Analog Devices Inc. LT1218CS8#PBF

Overview

LT1218CS8#PBF from Analog Devices (formerly Linear Technology) is a precision rail-to-rail input and output bipolar operational amplifier optimized for low-voltage, high-accuracy signal conditioning. It delivers 90µV max input offset voltage across the full rail-to-rail common-mode range, 97dB min CMRR, 300kHz gain-bandwidth product, 0.10V/µs slew rate, and operates from ±2V to ±15V supplies - enabling high-fidelity buffering of 12-bit ADC inputs in battery-powered instrumentation.

For engineers reviewing the LT1218CS8#PBF datasheet, LT1218CS8#PBF pinout, LT1218CS8#PBF application, or LT1218CS8#PBF equivalent, this page provides verified package mapping (SO-8), confirmed rail-to-rail I/O behavior, validated shutdown functionality (IS < 30µA), precise offset trim capability, and real-world performance data for A/D converter driving, multiplexer amplification, and test equipment front-ends.

Technical Context

The LT1218CS8#PBF employs a dual-input-stage architecture with independently trimmed PNP and NPN differential pairs, enabling consistent 90µV VOS across VCM = V– to V+, unlike conventional rail-to-rail op amps. Its patented trimming ensures CMRR ≥97dB over temperature and supply variations.

It uses conventional internal compensation, guaranteeing stability with capacitive loads ≤1000pF without external components. The output stage features complementary Darlington pairs (Q23–Q26) fabricated on Linear's proprietary bipolar process, delivering true rail-to-rail swing (VOL ≤12mV, VOH ≥ V+ – 12mV at 0.5mA) and low output impedance up to 100kHz.

Key Specifications

Pinout & Package

LT1218CS8#PBF is housed in an 8-lead plastic SOIC (Small Outline Integrated Circuit) package, narrow body (0.150"), JEDEC MS-012AC compliant, with θJA = 190°C/W. Pin 1 is marked with a dot or beveled corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision rail-to-rail op amp applications.

Compared with LT1218CS8#PBF, LT1219CS8#PBF trades bandwidth for supply noise immunity, while OPA333AIDBVR sacrifices rail-to-rail input and power efficiency for near-zero drift - making LT1218CS8#PBF the optimal balance for general-purpose 12-bit precision signal conditioning with low supply current and full input range.

Availability

LT1218CS8#PBF is available at Aetrix Electronics and suitable for portable instrumentation, automated test equipment, and industrial sensor interfaces requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LT1218CS8#PBF 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 acquired Linear Technology in 2017 and maintains full product support, manufacturing, and documentation for legacy Linear op amps including the LT1218 family.

The LT1218 series was designed specifically for precision rail-to-rail signal conditioning in low-voltage, low-power applications - targeting high-resolution data acquisition, portable test gear, and sensor interface circuits where DC accuracy and supply flexibility are critical.

FAQ

What is the maximum capacitive load the LT1218CS8#PBF can drive without oscillation?

The LT1218CS8#PBF is internally compensated for stable operation with capacitive loads up to 1000pF. This specification is explicitly guaranteed in the datasheet and validated across temperature and supply conditions. Exceeding 1000pF requires external compensation or isolation; for example, driving a 1000pF ADC input capacitor is fully supported, but a 2200pF filter network would require a series resistor or buffer stage. Always verify stability using phase margin measurements under actual load conditions.

Does the LT1218CS8#PBF support true rail-to-rail input when powered from a single 3.3V supply?

Yes, the LT1218CS8#PBF supports rail-to-rail input common-mode range from V– to V+, meaning it accepts input voltages from 0V to 3.3V when operated on a single 3.3V supply (V– = 0V, V+ = 3.3V). This is confirmed by the "Rail-to-Rail Input" feature and electrical specifications showing VOS tested at VCM = V– and VCM = V+. The input stage uses complementary PNP/NPN pairs that remain linear across the full range, unlike many competitors that degrade near the rails.

How does the shutdown function of the LT1218CS8#PBF behave during power-up?

The LT1218CS8#PBF enters shutdown mode when the SHDN pin is pulled below ~0.8V relative to V+. During power-up, if SHDN is tied directly to V+ (or left floating with no pull-down), the device remains active. However, if SHDN is driven by open-drain logic referenced to a different supply, improper sequencing may cause temporary shutdown until the control rail stabilizes. The datasheet specifies a 20µs activation delay, plus additional time equal to the output slew time to reach final DC value - e.g., transitioning from 0V to –2V output requires ~40µs total.

Can the LT1218CS8#PBF be used in a single-supply photodiode transimpedance configuration?

Yes, the LT1218CS8#PBF is suitable for single-supply photodiode TIA applications due to its rail-to-rail output and low input bias current (18nA typical). When configured with V– grounded and V+ = 5V, the output can swing to within 12mV of ground, enabling accurate low-current measurement. However, its 33nV/√Hz input voltage noise is higher than FET-input alternatives, so for sub-nA photocurrents, consider noise optimization via feedback network design and bandwidth limiting.

What is the purpose of the two VOS TRIM pins on the LT1218CS8#PBF?

The LT1218CS8#PBF includes two dedicated offset null pins (Pins 1 and 5) to accommodate standard 10kΩ potentiometer connections for manual VOS calibration. Pin 1 connects to the potentiometer wiper, while Pin 5 connects to one end; the other end ties to Pin 4 (V–). This configuration allows ±2.3mV adjustment range, compensating for unit-to-unit VOS variation and thermally induced drift. It is especially valuable in high-precision DC measurement systems where factory calibration alone is insufficient.