Texas Instruments CDCE18005RGZT

Overview

CDCE18005 from Texas Instruments is a programmable 5-output (or 10 LVCMOS) clock buffer with universal differential inputs, supporting LVPECL up to 1.5 GHz, LVDS up to 800 MHz, and LVCMOS up to 250 MHz; features on-chip crystal oscillator (2–42 MHz), independent output dividers (1–80), and 50 fs RMS additive jitter - deployed in high-speed data converter clocking and wireless infrastructure baseband timing.

For engineers reviewing the CDCE18005 datasheet, CDCE18005 pinout, CDCE18005 application, or CDCE18005 equivalent, key selection criteria include input signal compatibility (LVPECL/LVDS/LVCMOS), output format flexibility per channel, EEPROM-configurable power-up state, low-skew multi-format fan-out, and SPI-programmable divider/skew settings for deterministic timing alignment.

Technical Context

The CDCE18005 integrates three reference inputs - two universal differential buffers (PRI_REF/SEC_REF) accepting LVPECL (≤1500 MHz), LVDS (≤800 MHz), or LVCMOS (≤250 MHz), plus an auxiliary crystal oscillator input (2–42 MHz AT-cut) - all routed to a shared internal clock distribution bus. Each of five output channels includes a multiplexer selecting among reference sources, a programmable divider (1–80), and a 7-bit digital phase adjust block.

Output blocks support mixed-mode operation: up to five differential outputs (LVPECL or LVDS) or ten single-ended LVCMOS outputs, with independent format, frequency, and coarse skew control per channel; VBB termination voltage (0.9–1.9 V) enables precise input biasing, and EEPROM stores default register states for autonomous startup without host intervention.

Key Specifications

Pinout & Package

The CDCE18005 is housed in a 48-pin QFN package (RGZ) with exposed thermal pad (Texas Instruments package designator S-PQFP-N48), optimized for thermal dissipation in high-power clock distribution applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar clock buffer applications.

Compared with CDCE62005RGZT and LMK00306RGTT, the CDCE18005 uniquely combines crystal oscillator integration, EEPROM-based autonomous startup, and five independently configurable outputs - making it optimal for space-constrained, self-booting systems requiring multi-format clock fan-out without external components.

Availability

CDCE18005 is available at Aetrix Electronics and suitable for data converter clocking, wireless infrastructure timing, and switch/router line card applications requiring stable component supply across extended product lifecycles.

Supply support for CDCE18005 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies, with broad portfolio coverage across industrial, automotive, and communications markets.

The CDCE18005 belongs to TI's high-performance clock distribution product line, designed specifically for low-jitter, multi-format fan-out in data-intensive systems such as wireless base stations, test equipment, and medical imaging platforms.

FAQ

What is the maximum supported crystal frequency for the CDCE18005 AUX_IN input?

The CDCE18005 AUX_IN input supports AT-cut crystals in the range of 2 MHz to 42 MHz, as specified in the official datasheet (SCAS863B). This range accommodates common reference frequencies including 10 MHz, 25 MHz, and 40 MHz crystals used in telecom and instrumentation applications. Operation outside this range is not guaranteed and may result in oscillator failure or degraded jitter performance. The CDCE18005 does not support overtone or TCXO modules on AUX_IN.

Does the CDCE18005 support LVCMOS outputs at 25 MHz, and what is the typical duty cycle accuracy?

Yes, the CDCE18005 supports LVCMOS outputs up to 250 MHz, including 25 MHz operation. When configured for LVCMOS, the device delivers a typical duty cycle of 45%–55% under 50% input duty cycle conditions, as verified in the Electrical Characteristics table (page 10 of SCAS863B). This specification ensures compatibility with standard logic families and timing-critical interfaces requiring symmetrical clock edges.

How many independent output dividers does the CDCE18005 provide, and what is the divider range?

The CDCE18005 provides five independent output dividers - one per output channel (U0 through U4). Each divider supports integer ratios from 1 to 80, as confirmed in the Functional Description section and Register Configuration tables of the datasheet. These dividers operate digitally and are programmable via SPI or EEPROM, enabling precise frequency synthesis without external components.

Can the CDCE18005 generate both LVPECL and LVDS outputs simultaneously, and what design considerations apply?

Yes, the CDCE18005 can generate LVPECL and LVDS outputs simultaneously on different channels (e.g., U0P/U0N as LVPECL, U1P/U1N as LVDS), as stated in the Features and Output Block sections. Critical design considerations include separate VCC_OUT decoupling for each output bank, proper termination (50 Ω AC for LVPECL, 100 Ω for LVDS), and adherence to layout guidelines for minimizing crosstalk between differential pairs operating at different voltage levels.

What is the additive jitter performance of the CDCE18005 when using a 25 MHz crystal reference?

When using a 25 MHz crystal reference (LVCMOS input), the CDCE18005 achieves 275 fs RMS additive jitter (10 kHz–5 MHz integration bandwidth), as documented in Table 2 of the datasheet (SCAS863B, page 14). This value reflects total jitter after internal multiplication and distribution, and is measured with LVPECL output configuration. Performance varies slightly by output format: LVDS yields 345 fs, LVCMOS yields 249 fs under identical conditions.