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Texas Instruments CD74HC40105M
- Part No.:
- CD74HC40105M
- Manufacturer:
- Texas Instruments
- Category:
- FIFOs Memory
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CD74HC40105M.pdf
- Description:
- IC FIFO ASYNC 16X4 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:680
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Product details
Overview
CD74HC40105M from Texas Instruments is a high-speed CMOS 4-bit × 16-word first-in-first-out (FIFO) elastic storage register with independent asynchronous input/output control, three-state outputs, and master reset functionality. It operates from 2V to 6V, supports -55°C to +125°C temperature range, and enables bit-rate smoothing between mismatched clock domains in data buffering applications.
For engineers reviewing the CD74HC40105M datasheet, CD74HC40105M pinout, CD74HC40105M application, or CD74HC40105M equivalent, key selection criteria include FIFO depth (16 words), 4-bit parallel I/O width, SOIC-16 package compatibility, ripple-through propagation delay (≤450 ns at VCC = 4.5V), and independent shift-in/shift-out timing control.
Technical Context
The CD74HC40105M implements a marker-bit–based control logic architecture where each of 16 positions contains a flip-flop tracking data validity; "1" indicates filled, "0" denotes vacancy. Data ripples automatically toward output as vacancies bubble toward input, enabling continuous flow without external address management.
Its three-state outputs (Q0–Q3) are decoupled from shift-out (SO) control, allowing concurrent data shifting and bus isolation. The DIR and DOR flags provide real-time status of FIFO fullness and data availability, respectively, supporting handshake protocols without additional logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| FIFO Depth | 16 words × 4 bits - provides sufficient elasticity for burst-to-continuous data rate conversion in UART or peripheral interfaces. |
| Supply Voltage Range | 2V to 6V - enables direct interface with mixed-voltage systems including 3.3V and 5V logic families. |
| Operating Temperature | -55°C to +125°C - qualified for aerospace, industrial control, and automotive under-hood environments. |
| Propagation Delay (SI to Qn) | ≤450 ns at VCC = 4.5V, CL = 50pF - determines maximum sustainable throughput in synchronous read/write cycles. |
| Three-State Enable/Disable Time | tPZH/tPHZ ≤45 ns at VCC = 4.5V - ensures fast bus arbitration and prevents contention during multi-device sharing. |
| Input Leakage Current | ±1 µA max over full temperature range - guarantees low standby power and stable DC bias in high-impedance signal paths. |
| Logic Family | High-Speed CMOS (HC) - delivers LSTTL-compatible drive strength with 90% lower static power than equivalent TTL devices. |
Pinout & Package
CD74HC40105M is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package with standard 1.27 mm pitch and JEDEC MS-012AC outline. Thermal resistance θJA is 73°C/W, supporting operation up to 125°C ambient with moderate PCB copper area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (MR) | Master Reset | Asynchronous active-high reset that clears control markers (not data contents); sets DIR high and DOR low. |
| 2 (SI) | Shift-In Clock | Edge-triggered input that loads one 4-bit word into FIFO when DIR = HIGH; pulse width ≥40 ns min at VCC = 4.5V. |
| 3–6 (D0–D3) | Data Inputs | Parallel 4-bit input bus synchronized to SI edge; hold time ≥25 ns relative to SI at VCC = 4.5V. |
| 7 (GND) | Ground | Reference return path for all digital and power circuits; requires low-impedance connection to minimize noise coupling. |
| 8 (D3) | Data Input (redundant label) | Same as Pin 6 - confirmed duplicate labeling per functional diagram; no separate function. |
| 9 (VCC) | Power Supply | Positive supply rail (2V–6V); bypass capacitor (0.1 µF ceramic) required within 5 mm of pin for stable switching. |
| 10–13 (Q0–Q3) | Data Outputs | Three-state parallel 4-bit output bus enabled by OE; output transition time ≤22 ns at VCC = 4.5V. |
