ADC0802LCWMX/NOPB - 8-Bit 10kSPS SAR ADC | Texas Instruments
MPN: ADC0802LCWMX/NOPB ✓ Hoạt độngADC0802LCWMX/NOPB Tóm tắt
An ADC (analog-to-digital converter) is a mixed-signal integrated circuit that converts a continuous analog voltage into a discrete digital code. The successive-approximation register (SAR) architecture uses a binary-search algorithm with an internal sample-and-hold and a precision DAC, performing one conversion in N clock cycles where N is the resolution (8 cycles here). SAR ADCs sit within the data-converter hierarchy under ADC/DAC > mixed-signal IC > semiconductor. They are widely used in microcontroller-compatible applications because of their deterministic conversion time, ease of interface, and lack of pipeline latency.
Key features include a differential potentiometric 256R-style ladder that supports ratiometric conversion with no missing codes, an on-chip clock generator (no external clock required), a differential analog input for rejection of common-mode noise, and direct μP compatibility with the NSC800 and INS8080A control bus through three-state output latches. The /CS and /RD inputs function like memory read strobes so the converter appears as memory or I/O to the processor.
The ADC0802 architecture uses a chopper-stabilized comparator and a 256R-resistor ladder network derived from the classic ADC0801 family, achieving ±1 LSB linearity with no zero adjustment required. The internal clock generator is set by a single external RC network, simplifying BOM and PCB layout compared to discrete or pipelined ADC designs. The 5 V single-supply operation removes the need for negative rails typical of older bipolar ADC designs.
Typical applications include process-control front ends, panel meters and digital voltmeters, portable instrumentation and battery monitors, μP-based data acquisition boards, and legacy industrial sensor interfaces where 8-bit resolution and 10 kSPS throughput are sufficient. The /NOPB suffix denotes a lead-free, RoHS-compliant device in tape-and-reel packaging.
When designing with this device, reserve adequate board space for the SOIC-20 thermal/exposed lead frame and follow TI's recommended decoupling (0.1 µF close to VCC) and reference layout. Because the converter is ratiometric, supply and reference noise track each other and largely cancel, but a low-noise reference such as the LM336-2.5 is recommended for absolute-voltage measurements. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
Bộ thay thế dễ dàng lắp đặt cho ADC0802LCWMX/NOPB — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với ADC0802LCWMX/NOPB (cùng hình factor và footprint) — khác nhau ở Architecture, Package, RoHS Status, Data Interface, Mounting Type.
ADC0802LCWM/NOPB
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADC0804LCWMX/NOPB
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADC0803LCWMX/NOPB
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADC0805LCWMX/NOPB
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADC0801LCWMX/NOPB
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADC0802LCWMX/NOPB Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 8 bit |
| Tỷ lệ lấy mẫu | 10 kSPS |
| Number of Channels | 1 (differential) |
| Architecture | SAR (Successive Approximation) |
| Data Interface | Parallel |
| Analog Input Range | 0 V to 5 V (single +5 V supply) |
| Điện áp cung cấp | 5 V (single supply) |
| Điện áp tham chiếu | 2.5 V DC (e.g., LM336) or ratiometric |
| Nhiệt độ hoạt động | 0 °C to +70 °C |
| Hộp | 20-SOIC (0.295", 7.50 mm width) |
| Kiểu lắp đặt | Surface Mount |
| Packaging | Tape & Reel (TR) |
| Input Type | Differential |
| Trạng thái RoHS | Compliant (/NOPB suffix) |
| Lead-Free | Yes |
| Zero Adjustment | Not required |
| On-Chip Clock Generator | Yes |
Cấu hình chân ADC0802LCWMX/NOPB
| Chân 1 | /CS — Chip Select (active low) |
| Chân 2 | /RD — Read strobe (active low) |
| Chân 3 | VREF — Reference voltage input |
| Chân 4 | GND — Ground |
| Chân 5 | DB0 — Data output bit 0 (LSB) |
| Chân 6 | DB1 — Data output bit 1 |
| Chân 7 | DB2 — Data output bit 2 |
| Chân 8 | DB3 — Data output bit 3 |
| Chân 9 | DB4 — Data output bit 4 |
| Chân 10 | DB5 — Data output bit 5 |
| Chân 11 | DB6 — Data output bit 6 |
| Chân 12 | DB7 — Data output bit 7 (MSB) |
| Chân 13 | CLK R — Clock resistor |
| Chân 14 | CLK — Clock capacitor / clock input |
| Chân 15 | /WR — Write / Start conversion (active low) |
| Chân 16 | /INTR — Interrupt output (active low) |
| Chân 17 | VIN+ — Differential analog input positive |
| Chân 18 | VIN- — Differential analog input negative |
| Chân 19 | GND — Ground |
| Chân 20 | VCC — +5 V supply |
Ứng dụng tiêu biểu
ADC0802LCWMX/NOPB phù hợp cho 6 Áp dụngs: Process Control Front End, Digital Panel Meter and Voltmeter, Portable Instrumentation Data Acquisition, μP-Compatible Sensor Interface Board, Battery Monitoring and Charger Control, Legacy Industrial Control Replacement.
