NE5209N
Philips Semiconductors
SA5209
Wideband variable gain amplifier
Product specification
Replaces data of 1990 Aug 20
1997 Nov 07
INTEGRATED CIRCUITS
IC17 Data Handbook
Philips Semiconductors Product specification
SA5209Wideband variable gain amplifier
2
1997 Nov 07 853-1453 18663
DESCRIPTION
The SA5209 represents a breakthrough in monolithic amplifier
design featuring several innovations. This unique design has
combined the advantages of a high speed bipolar process with the
proven Gilbert architecture.
The SA5209 is a linear broadband RF amplifier whose gain is
controlled by a single DC voltage. The amplifier runs off a single 5
volt supply and consumes only 40mA. The amplifier has high
impedance (1kΩ) differential inputs. The output is 50Ω differential.
Therefore, the 5209 can simultaneously perform AGC, impedance
transformation, and the balun functions.
The dynamic range is excellent over a wide range of gain setting.
Furthermore, the noise performance degrades at a comparatively
slow rate as the gain is reduced. This is an important feature when
building linear AGC systems.
FEA TURES
•Gain to 1.5GHz
•850MHz bandwidth
•High impedance differential input
•50Ω differential output
•Single 5V power supply
•0 - 1V gain control pin
•>60dB gain control range at 200MHz
•26dB maximum gain differential
•Exceptional V
CONTROL
/ V
GAIN
linearity
•7dB noise figure minimum
•Full ESD protection
•Easily cascadable
PIN CONFIGURATION
N, D PACKAGES
OUT
A
V
CC1
IN
A
GND
2
V
CC2
GND
1
GND
1
GND
2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
16
15
IN
B
GND
1
V
BG
V
AGC
OUT
B
GND
2
GND
2
GND
2
SR00237
Figure 1. Pin Configuration
APPLICATIONS
•Linear AGC systems
•Very linear AM modulator
•RF balun
•Cable TV multi-purpose amplifier
•Fiber optic AGC
•RADAR
•User programmable fixed gain block
•Video
•Satellite receivers
•Cellular communications
ORDERING INFORMATION
DESCRIPTION TEMPERATURE RANGE ORDER CODE DWG #
16-Pin Plastic Small Outline (SO) package -40 to +85°C SA5209D SOT109-1
16-Pin Plastic Dual In-Line Package (DIP) -40 to +85°C SA5209N SOT38-4
Philips Semiconductors Product specification
SA5209Wideband variable gain amplifier
1997 Nov 07
3
ABSOLUTE MAXIMUM RATINGS
SYMBOL PARAMETER RATING UNITS
V
CC
Supply voltage -0.5 to +8.0 V
P
D
Power dissipation, T
A
= 25
o
C (still air)
1
16-Pin Plastic DIP
16-Pin Plastic SO
1450
1100
mW
mW
T
JMAX
Maximum operating junction temperature 150
°C
T
STG
Storage temperature range -65 to +150
°C
NOTES:
1. Maximum dissipation is determined by the operating ambient temperature and the thermal resistance, θ
JA
:
16-Pin DIP: θ
JA
= 85°C/W
16-Pin SO: θ
JA
= 110°C/W
RECOMMENDED OPERATING CONDITIONS
SYMBOL PARAMETER RATING UNITS
V
CC
Supply voltage V
CC1
= V
CC2
= 4.5 to 7.0V V
T
A
Operating ambient temperature range
SA Grade
-40 to +85
°C
T
J
Operating junction temperature range
SA Grade
-40 to +105
°C
DC ELECTRICAL CHARACTERISTICS
T
A
= 25
o
C, V
CC1
= V
CC2
= +5V, V
AGC
= 1.0V , unless otherwise specified.
LIMITS
SYMBOL
PARAMETER
TEST
CONDITIONS
MIN TYP MAX
UNIT
pp
DC tested 38 43 48
I
CC
S
u
ppl
y
c
u
rrent
Over temperature
1
30 55
mA
DC tested, R
L
= 10kΩ 17 19 21
A
V
Voltage
gain
(single
-
ended
in/single
-
ended
o
u
t)
Over temperature
1
16 22
dB
DC tested, R
L
= 10kΩ 23 25 27
A
V
Voltage
gain
(single
-
ended
in/differential
o
u
t)
Over temperature
1
22 28
dB
p
DC tested at ±50µA 0.9 1.2 1.5
R
IN
In ut
resistance
(single
-
ended)
Over temperature
1
0.8 1.7
kΩ
p
DC tested at ±1mA 40 60 75
R
OUT
Out ut
resistance
(single
-
ended)
Over temperature
1
35 90
Ω
p
p
+20 ±100
V
OS
Out ut
offset
voltage
(out ut
referred)
Over temperature
1
±250
mV
p
1.6 2.0 2.4
V
IN
DC
level
on
in uts
Over temperature
1
1.4 2.6
V
p
1.9 2.4 2.9
V
OUT
DC
level
on
out uts
Over temperature
1
1.7 3.1
V
Output offset supply rejection ratio
20 45
PSRR
(output referred)
Over temperature
1
15
dB
V
BG
Bandgap reference voltage
4.5V<V
CC
<7V
R
BG
= 10kΩ
1.2 1.32 1.45
V
BG
gg
Over temperature
1
1.1 1.55
Philips Semiconductors Product specification
SA5209Wideband variable gain amplifier
1997 Nov 07
4
DC ELECTRICAL CHARACTERISTICS
T
A
= 25
o
C, V
CC1
= V
CC2
= +5.0V, V
AGC
= 1.0V , unless otherwise specified.
