Programmable Gain Amplifier

Takashi Yamaguchi

Other Parts Discussed in Thread: PGA2505, PGA4311, PGA2500, PGA103, PGA112, PGA113, PGA116, PGA117, PGA202, PGA203, PGA204, PGA205, PGA206, PGA207, PGA280, PGA281, VCA810, VCA2612, VCA822, VCA820

Hi team,

Do you have a programmable gain amp (PGA) or AD converter that can change the gain in an analog (continuous) manner?
I could only find the ones that set the discrete values such as 1,2,4,8 ~ 256,512.
For example, from 1 to 1000, it would be nice to have something that can be done in 1 or 10 increments.

Regards,

Yamaguchi

over 3 years ago

0 Luis Chioye over 3 years ago

TI__Mastermind 49405 points

HI Takashi,

As you have mentioned, the Programmable Gain Amplifiers on the precision amplifiers portfolio offer gains in binary, decade or scope increments.

Decade Gains: 1, 10, 100...

Binary Gains: 1, 2, 4, 8, 16...

Scope gains: 1, 2, 5, 10, 20, 50, 100, 200

Beyond these, there are Audio PGA Audio volume control devices such as the PGA4311, PGA2500/PGA2505 that have gain increments in ~0.5 dB (or 3dB steps).

Unfortunately, there are no PGAs with 1V/V or 10 V/V increment steps.

Please find below a table with Precision PGA devices.

Thank you and Regards,

Luis

*Table 1: Single-Ended to Single-Ended*
Part	Supply	Channels	Gain (dB)	Number of	Gain Scale	Interface
Number	Min (V)		Min	Gains
	Max (V)		Max
PGA103	9	1	0	3	Decade	Parallel
	36		40
PGA112	2.2	2	0	8	Binary	SPI
	5.5		42
PGA113	2.2	2	0	8	Scope	SPI
	5.5		42
PGA116	2.2	10	0	8	Binary	SPI
	5.5		46
PGA117	2.2	10	0	8	Scope	SPI
	5.5		46
*Table 2: Differential to Single-Ended*
Part	Supply	Channels	Gain (dB)	Number of	Gain Scale	Interface
Number	Min (V)		Min	Gains
	Max (V)		Max
PGA202	12	1	0	4	Decade	Parallel
	36		60
PGA203	12	1	0	4	Binary	Parallel
	36		18
PGA204	9	1	0	4	Decade	Parallel
	36		60
PGA205	9	1	0	4	Binary	Parallel
	36		18
PGA206	9	1	0	4	Binary	Parallel
	36		18
PGA207	9	1	0	4	Decade	Parallel
	36		20
*Table 3: Differential to Differential*
Part	Supply	Channels	Gain (dB)	Number of	Gain Scale	Interface
Number	Min (V)		Min	Gains
	Max (V)		Max
PGA280	10	2	-18	11	Binary	SPI
	36		42
PGA281	10	1	-18	11	Binary	Parallel
	36		42

0 Thomas Kuehl over 3 years ago

TI__Guru* 93105 points

Yamaguchi-san,

None of TI Precision Amplifiers PGAs can be stepped from gains of 1x to 1000x, in G = 1 or 10 V/V steps. The internal resistor combinations required to do the G = 1 or 10 V/V increments through a gain of 1000x, would require a massive amount of resistor die area and resistor trimming making it impractical to to manufacture.

Regards, Thomas

Precision Amplifiers Applications Engineering

0 Michael Steffes over 3 years ago

Guru 47485 points

Hello Takashi-san

There are a few continuous time VCA's that take an analog control voltage, you could consider the (none of these are particularly good DC precision)

VCA810 (lower speed, very poor harmonic distortion, but good for time domain)

And then there are a string of multichannel parts for ultrasound like the VCA2612 - better noise - but also digital gain control

And then there are very fast parts like these that have an analog control input - the 1st is dB/V adjust, the 2nd is V/V gain adjust.

VCA820 and VCA822 (which also have even faster variants).

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Programmable Gain Amplifier