onsemi DM74AS08N

Overview

DM74AS08N from Fairchild Semiconductor is a quad 2-input AND gate IC in a 14-lead PDIP package, operating at VCC = 4.5–5.5 V, with propagation delays as low as 1 ns (tPLH/tPHL), output drive capability of −30 mA (IO), and guaranteed performance across 0°C to +70°C. It performs discrete logic gating in TTL-based control and interface circuits.

For engineers reviewing the DM74AS08N datasheet, pinout, applications, or equivalent options, key selection criteria include its Schottky TTL-compatible timing (5.5 ns max delay), 20 mA sink current (IOL), −2 mA source current (IOH), and functional pin-for-pin compatibility with standard 74-series AND gates in industrial control and digital instrumentation.

Technical Context

The DM74AS08N implements four independent AND gates using advanced oxide-isolated, ion-implanted Schottky TTL process technology. It delivers improved AC performance over standard Schottky and low-power Schottky TTL families, with guaranteed switching specifications at CL = 50 pF across full temperature and supply voltage ranges.

Each gate accepts TTL-level inputs (VIL ≤ 0.8 V, VIH ≥ 2.0 V) and drives standard TTL loads, supporting direct interfacing with legacy 74LS, 74S, and 74ALS logic without level-shifting. Output voltage compliance meets VOH ≥ VCC − 2 V and VOL ≤ 0.5 V at IOL = 20 mA.

Key Specifications

Pinout & Package

DM74AS08N is housed in a 14-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" wide, with through-hole mounting and industry-standard lead pitch (0.100"). Thermal resistance θJA is 84.0°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar AND gate applications.

Compared with SN74AS08N and 74F08PC, the DM74AS08N offers the fastest guaranteed propagation (5.5 ns max), highest sink current (20 mA), and broadest commercial temperature support-making it optimal for time-critical industrial logic where legacy compatibility and margin are essential.

Availability

DM74AS08N is available at Aetrix Electronics and suitable for industrial control logic, digital instrumentation, legacy system repair, and test equipment signal routing requiring stable component supply and long-term obsolescence management.

Supply support for DM74AS08N 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

Fairchild Semiconductor was a leading designer of analog and mixed-signal semiconductors, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and instrumentation systems.

The DM74AS08N belongs to the 74AS (Advanced Schottky) logic family, engineered for high-speed, low-power TTL-compatible digital control in commercial-grade embedded systems and test equipment.

FAQ

What logic family does the DM74AS08N belong to, and how does it differ from standard 74LS logic?

The DM74AS08N belongs to the 74AS (Advanced Schottky) TTL family. It differs from 74LS by delivering significantly faster propagation delays (1–5.5 ns vs. 15–30 ns), higher output drive (20 mA sink vs. 8 mA), and guaranteed AC performance across full temperature and voltage ranges. The DM74AS08N maintains full pin and functional compatibility with 74LS08, allowing direct replacement in most legacy designs without layout changes.

Is the DM74AS08N pin-for-pin compatible with other 74-series AND gate packages?

Yes, the DM74AS08N is pin-for-pin compatible with 74AS08, 74S08, and 74LS08 in the 14-lead PDIP package. Its pinout matches the industry-standard configuration: inputs on pins 1,2,4,5,8,9,12,13; outputs on pins 3,6,10,11; VCC on pin 14; GND on pin 7. This allows drop-in replacement in existing 74-series logic designs.

What are the absolute maximum ratings for the DM74AS08N, and why do they matter in circuit design?

The DM74AS08N has absolute maximum ratings of 7 V for supply and input voltage, and −65°C to +150°C for storage temperature. These define stress limits beyond which permanent damage may occur. They matter because exceeding VCC > 5.5 V or applying input voltages above VCC (e.g., during hot insertion) risks latch-up or junction breakdown-even if the device appears functional temporarily. Designers must enforce clamping and sequencing controls to stay within recommended operating conditions (4.5–5.5 V, 0–70°C).

Can the DM74AS08N drive LEDs directly, and what current limits apply?

Yes, the DM74AS08N can drive LEDs directly in common-anode configurations using its output as a sink. Its IOL rating is 20 mA per output, sufficient for standard indicator LEDs (typically 10–15 mA). However, continuous operation near 20 mA requires attention to power dissipation: with VOL ≈ 0.5 V at 20 mA, power per output is ~10 mW-well within the device's thermal limits in PDIP packaging, provided ambient temperature remains ≤70°C.

Does the DM74AS08N require decoupling capacitors, and where should they be placed?

Yes, the DM74AS08N requires a 0.1 µF ceramic decoupling capacitor placed as close as possible between pin 14 (VCC) and pin 7 (GND). This suppresses high-frequency supply noise generated during fast output transitions (tPLH/tPHL < 6 ns), preventing ground bounce and false triggering in adjacent logic. A bulk capacitor (e.g., 10 µF) on the board's main +5 V rail further stabilizes long-term supply integrity.