LIMITS
SYMBOL
PARAMETER
TEST
CONDITIONS
MIN TYP MAX
UNIT
R
BG
Bandgap loading Over temperature
1
2 10
kΩ
V
AGC
AGC DC control voltage range Over temperature
1
0-1.3 V
p
0V<V
AGC
<1.3V -0.7 -6
I
BAGC
AGC
in
DC
bias
current
Over temperature
1
-10
µA
NOTES:
1. “Over Temperature Range” testing is as follows:
SA is -40 to +85°C
At the time of this data sheet release, the D package over-temperature data sheet limits are guaranteed via guardbanded room temperature
testing only.
AC ELECTRICAL CHARACTERISTICS
T
A
= 25
o
C, V
CC1
= V
CC2
= +5.0V, V
AGC
= 1.0V , unless otherwise specified.
LIMITS
SYMBOL
PARAMETER
TEST
CONDITIONS
MIN TYP MAX
UNIT
600 850
BW
-
3dB
bandwidth
Over temperature
1
500
MHz
DC - 500MHz +0.4
GF
Gain
flatness
Over temperature
1
+0.6
dB
V
IMAX
Maximum input voltage swing (single-ended) for
linear operation
2
200 mV
P-P
Maximum output voltage swing (single-ended)
R
L
= 50Ω 400 mV
P-P
V
OMAX
for linear operation
2
R
L
= 1kΩ 1.9 V
P-P
NF Noise figure (unmatched configuration) R
S
= 50Ω, f = 50MHz 9.3 dB
V
IN-EQ
Equivalent input noise voltage spectral density f = 100MHz 2.5
nV/√Hz
S12 Reverse isolation f = 100MHz -60 dB
∆G/∆V
CC
Gain supply sensitivity (single-ended) 0.3 dB/V
∆G/∆T Gain temperature sensitivity R
L
= 50Ω 0.013
dB/°C
C
IN
Input capacitance (single-ended) 2 pF
BW
AGC
-3dB bandwidth of gain control function 20 MHz
P
O-1dB
1dB gain compression point at output f = 100MHz -3 dBm
P
I-1dB
1dB gain compression point at input
f = 100MHz, V
AGC
=0.1V
-10 dBm
IP3
OUT
Third-order intercept point at output
f = 100MHz, V
AGC
>0.5V
+13 dBm
IP3
IN
Third-order intercept point at input
f = 100MHz, V
AGC
<0.5V
+5 dBm
∆G
AB
Gain match output A to output B f = 100MHz, V
AGC
= 1V 0.1 dB
NOTE:
1. “Over Temperature Range” testing is as follows:
SA is -40 to +85°C
At the time of this data sheet release, the D package over-temperature data sheet limits are guaranteed via guardbanded room temperature
testing only.
2. With R
L
> 1kΩ, overload occurs at input for single-ended gain < 13dB and at output for single-ended gain > 13dB. With R
L
= 50Ω, overload
occurs at input for single-ended gain < 6dB and at output for single-ended gain > 6dB.
Philips Semiconductors Product specification
SA5209Wideband variable gain amplifier
1997 Nov 07
5
SA5209 APPLICATIONS
The SA5209 is a wideband variable gain amplifier (VGA) circuit
which finds many applications in the RF, IF and video signal
processing areas. This application note describes the operation of
the circuit and several applications of the VGA. The simplified
equivalent schematic of the VGA is shown in Figure 2. Transistors
Q1-Q6 form the wideband Gilbert multiplier input stage which is
biased by current source I1. The top differential pairs are biased
from a buffered and level-shifted signal derived from the V
AGC
input
and the RF input appears at the lower differential pair. The circuit
topology and layout offer low input noise and wide bandwidth. The
second stage is a differential transimpedance stage with current
feedback which maintains the wide bandwidth of the input stage.
The output stage is a pair of emitter followers with 50Ω output
impedance. There is also an on-chip bandgap reference with
buffered output at 1.3V, which can be used to derive the gain control
voltage.
Both the inputs and outputs should be capacitor coupled or DC
isolated from the signal sources and loads. Furthermore, the two
inputs should be DC isolated from each other and the two outputs
should likewise be DC isolated from each other. The SA5209 was
designed to provide optimum performance from a 5V power source.
However, there is some range around this value (4.5 - 7V) that can
be used.
The input impedance is about 1kΩ. The main advantage to a
differential input configuration is to provide the balun function.
Otherwise, there is an advantage to common mode rejection, a
specification that is not normally important to RF designs. The
source impedance can be chosen for two different performance
characteristics: Gain, or noise performance. Gain optimization will
be realized if the input impedance is matched to about 1kΩ. A 4:1
balun will provide such a broadband match from a 50Ω source.
