SN74HC21PWR - Dual 4-Input AND Gate, 2-6V | TI
MPN: SN74HC21PWR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.29 | $0.29 |
| 10 | $0.26 | $2.60 |
| 100 | $0.22 | $22.00 |
| 500 | $0.18 | $90.00 |
| 1,000 | $0.15 | $150.00 |
Drop-in alternatives for SN74HC21PWR β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
SN74HC21QPWRQ1
β Drop-Inβ In Stock
$0.27 / Unit
View Datasheet βSN74HCS21PWR
β Drop-Inπ Reference alternative (not in catalog)
74HC21PW,118
β Drop-Inπ Reference alternative (not in catalog)
HD74HC21TELL
β Drop-Inπ Reference alternative (not in catalog)
SN74HC21PWR Maximum Ratings & Electrical Characteristics
| Logic Function | Dual 4-input positive-AND gate |
| Boolean Function | Y = A AND B AND C AND D (positive logic) |
| Number of Channels | 2 |
| Inputs per Gate | 4 |
| Supply Voltage Range | 2 V to 6 V |
| Output Drive Strength | 5.2 mA at 6 V |
| LSTTL Load Drive | Up to 10 LSTTL loads |
| Quiescent Supply Current | 20 uA maximum |
| Logic Family | HC (High-Speed CMOS) |
| Input Type | Standard CMOS (non-Schmitt) |
| Output Type | Push-pull (totem pole) |
| Operating Temperature Range | -40C to +85C |
| Package | TSSOP (PW), 14 pins |
| Mounting Type | Surface Mount |
| Technology | Silicon-gate CMOS |
SN74HC21PWR Pin Configuration
| Pin 1 | 1A β Gate 1 input A |
| Pin 2 | 1B β Gate 1 input B |
| Pin 3 | NC β Not connected (per datasheet) |
| Pin 4 | 1C β Gate 1 input C |
| Pin 5 | 1D β Gate 1 input D |
| Pin 6 | 1Y β Gate 1 output |
| Pin 7 | GND β Ground |
| Pin 8 | 2Y β Gate 2 output |
| Pin 9 | 2A β Gate 2 input A |
| Pin 10 | 2B β Gate 2 input B |
| Pin 11 | NC β Not connected (per datasheet) |
| Pin 12 | 2C β Gate 2 input C |
| Pin 13 | 2D β Gate 2 input D |
| Pin 14 | VCC β Positive supply, 2 V to 6 V |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this digital IC. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
SN74HC21PWR is suitable for 6 applications: Address Decoding and Chip-Enable Logic, Safety Interlock and Fault Aggregation Logic, Power Rail Sequencing and Enable Gating, Battery-Powered Portable Instruments, Industrial Control Panels and PLC I/O, Automotive Body and Module Enable Logic.
Address Decoding and Chip-Enable Logic
The SN74HC21PWR fits microcontroller and memory system address decoding where a chip-select signal must be asserted only when several address or status lines are simultaneously HIGH. Each 4-input gate performs Y = A AND B AND C AND D in one propagation delay, replacing multiple 2-input gates and reducing package count. With a 2V to 6V supply range it interfaces directly with 5V buses and 3.3V MCUs, and its 5.2 mA output drive at 6V easily drives chip-enable pins or an LED status indicator. Place the gate close to the load to minimize stub reflections, and keep unused NC pins (3, 11) unrouted. Its 20 uA maximum quiescent current keeps decode logic negligible in standby power budgets.
Recommended
Safety Interlock and Fault Aggregation Logic
In industrial equipment, an enable output must be HIGH only when multiple safety conditions (door closed, guard present, pressure OK, E-stop clear) are all true. The SN74HC21PWR implements this AND-logic aggregation in a single TSSOP-14, with the push-pull output swinging rail-to-rail for a clean enable to a relay driver or gate driver input. Its HC CMOS inputs present high impedance, allowing direct connection to optocoupler outputs with pull-up resistors. For inputs derived from slow RC-filtered sensor lines, pair the board with the SN74HCS21PWR, whose Schmitt-trigger inputs in the same footprint remove oscillation risk. Operating from -40C to +85C suits factory floor environments.
Recommended
Power Rail Sequencing and Enable Gating
The SN74HC21PWR is well suited for power-supply enable logic: the four inputs of one gate can combine power-good outputs from several regulators so a downstream rail turns on only after all upstream rails are valid. With a 2V to 6V range it operates from a 3.3V supervisory rail or 5V bias, and its 20 uA maximum quiescent current adds negligible load to always-on standby supplies. The 5.2 mA drive easily satisfies PMIC enable-pin sink/source requirements. Keep each power-good trace short and add a 0.1 uF decoupling capacitor within 2 mm of VCC (pin 14). For slow power-good edges, the SN74HCS21PWR Schmitt-input version is the recommended drop-in substitute.
Recommended
Battery-Powered Portable Instruments
Portable meters, dataloggers, and handheld instruments benefit from the SN74HC21PWR's 20 uA maximum quiescent current and operation down to 2V, which permits running directly from two NiMH cells (2.4V) or a 3V lithium coin cell without a boost converter. The dual 4-input gates combine key-cap condition, range-select, and interlock signals before waking the MCU or an analog front end. Push-pull outputs eliminate pull-up resistors that would otherwise leak current continuously. Because standard HC inputs require fast edge rates, gate any RC-derived signals through a Schmitt buffer or specify the SN74HCS21PWR. The compact TSSOP-14 saves board area in handheld enclosures.
