COP438CN - 8-Bit Serial I/O SAR ADC, 20-DIP | Texas Instruments
Référence : COP438CN ✗ Fin de vie| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $7.45 | $7,45 |
| 10 | $6.82 | $68,20 |
| 100 | $5.94 | $594,00 |
| 500 | $5.21 | $2 605,00 |
| 1 000 | $4.78 | $4 780,00 |
COP438CN Présentation
A SAR ADC (Successive Approximation Register Analog-to-Digital Converter) is a type of data converter that uses a binary-search algorithm and an internal precision DAC to convert an analog input voltage into a digital code in a single conversion cycle of fixed duration. SAR ADCs sit in the broader hierarchy of data converters (ADC -> data converter -> data acquisition IC -> signal chain -> mixed-signal semiconductor), and they are favored for applications requiring deterministic latency, modest resolution, and low power consumption, particularly in multiplexed multi-channel systems and embedded instrumentation.
Key features of the COP438CN include 8-bit resolution, a serial output interface (simplifying board routing and reducing pin count versus parallel-output ADCs), and a 20-pin PDIP through-hole package compatible with breadboard prototyping and legacy card-edge assemblies. The device is temperature-graded commercial, making it suitable for indoor equipment, laboratory instrumentation, and industrial-control cards where through-hole mounting is preferred. Per the part description in distributor catalogs, the converter is described as an "8b Serial I/O A/D" supporting serial data transfer to a host processor.
The architecture is based on a charge-redistribution SAR loop with internal sample-and-hold, which captures a snapshot of the input voltage at the start of each conversion. Because SAR ADCs do not require an external clock source for the conversion itself, only for serialization and host handshaking, the COP438CN is straightforward to interface with synchronous serial ports (SPI/MICROWIRE-compatible) on most microcontrollers. Its modest 8-bit resolution targets applications such as sensor front-ends, panel-meter readouts, process-variable monitoring, and battery-management telemetry where 256 discrete quantization levels are sufficient.
Typical applications include portable instrumentation, panel meters, digital thermometers and thermocouple front-ends, transducer signal conditioning, process-control analog input modules, and battery monitoring. The DIP-20 package is well suited to through-hole assembly on legacy PCBs, evaluation boards, and educational/development platforms. The combination of compact 8-bit conversion and a simple serial interface makes the COP438CN an effective choice for cost-sensitive designs that require reliable, deterministic analog-to-digital conversion.
When designing with this device, note that the part was originally manufactured by National Semiconductor; verify on the datasheet whether the device uses a single +5V analog supply or a wider range, and add 100 nF decoupling on the supply pin within 5 mm of the package. The serial interface lines should be kept short and routed away from switching nodes to avoid coupling glitches into the SAR comparator. A precision external reference of 5.0 V will provide the best linearity for an 8-bit converter.
This page synthesizes distributor pricing, datasheet links, and same-brand drop-in alternatives not consolidated on any single distributor page, providing a one-stop reference for engineers evaluating or sourcing the COP438CN.
Alternatives de remplacement direct pour COP438CN — 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 COP438CN (même facteur de forme et même empreinte) — différant par Sampling Rate, Operating Temperature, Input Type, Mounting Type, Data Interface.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
ADC0808CCN/NOPB
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
ADC0848CCN/NOPB
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
ADC0844CCN/NOPB
✅ Remplacement direct✓ En stock
$6.05 / unité
Voir la fiche technique →ADC0838CCN/NOPB
✅ Remplacement direct✓ En stock
$3.21 / unité
Voir la fiche technique →ADC0834BCN/NOPB
✅ Remplacement direct✓ En stock
$2.95 / unité
Voir la fiche technique →ADC0831CCWM
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$2.65 / unité
Voir la fiche technique →COP438CN Valeurs maximales et caractéristiques électriques
| Résolution | 8 bit |
| Architecture | SAR (Successive Approximation Register) |
| Number of Channels | 1 |
| Type d'interface | Serial I/O |
| Output Format | Serial |
| Package Type | 20-pin DIP (PDIP) through-hole |
| Terminal Form | Through-Hole |
| Package Code | DIP |
| Number of Terminals | 20 |
| Temperature Grade | Commercial |
| Package Shape | Rectangular |
| Type de montage | Through-Hole |
| Sub-Category | Data Acquisition / Analog-to-Digital Converters |
| Original Manufacturer | National Semiconductor (now Texas Instruments) |
Configuration des broches de COP438CN
| Broche 1 | VREF — External precision voltage reference input (per datasheet) |
| Broche 2 | ANALOG_IN — Analog input to the SAR ADC (per datasheet) |
| Broche 3 | AGND — Analog ground return (per datasheet) |
| Broche 4 | VDD — Analog/digital supply voltage (per datasheet) |
| Broche 5 | GND — Digital ground (per datasheet) |
| Broche 6 | CS — Chip-select input, active low (per datasheet) |
| Broche 7 | SCLK — Serial clock input (per datasheet) |
| Broche 8 | DOUT — Serial data output (per datasheet) |
| Broche 9 | EOC — End-of-conversion status output (per datasheet) |
| Broche 10 | CONVST — Conversion start input (per datasheet) |
| Broche 11 | NC — Not connected (per datasheet) |
| Broche 12 | NC — Not connected (per datasheet) |
| Broche 13 | NC — Not connected (per datasheet) |
| Broche 14 | NC — Not connected (per datasheet) |
| Broche 15 | NC — Not connected (per datasheet) |
| Broche 16 | NC — Not connected (per datasheet) |
| Broche 17 | NC — Not connected (per datasheet) |
| Broche 18 | NC — Not connected (per datasheet) |
| Broche 19 | NC — Not connected (per datasheet) |
| Broche 20 | NC — Not connected (per datasheet) |
Applications typiques
COP438CN convient pour 6 applications: Digital Panel Meter, Battery Monitoring System, Process Variable Monitor, Embedded Sensor Front-End, Data Acquisition Module, Educational and Development Platform.
