Renesas CD40105BHSR

Overview

CD40105BHSR from Intersil is a 4-bit × 16-word CMOS FIFO register designed for asynchronous data buffering between mismatched clock domains. It features independent shift-in/shift-out control, 3-state outputs, DATA-IN READY (DIR) and DATA-OUT READY (DOR) status flags, and operates across 5V–15V supply rails with full −55°C to +125°C temperature range support - enabling use in radar data acquisition and CPU/terminal interfaces.

For engineers reviewing the CD40105BHSR datasheet, CD40105BHSR pinout, CD40105BHSR application, or CD40105BHSR equivalent, key selection considerations include its elastic storage architecture, ripple-through propagation timing (≤1.4 µs at VDD = 15V), master reset capability, and radiation-tolerant design validated per MIL-STD-883 Group E irradiation testing.

Technical Context

The CD40105BHSR implements a marker-bit–based control logic architecture where 16 cascaded flip-flops track data occupancy; each "1" bit indicates valid data, and "0" denotes vacancy. Data transfer occurs via edge-triggered ripple propagation: a falling SO edge unloads output data while advancing the next word, and a rising SI edge loads input data when DIR is high.

Its 3-state output buffers are controlled independently of shift operations, allowing bus sharing without interference. The FIFO supports expansion in length (cascading via DIR→SO and DOR→SI) and width (parallel 4-bit banks with AND-gated DIR/DOR), with master reset (MR) forcing all markers to "0" while preserving stored data values until first load.

Key Specifications

Pinout & Package

CD40105BHSR is supplied in a 16-lead ceramic flatpack (H6W) package with hermetic sealing suitable for high-reliability environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar FIFO register applications.

Compared with CD40105BHSR, CD40105BM96 trades hermetic reliability for volume packaging efficiency, while 74HC40105 sacrifices voltage margin and radiation hardness for higher speed and lower supply voltage - making CD40105BHSR uniquely suited for mission-critical analog/digital interface buffering under extreme conditions.

Availability

CD40105BHSR is available at Aetrix Electronics and suitable for radar data acquisition, CPU/terminal buffering, and peripheral interfacing requiring stable component supply across extended temperature and radiation-exposed environments.

Supply support for CD40105BHSR 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

Intersil Corporation is a U.S.-based semiconductor manufacturer specializing in high-reliability analog and mixed-signal ICs for aerospace, defense, and industrial markets.

The CD40105BHSR belongs to Intersil's radiation-hardened CMOS logic family, engineered specifically for timing-critical data buffering in harsh electromagnetic and thermal environments.

FAQ

What is the function of the MASTER RESET (MR) pin on the CD40105BHSR?

The MASTER RESET (MR) pin on the CD40105BHSR is an asynchronous active-high input that forces all internal marker bits to "0", declaring the entire FIFO empty without altering the contents of the data latches. After MR deassertion, the first valid shift-in pulse restores functionality, and CD40105BHSR resumes normal elastic buffering behavior with DIR going high once space becomes available.

Does the CD40105BHSR support cascading to increase FIFO depth?

Yes, the CD40105BHSR supports depth expansion via cascading: connect DIR of one unit to SO of the next, and DOR of the next to SI of the first. A master reset pulse must be applied after power-up in cascaded configurations. This allows building longer FIFOs while retaining independent status signaling - a capability confirmed in the CD40105BHSR functional diagram and timing specifications.

What is the minimum pulse width required for SHIFT-IN (SI) on the CD40105BHSR?

The minimum SHIFT-IN (SI) pulse width for CD40105BHSR is 60 ns at VDD = 15V, 75 ns at VDD = 10V, and 200 ns at VDD = 5V, as specified in Table 6 of the datasheet. These values ensure reliable capture of the rising edge under worst-case temperature and voltage conditions, and CD40105BHSR will ignore subsequent SI pulses if DIR remains low due to full buffer state.

How does the 3-state control interact with data unloading on the CD40105BHSR?

On the CD40105BHSR, the 3-state control (Pin 9) must be held LOW before applying a falling edge to SHIFT-OUT (SO) to enable Q0–Q3 outputs. If 3-state transitions from HIGH to LOW while SO is at logic 0, the first word shifts out immediately and is lost. Therefore, proper sequencing - enable outputs first, then assert SO - is mandatory for reliable CD40105BHSR operation.

Is the CD40105BHSR qualified for radiation exposure environments?

Yes, the CD40105BHSR is radiation-hardened and qualified per MIL-STD-883 Group E Subgroup 2 for total ionizing dose (TID) exposure. Post-irradiation testing confirms functional integrity and parameter stability up to specified limits, including threshold voltage shifts ≤±1 V and supply current change ≤25 µA at +25°C - critical for CD40105BHSR deployment in satellite, avionics, and nuclear instrumentation systems.