08-10-2023, 11:41 AM
(This post was last modified: 08-10-2023, 11:45 AM by Mike Watterson.)
The SA612A is cheap, single low voltage supply and operates to at least 500MHz (input).
It's a double balanced mixer with voltage regulator and optional local oscillator (LC, crystal or ceramic). The Pin 6 (osc In) can be fed from a buffer of a VCO in something else and then Pin7 is LO buffer out.
If pin1 & 2 (balanced input) is unbalanced with a resistor from 1.2V to pin 1 and pin 2 to 0V. then it will work as an AM modulator for audio or video from 40KHz to more than 200MHz RF out.
If the local oscillator output is phase shifted and mixed additively with the output you have a phase modulator.
It can be used to down mix IF to 12.5kHz and feed Android phone or tablet that has 3.5mm jack and free audio spectrum software (or a 96 KHz sampling USB audio on a Raspberry Pi or PC/Laptop and a 24kHz from the SA612.
8 Pin DIL or SMD SO8. SA612A test circuit
C3 and L1 omitted for fundamental mode crystals or resonators. They form a series trap.
A direct VCO using varicap is possible, but a separate oscillator might be better.
Single ended direct feed of CFU455 filter possible. Mmore complex filters use 12pF series.
Inputs 1.5 K Ohm in parallel with 3pf. DC to 500MHz (DC operation verified to get AM, recommendation is AC coupled)
Osc typical max 200 MHz (but depends on circuit and may be up to 500Mhz with exterrnal Osc).
External LO 200mV to 300mV ppk.
Outputs 1.5K Ohm (with DC)
Vcc 4.5V to 8.0V, typically 2.2mA to 3.2mA.
17db Conversion gain at 45 MHz.
5 dB NF at 45 MHz (which is OK for anything other than direct UHF RF input from an aerial).
I'd use a J310 or similar FET with a 1.5 K follower resistor as an IF Buffer in any radio if the SA612 is fitted internally.
It's a double balanced mixer with voltage regulator and optional local oscillator (LC, crystal or ceramic). The Pin 6 (osc In) can be fed from a buffer of a VCO in something else and then Pin7 is LO buffer out.
If pin1 & 2 (balanced input) is unbalanced with a resistor from 1.2V to pin 1 and pin 2 to 0V. then it will work as an AM modulator for audio or video from 40KHz to more than 200MHz RF out.
If the local oscillator output is phase shifted and mixed additively with the output you have a phase modulator.
It can be used to down mix IF to 12.5kHz and feed Android phone or tablet that has 3.5mm jack and free audio spectrum software (or a 96 KHz sampling USB audio on a Raspberry Pi or PC/Laptop and a 24kHz from the SA612.
8 Pin DIL or SMD SO8. SA612A test circuit
C3 and L1 omitted for fundamental mode crystals or resonators. They form a series trap.
A direct VCO using varicap is possible, but a separate oscillator might be better.
Single ended direct feed of CFU455 filter possible. Mmore complex filters use 12pF series.
Inputs 1.5 K Ohm in parallel with 3pf. DC to 500MHz (DC operation verified to get AM, recommendation is AC coupled)
Osc typical max 200 MHz (but depends on circuit and may be up to 500Mhz with exterrnal Osc).
External LO 200mV to 300mV ppk.
Outputs 1.5K Ohm (with DC)
Vcc 4.5V to 8.0V, typically 2.2mA to 3.2mA.
17db Conversion gain at 45 MHz.
5 dB NF at 45 MHz (which is OK for anything other than direct UHF RF input from an aerial).
I'd use a J310 or similar FET with a 1.5 K follower resistor as an IF Buffer in any radio if the SA612 is fitted internally.
