MAX172BCNG - 12-Bit 100kSPS CMOS ADC with On-Chip Reference | DIP-24
MPN: MAX172BCNG ✗ סוף ייצורMAX172BCNG סקירה
An SAR ADC is a type of analog-to-digital converter that uses a binary search algorithm across an internal capacitive DAC to digitize an analog input in N clock cycles for N-bit resolution. The MAX172 sits in the broader hierarchy of ADC architectures: it is a SAR ADC, which itself is a sub-type of medium-speed, medium-resolution data converter (12 bits, 100 kSPS) sitting between slower integrating ADCs (e.g., dual-slope) and faster flash or pipelined ADCs. SAR ADCs are favored when designers need deterministic latency, zero pipeline delay, and a small external component count - making the MAX172 a typical choice for embedded instrumentation front-ends.
Key features include a built-in buried-zener reference for low drift and low noise, ±5V input range (unipolar 0 to 5V or bipolar ±5V via external scaling), three-state outputs for direct bus connection, and an on-chip clock. The buried-zener reference topology provides better long-term stability and lower temperature drift than bandgap references common in CMOS ADCs of this era, which directly improves absolute-accuracy and gain-drift performance across -40C to +85C commercial operating temperatures.
Typical applications include process control, data acquisition boards, panel meters, weigh scales, digital signal processor front-ends, and any 12-bit measurement channel where simple parallel-readback from a microcontroller or FPGA is preferred over a serial interface.
When designing with this part, note that 12-bit absolute accuracy requires careful analog front-end design (input amplifier settling, charge-kickback filtering) and that the through-hole PDIP package is preferred for hand-soldered prototypes and industrial control modules rather than high-density SMT boards.
חלופות תחליף ישיר עבור MAX172BCNG — אותו מארז, תואם פין-לפין. חלקים במארז שונה הדורשים עיבוד מחדש של ה-PCB אינם נכללים.
וריאנטים בסדרה זו
דגמים מאותה סדרה התואמים Drop-in עם MAX172BCNG (אותו גורם צורה וטביעת רגל) — שונים ב Package, Resolution, Mounting Type, Data Interface, Input Voltage Range.
MAX172BCNG+
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
MAX172AENG
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
MAX173CNG
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
MAX191ACNG
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
MAX128BCNG
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←MAX156BCNG
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←MAX172BCNG דירוגים מרביים ומאפיינים חשמליים
| רזולוציה | 12 bits |
| Conversion Time | 10 us |
| Throughput (Sample Rate) | 100 kSPS |
| Architecture | SAR (Successive Approximation) |
| Number of Channels | 1 |
| Input Type | Single-Ended |
| Data Interface | Parallel (12-bit) |
| טווח מתח כניסה | 0 V to 5 V (unipolar) / ±5 V (bipolar with external scaling) |
| מתח אספקה | +5 V (single supply) |
| Reference Type | Internal buried zener |
| טמפרטורת פעולה | 0C to +70C (commercial grade, B suffix) |
| מארז | 24-pin PDIP (NG) |
| סוג הרכבה | Through-Hole (DIP) |
| Sample Rate (max) | 100 kSPS |
תצורת פינים של MAX172BCNG
| פין 1 | VREF — Reference Voltage Output/Input (buffered buried zener) |
| פין 2 | REFADJ — Reference adjust |
| פין 3 | AGND — Analog Ground |
| פין 4 | AIN — Analog Input |
| פין 5 | RANGE — Input range select |
| פין 6 | DGND — Digital Ground |
| פין 7 | VDD — +5V supply |
| פין 8 | CS — Chip Select (active low) |
| פין 9 | RD — Read (active low) |
| פין 10 | BUSY — Busy / End of Conversion |
| פין 11 | HBEN — High Byte Enable |
| פין 12 | D11 — Data Bit 11 (MSB) |
| פין 13 | D10 — Data Bit 10 |
| פין 14 | D9 — Data Bit 9 |
| פין 15 | D8 — Data Bit 8 |
| פין 16 | D7 — Data Bit 7 |
| פין 17 | D6 — Data Bit 6 |
| פין 18 | D5 — Data Bit 5 |
| פין 19 | D4 — Data Bit 4 |
| פין 20 | D3 — Data Bit 3 |
| פין 21 | D2 — Data Bit 2 |
| פין 22 | D1 — Data Bit 1 |
| פין 23 | D0 — Data Bit 0 (LSB) |
| פין 24 | WR/RCLK — Write / Conversion Start |
יישומים טיפוסיים
MAX172BCNG מתאים עבור 6 יישוםs: Industrial Data Acquisition Board, Process Control Analog Front-End, Panel Meter and Weigh-Scale Design, Embedded DSP / Microcontroller Sensor Input, Rack-Mount Instrumentation Module, Legacy Replacement in Maintenance / Repair Operations.
Industrial Data Acquisition Board
The MAX172BCNG's 12-bit resolution at 100 kSPS and parallel data bus are well-matched to multi-channel industrial data-acquisition cards that read sensors at moderate speeds. The internal buried-zener reference eliminates the cost of an external REF02/ADR01 chip, while the 24-pin PDIP package is preferred for ruggedized through-hole industrial PCBs. Designers typically pair the ADC with an input op-amp front-end, then latch D0-D11 into an FPGA or 8051 family microcontroller using CS and RD control lines.
