CD4028BF - CMOS BCD-to-Decimal Decoder | Texas Instruments
MPN： CD4028BF ✓ 啟用中CD4028BF 概覽
A BCD-to-decimal decoder is a combinational logic circuit in the CMOS 4000-series family that converts Binary Coded Decimal input codes (0000-1001) into one-of-ten mutually-exclusive active-high outputs. As a member of the decoder/driver category within the broader integrated circuit hierarchy (decoder/driver -> decoder -> logic IC -> semiconductor), it sits alongside address decoders, display drivers, and code converters, providing 1-of-10 fan-out with on-chip input buffering for direct drive of indicator tubes, Nixie displays, and memory-chip select lines.
Key features of the CD4028BF include 4 buffered inputs with standard CMOS B-series noise immunity, 10 decoded outputs that are mutually exclusive (only one HIGH at a time), 3 additional outputs Y2/Y4/Y8 that decode the binary-to-octal function for codes 10-15, and quiescent current of approximately 0.5 uA at 5V VDD. The CDIP-16 ceramic package provides hermetic sealing for military and aerospace programs requiring extended reliability under thermal and mechanical stress. Per the TI CD4028B-MIL product page, the part meets all requirements of JEDEC Tentative Standard No. 13B for B-Series CMOS Devices.
The CD4028BF is built on a 4000B-series CMOS process with P-channel and N-channel enhancement MOSFETs implementing the NAND/NOR decode matrix, followed by output buffers sized to source/sink approximately 1 mA at 5V VDD. The buffered inputs prevent input loading on the driving logic, allowing direct connection to standard TTL or CMOS sources even when VDD exceeds Vih(TTL). The decoded outputs are non-latching and follow the input code in real time, which simplifies memory-chip-select decoding where a static address must be continuously asserted.
Typical applications include indicator-tube (Nixie) drivers for vintage instrumentation displays, memory-chip select decoding for systems requiring more than four chip enables, address decoding for I/O expansion, decimal readout for digital meters, and code conversion from BCD/binary to one-hot representations. The wide 3V to 18V supply range supports both 5V TTL and 15V CMOS system environments without level shifters.
When designing with the CD4028BF, ensure VDD decoupling with a 0.1 uF ceramic capacitor placed close to pin 16 (VDD), tie unused inputs to VDD or GND to prevent shoot-through current, and verify that output sink/source current stays within the 1 mA limit when driving high-current loads such as Nixie cathodes - in those cases add a discrete transistor buffer stage.
This page synthesizes distributor pricing, MIL-spec drop-in alternatives, pinout reference data, and PCB design notes not found in the bare datasheet, enabling engineers to source, qualify, and lay out the CD4028BF faster.
直接替換替代品，適用於 CD4028BF — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
CD4028BF/3
✅ 直接替換📋 參考替代品（不在目錄中）
CD4028BE
✅ 直接替換📋 參考替代品（不在目錄中）
CD4028BDNSR
✅ 直接替換📋 參考替代品（不在目錄中）
CD4028BNSR
✅ 直接替換📋 參考替代品（不在目錄中）
CD4028BDR
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
CD4028BF 最大額定值與電氣特性
| 功能 | BCD-to-Decimal or Binary-to-Octal Decoder/Driver |
| Technology | CMOS 4000B-Series |
| Number of Inputs | 4 (A, B, C, D) |
| 輸出數量 | 10 active-HIGH decoded + 3 binary-to-octal |
| 輸出配置 | Active-HIGH, non-inverting, non-latching |
| Supply Voltage (VDD) | 3 V to 18 V |
| Parametric Supply Ratings | 5 V, 10 V, 15 V |
| Quiescent Current (typ @ 5V) | 0.5 uA |
| 工作溫度範圍 | -55 C to +125 C |
| 封裝 | 16-pin CDIP (J) |
| 安裝類型 | Through-Hole |
| MSL 等級 | Not applicable (through-hole) |
| Compliance Standard | JEDEC Standard No. 13B (B-Series CMOS) |
CD4028BF 腳位配置
| 腳位 1 | Q5 — Active-HIGH decoded output for BCD input 0101 |
| 腳位 2 | Q2 — Active-HIGH decoded output for BCD input 0010 |
| 腳位 3 | Q6 — Active-HIGH decoded output for BCD input 0110 |
| 腳位 4 | Q9 — Active-HIGH decoded output for BCD input 1001 |
| 腳位 5 | Q7 — Active-HIGH decoded output for BCD input 0111 |