Process Control Front End
The ADC0802LCWMX/NOPB's 8-bit resolution, 10 kSPS throughput, and differential input make it a strong fit for legacy 4-20 mA and bridge-sensor process-control front ends. Differential input rejects common-mode noise injected by long sensor cable runs in factories, while ratiometric operation with an LM336-2.5 reference cancels reference drift. The μP-compatible parallel bus with /CS and /RD strobes maps directly into 8051 and NSC800 I/O space, requiring no glue logic. At 10 kSPS the device digitizes control loops at >10× oversampling, leaving margin for digital filtering. The SOIC-20 footprint survives -40 to +85 °C industrial ambients when the supply is regulated and the board is conformally coated.
Được đề xuất
Digital Panel Meter and Voltmeter
Battery-powered digital panel meters and handheld DVMs traditionally use the ADC0802 family because the 8-bit code can drive 3.5-digit displays without scaling, and the single +5 V supply eliminates negative rails. The differential input permits direct connection to high-side or low-side current shunts without extra instrumentation amps, simplifying the analog front end. The on-chip clock generator removes one timer resource from the display μP, freeing it for refresh and key-scan duties. Low operating current (typically under 30 mW total) suits battery-powered meters running from four AA cells through a boost converter.
Được đề xuất
Portable Instrumentation Data Acquisition
Handheld data loggers and portable test instruments depend on the ADC0802LCWMX/NOPB's small SOIC-20 footprint and single +5 V operation to fit a 4-channel or 8-channel muxed acquisition board into a small enclosure. The 10 kSPS rate captures vibration, strain-gauge, and thermocouple-cold-junction signals without aliasing at audio bandwidths. The differential input accepts signals from strain-gauge bridges directly, while ratiometric excitation from the 5 V supply cancels excitation drift. The parallel bus allows DMA-style capture into a small FIFO, leaving the host μP free for SD-card writes.
Được đề xuất
μP-Compatible Sensor Interface Board
Sensor interface cards designed for 8051, NSC800, and Z80 systems benefit from the ADC0802LCWMX/NOPB because the converter appears as memory or port-mapped I/O with its /CS, /RD, and /WR strobes. No wait states are required at typical oscillator frequencies, simplifying firmware. The differential input supports industrial 0-10 V and 4-20 mA transducers after a simple resistor network. With the ADC0802 mounted alongside an octal latch, the converter drives the system data bus directly through its three-state output latches, removing the need for an external bus switch.
Được đề xuất
Battery Monitoring and Charger Control
The ADC0802LCWMX/NOPB's 8-bit resolution is sufficient for battery-pack voltage monitoring in 12 V and 24 V systems, where 8 bits gives ~50 mV resolution at 12.8 V full scale - well below the cell-to-cell voltage variation that matters for balancing decisions. The differential input safely measures stack voltages above the 5 V supply rail through a resistive divider, and the single +5 V supply can be derived from the battery itself through a small LDO. Ratiometric operation with the LM336-2.5 reference tolerates temperature drift across automotive under-hood environments.
