Philips sa620 DATASHEETS

Philips Semiconductors RF Communications Products Product specification

SA620Low 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°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

= –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

1 2 3 4 5 6 7 8 9

20 19 18 17 16 15

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 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°C

SA620DK 1563

BLOCK DIAGRAM

4321 5

20 19 18 17 16

76 1098

15 14 13 12 11

MIXER OSC

PWRDN

OSC1 OSC2

LNA LNA

BIAS

MIXERINMIXER

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

SA620Low voltage LNA, mixer and VCO — 1GHz

December 15, 1993

ABSOLUTE MAXIMUM RATINGS

SYMBOL PARAMETER RATING UNITS

Supply voltage

-0.3 to +6 V

Voltage applied to any other pin -0.3 to (VCC + 0.3) V

Power dissipation, TA = 25°C (still air)

20-Pin Plastic SSOP 980 mW

JMAX

Maximum operating junction temperature 150 °C

MAX

Maximum power input/output +20 dBm

STG

Storage temperature range –65 to +150 °C

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 V

Operating ambient temperature range -40 to +85 °C

Operating junction temperature -40 to +105 °C

DC ELECTRICAL CHARACTERISTICS

VCC = +3V, TA = 25°C; unless otherwise stated.

SYMBOL

PARAMETER TEST CONDITIONS LIMITS UNITS

MIN TYP MAX

LNA enable input high 10.4 mA

LNA enable input low 7.2 mA

Supply current VCO power-down input low 7.4 mA

Mixer power-down input low 7.4 mA

Full chip power-down 1.2 mA

Enable logic threshold voltage

NO TAG

1.2 1.5 1.8 V

Logic 1 level RF amp on 2.0 V

Logic 0 level RF amp off –0.3 0.8 V

Enable input current Enable = 0.4V -1 0 1 µA

Enable input current Enable = 2.4V -1 0 1 µA

LNA–IN

LNA input bias voltage Enable = 2.4V 0.78 V

LNA–OU

LNA output bias voltage Enable = 2.4V 2.1 V

LNA bias voltage Enable = 2.4V 2.1 V

MX–IN

Mixer RF input bias voltage 0.94 V

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

SA620Low voltage LNA, mixer and VCO — 1GHz

December 15, 1993

AC ELECTRICAL CHARACTERISTICS

VCC = +3V, TA = 25°C; Enable = +3V; unless otherwise stated.

SYMBOL

PARAMETER TEST CONDITIONS LIMITS UNITS

-3σ TYP +3σ

Amplifier gain 900MHz 10 11.5 13 dB

Amplifier gain in through mode Enable = 0.4V, 900MHz -9 -7.5 -6 dB

∆S21/∆T Gain temperature sensitivity in pwr-dwn mode 900MHz -0.014 dB/°C ∆S21/∆T Gain temperature sensitivity enabled 900MHz 0.003 dB/°C

∆S21/∆f Gain frequency variation 800MHz - 1.2GHz 0.01 dB/MHz

Amplifier reverse isolation 900MHz -20 dB

Amplifier input match

900MHz -10 dB

Amplifier output match

900MHz -12 dB

-1dB

Amplifier input 1dB gain compression 900MHz -16 dBm IP3 Amplifier input third order intercept 900MHz -4.5 -3 -1.5 dBm NF Amplifier noise figure 900MHz 1.3 1.6 1.9 dB t

Amplifier turn-on time (Enable Lo → Hi) See Figure 1 50 µs

OFF

Amplifier turn-off time (Enable Hi → Lo) See Figure 1 5 µs

Mixer voltage conversion gain: RP = RL = 1kΩ,

fS = 0.9GHz, fLO = 0.8GHz,

= 100MHz

14.5 16 17.5 dB

Mixer power conversion gain: RP = RL = 1kΩ,

fS = 0.9GHz, fLO = 0.8GHz,

= 100MHz

1.5 3 4.5 dB

11M

Mixer input match

900MHz -10 dB

Mixer SSB noise figure 900MHz 7.5 9 10.5 dB

-1dB

Mixer input 1dB gain compression 900MHz -13 dBm

IP3

Mixer input third order intercept f2–f1 = 1MHz, 900MHz -7.5 -6 -4.5 dBm

2INT

Mixer input second order intercept 900MHz 12 dBm

RFM-IF

Mixer RF feedthrough 900MHz -20 dB

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

SA620Low voltage LNA, mixer and VCO — 1GHz

December 15, 1993

Figure 1. A Complete LNA, Mixer and VCO

1 2 3 4 5 6 7 8 9

20 19 18 17 16 15 14 13 12 11

LNA ENABLE LNA GND LNA IN LNA GND 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

1.8pF

2.7nH

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 (V

– 1)

C20

100pF

C21

C13

12pF

150nH

C15

C12 10pF

MIXER OUT

L = 260 mils

w = 15 mils

VCO OUT

100pF

C10 100pF

1µF

0.44µF/(V

–1)

0.1µF

10µF

100pF

0.1µF

(50Ω)

V_CONTROL

(0 to VCC)

SA620

LNA ENABLE

51Ω

(1kΩ, 83MHz)

10kΩ

22Ω

10kΩ

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

1kΩ

MIXER OUT

(50Ω, 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 –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

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.

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