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Texas Instruments CD74HC237E
- Part No.:
- CD74HC237E
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74HC237E.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,699
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Product details
Overview
CD74HC237E from Texas Instruments is a high-speed CMOS 3-to-8 line decoder/demultiplexer with address latches, configured for active-high output selection. It features three binary select inputs (A0–A2), dual output enables (OE0, OE1), latch enable (LE), and operates from 2V to 6V. With typical propagation delay of 13ns at VCC = 5V/15pF and wide temperature range (–55°C to +125°C), it serves in memory address decoding and data routing within industrial control logic systems.
For engineers reviewing the CD74HC237E datasheet, CD74HC237E pinout, CD74HC237E application, or CD74HC237E equivalent, this page delivers verified functional behavior, latch-controlled demultiplexing capability, HC-series noise immunity (NIL/NIH = 30% of VCC), fanout of 10 LSTTL loads, and PDIP-16 package compatibility for through-hole prototyping and legacy board upgrades.
Technical Context
The CD74HC237E implements a 3-bit address latch followed by an active-high 1-of-8 decoder. Input addresses are latched on rising LE, isolating outputs from subsequent A0–A2 changes until next latch event. Demultiplexing is achieved by using A0–A2 to select one of eight outputs while routing data through OE0 or OE1 - with the unselected enable held active.
Its HC logic family ensures CMOS-level power efficiency with TTL-compatible speed: propagation delay scales inversely with supply voltage (e.g., 32ns typ. at 4.5V/50pF), and output transition times remain balanced (<19ns typ. at 4.5V). The device supports cascading via two independent output enables and exhibits low input leakage (±1µA max) across full temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | High-speed CMOS (HC), not TTL-compatible; requires 2V–6V supply for full spec compliance |
| Output Polarity | Active-high selected output (Y0–Y7); contrasts with CD74HC137's active-low behavior |
| Propagation Delay | 13ns typical at VCC = 5V, CL = 15pF - enables timing-critical address decoding in ≤77MHz systems |
| Operating Temperature | –55°C to +125°C - qualified for aerospace, automotive under-hood, and industrial motor control environments |
| Fanout Capability | 10 LSTTL loads - sufficient to drive multiple downstream logic gates without buffering |
| Noise Immunity | NIL = NIH = 30% of VCC at VCC = 5V - rejects >1.5V noise spikes on inputs, critical in noisy PLC backplanes |
| Power Dissipation Cap. | CPD = 23pF at VCC = 5V - used to calculate dynamic power: PD = VCC² × f × (CPD + CL) |
Pinout & Package
CD74HC237E is supplied in a 16-pin plastic dual in-line package (PDIP), compliant with JEDEC MS-001, 0.300" wide body, 0.100" lead pitch. Package thermal impedance θJA = 67°C/W supports operation up to 125°C ambient with minimal heatsinking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A0) | Binary Address Input | LSB of 3-bit address; latched on LE rising edge; determines Y0–Y7 selection |
| 2 (A1) | Binary Address Input | Middle bit of address; combined with A0/A2 to uniquely select one output |
| 3 (A2) | Binary Address Input | MSB of address; completes 3-bit decode word for 1-of-8 output activation |
| 4 (LE) | Latch Enable | Active-high signal; captures A0–A2 state on rising edge; holds outputs stable thereafter |
| 5 (OE1) | Output Enable 1 | Active-low enable; when low and OE0 high, enables demux mode using OE1 as data input |
| 6 (OE0) | Output Enable 0 | Active-low enable; primary enable for decoder function; both OE0/OE1 must be low to disable all outputs |
| 7 (GND) | Ground Reference | Logic and power ground return; must be low-impedance connection to minimize switching noise |
| 8 (Y0) | Output 0 | Active-high decoded output; asserted only when A2A1A0 = 000 and both OEs enabled |
| 9 (Y1) | Output 1 | Active-high decoded output; asserted only when A2A1A0 = 001 and both OEs enabled |
| 10 (Y2) | Output 2 | Active-high decoded output; asserted only when A2A1A0 = 010 and both OEs enabled |
| 11 (Y3) | Output 3 | Active-high decoded output; asserted only when A2A1A0 = 011 and both OEs enabled |
