OPA2134 — SoundPlus™ FET-Input Dual Audio Operational Amplifier

Overview

The OPA2134 (commonly OPA2134PA in DIP-8 or OPA2134UA in SOIC-8) is a legendary SoundPlus™ FET-input dual audio operational amplifier manufactured by Texas Instruments (originally Burr-Brown). Iconic among audiophiles and DIY audio builders, its true FET-input stage provides ultra-low input bias current ( $5\text{ pA}$ ) while delivering ultra-low distortion ( $\text{THD+N} = \mathbf{0.00008\%}$ ).

Featuring a fast slew rate of $20\text{ V}/\mu\text{s}$ , an $8\text{ MHz}$ gain bandwidth, and high output drive capacity into $600\ \Omega$ loads, the OPA2134 is widely used in high-end headphone amplifiers, active crossover networks, studio mixing consoles, and phono preamp stages.

Quick reference


Op-Amp Type	SoundPlus™ FET-Input Dual Audio Operational Amplifier
Package	8-Pin DIP (Through-Hole) / SOIC-8
Supply Voltage Range ( $V_{CC}$ )	$\pm 2.5\text{ V}$ to $\pm 18.0\text{ V}$ ( $5.0\text{ V}$ to $36.0\text{ V}$ single supply)
THD+N	$0.00008\%$ typical ( $f = 1\text{kHz}, R_L = 2\text{k}\Omega$ )
Input Bias Current	$5.0\text{ pA}$ typical (FET Input)
Input Voltage Noise	$8.0\text{ nV}/\sqrt{\text{Hz}}$ at $f = 1\text{kHz}$
Slew Rate	$20.0\text{ V}/\mu\text{s}$
Gain Bandwidth Product (GBW)	$8.0\text{ MHz}$

Pinout (Standard Dual Op-Amp 8-Pin Package)

text

        ┌──────────┐
  OUT A ─│ 1      8 │─ V+
  -IN A ─│ 2      7 │─ OUT B
  +IN A ─│ 3      6 │─ -IN B
     V- ─│ 4      5 │─ +IN B
        └──────────┘

Pin	Name	Description
1	`OUT A`	Operational Amplifier A output
2	`-IN A`	Operational Amplifier A inverting input
3	`+IN A`	Operational Amplifier A non-inverting input
4	`V-` / `GND`	Negative power supply rail ( $-15\text{V}$ for dual supply, $0\text{V}$ for single supply)
5	`+IN B`	Operational Amplifier B non-inverting input
6	`-IN B`	Operational Amplifier B inverting input
7	`OUT B`	Operational Amplifier B output
8	`V+`	Positive power supply rail ( $+15\text{V}$ for dual supply)

Specifications

Parameter	Symbol	Min	Typ	Max	Unit	Conditions
Supply Voltage Range	$V_{CC}$	$\pm 2.5$	$\pm 15$	$\pm 18$	V	Dual supply range
Total Harmonic Distortion	$\text{THD+N}$	—	0.00008	—	%	$f = 1\text{kHz}, V_{OUT} = 3\text{Vrms}, R_L = 2\text{k}\Omega$
Input Bias Current	$I_{B}$	—	5	100	pA	$V_{CM} = 0\text{V}$
Input Noise Density	$e_n$	—	8.0	—	$\text{nV}/\sqrt{\text{Hz}}$	$f = 1\text{kHz}$
Slew Rate	$SR$	15	20	—	$\text{V}/\mu\text{s}$	$R_L = 2\text{k}\Omega$
Gain Bandwidth Product	$GBW$	—	8.0	—	MHz
Quiescent Current	$I_Q$	—	4.0	5.0	mA	Per amplifier ( $I_O = 0$ )

Common mistakes

Leaving inputs floating in high-impedance circuits: Because the FET inputs consume virtually zero bias current ( $5\text{ pA}$ ), an unconnected input pin will drift to a supply rail, saturating the output. Always provide a DC path to ground (e.g. $100\text{k}\Omega \dots 1\text{M}\Omega$ resistor).
Substituted into low-voltage 3.3V circuits: The OPA2134 requires at least $5.0\text{ V}$ ( $\pm 2.5\text{ V}$ ) for linear operation. Do not use in 3.3V single-supply systems.

Notes

SoundPlus Audio Pedigree: Designed specifically by Burr-Brown for audio, offering warm, natural sonic reproduction with virtually zero crossover distortion.

Interface	Dual Op-Amp Terminals (+IN A, -IN A, OUT A, +IN B, -IN B, OUT B)
Package	8-pin PDIP / SOIC-8