Analog Devices Inc. LT1368CN8#PBF

Overview

LT1368CN8#PBF from Analog Devices (formerly Linear Technology) is a dual precision rail-to-rail input/output operational amplifier in 8-lead PDIP package, featuring 475 µV max input offset voltage at 25°C, 0.13 V/µs slew rate, and 400 kHz gain-bandwidth product. It operates from 1.8 V to ±15 V supplies and delivers ±30 mA output drive, enabling high-fidelity signal conditioning in low-voltage sensor interfaces and A/D converter drivers.

For engineers reviewing the LT1368CN8#PBF datasheet, LT1368CN8#PBF pinout, LT1368CN8#PBF application, or LT1368CN8#PBF equivalent, key selection criteria include its 0.1 µF required output capacitor for stability, rail-to-rail CMRR of 90 dB over full input range, and guaranteed performance across 0°C to 70°C ambient temperature.

Technical Context

The LT1368CN8#PBF employs a dual-input-stage architecture-comprising PNP and NPN differential pairs-switched by a comparator to maintain rail-to-rail common-mode input range without clamps. Its output stage uses complementary Darlington pairs with local C1/C2 feedback to achieve rail-to-rail swing and reduced high-frequency output impedance.

Unlike the LT1366/LT1367 variants, the LT1368/LT1369 family requires a mandatory 0.1 µF output capacitor for compensation, which improves PSRR by ~20 dB at 50 kHz and filters high-frequency supply noise-critical for mixed-signal systems driving SAR ADCs or operating with switching regulators.

Key Specifications

Pinout & Package

LT1368CN8#PBF is housed in an 8-lead plastic DIP (N8) package with standard dual op amp pinout and 130°C/W junction-to-ambient thermal resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT1366CN8#PBF, LT1368CN8#PBF trades capacitor-dependent layout constraints for superior PSRR and noise filtering-making it preferred for mixed-signal ADC interfaces. Versus OP2177ARZ-REEL, LT1368CN8#PBF offers wider supply flexibility and true rail-to-rail input at the cost of higher offset.

Availability

LT1368CN8#PBF is available at Aetrix Electronics and suitable for current-sense amplification, A/D converter driving, low-voltage sensor interfacing, and rail-to-rail signal conditioning requiring stable component supply across commercial temperature grades.

Supply support for LT1368CN8#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 its precision analog portfolio with rigorous process control and long-term product longevity commitments.

The LT1368 belongs to Linear's rail-to-rail precision op amp family designed specifically for high-accuracy signal conditioning in space-constrained, noise-sensitive applications where input/output voltage headroom is critical.

FAQ

What is the required output capacitor value for stable operation of the LT1368CN8#PBF?

The LT1368CN8#PBF requires a 0.1 µF ceramic capacitor connected from each output pin to ground for proper frequency compensation and stability. This capacitor is mandatory-not optional-and directly enables its improved PSRR and reduced high-frequency output impedance. Omitting it risks oscillation or degraded transient response, especially when driving A/D converters or operating with switching power supplies.

Does the LT1368CN8#PBF support true rail-to-rail input common-mode voltage range?

Yes, the LT1368CN8#PBF supports a true rail-to-rail input common-mode voltage range-from V– to V+. Its dual-input-stage architecture (PNP + NPN differential pairs) allows continuous operation across the entire supply range without phase reversal or increased input bias current. This is confirmed in the datasheet's "Input Common Mode Range Includes Both Rails" feature and validated by input bias current plots showing stable behavior at VCM = V– and VCM = V+.

What is the maximum output current capability of the LT1368CN8#PBF?

The LT1368CN8#PBF delivers ±30 mA output current per amplifier, as specified in the Absolute Maximum Ratings and verified in Electrical Characteristics tables. This enables direct driving of moderate loads such as 150 Ω termination resistors, LED indicators, or low-impedance transducer interfaces without external buffers-reducing component count and board area in compact designs.

Can the LT1368CN8#PBF operate from a single 3.3 V supply?

Yes, the LT1368CN8#PBF is fully specified for operation from 1.8 V to 36 V total supply range, including single 3.3 V supplies. Its rail-to-rail input/output architecture ensures usable signal swing from near 0 V to near 3.3 V, and its 375 µA typical supply current per amplifier makes it suitable for battery-powered 3.3 V systems. Performance parameters like V_OS, CMRR, and GBW are guaranteed across this range.

How does the LT1368CN8#PBF differ from the LT1366CN8#PBF in terms of compensation and stability?

The LT1368CN8#PBF uses internal compensation optimized for use with a 0.1 µF output capacitor, which enhances PSRR and lowers high-frequency output impedance. In contrast, the LT1366CN8#PBF uses conventional compensation stable for capacitive loads ≤1000 pF without external capacitance. This fundamental difference means LT1368CN8#PBF cannot substitute directly for LT1366CN8#PBF in capacitor-free layouts, and vice versa-designers must select based on whether PSRR or capacitive-load tolerance is prioritized.