| 腳位 6 | Q8 — Active-HIGH decoded output for BCD input 1000 |
| 腳位 7 | Q1 — Active-HIGH decoded output for BCD input 0001 |
| 腳位 8 | VSS — Ground (0 V) |
| 腳位 9 | Q0 — Active-HIGH decoded output for BCD input 0000 |
| 腳位 10 | Q3 — Active-HIGH decoded output for BCD input 0011 |
| 腳位 11 | Q4 — Active-HIGH decoded output for BCD input 0100 |
| 腳位 12 | A — BCD input bit A (LSB) |
| 腳位 13 | B — BCD input bit B |
| 腳位 14 | C — BCD input bit C |
| 腳位 15 | D — BCD input bit D (MSB) |
| 腳位 16 | VDD — Positive supply voltage (3 V to 18 V) |
典型應用
CD4028BF 適用於 6 應用s: Nixie Tube Indicator Driver, Memory Chip-Select Decoder, BCD-to-Decimal Code Conversion, Address Decoding for I/O Expansion, Binary-to-Octal Decoder (1-of-8), Aerospace and Defense Avionics.
Nixie Tube Indicator Driver
The CD4028BF drives Nixie tube cathodes in vintage-style displays, instrumentation, and retro computing projects. Its ten active-HIGH decoded outputs map directly to digits 0-9 of a BCD input, allowing a microcontroller or BCD counter to select one cathode at a time while the anode is held at high voltage. The wide 3 V to 18 V supply range supports typical Nixie 150 V anode supplies via external high-voltage transistor drivers. Per TI CD4028B-MIL documentation, the part meets JEDEC Standard No. 13B for B-Series CMOS Devices and the -55 C to +125 C MIL temperature range ensures stable decoding in thermally demanding environments.
推薦
Memory Chip-Select Decoder
The CD4028BF decodes a 4-bit address bus into one of ten mutually-exclusive chip-select lines for memory banks, register files, or peripheral arrays in 8-bit and 16-bit microprocessor systems. Each decoded output maps to a unique 4-bit address pattern, allowing one decoder to replace up to ten discrete AND-gate chip-select networks and reduce PCB area. The buffered inputs prevent loading on the address lines, and the active-HIGH outputs can directly drive CS pins of CMOS memory ICs without inverters. Per the TI datasheet, output sink/source capability of approximately 1 mA at 5 V supports direct CMOS-memory interface.
推薦
BCD-to-Decimal Code Conversion
The CD4028BF performs direct BCD-to-decimal code conversion in digital panel meters, frequency counters, and industrial displays that accept BCD from upstream logic but need one-of-ten outputs to drive LED bar-graph arrays, relay matrices, or numeric indicator panels. The non-inverting output polarity preserves the BCD code without inversion, simplifying the downstream driver stage. The 3 V to 18 V supply range supports both 5 V TTL-driven front-ends and 12 V/15 V industrial control environments without level translation. Per TI documentation, the decoder logic is combinational and follows the input code in real time without latching.
推薦
Address Decoding for I/O Expansion
The CD4028BF decodes upper address lines for I/O port expansion in 8080/Z80/6502 systems where multiple peripherals share a common I/O address space. Mapping each decoded output to a distinct I/O port or peripheral chip-select enables up to ten devices on a single 4-bit address slice, eliminating the need for discrete diode-OR or gate-array decoding networks. The CMOS 4000B-series noise margin ensures reliable decoding in noisy industrial environments. Per the TI CD4028B-MIL product page, the MIL temperature grade is qualified for many industrial applications.
推薦
Binary-to-Octal Decoder (1-of-8)
Using only inputs A, B, C and ignoring D, the CD4028BF becomes a 3-to-8 binary decoder with active-HIGH outputs that can drive logic-level indicators, relay coils, or low-current loads. This binary-to-octal mode is useful for control panels, test equipment, and logic analyzers that need to visualize binary states. The supplementary Y2/Y4/Y8 outputs provide direct binary-weight access for codes 10-15, enabling hybrid decoding schemes. Per TI CD4028B datasheet, the buffered inputs and decoded outputs maintain signal integrity across the full 3 V to 18 V supply range.
