Philips Semiconductors RF Communications Products

Product specification

SA620

Low voltage LNA, mixer and VCO -- 1GHz

December 15, 1993

853-1725 11658

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

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

= 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

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

Internal VCO automatic leveling loop

Monotonic VCO frequency vs control
voltage

APPLICATIONS

900MHz cellular front-end

900MHz cordless front-end

Spread spectrum receivers

RF data links

UHF frequency conversion

Portable radio

PIN CONFIGURATION

DK Package

VCC

LNA GND

LNA OUT

LNA BIAS

MIXER IN

MIXER GND

MIXER BYPASS

MIXER OUT

OSC GND

VCO OUT

LNA ENABLE

LNA GND

LNA IN

LNA GND

OSC GND

MIXER PWRDN

OSC PWRDN

OSC1

OSC2

ORDERING INFORMATION

DESCRIPTION

TEMPERATURE RANGE

ORDER CODE

DWG #

20-Pin Plastic Shrink Small Outline Package (Surface-mount, SSOP)

-40 to +85

SA620DK

1563

BLOCK DIAGRAM

MIXER

OSC

PWRDN

OSC1

OSC2

VCC

LNA

BIAS

MIXER

GND

MIXER

OUT

OSC
GND

VCO
OUT

LNA

VCO

LNA

ENABLE

LNA

GND

LNA IN

LNA

OSC
GND

AUTOMATIC

LEVELING

LOOP

TRACKING

BANDPASS

FILTER

GND

LNA

OUT

GND

LNA

GND

PWRDN

MIXER

BYPASS

Philips Semiconductors RF Communications Products

Product specification

SA620

Low voltage LNA, mixer and VCO -- 1GHz

December 15, 1993

ABSOLUTE MAXIMUM RATINGS

SYMBOL

PARAMETER

RATING

UNITS

Supply voltage

-0.3 to +6

Voltage applied to any other pin

-0.3 to (V

+ 0.3)

Power dissipation, T

= 25

C (still air)

20-Pin Plastic SSOP

980

JMAX

Maximum operating junction temperature

150

MAX

Maximum power input/output

+20

dBm

STG

Storage temperature range

65 to +150

NOTE:
1. Transients exceeding 8V on V

pin may damage product.

2. Maximum dissipation is determined by the operating ambient temperature and the thermal resistance,

: 20-Pin SSOP

= 110

C/W

RECOMMENDED OPERATING CONDITIONS

SYMBOL

PARAMETER

RATING

UNITS

Supply voltage

2.7 to 5.5

Operating ambient temperature range

-40 to +85

Operating junction temperature

-40 to +105

DC ELECTRICAL CHARACTERISTICS

= +3V, T

= 25

C; unless otherwise stated.

SYMBOL

PARAMETER

TEST CONDITIONS

LIMITS

UNITS

MIN

TYP

MAX

LNA enable input high

10.4

LNA enable input low

7.2

Supply current

VCO power-down input low

7.4

Mixer power-down input low

7.4

Full chip power-down

1.2

Enable logic threshold voltage

NO TAG

1.2

1.5

1.8

Logic 1 level

RF amp on

2.0

Logic 0 level

RF amp off

0.3

0.8

Enable input current

Enable = 0.4V

-1

Enable input current

Enable = 2.4V

-1

LNAIN

LNA input bias voltage

Enable = 2.4V

0.78

LNAOU

LNA output bias voltage

Enable = 2.4V

2.1

LNA bias voltage

Enable = 2.4V

2.1

MXIN

Mixer RF input bias voltage

0.94

NOTE:
1. The ENABLE input must be connected to a valid logic level for proper operation of the SA620 LNA.

Philips Semiconductors RF Communications Products

Product specification

SA620

Low voltage LNA, mixer and VCO -- 1GHz

December 15, 1993

AC ELECTRICAL CHARACTERISTICS

= +3V, T

= 25

C; Enable = +3V; unless otherwise stated.

