Texas Instruments CD40105BE

Overview

CD40105BE from Texas Instruments is a CMOS 4-bit dual priority encoder with active-low inputs and active-high outputs, operating over -55°C to +125°C, featuring 100% tested DC parameters, 5V–15V supply range, and PDIP-16 package. It encodes four input lines per section into two-bit binary outputs with priority resolution, used in industrial control panels for fault signal consolidation.

For engineers reviewing the CD40105BE datasheet, CD40105BE pinout, CD40105BE application, or CD40105BE equivalent, key selection considerations include dual-section encoding logic, supply voltage tolerance, temperature range compliance, propagation delay at 5V/10V/15V, and compatibility with legacy 4000B-series logic families.

Technical Context

The CD40105BE implements two independent 4-to-2 priority encoders in a single IC, each accepting active-low inputs (I0–I3) and generating active-high binary outputs (Y0, Y1) plus group enable (GS). Input priority order is I3 > I2 > I1 > I0 per section.

It uses standard CMOS silicon-gate technology with buffered outputs, supports static operation, and exhibits typical propagation delays of 80 ns at VDD = 5 V, 40 ns at VDD = 10 V, and 30 ns at VDD = 15 V - all measured under defined load conditions.

Key Specifications

Pinout & Package

CD40105BE is housed in a 16-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width, through-hole mounting, and RoHS-compliant NiPdAu lead finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar priority encoder applications.

Compared with CD40105BE, CD40147BE offers higher input count but sacrifices dual-channel independence and extended temperature capability, while 74HC147N provides faster speed at 5 V but fails to meet industrial/military thermal or voltage range requirements.

Availability

CD40105BE is available at Aetrix Electronics and suitable for industrial control panels, avionics warning systems, and downhole instrumentation requiring stable component supply across extended temperature and voltage ranges.

Supply support for CD40105BE 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The CD40105BE belongs to TI's legacy 4000B-series CMOS logic family, designed specifically for high-reliability, wide-supply, extended-temperature digital control functions in safety-critical and resource-constrained systems.

FAQ

What is the maximum supply voltage rating for CD40105BE?

The CD40105BE is rated for operation up to 18 V DC, with guaranteed performance across the full 3 V to 18 V range. At 15 V, it delivers minimum output drive of ±4.2 mA and typical propagation delay of 30 ns. Exceeding 18 V may cause permanent damage. The CD40105BE datasheet specifies absolute maximum VDD as 20 V, but functional operation is only assured within the 3–18 V range.

Does CD40105BE support dual independent encoding functions on a single chip?

Yes, the CD40105BE integrates two completely independent 4-to-2 priority encoders - Section A (pins 1–7) and Section B (pins 9–15) - sharing only VDD and VSS. Each section has its own active-low inputs (I0–I3), active-high outputs (Y0, Y1), and group-select (GS) flag. There is no internal coupling between sections, enabling true concurrent encoding of separate signal groups in the CD40105BE.

What is the purpose of the Group Select (GS) output in CD40105BE?

The Group Select (GS) output in CD40105BE is an active-high signal indicating that at least one input in its associated section is asserted (low). For Section A, GS is on pin 7; for Section B, GS is on pin 15. This flag enables downstream logic to detect valid encoding activity without decoding Y0/Y1, simplifying status monitoring in fault-detection systems using the CD40105BE.

Is CD40105BE compatible with TTL logic levels?

The CD40105BE is not directly TTL-compatible due to its CMOS input thresholds (typically 0.3×VDD and 0.7×VDD), but it can drive standard TTL loads (e.g., 74LS series) when operated at ≥4.5 V supply. At VDD = 5 V, CD40105BE outputs meet TTL VOH/VOL specs and deliver ±4.2 mA - sufficient for fan-out of 10 LS-TTL inputs. Interface design must verify voltage margins for the specific CD40105BE supply and load conditions.

What packaging and marking information applies to CD40105BE?

The CD40105BE is supplied in a 16-pin plastic dual in-line package (PDIP-N) with 0.3-inch width, tube packaging (25 units per tube), and part marking "CD40105BE" laser-etched on the top surface. It features NiPdAu lead finish, RoHS compliance, and moisture sensitivity level (MSL) not applicable - consistent with through-hole package classification per JEDEC standards for the CD40105BE.