Noise performance will be optimized if the input impedance is
matched to about 200Ω. A 2:1 balun will provide such a broadband
match from a 50Ω source. The minimum noise figure can then be
expected to be about 7dB. Maximum gain will be about 23dB for a
single-ended output. If the differential output is used and properly
matched, nearly 30dB can be realized. With gain optimization, the
noise figure will degrade to about 8dB. With no matching unit at the
input, a 9dB noise figure can be expected from a 50Ω source. If the
source is terminated, the noise figure will increase to about 15dB.
All these noise figures will occur at maximum gain.
The SA5209 has an excellent noise figure vs gain relationship. With
any VGA circuit, the noise performance will degrade with decreasing
gain. The 5209 has about a 1.2dB noise figure degradation for
each 2dB gain reduction. With the input matched for optimum gain,
the 8dB noise figure at 23dB gain will degrade to about a 20dB
noise figure at 0dB gain.
The SA5209 also displays excellent linearity between voltage gain
and control voltage. Indeed, the relationship is of sufficient linearity
that high fidelity AM modulation is possible using the SA5209. A
maximum control voltage frequency of about 20MHz permits video
baseband sources for AM.
A stabilized bandgap reference voltage is made available on the
SA5209 (Pin 7). For fixed gain applications this voltage can be
resistor divided, and then fed to the gain control terminal (Pin 8).
Using the bandgap voltage reference for gain control produces very
stable gain characteristics over wide temperature ranges. The gain
setting resistors are not part of the RF signal path, and thus stray
capacitance here is not important.
The wide bandwidth and excellent gain control linearity make the
SA5209 VGA ideally suited for the automatic gain control (AGC)
function in RF and IF processing in cellular radio base stations,
Direct Broadcast Satellite (DBS) decoders, cable TV systems, fiber
optic receivers for wideband data and video, and other radio
communication applications. A typical AGC configuration using the
SA5209 is shown in Figure 3. Three SA5209s are cascaded with
appropriate AC coupling capacitors. The output of the final stage
drives the full-wave rectifier composed of two UHF Schottky diodes
BAT17 as shown. The diodes are biased by R1 and R2 to V
CC
such
that a quiescent current of about 2mA in each leg is achieved. An
SA5230 low voltage op amp is used as an integrator which drives
the V
AGC
pin on all three SA5209s. R3 and C3 filter the high
frequency ripple from the full-wave rectified signal. A voltage
divider is used to generate the reference for the non-inverting input
of the op amp at about 1.7V . Keeping D3 the same type as D1 and
D2 will provide a first order compensation for the change in Schottky
voltage over the operating temperature range and improve the AGC
performance. R6 is a variable resistor for adjustments to the op
amp reference voltage. In low cost and large volume applications
this could be replaced with a fixed resistor, which would result in a
slight loss of the AGC dynamic range. Cascading three SA5209s
will give a dynamic range in excess of 60dB.
The SA5209 is a very user-friendly part and will not oscillate in most
applications. However, in an application such as with gains in
excess of 60dB and bandwidth beyond 100MHz, good PC board
layout with proper supply decoupling is strongly recommended.
Q
1
Q
2
V
CC
Q
3
Q
4
Q
5
Q
6
V
BG
BANDGAP
REFERENCE
OUT
A
OUT
B
Q
8
Q
7
A1
V
AGC
0–1V
I
1
I
2
I
3
50
Ω
50
Ω
R
1
R
2
R
3
R
4
IN
A
IN
B
+
–
SR00238
Figure 2. Equivalent Schematic of the VGA
Philips Semiconductors Product specification
SA5209Wideband variable gain amplifier
1997 Nov 07
6
RF/IF
INPUT
AGC
OUTPUT
BAT 17
BAT 17
5209 5209
5209
R4
C4
D1 D2
D3
R6
R1
R2
L1 L2
R3
C3
R5
5230
+
–
V
CC
V
CC
R
1
=R
2
= 3.9k
R
3
= 360Ω
R
4
= 62k
R
5
= 100Ω
R
6
= 1k pot
2πfL
1
= 10k
L
1
=L
2
SR00239
Figure 3. AGC Configuration Using Cascaded SA5209s
1
2
3
4
5
6
7
8
9
10
11
12
13
14
16
15
OUT
A
V
CC1
IN
A
GND2
V
CC2
GND1
GND1
GND2
IN
B
GND1
V
BG
V
AGC
GND
2
OUT
B
GND2
GND2
V
OUT
A
OUT
B
V
CC
5VDC
+
V
IN
10µF
0.1µF
0.1µF
0.1µF
0.1µF
0.1µF
0.1µF
50Ω
(16-Pin SO, 150-mil wide)
SR00240
Figure 4. VGA AC Evaluation Board
This circuit will exhibit about a 7dB
noise figure with approximately
22dB gain.
50Ω
50Ω
50Ω
+5V
+1V
MINI CIRCUITS
2:1 BALUN
OR SIMILAR
SOURCE
OUTPUT
5209
1 : 2
V
AGC
SR00241
Figure 5. Broadband Noise Optimization
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