Analog Devices Inc. LTC6904IMS8#TRPBF

Overview

LTC6904IMS8#TRPBF from Analog Devices (formerly Linear Technology) is an I²C-compatible, digitally programmable oscillator IC delivering a precise 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 from a single 2.7V–5.5V supply. Used in microcontroller clocking, power management, and switched-capacitor filter timing.

For engineers reviewing the LTC6904IMS8#TRPBF datasheet, LTC6904IMS8#TRPBF pinout, LTC6904IMS8#TRPBF application, or LTC6904IMS8#TRPBF equivalent, key selection considerations include its I²C interface, MS8 package, –40°C to 85°C industrial temperature range, output enable control, and jitter performance below 0.4% (1kHz–8MHz).

Technical Context

The LTC6904IMS8#TRPBF integrates a high-frequency VCO (34–68 MHz) with a proprietary feedback loop that linearizes digital-to-frequency mapping via a 10-bit DAC and 4-bit octave divider. Frequency is set using the equation f = 2078 × 2^(OCT − 10)/DAC (Hz), where OCT ∈ [0,15] and DAC ∈ [0,1023].

It implements a receive-only I²C slave interface with two configurable 7-bit addresses (ADR pin-selectable), supports SMBus timing (10–100 kHz), and provides dual complementary CMOS outputs (CLK/CLK) with asynchronous OE control and four output configuration modes via CNF[1:0] bits.

Key Specifications

Pinout & Package

Package: 8-lead plastic MSOP (MS8), 3.0 mm × 3.0 mm × 0.86 mm, –40°C to 85°C operating range, RoHS-compliant, tape-and-reel packaging (TRPBF).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC6904IMS8#TRPBF, LTC6903IMS8#TRPBF offers identical performance but requires SPI infrastructure, while LTC6900CMS8#TRPBF trades frequency range and OE functionality for reduced power and cost - making each optimal for distinct system architecture constraints.

Availability

LTC6904IMS8#TRPBF is available at Aetrix Electronics and suitable for microcontroller clocking, power management timing, and switched-capacitor filter applications requiring stable component supply, industrial temperature support, and I²C configurability.

Supply support for LTC6904IMS8#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 acquired Linear Technology in 2017 and maintains its precision analog and mixed-signal product lines with rigorous automotive and industrial qualification standards.

The LTC6904IMS8#TRPBF belongs to Linear's programmable oscillator family, designed specifically for replacing crystals and discrete PLLs in space- and cost-constrained embedded systems requiring digital frequency agility and guaranteed stability.

FAQ

What is the default output frequency of the LTC6904IMS8#TRPBF at power-up?

At power-up, all internal registers reset to zero, resulting in an output frequency of 1.039 kHz on both CLK and CLK pins. This is determined by the minimum DAC (0) and OCT (0) settings per the frequency equation f = 2078 × 2^(OCT−10)/DAC. The LTC6904IMS8#TRPBF maintains this default until reprogrammed via I²C, ensuring predictable startup behavior without external configuration.

Does the LTC6904IMS8#TRPBF require external passive components to operate?

No, the LTC6904IMS8#TRPBF requires only a 0.1 µF ceramic bypass capacitor between V+ and GND, placed within millimeters of the pins. Unlike crystal oscillators or PLL-based solutions, it contains all necessary timing circuitry internally - no external resistors, capacitors, or inductors are needed for basic operation. The LTC6904IMS8#TRPBF achieves this via an integrated VCO and digital divider architecture.

Can both CLK and CLK outputs of the LTC6904IMS8#TRPBF be disabled independently?

No - the LTC6904IMS8#TRPBF does not support independent enable/disable of CLK and CLK. Output behavior is controlled jointly via the CNF[1:0] register bits, offering four fixed modes: both outputs active (180° out-of-phase), CLK only, CLK only, or powered-down (low-power standby). Asynchronous OE pin disables both simultaneously. The LTC6904IMS8#TRPBF's dual-output control is functionally grouped, not per-pin.

What is the maximum capacitive load the LTC6904IMS8#TRPBF can drive without accuracy degradation?

The LTC6904IMS8#TRPBF is specified to drive up to 5 pF on each CLK/CLK output with no degradation in frequency accuracy. This load corresponds to one or two HC-series logic inputs. Driving >5 pF (e.g., a 10× oscilloscope probe at 10–15 pF) may cause up to 0.5% accuracy loss at 68 MHz. For heavier loads, a high-speed buffer is recommended. The LTC6904IMS8#TRPBF's output driver is optimized for minimal loading impact within its rated specification.

How does the ADR pin affect I²C communication with the LTC6904IMS8#TRPBF?

Pin 4 (ADR) sets the least significant bit of the LTC6904IMS8#TRPBF's 7-bit I²C slave address: ADR = LOW → address 0x2E (0010110), ADR = HIGH → address 0x2F (0010111). This allows two LTC6904IMS8#TRPBF devices to share the same I²C bus without address conflict. The ADR pin is sampled at power-up and latched; changing it mid-operation has no effect. The LTC6904IMS8#TRPBF relies solely on this pin for address differentiation - no software-configurable address bits exist.