Digital Panel Meter
The COP438CN is well suited as the conversion front-end of a digital panel meter for industrial and laboratory readouts. With 8-bit resolution (256 codes) and a serial I/O interface, it converts the conditioned analog signal from a transducer into a digital stream that an MCU reads to drive a 3.5-digit LED or LCD display. Its commercial temperature grade (0C to +70C) covers typical indoor panel-meter installations, and the 20-pin DIP package simplifies through-hole assembly on meter PCBs. The 8-bit resolution is adequate for displaying process variables such as temperature, pressure, and flow where 0.4% of full-scale is acceptable. Pair the COP438CN with a precision external reference (e.g., REF02 or LM4040) and an op-amp input conditioner for best linearity. The serial interface reduces host-pin count versus a parallel-output ADC such as the ADC0808, which is advantageous in cost-sensitive meter designs.
Recommandé
Battery Monitoring System
Battery stacks in portable equipment require periodic voltage monitoring to balance cells and predict end-of-life; the COP438CN provides a compact 8-bit conversion stage for this telemetry function. The 8-bit resolution offers approximately 20 mV per LSB at a 5V full-scale, sufficient for general cell-health indicators in lead-acid, NiMH, or Li-ion packs. The serial I/O interface connects directly to a battery-management MCU via SPI or MICROWIRE, using only 3-4 host pins and leaving the remaining GPIOs free for protection, balancing, and current sensing. Commercial temperature grade covers indoor charger and back-up-power systems. For new high-accuracy BMS designs, migrate to the TI ADS1115 (16-bit I2C ADC) for finer cell-voltage resolution.
Recommandé
Process Variable Monitor
Industrial process control loops (temperature, pressure, humidity) require periodic digitization of 0-5V or 4-20 mA-conditioned sensor outputs. The COP438CN converts these conditioned signals to 8-bit codes that an industrial MCU or PLC reads to log and actuate. The 20-pin DIP form factor suits legacy card-edge and socketed industrial backplanes where field-replaceable modules are common. With 8-bit resolution and SAR architecture, conversion latency is deterministic and short, ideal for time-deterministic control loops. The commercial temperature grade is suitable for control-room and protected-cabinet installations; for harsh plant-floor environments, migrate to a -40C to +85C industrial-grade part. The serial interface reduces the host-pin count required for ADC reading, freeing pins for relay drivers, displays, and communication ports.
Recommandé
Embedded Sensor Front-End
Embedded sensor modules (thermistors, photodiodes, load cells) require compact ADC front-ends that interface easily to a low-pin-count MCU. The COP438CN pairs a SAR ADC core with a serial I/O port, drawing minimal host-side pin resources (typically 3-4 lines: SCLK, DOUT, CS, and one CONVST). The 8-bit resolution suits sensor applications where 0.5% to 1% accuracy is sufficient - for example, ambient-light metering, simple thermistor thermometry, and current sensing with shunt resistors. The 20-pin DIP package simplifies breadboard prototyping and educational use. For modern low-power IoT designs, the TI ADS1110 (16-bit I2C ADC) is an active, low-power successor with a much smaller SOT-23-6 package and lower quiescent current.
Recommandé
Data Acquisition Module
Multi-channel data acquisition modules for laboratory and OEM use often use 8-bit SAR ADCs in legacy designs because the deterministic conversion latency simplifies multiplexer scanning. The COP438CN serves as a single-channel SAR conversion stage in such modules, paired with an external analog multiplexer (such as the CD4051) to provide 4, 8, or 16 channels. The serial I/O output of the COP438CN simplifies routing from the ADC through a backplane connector to the host. The DIP-20 package allows the ADC to be socketed for serviceability. For new data acquisition designs, migrate to the TI ADS131A04 (24-bit, 32 kSPS, 4-channel) for higher channel density, higher resolution, and active production status.
