Philips NE5219N, NE5219D, SA5219D, SA5219N Datasheet

Philips Semiconductors

SA5219

Wideband variable gain amplifier

Product specification
Replaces data of 1993 Dec 10

1997 Nov 07

INTEGRATED CIRCUITS

IC17 Data Handbook

Philips Semiconductors Product specification

SA5219Wideband variable gain amplifier

2

1997 Nov 07 853-1724 18663

DESCRIPTION

The SA5219 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 SA5219 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 5219 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

•700MHz 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

SR00273

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 SA5219D SOT109-1
16-Pin Plastic Dual In-Line package (DIP) -40 to +85°C SA5219N SOT38-4

Philips Semiconductors Product specification

SA5219Wideband 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, TA = 25oC (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

TA = 25oC, V

CC1

= V

CC2

= +5V , V

AGC

= 1.0V , unless otherwise specified.

LIMITS

SYMBOL

PARAMETER

TEST CONDITIONS

MIN TYP MAX

UNIT

I

CC

Supply current DC tested 36 43 50 mA

A

V

Voltage gain (single-ended in/single-ended out) DC tested, RL = 10kΩ 16 19 22 dB

A

V

Voltage gain (single-ended in/differential out) DC tested, RL = 10kΩ 22 25 28 dB

R

IN

Input resistance (single-ended) DC tested at ±50µA 0.8 1.2 1.6 kΩ

R

OUT

Output resistance (single-ended) DC tested at ±1mA 35 60 80 Ω

V

OS

Output offset voltage (output referred) +20 ±150 mV

V

IN

DC level on inputs 1.6 2.0 2.4 V

V

OUT

DC level on outputs 1.9 2.4 2.9 V

PSRR Output offset supply rejection ratio 18 45 dB

V

BG

Bandgap reference voltage

4.5V<VCC<7V
RBG = 10kΩ

1.2 1.32 1.45 V

R

BG

Bandgap loading 2 10

kΩ

V

AGC

AGC DC control voltage range 0-1.3 V

I

BAGC

AGC pin DC bias current 0V<V

AGC

<1.3V -0.7 -6 µA

Philips Semiconductors Product specification

SA5219Wideband variable gain amplifier

1997 Nov 07

4

AC ELECTRICAL CHARACTERISTICS

TA = 25oC, V

CC1

= V

CC2

= +5.0V , V

AGC

= 1.0V , unless otherwise specified.

LIMITS

SYMBOL

PARAMETER

TEST CONDITIONS

MIN TYP MAX

UNIT

BW -3dB bandwidth 700 MHz

GF Gain flatness DC - 500MHz +0.4 dB

V

IMAX

Maximum input voltage swing (single-ended) for
linear operation

1

200 mV

P-P

Maximum output voltage swing (single-ended)

RL = 50Ω 400 mV

P-P

V

OMAX

for linear operation

1

RL = 1kΩ 1.9 V

P-P

NF Noise figure (unmatched configuration) RS = 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 RL = 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. With R

L

> 1kΩ, overload occurs at input for single-ended gain < 13dB and at output for single-ended gain > 13dB. With RL = 50Ω, overload

occurs at input for single-ended gain < 6dB and at output for single-ended gain > 6dB.

SA5219 APPLICATIONS

The SA5219 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 SA5219 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 SA5219 has an excellent noise figure vs gain relationship. With
any VGA circuit, the noise performance will degrade with decreasing
gain. The 5219 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 SA5219 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 SA5219. A

Philips Semiconductors Product specification

SA5219Wideband variable gain amplifier

1997 Nov 07

5

maximum control voltage frequency of about 20MHz permits video
baseband sources for AM.

A stabilized bandgap reference voltage is made available on the
SA5219 (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
SA5219 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
SA5219 is shown in Figure 3. Three SA5219s 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 SA5219s. 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 SA5219s
will give a dynamic range in excess of 60dB.

The SA5219 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

+

–

SR00274

Figure 2. Equivalent Schematic of VGA

RF/IF
INPUT

AGC
OUTPUT

BAT 17

BAT 17

5219 5219

5219

R4

C4

D1 D2

D3

R6

R1

R2

L1 L2

R3

C3

R5

5230

+

–

V

CC

V

CC

SR00275

Figure 3. AGC Configuration Using Cascaded SA5219s

Philips Semiconductors Product specification

SA5219Wideband variable gain amplifier

1997 Nov 07

6

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

SR00276

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

5219

1 : 2

V

AGC

SR00277

Figure 5. Broadband Noise Optimization

This circuit will exhibit about a 7dB
noise figure with approximately
22dB gain. Narrowband circuits
have the advantage of greater stabil­ity, particularly when multiple de­vices are cascaded.

50Ω

50Ω

50Ω

+5V

+1V

2:1 TURNS RATIO
LC TUNED
TRANSFORMER

SOURCE

OUTPUT

5219

V

AGC

SR00278

Figure 6. Narrowband Noise Optimization

This circuit will exhibit about an 8dB
noise figure with 24dB gain.

50Ω

50Ω

50Ω

+5V

+1V

MINI CIRCUITS
4:1 BALUN OR
EQUIVALENT

SOURCE

OUTPUT

5219

1 : 4

V

AGC

SR00279

Figure 7. Broadband Gain Optimization