| 12 (Y4) | Output 4 | Active-high decoded output; asserted only when A2A1A0 = 100 and both OEs enabled |
| 13 (Y5) | Output 5 | Active-high decoded output; asserted only when A2A1A0 = 101 and both OEs enabled |
| 14 (Y6) | Output 6 | Active-high decoded output; asserted only when A2A1A0 = 110 and both OEs enabled |
| 15 (Y7) | Output 7 | Active-high decoded output; asserted only when A2A1A0 = 111 and both OEs enabled |
| 16 (VCC) | Positive Supply | CMOS supply rail; must be decoupled locally with 0.1µF ceramic capacitor near pin |
Key Features
| Feature | Design Value |
|---|---|
| Address Latching | LE input captures A0–A2 state synchronously, enabling glitch-free output hold during address bus transitions |
| Dual Output Enables | OE0 and OE1 allow flexible cascading of multiple CD74HC237E devices or use as 1-of-16 demux with external gating |
| Demultiplexing Mode | One enable pin acts as data input while the other remains active, converting decoder into 1:8 data distributor |
| Wide Voltage Operation | 2V–6V supply range supports mixed-voltage system interfacing (e.g., 3.3V logic controlling 5V peripherals) |
| High Noise Immunity | 30% VCC noise margin ensures reliable operation in electrically noisy industrial cabinets with relay coils and motor drives |
| Low Quiescent Current | ICC ≤ 160µA max over –55°C to +125°C - enables battery-backed or energy-sensitive applications |
Applications
| Industrial PLC I/O Expansion | Legacy Microcontroller Address Decoding |
|---|---|
Use Scenario: Expanding discrete I/O points in programmable logic controllers using shared address/data buses. IC Role / Device Role / Timing Role: CD74HC237E decodes microprocessor address lines to enable specific I/O peripheral chips (e.g., ADCs, DACs, GPIO expanders). Use Value: Latch functionality prevents spurious I/O selection during address bus settling; active-high outputs interface directly with 5V TTL-compatible peripherals. |
Use Scenario: Selecting memory-mapped peripherals in 8-bit embedded systems (e.g., Z80, 8051 derivatives) with limited address lines. IC Role / Device Role / Timing Role: CD74HC237E acts as address space partitioner, assigning unique chip-select signals to UARTs, timers, and interrupt controllers. Use Value: 13ns propagation delay meets tight timing budgets of 4–6MHz CPU buses; PDIP-16 package allows hand-soldered field repairs. |
| Test Equipment Signal Routing | Automotive ECU Subsystem Enable |
Use Scenario: Routing stimulus signals to individual DUT channels in automated test fixtures with multiplexed analog/digital paths. IC Role / Device Role / Timing Role: CD74HC237E functions as a synchronous demultiplexer, using LE to freeze channel selection during measurement cycles. Use Value: Dual OE inputs permit gated channel activation synchronized to test sequencer clocks; wide temp range supports environmental chamber operation. |
Use Scenario: Enabling safety-critical subsystems (e.g., airbag sensors, ABS modules) based on vehicle mode commands in engine control units. IC Role / Device Role / Timing Role: CD74HC237E provides fail-safe enable signals derived from redundant MCU outputs and watchdog status bits. Use Value: –55°C to +125°C rating matches under-hood ECU requirements; low ICC minimizes standby current draw in sleep modes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar decoder/demultiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CD74HC137E | Identical pinout and package, but active-low outputs (Y0–Y7 sink current when selected) | Requires external pull-ups or level-shifting for systems expecting active-high enables | Select CD74HC137E only if downstream logic interprets low-state enables or if redesign accommodates inverted outputs |
| CD74HCT237E | Same functionality and pinout, but HCT logic family (4.5V–5.5V only, LSTTL-input compatible) | Direct replacement for 5V-only systems with legacy TTL inputs; not suitable for 3.3V or mixed-supply designs | Choose CD74HCT237E when interfacing with 5V TTL sources and strict 5V supply constraints apply |
Compared with CD74HC237E, CD74HC137E offers inverted output polarity requiring circuit adaptation, while CD74HCT237E sacrifices voltage flexibility for guaranteed TTL input compatibility - making CD74HC237E the optimal choice for wide-supply, active-high decode applications.
