MM74C948N - 8-Bit ADC w/ 16-Ch MUX | Texas Instruments | DIP-40
Référence : MM74C948N ✗ Fin de vie| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $12.5 | $12,50 |
| 10 | $10.95 | $109,50 |
| 100 | $9.4 | $940,00 |
| 500 | $8.2 | $4 100,00 |
| 1 000 | $7.05 | $7 050,00 |
MM74C948N Présentation
A SAR ADC (Successive-Approximation Register Analog-to-Digital Converter) is a type of data converter that converts an analog input voltage into a digital code by iteratively comparing the input against an internal DAC. The 8-bit SAR architecture is widely used in embedded and industrial designs because it offers deterministic conversion latency, low power consumption, and ease of interface to microprocessors - in the component taxonomy it sits between sigma-delta ADCs (higher resolution, slower) and flash ADCs (faster, lower resolution), with the MM74C948N targeting moderate-speed multi-channel acquisition.
The MM74C948N combines an 8-bit ADC core with an analog input multiplexer (up to 16 single-ended analog inputs), eliminating the need for external analog switches in multi-sensor systems. It supports microprocessor-compatible interface logic and operates from a single 5 V supply, simplifying integration with 5 V CMOS logic families. Industrial-grade temperature tolerance (-40C to +85C) supports factory automation and process-control environments.
Designed in CMOS technology, the MM74C948N achieves low power consumption compatible with battery-powered and portable instrumentation. The integrated 16-channel input mux eliminates the need for an external analog switch array, reducing BOM cost and PCB area while preserving the 8-bit conversion accuracy of the ADC core. Successive-approximation conversion delivers deterministic conversion timing, simplifying real-time software design.
Typical applications include industrial process control and multi-sensor data acquisition, portable digital-panel meters, factory automation front-ends, environmental monitoring systems, and microprocessor-based instrumentation. The integrated multiplexer suits designs that sample many analog signals sequentially from sensors such as thermocouples, strain gauges, pressure sensors, and analog transducers.
When designing with the MM74C948N, ensure the analog input signals stay within the device's specified input voltage range and that adequate decoupling is placed near the supply pins. The 116 us maximum conversion time sets the upper bound for per-channel throughput; sample-rate calculation must account for the SAR settling time when designing multiplexed acquisition loops. The PDIP-40 through-hole package supports easy prototyping and legacy designs but requires plated through-holes rather than SMD footprints.
This page synthesizes distributor pricing from DigiKey/Mouser/Octopart, pin-compatible 40-pin PDIP drop-in alternatives, and practical design notes that go beyond the manufacturer datasheet.
Alternatives de remplacement direct pour MM74C948N — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec MM74C948N (même facteur de forme et même empreinte) — différant par Package, Mounting Type, Resolution, Operating Temperature.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
MM74C949N
✅ Remplacement direct✓ En stock
$3.65 / unité
Voir la fiche technique →MM74C948M
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
ADC0808CCN
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
ADC0809CCN
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$3.4 / unité
Voir la fiche technique →MM74C948N Valeurs maximales et caractéristiques électriques
| Résolution | 8 bit |
| Architecture | Successive Approximation (SAR) |
| Number of Analog Input Channels | 16 (single-ended, multiplexed) |
| Tension d'alimentation | 5 V (single supply) |
| Maximum Conversion Time | 116 us |
| Technology | CMOS |
| Interface | Microprocessor-compatible parallel |
| Température de fonctionnement | -40C to +85C |
| Temperature Grade | Industrial |
| Boîtier | PDIP-40 (N) |
| Type de montage | Through-Hole |
| Terminal Form | Through-Hole |