מומלץ
Process Control Analog Front-End
The MAX172BCNG converts a 0-5V or ±5V analog process variable (temperature, pressure, flow) into a 12-bit parallel word read directly by a PLC or DSP controller. With 10us conversion time and single +5V supply, it suits 4-20mA loop-powered or panel-mount instrumentation. The internal buried-zener reference provides low drift over the commercial 0-70C operating range, which is important for stable process measurements in factory-floor environments.
מומלץ
Panel Meter and Weigh-Scale Design
Weigh scales and digital panel meters require stable 12-bit accuracy and an internal reference to keep the BOM small. The MAX172BCNG's buried-zener reference, parallel interface, and easy through-hole DIP-24 package suit handheld bench instruments and through-hole production modules. With one ADC per scale channel, the device pairs with a load-cell op-amp (e.g., MAX145 series instrumentation front-end) and a display driver for a complete weigh-scale bill of materials.
מומלץ
Embedded DSP / Microcontroller Sensor Input
Embedded DSP and 8/16-bit microcontroller boards use the MAX172BCNG to digitize analog sensors at 100 kSPS while the CPU performs the read in a single bus cycle. The MAX172's three-state output buffers prevent bus contention on shared data buses, and the BUSY/EOC pin allows the CPU to wait or interrupt on conversion-complete. Common pairings include an 8051 or HC11 reading motor-control sensor signals, with D0-D11 directly captured on a single MOV instruction.
מומלץ
Rack-Mount Instrumentation Module
Rack-mount test and measurement modules use the MAX172BCNG because its parallel interface eliminates the latency of serial ADC protocols. The 24-pin DIP package is well suited to hand-soldered prototype instrumentation and through-hole backplanes that require industrial robustness. Combined with the buried-zener reference, the MAX172 delivers stable 12-bit absolute accuracy across the 0-70C commercial temperature range, which is important for laboratory and production-line test gear.
מומלץ
Legacy Replacement in Maintenance / Repair Operations
Many production-line test fixtures and military/aerospace subsystems designed in the 1990s still use the MAX172BCNG on their analog input boards. With the part in NRND status, MRO operations rely on remaining distributor stock plus drop-in replacements such as the MAX172BCNG+ (RoHS version) or the MAX172AENG (extended-temperature grade) to keep equipment running. The shared 24-pin PDIP footprint means a repair technician can swap the chip without modifying the surrounding analog front-end or microcontroller interface logic.
מומלץ
סיכום מוצרים מומלצים
נתוני עזר הנדסיים עבור MAX172BCNG — השוואה, הנחיות תכנון ומידע על תאימות.
מדריך בחירה
השוואה עם חלופות
| פרמטר | מוצר זה | MAX172BCNG+ | MAX172AENG | MAX173CNG | MAX191ACNG | MAX128BCNG | MAX156BCNG |
|---|---|---|---|---|---|---|---|
| Brand | Analog Devices (formerly Maxim Integrated) | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | PDIP-24 (NG) | PDIP-24 (NG) - same | PDIP-24 (NG) - same | PDIP-24 (NG) - same | PDIP-24 (NG) - same | PDIP-24 (NG) - same | PDIP-24 (NG) - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits (multi-channel) | 12 bits (multi-channel) |
| Architecture | SAR | SAR | SAR | SAR | SAR | SAR | SAR |
| Data Interface | Parallel 12-bit | Parallel 12-bit | Parallel 12-bit | Parallel | Parallel | Parallel | Parallel |
מבדילים עיקריים
- Integrated buried-zener voltage reference (לעומתMAX173CNG)
- Single-supply +5V operation with parallel 12-bit bus (לעומתMAX155AEWI (8-bit multi-channel))
- Commercial 0-70C 'B' temperature grade (לעומתMAX172AEWG (extended -40 to +85C))
הערות תכנון
Decouple VDD (pin 7) with a 10uF electrolytic bulk capacitor and a 100nF ceramic capacitor placed within 5 mm of the supply pin. According to the MAX172 datasheet, clean analog supply decoupling is required to keep the internal buried-zener reference free from digital switching noise. Avoid running high-current digital return currents under the AGND/DGND pins - use separate analog and digital ground returns that meet only at the ADC's GND pins. Estimated: assuming VDD = 5V and typical quiescent current per the datasheet, the device draws modest active power; for absolute quiescent/active numbers consult the datasheet Electrical Characteristics table.
For through-hole DIP-24 designs, route the 12 parallel data lines (D0-D11) as a clean bus with matched lengths, and keep the analog input trace short and guarded by ground copper on both sides. According to the MAX172 datasheet application section, the AIN trace should be isolated from digital bus lines to avoid capacitive coupling. Place the analog input RC filter (typically 1kohm + 10nF) within 5 mm of pin 4 to provide charge-kickback absorption between conversions.
Do not leave unused digital output pins floating if they share a bus - tie them to VDD through 100 kohm resistors or enable the HBEN/three-state control per the datasheet timing diagram. Avoid driving the analog input above VDD or below AGND; if bipolar ±10V signals are needed, use an external op-amp front-end to scale into the 0-5V input range. According to the datasheet, exceeding the input range permanently damages the ADC. CS must be held high (de-selected) when not reading to keep BUSY/CNT in the correct state.
מידע על תאימות
RoHS/REACH/lead-free compliance not specified in the verified data supplied - the '+' suffix version (MAX172BCNG+) is documented as RoHS-compliant per distributor listings, but the bare MAX172BCNG status was not confirmed. AEC-Q100 not applicable (this is a through-hole legacy ADC, not automotive-qualified).