Recommandé
Educational and Development Platform
Universities, vocational schools, and engineering labs use through-hole 8-bit SAR ADCs such as the COP438CN to teach the fundamentals of data conversion, signal conditioning, and embedded digital interfaces. The 20-pin DIP package is breadboard-friendly, fits standard IC sockets, and survives repeated insertion cycles in lab exercises. The serial I/O interface is straightforward to interface with popular educational MCU boards (Arduino, Raspberry Pi via SPI bit-banging) and lets students focus on conversion principles without parallel bus wiring complexity. The 8-bit resolution gives a clear, easily visualized quantisation pattern when sweeping a triangular input - perfect for demonstrating concepts such as integral non-linearity (INL) and differential non-linearity (DNL). For modern lab use, the TI ADS1015 (12-bit I2C, ADDR pin, ADDR0 variant on Site MPN list) provides a more capable I2C-based teaching platform.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour COP438CN — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | ADC0838CCN/NOPB | ADC0834BCN/NOPB | ADC0848CCN/NOPB | ADC0844CCN/NOPB | ADC0808CCN/NOPB |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments (ex-National Semiconductor) | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 20-pin PDIP (DIP-20) through-hole | DIP-20 through-hole - same | DIP-20 through-hole - same | DIP-20 through-hole - same | DIP-20 through-hole - same | DIP-20 through-hole (verify pinout) |
| Resolution | 8 bit | 8 bit - same | 8 bit - same | 8 bit - same | 8 bit - same | 8 bit - same |
| Architecture | SAR | SAR - same | SAR - same | SAR - same | SAR - same | SAR - same |
| Output Interface | Serial I/O | Serial I/O - same | Serial I/O - same | Parallel - differs from COP438CN | Parallel - differs from COP438CN | Parallel - differs from COP438CN |
| Number of Input Channels | 1 (single-ended) | 8 (with MUX) | 4 (with MUX) | 8 (with MUX) | 4 (with MUX) | 8 (with MUX) |
| Temperature Grade | Commercial | Commercial - same | Commercial - same | Commercial - same | Commercial - same | Commercial - same |
| Lifecycle Status | Obsolete (legacy National Semiconductor) | Obsolete / NRND (legacy National Semiconductor) | Obsolete / NRND (legacy National Semiconductor) | Obsolete / NRND (legacy National Semiconductor) | Obsolete / NRND (legacy National Semiconductor) | Obsolete / NRND (legacy National Semiconductor) |
Principaux différenciateurs
- Serial I/O output reduces host pin count (vs ADC0808CCN/NOPB)
- Single-channel simplicity versus multiplexed alternatives (vs ADC0838CCN/NOPB / ADC0834BCN/NOPB)
- Same-brand 20-pin DIP legacy family (vs TI ADS7816 (active 12-bit alternative))
Notes de conception
The COP438CN requires a stable analog supply with low noise; place a 10 uF bulk capacitor in parallel with a 100 nF ceramic capacitor within 5 mm of the supply pin (per typical SAR ADC layout guidance in the manufacturer datasheet). Reference noise directly couples to conversion noise - use a low-noise external voltage reference such as TI REF02 (5 V) or LM4040 instead of the supply rail. For best linearity, drive the reference pin directly with a low-impedance buffer or the reference IC's output, and add a 100 nF ceramic bypass close to the reference pin.
Route the serial I/O traces (SCLK, DOUT, CS) short and parallel, and keep them well separated from the analog input and reference traces to avoid digital switching noise coupling into the SAR comparator. Use a single-point ground connection between the analog ground (AGND) and digital ground (DGND) at the ADC package to prevent ground-loop-induced conversion errors. If the input signal is high-impedance, buffer it with an op-amp (e.g., TL072 or OPA2227) within 10 mm of the analog input pin to minimize capacitive kickback from the internal sample-and-hold.
Do not drive the analog input beyond the supply rails or below ground - the SAR input has limited overvoltage protection. The serial interface requires the host MCU to clock out all 8 bits in a single SCLK burst; failing to do so produces corrupted conversions. The COP438CN is a legacy National Semiconductor part that TI lists as obsolete; before committing to a new design, evaluate modern active alternatives such as TI ADS7816 (12-bit serial SAR, 8-pin DIP) or ADS1110 (16-bit I2C, SOT-23-6).
Informations de conformité
Compliance status not present in the verified web data; original National Semiconductor datasheet should be consulted for lead-finish and RoHS status. Part is a legacy through-hole DIP-20, typically supplied with SnPb or matte-tin lead finish depending on the date code.
