Analog Devices Inc. SSM2135SZ

Overview

SSM2135SZ from Analog Devices is a dual, single-supply audio operational amplifier optimized for low-noise, low-distortion signal conditioning in portable and multimedia audio systems. It delivers 5.2 nV/√Hz input voltage noise, 0.003% THD+N at 1 kHz (1 V p-p), 3.5 MHz gain bandwidth, rail-to-rail output swing capability under moderate loads, and operates from 4 V to 36 V single supply. It serves as stereo headphone driver, microphone preamplifier, and balanced line receiver in 5 V audio subsystems.

For engineers reviewing the SSM2135SZ datasheet, SSM2135SZ pinout, SSM2135SZ application, or SSM2135SZ equivalent, key selection considerations include its unity-gain stability with capacitive loads up to 500 pF, −40°C to +85°C industrial temperature rating, SOIC_N-8 package compatibility, and verified performance driving 32 Ω headphones and 600 Ω line terminations.

Technical Context

The SSM2135SZ integrates two independent, fully matched op-amps in a single SOIC-8 package, each featuring a proprietary output stage enabling output swing within ~3.5 mV of ground and ~4.1 V of V+ at 5 V supply. Its internal architecture supports true single-supply operation with input common-mode range extending to ground and output swing approaching both rails - critical for maximizing dynamic range in bias-referenced audio circuits.

It employs a high-slew-rate (0.6–0.9 V/μs), wide-bandwidth (3.5 MHz GBW) design with excellent PSRR (90–120 dB) and CMRR (87–112 dB), enabling robust operation in electrically noisy environments such as PC audio boards or portable DAC output stages. The device is explicitly characterized for unity-gain stability and maintains ultralow distortion (<0.005%) even into 32 Ω loads.

Key Specifications

Pinout & Package

SSM2135SZ is housed in an 8-lead narrow-body SOIC (SOIC_N, R-8 package), JEDEC MS-012-AA compliant, with 1.27 mm lead pitch and 4.9 mm × 3.9 mm body dimensions.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual audio op-amp applications.

Compared with OPA2134PA and LM4562MAX, the SSM2135SZ uniquely combines rail-swing capability, 5 V single-supply operation, and sub-0.005% THD+N into 32 Ω - making it the only option among the three qualified for integrated 5 V headphone amplifier designs without external level-shifting or boost circuitry.

Availability

SSM2135SZ is available at Aetrix Electronics and suitable for multimedia audio systems, portable digital audio units, and single-supply Σ-Δ ADC input conditioning requiring stable component supply across industrial temperature ranges.

Supply support for SSM2135SZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, and audio markets since 1965.

The SSM2135SZ belongs to Analog Devices' legacy audio amplifier product line, designed specifically for low-voltage, low-noise, single-supply audio signal conditioning in cost-sensitive consumer and professional portable equipment.

FAQ

What is the maximum load the SSM2135SZ can drive while maintaining 0.005% THD+N?

The SSM2135SZ maintains ≤0.005% THD+N into 32 Ω loads at 1 V p-p output and 1 kHz, as specified in Table 1 of the Rev. G datasheet. At higher output amplitudes or frequencies, distortion increases slightly - e.g., 0.01% at 20 kHz into 32 Ω. For 600 Ω line-driving applications, THD+N remains below 0.003% across the full audio band. The SSM2135SZ's short-circuit current limit of ±30 mA ensures safe operation into demanding loads without latch-up.

Does the SSM2135SZ require external compensation for unity-gain stability?

No, the SSM2135SZ is internally compensated for unity-gain stability and requires no external components to remain stable at AV = +1. It remains stable driving capacitive loads up to 500 pF, as confirmed in the Applications Information section (Page 10). Overshoot increases marginally above 100 pF, but phase margin remains sufficient for reliable operation in typical PCB layouts with decoupling and routing parasitics.

Can the SSM2135SZ operate from a 3.3 V supply?

No - the absolute minimum single-supply voltage for the SSM2135SZ is 4 V, as stated in the Absolute Maximum Ratings table (Page 4). Operation below 4 V risks degraded output swing, increased distortion, and potential failure to meet specifications. For 3.3 V systems, consider newer alternatives like the SSM2167 or ADA4891-2, which are explicitly rated down to 2.7 V.

What is the purpose of the V–/GND pin (Pin 4) in single-supply configuration?

In single-supply operation, Pin 4 (V–/GND) serves as the circuit ground reference and negative supply terminal - it must be connected directly to the system's 0 V plane. Unlike dual-supply op-amps, the SSM2135SZ does not float this pin; grounding it establishes the common-mode baseline for both inputs and defines the lower bound of output swing. Failure to tie Pin 4 solidly to ground will result in undefined biasing and loss of rail-swing capability.

Is the SSM2135SZ RoHS compliant and lead-free?

Yes - the "Z" suffix in SSM2135SZ explicitly denotes RoHS-compliant, lead-free packaging per the Ordering Guide (Page 14). The device uses matte tin lead finish and meets JEDEC J-STD-020 moisture sensitivity level 3 (MSL-3) requirements. All variants ending in "SZ" or "SZ-REEL7" are Pb-free and halogen-free, qualified for modern electronics assembly processes including reflow soldering.