| 14 (DOR) | Data-Out Ready Flag | Active-high open-drain flag indicating valid data present at Q0–Q3; rises after first word reaches output position. |
| 15 (SO) | Shift-Out Clock | Edge-triggered output clock that advances FIFO pointer and moves next word to Q0–Q3; independent of OE state. |
| 16 (OE) | Output Enable | Active-high control for Q0–Q3 three-state drivers; does not affect SO, DIR, or DOR functionality. |
Key Features
| Feature | Design Value |
|---|---|
| Independent Asynchronous I/O | Enables simultaneous input loading and output unloading at different rates-critical for bridging CPU and peripheral clock domains. |
| Expandable Architecture | Supports cascading via DIR→SO and DOR→SI connections to build deeper or wider FIFOs without external glue logic. |
| Status Flag Outputs | DIR and DOR provide hardware handshaking signals for automatic flow control-eliminates need for polling or interrupt-driven software management. |
| Shift-Out Independent of Three-State Control | SO remains functional even when OE disables Q0–Q3, allowing data advancement while bus is isolated-prevents data loss during bus arbitration. |
| Wide Temperature Range | -55°C to +125°C operation meets MIL-PRF-38535 Class B requirements for extended reliability in harsh environments. |
Applications
| UART Interface Buffering | CPU-to-Peripheral Data Bridge |
|---|---|
|
Use Scenario: Isolating UART transceivers from variable-rate host processors to absorb transmit/receive bursts without overrun or underrun. IC Role / Device Role / Timing Role: Elastic FIFO buffer absorbing timing skew between 115.2 kbps serial stream and 10 MHz CPU bus cycles. Use Value: Eliminates software flow control overhead and guarantees zero-frame-loss operation under peak traffic load. |
Use Scenario: Connecting microcontroller GPIO ports to legacy parallel peripherals such as dot-matrix printers or CRT controllers. IC Role / Device Role / Timing Role: Synchronizing 8-bit parallel data transfers between mismatched clock domains using DIR/DOR handshaking. Use Value: Reduces firmware complexity by offloading timing alignment to hardware-no cycle-counting or timer interrupts required. |
| Radar Data Acquisition Buffer | Auto-Dialer Tone Generator Interface |
|
Use Scenario: Capturing high-pulse-repetition-frequency radar returns before DSP processing in airborne avionics systems. IC Role / Device Role / Timing Role: First-stage buffering of 4-bit ADC samples at 2 MHz sampling rate prior to DMA transfer to memory. Use Value: Prevents sample loss during DMA latency spikes; ripple-through delay <450 ns ensures deterministic jitter <1 LSB at 12-bit resolution. |
Use Scenario: Interfacing DTMF tone generator ICs with telephony line interface circuits requiring precise timing alignment. IC Role / Device Role / Timing Role: Aligning 4-bit tone code outputs with analog switch enable timing to avoid click artifacts. Use Value: Guarantees glitch-free tone transitions by enforcing strict setup/hold timing on Dn inputs relative to SI edge. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FIFO register applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CD74HCT40105M | HCT variant: TTL-compatible input thresholds (VIH = 2V min, VIL = 0.8V max); identical SOIC-16 package and pinout. | Required when interfacing directly with legacy 5V TTL logic without level shifters; not suitable for 3.3V-only systems. | Select CD74HCT40105M only if driving from standard LS-TTL outputs; otherwise CD74HC40105M offers broader voltage flexibility. |
| SN74ACT2227N | 8-bit × 16-word FIFO in PDIP-24; higher data width but incompatible pinout and control signaling (clocked vs. flag-driven). | Used in wide-bus applications like video frame buffering; lacks DIR/DOR handshaking and requires external clock management. | Choose SN74ACT2227N only when 8-bit parallel throughput is mandatory; CD74HC40105M provides simpler integration for 4-bit interfaces. |
Compared with CD74HCT40105M and SN74ACT2227N, the CD74HC40105M uniquely combines 4-bit width, asynchronous flag-based control, and 2V–6V operation-making it optimal for low-power, mixed-voltage embedded buffering where minimal external logic is critical.
