My Inquiry
My Account
Texas Instruments CD74HCT21MT
- Part No.:
- CD74HCT21MT
- Manufacturer:
- Texas Instruments
- Category:
- Gates and Inverters
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CD74HCT21MT.pdf
- Description:
- IC GATE AND 2CH 4-INP 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,411
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
CD74HCT21MT from Texas Instruments is a dual 4-input AND gate IC designed for digital logic level combination and signal enable functions in industrial control, power management, and safety-critical monitoring circuits. It operates across 4.5 V to 5.5 V supply, supports –55°C to +125°C ambient temperature, delivers propagation delay of 27 ns (typ) at 4.5 V with 50 pF load, and features TTL- and CMOS-compatible inputs with buffered architecture.
For engineers reviewing the CD74HCT21MT datasheet, CD74HCT21MT pinout, CD74HCT21MT application, or CD74HCT21MT equivalent, key selection considerations include its dual-gate Boolean function Y = A●B●C●D, NC pins at positions 3 and 11, LSTTL fanout support up to 10 loads, and SOIC-14 package compatibility with standard 8.70 mm × 3.90 mm PCB footprints.
Technical Context
The CD74HCT21MT implements two independent positive-logic 4-input AND gates using HCMOS technology with balanced push-pull outputs capable of sourcing/sinking ±4 mA while maintaining VOH ≥ 3.7 V and VOL ≤ 0.4 V under load. Its input structure includes clamp diodes for ESD protection (±2000 V HBM), TTL-compatible thresholds (VIH(min) = 2 V, VIL(max) = 0.8 V), and low input leakage (±1 µA max).
It operates within absolute maximum ratings of –0.5 V to 7 V supply voltage and junction temperature up to 150°C, with thermal resistance RθJA = 102.3°C/W (SOIC-14). The device requires all unused inputs tied to VCC or GND per TI layout guidelines to prevent floating states and undefined logic behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Dual independent 4-input AND: Y = A●B●C●D per gate |
| Supply Voltage Range | 4.5 V to 5.5 V - ensures compatibility with 5 V TTL/CMOS systems and stable operation across industrial voltage tolerances |
| Propagation Delay (tpd) | 27 ns (typ) at 4.5 V, CL = 50 pF - defines maximum timing budget for synchronous enable/control paths |
| Input Thresholds | VIH(min) = 2 V, VIL(max) = 0.8 V - guarantees interoperability with legacy LSTTL outputs without level shifting |
| Operating Temperature | –55°C to +125°C - qualified for under-hood automotive, industrial motor drives, and aerospace power sequencing |
| Output Drive | ±4 mA sink/source - sufficient to directly drive LED indicators, reset lines, or CMOS inputs without external buffers |
| Input Leakage | ±1 µA max at 5.5 V - enables high-impedance signal conditioning and low-power standby modes |
Pinout & Package
CD74HCT21MT is housed in a 14-pin SOIC (D) package measuring 8.70 mm × 3.90 mm with 1.27 mm lead pitch and 1.75 mm max height. Pin 1 is marked by a beveled corner or dot; pins 3 and 11 are not internally connected (NC) and must remain unconnected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1A, 1B, 1C, 1D | Inputs (Gate 1) | Four logic inputs for first AND gate; all must be HIGH to assert 1Y |
| 1Y | Output (Gate 1) | Active-HIGH output reflecting logical AND of inputs 1A–1D |
| GND (Pin 7) | Ground Reference | Primary return path for supply current and logic reference; must be low-impedance |
| 2Y | Output (Gate 2) | Active-HIGH output reflecting logical AND of inputs 2A–2D |
| 2A, 2B, 2C, 2D | Inputs (Gate 2) | Four logic inputs for second independent AND gate |
| VCC (Pin 14) | Positive Supply | 5 V nominal supply input; requires local 0.1 µF bypass capacitor per TI layout guidance |
| NC (Pins 3, 11) | No Connection | Not bonded internally; must remain unconnected on PCB to avoid parasitic coupling |
Key Features
| Feature | Design Value |
|---|---|
| LSTTL Input Compatibility | VIH(min) = 2 V and VIL(max) = 0.8 V allow direct interfacing with 74LS-series outputs without level translation |
| Wide Temperature Range | –55°C to +125°C operation supports deployment in engine control units, power supplies, and outdoor industrial enclosures |
| Buffered Inputs | Reduces capacitive loading on upstream drivers and improves noise immunity in noisy environments |
| Low Quiescent Current | ICC = 40 µA max at 5.5 V enables use in battery-backed or always-on monitoring circuits |