SYMBOL

PARAMETER

TEST CONDITIONS

LIMITS

UNITS

-3

TYP

Amplifier gain

900MHz

11.5

Amplifier gain in through mode

Enable = 0.4V, 900MHz

-9

-7.5

-6

Gain temperature sensitivity in pwr-dwn mode

900MHz

-0.014

dB/

Gain temperature sensitivity enabled

900MHz

0.003

dB/

Gain frequency variation

800MHz - 1.2GHz

0.01

dB/MHz

Amplifier reverse isolation

900MHz

-20

Amplifier input match

900MHz

-10

Amplifier output match

900MHz

-12

-1dB

Amplifier input 1dB gain compression

900MHz

-16

dBm

IP3

Amplifier input third order intercept

900MHz

-4.5

-3

-1.5

dBm

Amplifier noise figure

900MHz

1.3

1.6

1.9

Amplifier turn-on time (Enable Lo

Hi)

See Figure 1

OFF

Amplifier turn-off time (Enable Hi

Lo)

See Figure 1

Mixer voltage conversion gain: R

= R

= 1k

= 0.9GHz, f

= 0.8GHz,

= 100MHz

14.5

17.5

Mixer power conversion gain: R

= R

= 1k

= 0.9GHz, f

= 0.8GHz,

= 100MHz

1.5

4.5

11M

Mixer input match

900MHz

-10

Mixer SSB noise figure

900MHz

7.5

10.5

-1dB

Mixer input 1dB gain compression

900MHz

-13

dBm

IP3

Mixer input third order intercept

= 1MHz, 900MHz

-7.5

-6

-4.5

dBm

2INT

Mixer input second order intercept

900MHz

dBm

RFM-IF

Mixer RF feedthrough

900MHz

-20

LO-IF

LO feedthrough to IF

900MHz

-25

dBm

LO-RFM

LO to mixer input feedthrough

900MHz

-30

dBm

LO-RF

LO to LNA input feedthrough

900MHz

-45

dBm

VCO

VCO buffer out

900MHz

-16

dBm

VCO frequency range

300

(min)

1200

(max)

MHz

VCO phase noise

Offset = 60kHz

-105

dBc/Hz

NOTE:
1. Simple L/C elements are needed to achieve specified return loss.

Philips Semiconductors RF Communications Products

Product specification

SA620

Low voltage LNA, mixer and VCO -- 1GHz

December 15, 1993

Figure 1. A Complete LNA, Mixer and VCO

LNA ENABLE

LNA GND

LNA IN

LNA GND

MIXER PD

OSC PD

OSC1

OSC2

Vcc

LNA GND

LNA OUT

LNA BIAS

MIXER IN

MIXER GND

MIXER BYPASS

MIXER OUT

OSC GND

VCO OUT

LNA IN

C23

C22

L1
56nH

C2
1.8pF

2.7nH

C7
3.3pF

SMV 1204 - 099
Alpha Industries

GND

100pF

C19

100pF

C18

2.2pF

LNA OUT

C17

100pF

MIXER IN

C16

5.6pF

C14
1-5pF

R = 9k x (VCC 1)

VCC

C20

100pF

C21

C13

12pF

150nH

C15

C12

10pF

MIXER OUT

L = 260 mils

w = 15 mils

VCO OUT

100pF

C10
100pF

VCC

0.44

F/(VCC1)

0.1

100pF

0.1

(50

)

V_CONTROL

(0 to VCC)

VCC

SA620

VCC

LNA ENABLE

(1k

, 83MHz)

10k

L = 260 mils

w = 15 mils

2.7nH

3.9pF

4.7nH

535 mils

4.7nH

535 mils

4.7nH

535 mils

4.7nH

535 mils

L = 160 mils

w = 15 mils

C11

1000pF

MIXER OUT

(50

, 83MHz)

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

= -10dB.

Further improvements in S

will slightly

increase the NF and S

Thru-Mode: A series switch can be activated
to feed RF signals from LNA input to output
with an attenuator (S

= 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

C to +85

Supply Voltage Compensation: Unique
circuitry provides gain stabilization over wide
supply voltage range. The gain changes no
more than 0.5dB when V

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 50

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.

Part Number SA620