Availability
CD74HC40105M is available at Aetrix Electronics and suitable for UART interface buffering, CPU-to-peripheral bridging, radar data acquisition, and auto-dialer tone generation requiring stable component supply across extended temperature ranges.
Supply support for CD74HC40105M 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 over 50 years of innovation in high-reliability IC design.
The CD74HC40105M belongs to TI's High-Speed CMOS Logic family, engineered specifically for asynchronous data buffering in mission-critical systems demanding wide temperature operation and low static power.
FAQ
What is the maximum operating frequency of the CD74HC40105M?
The CD74HC40105M supports a maximum SI/SO pulse frequency of 12 MHz at VCC = 4.5V and -40°C to +85°C ambient. At full industrial range (-55°C to +125°C), the guaranteed maximum is 10 MHz. This limit derives from propagation delay constraints and ripple-through timing across all 16 FIFO stages, not from individual gate switching speed.
Does the CD74HC40105M clear stored data during Master Reset?
No, the CD74HC40105M does not erase data contents during Master Reset (MR). MR resets only the control logic marker bits to "0", invalidating all positions and forcing DIR high and DOR low. Existing data in the 16-word register remains intact until overwritten by the next SI pulse, preserving integrity during partial system resets.
Can the CD74HC40105M be used in 3.3V systems?
Yes, the CD74HC40105M is fully compatible with 3.3V operation. Its HC logic family specifies VIH ≥1.5V and VIL ≤0.5V at VCC = 3.3V, providing >0.8V noise margin. All DC and AC parameters-including propagation delay, output drive, and leakage-are characterized down to 2V, making it ideal for mixed-voltage 3.3V/5V designs.
How does the CD74HC40105M handle FIFO overflow and underflow conditions?
The CD74HC40105M uses hardware flags to prevent overflow and underflow: DIR goes LOW when FIFO is full (all 16 positions marked "1"), ignoring further SI pulses; DOR stays LOW when FIFO is empty (no "1" marker at output stage), ignoring SO pulses. No internal error flags or interrupts are generated-designers must monitor DIR/DOR in real time.
Is the CD74HC40105M pin-compatible with the CD40105B?
No, the CD74HC40105M is not pin-compatible with the CD40105B. While functionally similar as 4×16 FIFOs, the CD40105B uses a different pin assignment: its MR is on Pin 15, OE on Pin 1, and SO on Pin 14. The CD74HC40105M reassigns these to Pins 1, 15, and 15 respectively-requiring PCB layout revision for replacement.
CD74HC40105M Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Size:
- 64 (16 x 4)
- Function:
- Asynchronous
- Data Rate:
- -
- Access Time:
- -
- Voltage - Supply:
- 2 V ~ 6 V
- Current - Supply (Max):
- -
- Bus Directional:
- Uni-Directional
- Expansion Type:
- Depth, Width
- Programmable Flags Support:
- No
- Retransmit Capability:
- No
- FWFT Support:
- No
- Operating Temperature:
- -55°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
CD74HC40105M FAQ
1.How can I place an order for CD74HC40105M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HC40105M 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 CD74HC40105M reliable?
The price and inventory of CD74HC40105M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HC40105M is usually 5 days.
3.What payment methods are accepted for CD74HC40105M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HC40105M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HC40105M?
CD74HC40105M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HC40105M 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 CD74HC40105M?
For technical support, including CD74HC40105M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HC40105M requirements.
6.How does Aetrix verify that CD74HC40105M is sourced from the original manufacturer or authorized distributors?
All CD74HC40105M 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 CD74HC40105M meets industry standards.
7.What is the process for return or replacement of CD74HC40105M?
All CD74HC40105M units undergo pre-shipment inspection (PSI). If there is an issue with CD74HC40105M, 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 CD74HC40105M part is unused and in its original packaging.
Return procedure for CD74HC40105M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
CD74HC40105M Tags
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