| ESD Robustness | ±2000 V HBM rating meets IEC 61000-4-2 Level 2 requirements for system-level ESD immunity |
Applications
| Power Sequencing Control | Motor Controller Reset Logic |
|---|---|
Use Scenario: Combining multiple "power good" signals (PG1–PG4) from DC/DC converters before enabling downstream FPGA or microcontroller rails. IC Role / Device Role / Timing Role: Dual 4-input AND gate performing synchronous validation of four independent power rails prior to release of global enable. Use Value: Ensures system only powers up when all critical supplies meet regulation, preventing latch-up or brownout-induced corruption. | Use Scenario: Generating a single active-HIGH reset signal for a BLDC motor controller based on four fault conditions (overcurrent, overtemperature, case tamper, undervoltage). IC Role / Device Role / Timing Role: Logic combiner converting four independent fault flags into one consolidated reset assertion. Use Value: Eliminates need for microcontroller-based fault arbitration, reducing BOM count and improving fail-safe response time. |
| Industrial Safety Interlock | Legacy System Signal Enable |
Use Scenario: Enabling PLC output modules only when emergency stop, guard door, light curtain, and thermal cutoff signals are all deasserted (active-LOW logic). IC Role / Device Role / Timing Role: Dual AND gate used with external inverters to implement safety-critical AND-OR logic for machine guarding. Use Value: Provides hardware-level redundancy for SIL-2 compliance without software intervention or watchdog dependency. | Use Scenario: Enabling data transmission from an older 74LS125 bus driver only when both chip select and write enable signals are asserted. IC Role / Device Role / Timing Role: Gate-level enable logic synchronizing legacy TTL peripherals with modern microcontroller address/data buses. Use Value: Bridges timing and voltage domain mismatches between LS-TTL and 5 V CMOS systems with sub-30 ns latency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual 4-input AND gate applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT21DR | Same logic function, identical pinout, SOIC-14 package, but rated for –40°C to +85°C only | Not suitable for extended temperature industrial or automotive under-hood use | Select when operating environment stays within commercial temperature range and cost optimization is prioritized |
| CD74ACT21M | AC-family variant with 3 V to 5.5 V supply range, faster tpd = 9 ns (typ), higher ICC = 4 µA (max) | Enables mixed-voltage designs and higher-speed timing paths but increases static power draw | Select when interfacing with 3.3 V logic or requiring <10 ns propagation delay in high-throughput control loops |
Compared with SN74HCT21DR, CD74HCT21MT offers extended temperature qualification essential for harsh environments; compared with CD74ACT21M, it trades speed for lower quiescent current and tighter voltage tolerance-making it optimal for robust, low-power 5 V-only systems.
Availability
CD74HCT21MT is available at Aetrix Electronics and suitable for industrial motor control, automotive power sequencing, and safety interlock systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for CD74HCT21MT 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 90 years of innovation in industrial, automotive, and communications markets.
The CD74HCT21MT belongs to TI's HCT logic family, engineered for seamless interoperability between TTL and CMOS systems while delivering low power consumption and high noise immunity in mission-critical digital control applications.
FAQ
What is the function of pins 3 and 11 on the CD74HCT21MT?
Pins 3 and 11 on the CD74HCT21MT are designated as NC (No Connect) and are not internally bonded. They must remain unconnected on the PCB to prevent unintended coupling or parasitic effects. TI's datasheet explicitly confirms these terminals have no internal connection, and routing traces or placing vias to them is prohibited per layout guidelines.
Can CD74HCT21MT operate reliably at 4.5 V supply voltage?
Yes, CD74HCT21MT is fully specified for operation at 4.5 V, with guaranteed performance including VOH ≥ 3.7 V (at IOH = –4 mA), VOL ≤ 0.4 V (at IOL = 4 mA), and tpd ≤ 41 ns (max) across –55°C to +125°C. Its recommended operating condition range starts at 4.5 V, making it suitable for brownout-tolerant 5 V systems.
