Analog Devices Inc. SDC1768411B

Overview

SDC1768411B from Analog Devices is a 14-bit hybrid synchro/resolver-to-digital converter with ±5.3 arc minute accuracy, internal isolating transformers, and TTL-compatible parallel natural binary output. It operates over –55°C to +125°C, supports 400 Hz or 2.6 kHz reference frequency, and delivers analog velocity and error outputs for real-time shaft angle tracking in high-reliability avionics servo systems.

For engineers reviewing the SDC1768411B datasheet, SDC1768411B pinout, SDC1768411B application, or SDC1768411B equivalent, this page provides verified technical context, confirmed pin functions, exact resolution and tracking rate values, and two validated alternative models for resolver/synchro conversion in MIL-spec embedded motion control.

Technical Context

The SDC1768411B implements a Type II servo loop architecture with phase-sensitive detection, integrator, and VCO to continuously null Sin(θ − φ), enabling true continuous tracking even during data transfer. Its internal Scott-T transformer pair converts 3-wire synchro inputs to resolver format, while 4-wire resolver inputs pass through isolation only.

It features dual three-state latch enable inputs-ENABLE M for MSB8 and ENABLE L for LSB6-allowing independent bus multiplexing without disrupting the internal tracking loop. The INHIBIT input freezes latched output without opening the servo loop, and BUSY signals settle within 1.2 µs (typ) after update.

Key Specifications

Pinout & Package

SDC1768411B is housed in a hermetically sealed 32-pin metal dual-in-line package (1.74″ × 1.14″ × 0.28″), with 14 digital output pins (pins 1–14, MSB to LSB), dedicated RHI/RLO, S1–S4, INHIBIT, BUSY, ENABLE M/L, and power/ground terminals.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar resolver-to-digital conversion applications.

Compared with SDC1768411B, SDC1767411B trades resolution and LSB count for higher tracking rate and lower cost, while DRC1765 serves an entirely inverse signal path-making it unsuitable as a functional substitute but relevant for complementary test equipment design.

Availability

SDC1768411B is available at Aetrix Electronics and suitable for avionic flight control, artillery fire control, and engine controller monitoring requiring stable component supply, long-term obsolescence management, and MIL-STD-883 Class B screening.

Supply support for SDC1768411B 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 semiconductor leader specializing in high-performance signal processing, precision conversion, and motion control ICs for aerospace, defense, and industrial applications.

The SDC1768411B belongs to Analog Devices' legacy hybrid resolver/synchro converter product line, engineered for extreme reliability in safety-critical motion feedback systems where isolation, accuracy, and continuous tracking are non-negotiable.

FAQ

What is the reference frequency supported by SDC1768411B?

The SDC1768411B supports a 400 Hz reference frequency, as indicated by the "Y=1" option code in its part number. This matches standard aircraft synchro excitation sources and is verified in the device's specification table. Operation at 2.6 kHz requires a different variant (Y=4). The 400 Hz setting ensures optimal loop stability and accuracy per the Type II servo design.

Does SDC1768411B support both synchro and resolver inputs?

Yes, SDC1768411B supports both 3-wire synchro and 4-wire resolver inputs. For synchro, internal Scott-T transformers convert the input to resolver format; for resolver, signals pass directly through isolation transformers. The Z=1 option code confirms 11.8 Vrms signal/reference compatibility for both formats, as documented in the ordering information section.

What is the meaning of the "411B" suffix in SDC1768411B?

The "411B" suffix in SDC1768411B decodes as X=4 (–55°C to +125°C operating range), Y=1 (400 Hz reference frequency), and Z=1 (11.8 Vrms signal and reference voltage). The "B" denotes standard processing per MIL-STD-883 Class B screening-verified in the reliability section and packaging specifications.

Can SDC1768411B operate without external scaling resistors?

Yes, SDC1768411B can operate without external scaling resistors when used with nominal 11.8 Vrms signal and reference inputs, as specified by its Z=1 option code. The device's input impedance values (26 kΩ for 11.8 V reference, 200 kΩ for 11.8 V signal) are matched to this voltage level-scaling resistors are only required for non-standard voltages per the resistive scaling section.

What is the function of the ERROR output on SDC1768411B?

The ERROR output on SDC1768411B is a built-in test point that transitions from ±30 mV (normal tracking) to ±200 mV (fault condition) when the device loses lock-due to excessive acceleration, input failure, or servo loop instability. It is not linear with error magnitude and is intended solely for system-level fault detection, not closed-loop correction.