SN54HCT373FK Texas Instruments Integrated Circuit (Ceramic Dual-In-Line Packages) In Stock
SN54HCT373FK is an octal transparent D-type latch from Texas Instruments in the HCT logic family, providing 8 individually latched outputs with 3-state capability and an active-low output enable. The device supports a 150 pF load capacitance and 6 mA output sink current, making it suitable for bus-hold and data-register functions. Packaged in a 20-pin ceramic LCC, it serves high-reliability military and aerospace data bus buffering applications.
- Manufacturer
- Texas Instruments
- Package
- Ceramic Dual-In-Line Packages
- Pin Count
- 20
- Lifecycle
- OBSOLETE
- Datasheet
- SN54HCT373FK Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- -55.0°C to 125.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- Octal transparent D-type latch with 3-state outputs
- Active-low output enable for unidirectional bus isolation
- 150 pF load capacitance drive capability for backplane bus lines
- 6 mA output sink current in HCT logic family
- 20-pin ceramic LCC (S-CQCC-N20) package for high-reliability use
- HCT-family TTL-compatible input thresholds for 5 V system integration
Applications
SN54HCT373FK is used as a data bus interface latch in military and aerospace embedded processors, where its transparent latch mode captures and holds 8-bit parallel data from address/data multiplexed buses. The HCT logic family's TTL-compatible input thresholds and the hermetic ceramic LCC package make it well-suited for avionics computers, satellite command decoders, and radiation-hardened memory buffer circuits.
Specifications
| YTEOL | 0 |
| Control Type | ENABLE LOW |
| Count Direction | UNIDIRECTIONAL |
| Family | HCT |
| JESD-30 Code | S-CQCC-N20 |
| Load Capacitance (CL) | 150pF |
| Logic IC Type | BUS DRIVER |
| Max I(ol) | 0.006A |
| Number of Bits | 8 |
| Number of Functions | 1 |
| Number of Ports | 2 |
| Output Characteristics | 3-STATE |
| Output Polarity | TRUE |
| Package Body Material | CERAMIC, METAL-SEALED COFIRED |
| Package Equivalence Code | LCC20,.35SQ |
| Package Shape | SQUARE |
| Package Style | CHIP CARRIER |
| Peak Reflow Temperature (Cel) | NOT SPECIFIED |
| Power Supply Current-Max (ICC) | 0.16mA |
| Prop. Delay@Nom-Sup | 79ns |
| Propagation Delay (tpd) | 79ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 5.5V |
| Supply Voltage-Min (Vsup) | 4.5V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | YES |
| Technology | CMOS |
| Temperature Grade | MILITARY |
| Terminal Form | NO LEAD |
| Terminal Pitch | 1.27mm |
| Terminal Position | QUAD |
| Time@Peak Reflow Temperature-Max (s) | NOT SPECIFIED |
| Trigger Type | HIGH LEVEL |
| Package | Ceramic Dual-In-Line Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| HTS Code | 8542.39.00.60 |
Alternate & Equivalent Parts
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How does the transparent latch mode of SN54HCT373FK differ from a D flip-flop in a bus-buffer design?
In transparent mode (LE high), SN54HCT373FK allows data on all 8 D inputs to flow directly to the Q outputs without a clock edge, which is useful for demultiplexing address/data buses where the latch enable is a short strobe pulse. A D flip-flop, by contrast, captures data only on a clock edge. When LE goes low, the SN54HCT373FK holds its last state indefinitely, providing stable outputs even as the input bus changes.
What load capacitance does SN54HCT373FK support, and how does that compare with standard CMOS latch specifications?
SN54HCT373FK is rated for 150 pF load capacitance per output, which is higher than the 50 pF typical for commercial HCT parts, reflecting the device's qualification for military-grade backplane bus environments. This 150 pF rating ensures reliable signal integrity on longer PCB traces and backplane stubs common in 5 V avionics and ground-support equipment assemblies.
For which certification levels is the SN54HCT373FK ceramic LCC package qualified?
The SN54HCT373FK uses a hermetic 20-pin ceramic LCC (S-CQCC-N20) package, which is qualified per MIL-STD-883 for military and high-reliability industrial applications. This qualification covers temperature ranges from -55°C to +125°C, moisture resistance, and mechanical shock testing, making the device appropriate for avionics, defense electronics, and space-adjacent programs requiring documented reliability screening.
Can SN54HCT373FK receive logic signals from 3.3 V CMOS sources on its D inputs?
SN54HCT373FK has TTL-compatible input thresholds with a VIH minimum of 2 V, which means it can accept high logic levels from 3.3 V CMOS drivers that swing to 3.3 V. However, the output logic high swings near the VCC rail of 5 V, so level translation may still be required on the output side if downstream circuits operate exclusively at 3.3 V with a VIH maximum below 3.6 V.
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Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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