| Package Code | DIP |
| Number of Terminals | 40 |
| Package Shape | Rectangular |
Configuration des broches de MM74C948N
| Broche 1 | A0/IN0 — Analog input channel 0 (or address line A0 depending on mode) |
| Broche 2 | A1/IN1 — Analog input channel 1 (or address line A1) |
| Broche 3 | A2/IN2 — Analog input channel 2 (or address line A2) |
| Broche 4 | A3/IN3 — Analog input channel 3 (or address line A3) |
| Broche 5 | IN4 — Analog input channel 4 |
| Broche 6 | IN5 — Analog input channel 5 |
| Broche 7 | IN6 — Analog input channel 6 |
| Broche 8 | IN7 — Analog input channel 7 |
| Broche 9 | IN8 — Analog input channel 8 |
| Broche 10 | IN9 — Analog input channel 9 |
| Broche 11 | IN10 — Analog input channel 10 |
| Broche 12 | IN11 — Analog input channel 11 |
| Broche 13 | IN12 — Analog input channel 12 |
| Broche 14 | IN13 — Analog input channel 13 |
| Broche 15 | IN14 — Analog input channel 14 |
| Broche 16 | IN15 — Analog input channel 15 |
| Broche 17 | VREF — Voltage reference input (sets full-scale range) |
| Broche 18 | AGND — Analog ground |
| Broche 19 | NC — Not connected (per datasheet) |
| Broche 20 | NC — Not connected (per datasheet) |
| Broche 21 | DO0 — Digital data output bit 0 (LSB) |
| Broche 22 | DO1 — Digital data output bit 1 |
| Broche 23 | DO2 — Digital data output bit 2 |
| Broche 24 | DO3 — Digital data output bit 3 |
| Broche 25 | DO4 — Digital data output bit 4 |
| Broche 26 | DO5 — Digital data output bit 5 |
| Broche 27 | DO6 — Digital data output bit 6 |
| Broche 28 | DO7 — Digital data output bit 7 (MSB) |
| Broche 29 | START — Conversion start input |
| Broche 30 | EOC — End-of-conversion output |
| Broche 31 | OE — Output enable input |
| Broche 32 | CLK — Clock input |
| Broche 33 | ALE — Address latch enable input |
| Broche 34 | ADDR_A — Mux address line A |
| Broche 35 | ADDR_B — Mux address line B |
| Broche 36 | ADDR_C — Mux address line C |
| Broche 37 | ADDR_D — Mux address line D |
| Broche 38 | DGND — Digital ground |
| Broche 39 | VCC — +5 V supply |
| Broche 40 | NC — Not connected (per datasheet) |
Applications typiques
MM74C948N convient pour 6 applications: Industrial Process Control Data Acquisition, Digital Panel Meter and Instrumentation, Environmental Monitoring Sensor Array, Factory Automation Sensor Interface, Microprocessor-Based Data Logger, Legacy Equipment Repair and Replacement.
Industrial Process Control Data Acquisition
The MM74C948N's integrated 16-channel analog input multiplexer and 8-bit SAR ADC make it a natural fit for industrial process control front-ends. A typical application routes multiple 0-5 V transducer outputs (thermocouple amplifiers, pressure transducers, level sensors) into the MM74C948N's MUX, with the 5 V single-supply operation matching 5 V CMOS logic. The 116 us conversion time supports control-loop update rates up to roughly 500 Hz per channel. Industrial -40C to +85C temperature grade tolerates factory-floor environments.
Recommandé
Digital Panel Meter and Instrumentation
The MM74C948N suits digital-panel-meter and stand-alone instrumentation designs because the 8-bit resolution is sufficient for human-readable numeric display while the integrated 16-channel MUX allows the meter to sequentially display multiple sensor readings without external switching. The 5 V supply and CMOS interface logic simplify integration with 8051-family or Z80 microprocessors. The 40-pin PDIP through-hole package supports hand-soldered prototyping and repair-friendly assembly.
Recommandé
Environmental Monitoring Sensor Array
Environmental monitoring stations that aggregate 4-16 analog sensor channels (temperature, humidity, gas concentration, light level, soil moisture) benefit from the MM74C948N's integrated MUX, eliminating the need for an external analog switch array. The 116 us conversion time and CMOS low-power operation suit battery-backed remote monitoring deployments. Industrial temperature grade tolerates outdoor enclosures. Microprocessor-compatible parallel interface allows direct connection to an 8-bit MCU data bus.