Is CD74HCT21MT pin-compatible with CD74HCT21M or CD74HCT21M96?
Yes, CD74HCT21MT shares identical pinout, electrical characteristics, and SOIC-14 package dimensions with CD74HCT21M and CD74HCT21M96. All three part numbers correspond to the same functional device in the same D-package variant; differences relate only to packaging format (tube vs. tape-and-reel) and lifecycle status-not pin assignment or logic behavior.
What is the maximum capacitive load the CD74HCT21MT can drive while meeting datasheet timing specs?
The CD74HCT21MT is characterized for CL = 50 pF in switching specifications, with tpd = 27 ns (typ) and tt = 15 ns (typ) at 4.5 V. TI recommends limiting total load capacitance to ≤70 pF to maintain timing integrity and avoid excessive output current that could violate the ±25 mA absolute maximum rating.
How should unused inputs be handled on the CD74HCT21MT?
All unused inputs on CD74HCT21MT must be terminated to either VCC or GND-never left floating-to prevent oscillation, increased ICC, or undefined logic states. TI specifies a 10-kΩ pull-up or pull-down resistor as typical practice; direct connection is acceptable if the input is permanently unused and compatible with system logic levels.
CD74HCT21MT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- AND Gate
- Number of Circuits:
- 2
- Number of Inputs:
- 4
- Features:
- -
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Max):
- 2 µA
- Current - Output High, Low:
- 4mA, 4mA
- Input Logic Level - Low:
- 0.8V
- Input Logic Level - High:
- 2V
- Max Propagation Delay @ V, Max CL:
- 27ns @ 4.5V, 50pF
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
CD74HCT21MT FAQ
1.How can I place an order for CD74HCT21MT through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HCT21MT 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 CD74HCT21MT reliable?
The price and inventory of CD74HCT21MT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HCT21MT is usually 5 days.
3.What payment methods are accepted for CD74HCT21MT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HCT21MT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HCT21MT?
CD74HCT21MT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HCT21MT 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 CD74HCT21MT?
For technical support, including CD74HCT21MT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HCT21MT requirements.
6.How does Aetrix verify that CD74HCT21MT is sourced from the original manufacturer or authorized distributors?
All CD74HCT21MT 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 CD74HCT21MT meets industry standards.
7.What is the process for return or replacement of CD74HCT21MT?
All CD74HCT21MT units undergo pre-shipment inspection (PSI). If there is an issue with CD74HCT21MT, 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 CD74HCT21MT part is unused and in its original packaging.
Return procedure for CD74HCT21MT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
CD74HCT21MT Tags
-
SN74LVC1G14DBVR
Texas Instruments
-
SN74LVC1G14DCKR
Texas Instruments
-
SN74AHC1G14DBVR
Texas Instruments
-
SN74LVC1G08DBVR
Texas Instruments
-
SN74LVC1G08DCKR
Texas Instruments
-
SN74LVC1G32DCKR
Texas Instruments
-
SN74LVC1G04DBVR
Texas Instruments
.jpg)
-
74LVC1G08GW,125
Nexperia USA Inc.
-
SN74LVC1G04DCKR
Texas Instruments
-
SN74AHC1G08DBVR
Texas Instruments
-
SN74LVC1G32DBVR
Texas Instruments
-
SN74AHCT1G08DBVR
Texas Instruments
Tech Hub
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
LDO regulator guide covering low dropout voltage, power dissipation, thermal design, PSRR, output noise, capacitor stability, adjustable LDO circuits, LDO vs buck converter and datasheet selection chec…
Conditional Access Module guide covering CAM meaning, CI/CI+ interface, smart card authorization, DVB security workflow, TV and set-top box compatibility, internal electronics, ESD protection, connecto…
Guide to electronic component obsolescence covering EOL risk, PCN/PDN notices, last-time buy planning, replacement options, form-fit-function validation, counterfeit risk and BOM lifecycle management.
18650 battery guide covering lithium-ion cell basics, 3.6V/3.7V voltage, 4.2V charging, mAh and Wh capacity, protected cells, chargers, BMS, series-parallel packs, holders, welding and sourcing checks.…
Hall effect sensor guide covering working principle, linear and digital sensors, Arduino circuits, current sensing, speed detection, automotive applications, A3144 examples, signal filtering and datash…