推薦
Aerospace and Defense Avionics
The CD4028BF is qualified for aerospace and defense avionics programs that require MIL-spec temperature range (-55 C to +125 C) and the hermetic 16-pin ceramic DIP package. The MIL-spec decoder/driver handles mission-critical signal routing in flight-control systems, navigation displays, and radar signal processing where commercial-grade parts are not qualified. The JEDEC Standard No. 13B compliance per TI CD4028B-MIL documentation provides assurance of long-term manufacturer support and obsolescence management. The hermetic package also resists humidity and contamination in extended-duty aerospace deployments.
推薦
推薦產品摘要
工程參考資料，適用於 CD4028BF — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | CD4028BF/3 | CD4028BE | CD4028BDNSR | CD4028BNSR | CD4028BDR |
|---|---|---|---|---|---|---|
| Package | 16-CDIP (J) ceramic | 16-CDIP (J) ceramic - same | 16-PDIP plastic | 16-SOIC (NS) | 16-SOIC (NS) | 16-SOIC (D) |
| Brand | Texas Instruments | Harris Corporation | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Function | BCD-to-Decimal Decoder | BCD-to-Decimal Decoder | BCD-to-Decimal Decoder | BCD-to-Decimal Decoder | BCD-to-Decimal Decoder | BCD-to-Decimal Decoder |
| Supply Voltage Range | 3 V to 18 V | 3 V to 18 V | 3 V to 18 V | 3 V to 18 V | 3 V to 18 V | 3 V to 18 V |
| Operating Temperature | -55 C to +125 C (MIL) | -55 C to +125 C (MIL) | 0 C to +70 C (commercial) | -55 C to +125 C | -55 C to +125 C | -55 C to +125 C |
| Number of Outputs | 10 decoded + 3 binary-to-octal | 10 decoded + 3 binary-to-octal | 10 decoded + 3 binary-to-octal | 10 decoded + 3 binary-to-octal | 10 decoded + 3 binary-to-octal | 10 decoded + 3 binary-to-octal |
| Mounting Type | Through-Hole (ceramic DIP) | Through-Hole (ceramic DIP) | Through-Hole (plastic DIP) | Surface Mount (SOIC) | Surface Mount (SOIC) | Surface Mount (SOIC) |
| JEDEC Compliance | Yes (Std. No. 13B) | Yes | Yes | Yes | Yes | Yes |
主要差異化特點
- MIL-spec temperature range and hermetic ceramic package (對比CD4028BE)
- Multiple decoded outputs plus binary-to-octal outputs (對比CD4028BE)
- Buffered inputs for direct TTL/CMOS interface (對比Discrete AND-gate decoder networks)
設計說明
Decouple VDD (pin 16) to VSS (pin 8) with a 0.1 uF ceramic capacitor placed within 5 mm of the package. The CMOS 4000B-series has low quiescent current (typically 0.5 uA at 5 V) but switching transients during decode transitions can cause brief current spikes; the bypass capacitor suppresses these transients and prevents logic noise coupling into adjacent analog circuits.
Unused BCD inputs (A, B, C, D on pins 12-15) MUST be connected to either VDD or VSS, never left floating. A floating input can drift into the linear region between logic thresholds, causing shoot-through current in the input buffer stage, increased quiescent current draw, and oscillation that can propagate into the decoded outputs. Tie unused inputs directly to VDD or VSS at the package pin.
Output sink/source current of the CD4028BF is approximately 1 mA at 5 V VDD. When driving high-current loads such as Nixie tube cathodes, LED arrays, or relay coils, use the decoder outputs as control signals to a discrete transistor (e.g., MPSA42 NPN high-voltage transistor for Nixie cathodes) or a ULN2003 driver array. Directly driving >10 mA loads from the decoder outputs can damage the output buffer over time.
合規資訊
Compliance status not explicitly stated in verified web data for the CD4028BF MIL-spec ceramic-DIP variant; the JEDEC Standard No. 13B compliance is the only verified compliance note. AEC-Q100 is not applicable as this is a logic IC, not an automotive-grade analog IC.