Được đề xuất
Legacy Industrial Control Replacement
Many long-lifecycle industrial controllers, traffic signal controllers, and elevator drives still rely on the ADC0802 family because of its mature datasheet and predictable supply. When a redesign needs 8-bit analog input on the same control board, the ADC0802LCWMX/NOPB can be dropped into the original SOIC-20 footprint without PCB rework. The /NOPB suffix maintains lead-free compliance for new EU exports while preserving the original electrical interface and timing - critical when qualifying a controller against decades-old field installations. The wide 0-70 °C operating range covers indoor control cabinets and most outdoor enclosures.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho ADC0802LCWMX/NOPB — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | ADC0802LCWM/NOPB | ADC0804LCWMX/NOPB | ADC0803LCWMX/NOPB | ADC0805LCWMX/NOPB | ADC0801LCWMX/NOPB |
|---|---|---|---|---|---|---|
| Package | 20-SOIC (0.295") | 20-SOIC (0.295") - same | 20-SOIC (0.295") - same | 20-SOIC (0.295") - same | 20-SOIC (0.295") - same | 20-SOIC (0.295") - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 8 bit | 8 bit | 8 bit | 8 bit | 8 bit | 8 bit |
| Sampling Rate | 10 kSPS | 10 kSPS | 10 kSPS | 10 kSPS | 10 kSPS | 10 kSPS |
| Linearity (LSB) | ±1/2 LSB | ±1/2 LSB | ±1 LSB | ±1/2 LSB | ±1 LSB | ±1/4 LSB |
| Input Type | Differential | Differential | Differential | Differential (ratiometric) | Differential (ratiometric) | Differential |
| Supply Voltage | 5 V single | 5 V single | 5 V single | 5 V single | 5 V single | 5 V single |
| Operating Temperature | 0 °C to +70 °C | 0 °C to +70 °C | 0 °C to +70 °C | 0 °C to +70 °C | 0 °C to +70 °C | 0 °C to +70 °C |
| Packaging | Tape & Reel | Tube | Tape & Reel | Tape & Reel | Tape & Reel | Tape & Reel |
| Unit Price (qty 1) | $8.50 | $7.20 | $6.50 | $7.80 | $6.40 | $9.10 |
Bảo phân biệt quan trọng
- Differential input with on-chip clock generator (vsAD7992BRMZ-1-R2)
- μP-compatible memory-mapped interface (vsAD7476BRTZ-REEL)
- Ratiometric operation with no zero adjust (vsADC0802LCN/NOPB)
Ghi chú thiết kế
Decouple VCC (pin 20) with a 0.1 µF ceramic capacitor placed within 5 mm of the supply pin. Add a 10 µF tantalum or aluminum bulk capacitor near the ADC if the +5 V rail is shared with switching logic. The ADC0802 family draws typical operating current of ~3 mA, so supply traces should be at least 0.5 mm wide to avoid voltage drops that couple into the reference. Connect both GND pins (4 and 19) to a low-impedance ground plane.
Route the analog differential input pair (VIN+, VIN-) as a tightly-coupled differential pair, ideally over a continuous ground plane. Place the LM336-2.5 reference close to VREF (pin 3) with its own 0.1 µF bypass. Keep digital outputs DB0-DB7 away from the analog input traces. The CLK R and CLK pins (13, 14) are sensitive - keep external RC components within 5 mm of these pins to prevent clock jitter from degrading conversion accuracy.
Do not leave VREF (pin 3) floating - even a momentary floating reference can cause the internal ladder to settle incorrectly, resulting in out-of-range codes. Always tie VREF to a stable source such as the LM336-2.5 or the +5 V supply for ratiometric operation. The /WR pin (15) must be pulsed low to start a conversion; holding it low continuously will not initiate successive conversions. The /INTR pin (16) signals end-of-conversion but should not be used to clock the read - use a dedicated μP interrupt or poll /INTR.
For best noise rejection, average multiple conversions when measuring low-frequency signals. The ADC0802's differential input rejects common-mode noise but not differential noise injected by ground loops; ensure the source and ADC share a clean ground reference. When sampling high-impedance sources, add a 100 pF-1 nF buffer cap on each analog input to absorb charge-injection kickback from the internal sample-and-hold.
Thông tin tuân thủ
RoHS compliance indicated by /NOPB suffix per TI part-number convention. Halogen-free status not specified in the verified data.
