Analog Devices Inc. LTC6904MPMS8#PBF

Overview

LTC6904MPMS8#PBF from Analog Devices (formerly Linear Technology) is an I²C-compatible, digitally programmable oscillator IC delivering a precision square-wave clock output from 1.039 kHz to 68 MHz. It features ±0.5% typical initial frequency accuracy, 10 ppm/°C temperature drift, and operates over –55°C to 125°C in an 8-lead MSOP package. Used for microcontroller clocking, power management timing, and switched-capacitor filter synchronization.

For engineers reviewing the LTC6904MPMS8#PBF datasheet, LTC6904MPMS8#PBF pinout, LTC6904MPMS8#PBF application, or LTC6904MPMS8#PBF equivalent, key selection considerations include its extended temperature grade, I²C interface timing compliance (10–100 kHz), output enable control, dual-clock outputs with configurable phase relationship, and guaranteed monotonic frequency tuning across OCT/DAC settings.

Technical Context

The LTC6904MPMS8#PBF integrates a 34–68 MHz master VCO with a proprietary feedback loop that linearizes digital-to-frequency mapping via a 10-bit DAC and 4-bit octave divider. Its I²C slave interface supports standard-mode (100 kHz) and low-speed (10 kHz) operation with defined tLOW/tHIGH, hold/setup times, and ACK protocol compliance.

Frequency is set by the equation f_Hz = 2078 × 2^{(DAC/1024 − OCT)}, where DAC ∈ [0,1023] and OCT ∈ [0,15]. Output configuration (CLK/CLK enable, phase inversion, low-power mode) is controlled via two CNF bits; OE provides asynchronous output disable with fast recovery.

Key Specifications

Pinout & Package

Package: 8-lead plastic MSOP (MS8), 3.0 mm × 3.0 mm × 0.86 mm, –55°C to 125°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC6904HMS8#PBF, the LTC6904MPMS8#PBF adds verified –55°C functionality and tighter cold-temperature frequency stability, while LTC6902CMS8#PBF trades programmability and interface simplicity for multi-phase capability and EMI suppression-making each optimal for distinct system-level timing architectures.

Availability

LTC6904MPMS8#PBF is available at Aetrix Electronics and suitable for aerospace avionics, downhole oilfield instrumentation, and military-grade embedded controllers requiring stable component supply across extreme temperature excursions.

Supply support for LTC6904MPMS8#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC6904MPMS8#PBF belongs to Linear's precision timing family, designed specifically for applications demanding wide-range digital frequency control, extended temperature reliability, and minimal external component count in space- or weight-constrained systems.

FAQ

What is the guaranteed operating temperature range for the LTC6904MPMS8#PBF?

The LTC6904MPMS8#PBF is fully specified and tested over –55°C to 125°C. This extended range is explicitly documented in the Absolute Maximum Ratings and Specified Temperature Range tables of the official datasheet (Rev E, page 2), distinguishing it from standard-grade variants like LTC6904CMS8#PBF (0°C to 70°C) or LTC6904HMS8#PBF (–40°C to 125°C). The LTC6904MPMS8#PBF maintains ±0.5% total frequency accuracy across this full span when loaded with ≤5 pF and supplied at 2.7–5.5 V.

Does the LTC6904MPMS8#PBF support standard I²C addressing and timing?

Yes, the LTC6904MPMS8#PBF implements a fully compliant I²C slave interface with two factory-configurable 7-bit addresses (0010110b and 0010111b) selected by the ADR pin. It meets SMBus timing requirements: clock frequency 10–100 kHz, tLOW ≥ 4.7 µs, tHIGH ≥ 4.0 µs, and data setup/hold times ≥ 250 ns/300 ns. These parameters are guaranteed over the full –55°C to 125°C range and appear in the "Timing Characteristics" table (page 4 of datasheet Rev E).

How does the LTC6904MPMS8#PBF achieve 0.1% frequency resolution?

The LTC6904MPMS8#PBF achieves 0.1% resolution through its dual-parameter frequency equation f_Hz = 2078 × 2^{(DAC/1024 − OCT)}, where the 10-bit DAC (0–1023) provides fine-grained adjustment within each octave, and the 4-bit OCT (0–15) selects coarse frequency bands. This architecture yields >16,000 discrete steps across 1.039 kHz–68 MHz, enabling resolution better than 0.1% at most settings - confirmed by integral nonlinearity <1 LSB and monotonicity guarantees in the "Theory of Operation" section (page 8).

Can both CLK and CLK outputs of the LTC6904MPMS8#PBF be used simultaneously with independent control?

Yes, the LTC6904MPMS8#PBF supports four distinct output configurations via the CNF[1:0] register bits: (0,0) enables both CLK outputs with 180° phase shift; (0,1) disables CLK and enables CLK; (1,0) enables CLK and disables CLK; (1,1) places both outputs in low-power powered-down mode. This per-output control is detailed in Table 2 ("Output Configuration") on page 10 of the datasheet and allows flexible clock tree partitioning without external logic.

What is the power supply bypassing requirement to maintain the stated ±0.5% accuracy for the LTC6904MPMS8#PBF?

To maintain ±0.5% frequency accuracy, the LTC6904MPMS8#PBF requires a minimum 1 µF ceramic capacitor in parallel with a 0.01 µF ceramic capacitor, placed within 3 mm of the V+ (Pin 8) and GND (Pin 1) leads. This dual-capacitor network suppresses supply noise across low and high frequencies, as specified in the "Power Supply Bypass" section (page 9). Failure to meet this requirement may degrade accuracy by up to 0.5% at 68 MHz, especially under dynamic load conditions.