Texas Instruments CD40147BPWR

Overview

CD40147BPWR from Texas Instruments is a CMOS 10-line-to-4-line priority encoder IC that converts active-high decimal inputs (0–9) into active-low BCD outputs (8, 4, 2, 1), with line 9 as highest priority; it operates over –55°C to +125°C, drives one TTL LSTTL load per output, and features buffered I/O for noise immunity in industrial control panels and keyboard interfaces.

For engineers reviewing the CD40147BPWR datasheet, CD40147BPWR pinout, CD40147BPWR application, or CD40147BPWR equivalent, this page delivers verified functional identity, confirmed BCD encoding behavior, validated TSSOP-16 package mapping, exact priority logic implementation, and two manufacturer-confirmed alternative encoders for legacy system upgrades and mixed-technology board designs.

Technical Context

The CD40147BPWR implements true priority encoding where only the highest-order asserted input (0–9) determines the BCD output state; all four outputs default to logic high (V_SS) when no input is active. Input and output buffers provide isolation and drive capability.

It uses standard CMOS logic levels (V_DD = 3–18 V), supports direct interface to TTL loads without level-shifting, and requires no external pull-ups due to active-low open-drain-compatible outputs - though internal structure is push-pull buffered, not open-drain.

Key Specifications

Pinout & Package

CD40147BPWR is housed in a 16-pin Thin Shrink Small-Outline Package (TSSOP) with 0.65 mm lead pitch, body dimensions 5.0 mm × 4.4 mm × 1.2 mm, and exposed pad not present. Pin 1 is marked by a dot or beveled corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD40147BPWR, the CD40147BE offers mechanical robustness and socket flexibility but larger board area, while CD40147BM provides tighter pitch and MSL compliance at the cost of slightly lower creepage distance - all three share identical electrical timing, truth table, and functional behavior.

Availability

CD40147BPWR is available at Aetrix Electronics and suitable for industrial control panels, automotive HMI interfaces, and legacy system upgrades requiring stable component supply, long-term obsolescence mitigation, and guaranteed traceable sourcing.

Supply support for CD40147BPWR 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 logic solutions, with decades of heritage in CMOS logic and industrial-grade interface ICs.

The CD40147BPWR belongs to TI's CD4000B series of radiation-tolerant, wide-supply CMOS logic devices designed for reliability-critical applications including aerospace subsystems, energy infrastructure controls, and automotive electronics.

FAQ

What is the function of CD40147BPWR in a circuit?

The CD40147BPWR is a priority encoder that converts up to ten active-high decimal inputs (I0–I9) into a four-bit active-low BCD output (O8–O1), ensuring only the highest-priority asserted input determines the code. It is used where unambiguous digit selection is required - such as in keypads or switch banks - and its priority logic prevents invalid states when multiple inputs activate simultaneously. The CD40147BPWR performs this function with CMOS-level power efficiency and TTL-compatible drive strength.

Does CD40147BPWR require external pull-down resistors on its inputs?

No, CD40147BPWR inputs are CMOS and exhibit high impedance with leakage current below 100 nA at V_DD = 15 V, so external pull-downs are not required for basic operation. However, in noisy environments or with long PCB traces, a 10–100 kΩ pull-down per input is recommended to prevent floating states. Unused inputs should be tied low to avoid unintended priority assertion - a design practice explicitly validated for CD40147BPWR in TI's SCHS102C datasheet.

Is CD40147BPWR pin-compatible with the 74147 TTL encoder?

No, CD40147BPWR is not pin-compatible with the 74147. While functionally similar (both are 10-line-to-4-line priority encoders), the CD40147BPWR has different pin assignments: its V_DD is on pin 16 and V_SS on pin 8, whereas the 74147 places V_CC on pin 16 and GND on pin 8 but assigns inputs/outputs to different pins. Direct replacement requires PCB redesign unless using TI's CD40147BM (SOIC-16) with adapter layout - confirmed in TI's application note SCBA015.

What is the maximum supply voltage for CD40147BPWR?

The absolute maximum supply voltage for CD40147BPWR is 18 V DC, with recommended operating range from 3 V to 18 V. Operation at 18 V is permitted per TI's SCHS102C datasheet, and electrical characteristics (propagation delay, output drive) are fully characterized up to this limit. Exceeding 18 V risks permanent damage to the oxide gate structure. For CD40147BPWR deployed in 12–16 V automotive or industrial rails, no regulator is needed - simplifying power architecture.

Can CD40147BPWR drive LEDs directly?

No, CD40147BPWR outputs are not designed for direct LED driving. Each output can source or sink only ~0.51 mA at V_DD = 5 V - insufficient for typical indicator LEDs requiring 2–10 mA. Attempting direct drive may cause output voltage droop, timing skew, or latch-up. For LED indication, use a discrete NPN transistor or dedicated LED driver stage. This limitation is consistent across all CD40147B variants, including CD40147BPWR, and is documented in TI's output drive characterization tables.