NXP Semiconductors CBTU4411EE,518

Overview

CBTU4411EE,518 from NXP Semiconductors is an 11-bit DDR2 SDRAM multiplexer/bus switch optimized for 1.7 V to 1.9 V operation with SSTL_18 select inputs, 12 Ω nominal ON-resistance, <30 ps output skew, and integrated 400 Ω DIMM-port pull-down resistors. It serves as a high-speed, low-skew signal routing device between host controller and 1–2-rank DDR2 DIMMs in memory subsystems.

For engineers reviewing the CBTU4411EE,518 datasheet, CBTU4411EE,518 pinout, CBTU4411EE,518 application, or CBTU4411EE,518 equivalent, this device supports precise timing-critical DDR2 data bus switching at 200–400 MHz, offers configurable strobe channel handling on HP10/DP10, and delivers controlled enable/disable times for fast bus turnaround in server and embedded memory modules.

Technical Context

The CBTU4411EE,518 implements a 1:4 multiplexed architecture per channel using pseudo-differential SSTL_18 select inputs (S0/S1) referenced to VREF = 0.5×VDD, enabling accurate, slew-rate-independent switching control. Its decoder-driven EN/S0/S1 logic ensures only one DIMM port (0DPn–3DPn) connects to each Host port (HP0–HP10) at any time.

In strobe mode (STREN = HIGH), channel 10 provides differential strobe support with internal 3⁄4×VDD pull-up when idle and disables pull-down during disable for current savings. All switches feature matched rise/fall slew rates, <30 ps edge skew, and low crosstalk between data/data and data/DQM lines - critical for DDR2 signal integrity.

Key Specifications

Pinout & Package

LFBGA72 package (SOT856-1): plastic low-profile fine-pitch BGA, 7 × 7 × 1.05 mm body, 72 solder balls.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DDR2 bus switching applications.

Compared with NB7L14M and PI3CH4411, the CBTU4411EE,518 uniquely integrates SSTL_18 select inputs, programmable strobe channel behavior, and 400 Ω VBIAS-controlled pull-downs - making it the only option qualified for JEDEC-compliant DDR2 DIMM rank selection without external components.

Availability

CBTU4411EE,518 is available at Aetrix Electronics and suitable for DDR2 memory module interfacing, server memory subsystems, embedded DDR2 expansion, and industrial control memory interfaces requiring stable component supply and long-term lifecycle support.

Supply support for CBTU4411EE,518 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

NXP Semiconductors is a global semiconductor company specializing in secure connectivity solutions for automotive, industrial, and communication applications.

The CBTU4411EE,518 belongs to NXP's DDR2 interface IC product line, designed specifically to simplify high-speed memory routing in cost-sensitive, space-constrained DDR2 systems while meeting JEDEC timing and signal integrity requirements.

FAQ

What is the function of the STREN pin on the CBTU4411EE,518?

The STREN (strobe enable) pin configures channel 10 (HP10 and associated DIMM ports) as a differential strobe channel when driven HIGH. In this mode, the unselected DIMM port is pulled up to 3⁄4×VDD internally, and pull-down is disabled during disable states to reduce current. When STREN is LOW, channel 10 behaves identically to channels 0–9. This functionality is integral to DDR2 DQS signal handling in the CBTU4411EE,518.

Does the CBTU4411EE,518 support 1-rank and 2-rank DIMMs?

Yes, the CBTU4411EE,518 is explicitly optimized for connection to both 1-rank and 2-rank DDR2 DIMMs. Its 1:4 multiplexing per channel, low ON-resistance (12 Ω), and controlled skew (<30 ps) ensure signal integrity across rank-switching scenarios. Each of the 11 channels independently selects among four DIMM ports, accommodating dual-rank topologies without performance compromise in the CBTU4411EE,518.

What is the purpose of the VBIAS pin on the CBTU4411EE,518?

The VBIAS pin sets the bias voltage for the internal 400 Ω pull-down resistors on all DIMM ports (xDPn). When the switch is disabled (EN = HIGH), VBIAS determines termination strength - typically set to 0.3×VDD per datasheet guidance. This allows precise control of termination impedance to match DDR2 DIMM electrical requirements, eliminating need for external bias networks in the CBTU4411EE,518.

Can the CBTU4411EE,518 operate outside the 1.7 V to 1.9 V supply range?

No - the CBTU4411EE,518 is characterized and specified only for VDD = 1.7 V to 1.9 V operation. Absolute maximum ratings allow up to 2.5 V, but functional operation, SSTL_18 input compatibility, ON-resistance, and timing parameters are guaranteed solely within the 1.7–1.9 V window. Operating outside this range may cause undefined behavior or failure to meet DDR2 timing specs in the CBTU4411EE,518.

How does the TERM pin affect S0 and S1 inputs on the CBTU4411EE,518?

When TERM = HIGH, the CBTU4411EE,518 activates internal 80 Ω Thevenin termination on S0 and S1 inputs, referenced to VREF, to match SSTL_18 bus impedance and reduce stub reflections. When TERM = LOW, termination is disconnected (high-impedance). During disable (EN = HIGH), S0/S1 are pulled LOW regardless of TERM state - a power-saving feature confirmed in the CBTU4411EE,518 datasheet.