-22.93
Ω
6.31 pF
1100.000 000 MHz
1:
48.164
Ω
-35.754
Ω
800 MHz
44.574
Ω
-31.246
Ω
900 MHz
42.068
Ω
-25.799
Ω
1 GHz
2:
3:
START
800.000 000
MHz
STOP
1200.000 000
MHz
Figure 2. LNA Input and Output Match (at Device Pin)
December 15, 1993
6
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