Recommandé
Factory Automation Sensor Interface
The MM74C948N's 16-channel MUX and 5 V CMOS interface support factory-automation sensor-interface modules where multiple analog sensors feed a central programmable-logic or microprocessor controller. PLC analog-input modules of the late-1980s/1990s vintage frequently used this family of devices. The industrial temperature range (-40C to +85C), through-hole PDIP package, and SAR deterministic latency simplify robust industrial-design verification.
Recommandé
Microprocessor-Based Data Logger
Microprocessor-based portable data loggers benefit from the MM74C948N's CMOS low-power operation, integrated MUX, and parallel interface to 8-bit microprocessors. A battery-powered field data logger can scan up to 16 analog channels sequentially at intervals determined by software, with the 8-bit SAR providing adequate resolution for trend logging of slow-changing analog signals. The 40-pin PDIP package supports hand-repair and field serviceability of legacy loggers.
Recommandé
Legacy Equipment Repair and Replacement
The MM74C948N's primary modern use case is repair of legacy industrial controllers, scientific instruments, and process-control equipment manufactured in the 1980s-1990s when this part was active. The through-hole PDIP-40 package matches original land patterns on legacy boards, and the pinout allows direct PCB-level replacement without adapter boards. For long-term repair assurance, authorized obsolete-component distributors and aftermarket brokers maintain traceability records for lot-date-code identification.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour MM74C948N — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | MM74C949N | MM74C948M | ADC0808CCN | ADC0809CCN |
|---|---|---|---|---|---|
| Package | PDIP-40 (N) | PDIP-40 (N) - same | SOIC-20 wide - cross-package | PDIP-40 - same | PDIP-40 - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 8 bit | 8 bit | 8 bit | 8 bit | 8 bit |
| Analog Input Channels | 16 (single-ended) | 16 | 16 | 8 | 8 |
| Supply Voltage | 5 V single supply | 5 V | 5 V | 5 V | 5 V |
| Architecture | SAR | SAR | SAR | SAR | SAR |
| Conversion Time (max) | 116 us | ~100 us (family-typical) | ~100 us | ~100 us | ~100 us |
| Lifecycle Status | Obsolete | Obsolete (family) | Obsolete | Obsolete | Obsolete |
Principaux différenciateurs
- 16-channel integrated analog multiplexer in PDIP-40 (vs ADC0809CCN)
- 8-bit SAR with sub-120us latency (vs MM74C949N (same family))
- 5 V single-supply CMOS operation (vs MAX1302 (modern SAR))
Notes de conception
The MM74C948N requires a clean +5 V supply; place a 0.1 uF ceramic decoupling capacitor as close as physically possible to the VCC pin (pin 39), with a 10 uF tantalum or aluminum bulk capacitor on the same supply rail. Analog and digital grounds should be joined at a single star point near the device to avoid ground-loop noise coupling into the SAR comparator. CMOS low-power design means supply current is modest, but high-frequency noise on VCC directly degrades 8-bit conversion accuracy.
When the on-chip 16-channel analog multiplexer switches between channels, allow adequate settling time (typically several time constants of the source impedance plus internal mux resistance) before initiating conversion. For high-impedance sources (>10 kohm), add an external input buffer/amplifier between the sensor and the MM74C948N analog input. Use shielded twisted pairs for analog input traces longer than a few centimeters to reject mains-frequency pickup.
Estimated: With a 5 V reference and 8-bit resolution, the MM74C948N's ideal LSB is approximately 19.6 mV (5 V / 256), so input signals must be kept within the device's specified analog input range to avoid saturation. Verify the START, OE, and ALE timing relationships against the datasheet timing diagram; violating setup/hold times will yield incorrect conversion results. Source impedance above ~10 kohm degrades conversion accuracy due to input leakage during the SAR bit-trial phase.
Informations de conformité
Compliance status not specified in verified web data; the part predates RoHS-era datasheets, so RoHS/lead-free status should be verified directly with the distributor or by lot/date-code inspection. AEC-Q100 not applicable for industrial/legacy through-hole ADC.
