Analog Devices Inc. LTC6903IMS8#TRPBF

Overview

LTC6903IMS8#TRPBF from Analog Devices (formerly Linear Technology) is a serial-port programmable silicon oscillator IC delivering a precision square-wave clock output from 1.039 kHz to 68 MHz. It features SPI-compatible control, 0.5% typical initial frequency accuracy, ±0.75% min initial accuracy, and operates from a single 2.7V–5.5V supply across –40°C to +85°C. It serves as a digitally tunable replacement for crystal oscillators, VCOs, and DAC-based timing sources in microcontroller clocking and power management.

For engineers reviewing the LTC6903IMS8#TRPBF datasheet, LTC6903IMS8#TRPBF pinout, LTC6903IMS8#TRPBF application, or LTC6903IMS8#TRPBF equivalent, key selection considerations include its 8-pin MSOP package, SPI interface timing (20 MHz max SCK), output enable (OE) functionality, jitter performance (<0.4% typical from 1 kHz to 8 MHz), and guaranteed monotonic frequency tuning across OCT/DAC settings.

Technical Context

The LTC6903IMS8#TRPBF integrates a high-frequency master oscillator (34–68 MHz), a proprietary linearizing feedback loop, and a 16× binary divider to generate precise output frequencies. Its frequency is set via a 4-bit OCT code selecting one of 16 octave ranges and a 10-bit DAC code fine-tuning within that range using the equation f = 2078 × 2^(OCT−10) / DAC (Hz).

It uses an internal resistor DAC and analog control loop-not a PLL-to achieve low-jitter, deterministic frequency synthesis without external components beyond a bypass capacitor. Output enable (OE) asynchronously forces both CLK outputs low, while serial programming occurs on the rising edge of SCK with SEN active-low initiation.

Key Specifications

Pinout & Package

Package: 8-lead plastic MSOP (MS8), 3.0 mm × 3.0 mm × 1.1 mm, exposed pad not electrically connected, RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digitally programmable oscillator applications.

Compared with LTC6904IMS8#TRPBF, the LTC6903IMS8#TRPBF offers faster SPI programming and deterministic latency; compared with LTC6900CMS8#TRPBF, it delivers higher frequency headroom, dual-phase outputs, and output enable-making it optimal for reconfigurable timing in industrial control and mixed-signal systems.

Availability

LTC6903IMS8#TRPBF is available at Aetrix Electronics and suitable for microcontroller clocking, power management timing, switched-capacitor filter synchronization, and DDS reference applications requiring stable component supply across industrial temperature grades.

Supply support for LTC6903IMS8#TRPBF 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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC6903IMS8#TRPBF belongs to Linear's precision programmable oscillator family, designed specifically for applications demanding accurate, software-controlled clock generation without crystals or external tuning components.

FAQ

What is the maximum clock frequency supported by the LTC6903IMS8#TRPBF serial interface?

The LTC6903IMS8#TRPBF supports a maximum serial clock (SCK) frequency of 20 MHz across its full operating temperature range. This allows full 16-bit configuration in under 1 µs. The timing parameters-including tCKHI, tCKLO, tSU, and tHLD-are specified over –40°C to +85°C and guarantee robust communication even under worst-case voltage and temperature conditions. No external pull-ups are required on SDI or SCK.

Does the LTC6903IMS8#TRPBF require external passive components to operate?

No, the LTC6903IMS8#TRPBF requires only a single 0.1 µF ceramic bypass capacitor between V+ and GND, placed within 2 mm of the pins. Unlike crystal oscillators or PLL-based solutions, it needs no load capacitors, loop filter components, or trimming resistors. The internal master oscillator, DAC, and divider are fully integrated, enabling true "connect-and-run" clock generation with minimal board area and BOM count.

How does the LTC6903IMS8#TRPBF achieve 0.5% typical frequency accuracy without calibration?

The LTC6903IMS8#TRPBF achieves 0.5% typical initial accuracy through factory-trimmed resistor DAC elements and a proprietary analog feedback architecture that linearizes the frequency vs. digital code relationship. Its frequency equation f = 2078 × 2^(OCT−10) / DAC (Hz) is inherently monotonic and calibrated across process, voltage, and temperature. No system-level calibration or software compensation is needed for most industrial applications.

Can both CLK outputs of the LTC6903IMS8#TRPBF be used simultaneously, and what phase relationship do they have?

Yes, both CLK (Pin 5) and CLK (Pin 6) outputs of the LTC6903IMS8#TRPBF can be enabled simultaneously via CNF[1:0] = 00. In this mode, they deliver identical frequency with precise 180° phase opposition-ideal for differential clocking or push-pull driving. Each output is independently controllable; disabling one improves accuracy at high frequencies (e.g., ≤0.2% degradation at 68 MHz with one output active vs. ≤0.5% with both active and unloaded).

What is the function of the OE (Output Enable) pin on the LTC6903IMS8#TRPBF, and how fast does it respond?

The OE (Pin 7) on the LTC6903IMS8#TRPBF provides asynchronous, hardware-level control of both clock outputs: pulling OE low forces CLK and CLK immediately to logic LOW, regardless of internal state or serial commands. Response is sub-10 ns, with no propagation delay or settling time. This enables precise power gating, glitch-free clock stopping during sleep modes, or safe reset sequencing-distinct from the slower powered-down mode accessed via CNF[1:0]=11.