Availability
CD74HC237E is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy microcontroller address decoding, and automotive ECU subsystem enable applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for CD74HC237E 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 high-reliability logic families.
CD74HC237E belongs to TI's CD74HC high-speed CMOS logic portfolio, designed for robust, low-power digital interfacing in industrial, automotive, and aerospace systems where latch-stable decoding and wide operating margins are essential.
FAQ
What is the key functional difference between CD74HC237E and CD74HC137E?
The CD74HC237E provides active-high outputs (Y0–Y7 go high when selected), whereas CD74HC137E provides active-low outputs (Y0–Y7 go low when selected). Both share identical pinout, latch enable (LE), and dual output enable (OE0/OE1) architecture. This polarity difference dictates interface requirements: CD74HC237E drives high-side enables directly, while CD74HC137E suits sinking configurations or open-collector bus designs. The CD74HC237E datasheet confirms its truth table explicitly defines high-level assertion for selected outputs.
Can CD74HC237E operate reliably at 3.3V supply voltage?
Yes, CD74HC237E is fully specified for 2V to 6V operation per its HC logic family designation. At 3.3V, parameters including propagation delay (~22ns typ. at CL = 15pF), noise immunity (NIL/NIH = 30% of 3.3V ≈ 1.0V), and output drive (VOH ≥ 3.15V, VOL ≤ 0.1V) remain valid across –55°C to +125°C. This makes CD74HC237E suitable for mixed-voltage systems interfacing 3.3V microcontrollers with 5V peripherals, unlike the HCT variant which is restricted to 4.5V–5.5V.
How does the latch enable (LE) pin affect timing behavior in CD74HC237E?
The LE pin controls transparent vs. latched operation: when LE is low, outputs track A0–A2 in real time (transparent mode); on the rising edge of LE, the current A0–A2 state is captured and held, freezing outputs regardless of subsequent address changes. Setup (tSU = 13ns min at 4.5V) and hold (tH = 8ns min at 4.5V) times relative to LE ensure reliable capture. This eliminates glitches during address bus transitions - a critical feature for stable peripheral selection in microprocessor systems using CD74HC237E.
What is the maximum clock frequency supported by CD74HC237E in demultiplexer mode?
CD74HC237E does not specify a maximum clock frequency, but its propagation delay (tPLH/tPHL = 32ns typ. at VCC = 4.5V, CL = 50pF) and output transition time (tTLH/tTHL = 19ns typ.) define practical limits. For clean 50% duty-cycle signals, maximum reliable toggle rate is ~15MHz (1/(2 × 32ns)). In demux mode using OE0 as data input, timing is governed by OE0-to-Y delay (33ns typ.), supporting data rates up to ~15Mbps. System-level timing must also account for input rise/fall times (≤500ns max at 4.5V).
Is CD74HC237E RoHS compliant and lead-free?
Yes, CD74HC237E is RoHS compliant and lead-free. Per TI's packaging addendum, the PDIP (N) package uses NiPdAu (NIPDAU) lead finish and carries "Yes" in the RoHS column. It meets EU Directive 2011/65/EU and is suitable for environmentally regulated industrial and automotive applications. The part marking "CD74HC237E" appears on the package body, and no lead (Pb) is present in solderable terminations or die attach materials.
CD74HC237E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Decoder/Demultiplexer
- Circuit:
- 1 x 3:8
- Independent Circuits:
- 1
- Current - Output High, Low:
- 5.2mA, 5.2mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-PDIP
CD74HC237E FAQ
1.How can I place an order for CD74HC237E through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HC237E on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for CD74HC237E reliable?
The price and inventory of CD74HC237E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HC237E is usually 5 days.
3.What payment methods are accepted for CD74HC237E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HC237E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HC237E?
CD74HC237E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HC237E order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for CD74HC237E?
For technical support, including CD74HC237E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HC237E requirements.
6.How does Aetrix verify that CD74HC237E is sourced from the original manufacturer or authorized distributors?
All CD74HC237E products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that CD74HC237E meets industry standards.
7.What is the process for return or replacement of CD74HC237E?
All CD74HC237E units undergo pre-shipment inspection (PSI). If there is an issue with CD74HC237E, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The CD74HC237E part is unused and in its original packaging.
Return procedure for CD74HC237E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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