Recommended
Industrial Control Panels and PLC I/O
PLC input cards and industrial control panels use the SN74HC21PWR to combine permissive signals before latching a run command: for example, motor start requires contactor feedback, overload not tripped, local/remote switch, and start pushbutton all HIGH. The -40C to +85C rating covers panel environments, and the wide 2V to 6V supply tolerates regulated 5V or degraded industrial supplies. Outputs drive up to 10 LSTTL loads, so one gate output can fan out to isolators, LED indicators, and a microcontroller input simultaneously. Route optocoupler outputs with 10 kOhm pull-ups to the HC21 inputs, and verify transition times meet HC datasheet limits or use the SN74HCS21PWR for slow edges.
Recommended
Automotive Body and Module Enable Logic
For automotive modules the standard SN74HC21PWR is limited to -40C to +85C, so TI provides the SN74HC21QPWRQ1: the AEC-Q100 qualified, same-footprint TSSOP-14 variant rated -40C to +125C. Automotive boards use this family to combine ignition status, sleep-request, and diagnostics-enable signals into a single module-enable for power management ICs. The 2V to 6V range covers crank transients on regulated 5V rails, and the 20 uA quiescent current preserves key-off battery budget. When designing a new automotive module, specify the Q1 part directly; for industrial prototypes sharing the same PCB, either part may be stuffed without layout change.
Recommended
Recommended Products Summary
Engineering reference data for SN74HC21PWR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SN74HC21QPWRQ1 | SN74HCS21PWR | 74HC21PW,118 | HD74HC21TELL |
|---|---|---|---|---|---|
| Package | TSSOP-14 (PW) | TSSOP-14 (PW) - same | TSSOP-14 (PW) - same | TSSOP-14 (SOT362) - same footprint | TSSOP-14 - verify outline |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | NXP Semiconductors | Renesas Electronics |
| Logic Function | Dual 4-input AND | Dual 4-input AND | Dual 4-input AND (Schmitt inputs) | Dual 4-input AND | Dual 4-input AND |
| Supply Voltage Range | 2 V to 6 V | 2 V to 6 V | 2 V to 6 V | 2 V to 6 V | 2 V to 6 V |
| Output Drive Strength | 5.2 mA at 6 V | 5.2 mA at 6 V | [DATA_NEEDED] | 7.8 mA at 6 V (NXP datasheet) | [DATA_NEEDED] |
| Input Type | Standard CMOS | Standard CMOS | Schmitt trigger | Standard CMOS | Standard CMOS |
| Operating Temperature | -40C to +85C | -40C to +125C | -40C to +125C | -40C to +125C | [DATA_NEEDED] |
| AEC-Q100 Qualified | No | Yes (Grade 1) | No | No | No |
| Quiescent Current | 20 uA max | 20 uA max | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
Key Differentiators
- Lowest-cost standard-CMOS option in footprint (vs SN74HCS21PWR)
- Industrial temperature grade at consumer price (vs SN74HC21QPWRQ1)
- Multi-source drop-in availability (vs 74HC21PW,118)
Design Notes
Place a 0.1 uF ceramic decoupling capacitor within 2 mm of the VCC pin (pin 14) and GND (pin 7). HC CMOS logic draws dynamic shoot-through current at each switching event; without local decoupling this couples ground bounce into neighboring logic. For boards with multiple HC devices, add one 1 uF to 4.7 uF bulk capacitor per power region. Leave NC pins 3 and 11 unrouted; do not use them as jumper channels, since internal die connections are not guaranteed.
Standard HC-family inputs require input transition times within datasheet limits; edges slower than the specified maximum (typically around 500 ns at 4.5V for HC parts) can cause output oscillation or intermediate-level shoot-through. If inputs come from RC timers, power-good flags with weak pull-ups, or optocouplers, either add a Schmitt-trigger buffer upstream or substitute the pin-compatible SN74HCS21PWR, which adds input hysteresis in the identical TSSOP-14 footprint.
Unused HC inputs must never float. Tie unused gate inputs directly to GND (output then LOW) or to VCC through a 1 kOhm to 10 kOhm resistor. Floating CMOS inputs float to mid-rail, turning on both output transistors and raising supply current well above the 20 uA static figure while causing erratic switching. Also remember the 2V minimum supply: at VCC below 2V the output drive is unspecified, so brownout supervisors are advised on battery designs.
Estimated: thermal design is non-critical for this part. With 20 uA quiescent current and only a few mA of load current, dissipation is on the order of microwatts to low milliwatts, so the TSSOP-14 package requires no heatsink or thermal copper pour at any operating condition within the 2V to 6V range. Standard TSSOP land pattern per IPC-7351 with nominal solder mask is sufficient; verify against the manufacturer datasheet land-pattern data.
Compliance Information
RoHS compliant per TI product data (PWR suffix denotes RoHS-compliant tape and reel). Not AEC-Q100 qualified; use SN74HC21QPWRQ1 for automotive. REACH and halogen-free status not stated in provided data.
