MAX189BC/D - 12-Bit SAR ADC, Serial, 75ksps | Maxim Integrated
MPN: MAX189BC/D ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.85 | $9.85 |
| 10 | $8.95 | $89.50 |
| 100 | $7.4 | $740.00 |
| 500 | $6.1 | $3,050.00 |
| 1,000 | $5.2 | $5,200.00 |
MAX189BC/D Overview
A SAR ADC (Successive Approximation Register Analog-to-Digital Converter) is a type of ADC that converts an analog input to a digital output using a binary-search algorithm against an internal DAC. SAR ADCs balance conversion speed, power consumption, and resolution, making them the workhorse of medium-speed data-acquisition applications such as industrial sensors, handheld instruments, and process-control front-ends. In the broader IC taxonomy, an SAR ADC sits under Data Converters -> ADCs -> Medium-Speed ADCs -> Power-Efficient ADCs.
Key features of the MAX189BC/D include +/- 1/2 LSB integral nonlinearity (INL), a fast 1.5-microsecond acquisition-time track/hold, an internal 4.096V reference that can also drive external loads, a hardware- or software-controllable shutdown mode that drops supply current to 2 microamps, and 1.5 mA operating current. The serial interface is compatible with SPI, QSPI, and MICROWIRE, easing connection to most modern microcontrollers and DSPs without external glue logic.
The MAX189BC/D's architecture uses a capacitive-charge-distribution DAC at its core, with a precision comparator and SAR logic, plus an integrated reference and reference buffer. The "C" speed grade and "B" resolution grade (with +/- 1 LSB INL vs. the A grade +/- 1/2 LSB) make the BC variant an attractive cost-optimized option. The bare-die format allows hybrid-module integrators and MCM (multi-chip-module) designers to minimize parasitic inductance and shrink board area beyond what packaged parts permit.
Typical applications include portable data loggers, pen-tablet digitizers, battery-powered instrumentation, isolated sensor read-out stages, and industrial process-control front-ends. The combination of a single +5V supply, low power, and serial output suits distributed measurement nodes and space-constrained designs.
When designing with the MAX189BC/D, provide a clean analog ground plane separate from the noisy digital return, bypass VDD with a 0.1 microfarat ceramic close to each die supply bond, and use the SHDN pin for duty-cycling to extend battery life. The internal reference can source up to several hundred microamps; if your design also needs a reference for external ADCs, budget that current draw into the worst-case accuracy calculation.
This page synthesizes distributor pricing, pin-compatible alternatives, and practical design notes not found in the manufacturer datasheet.
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Request AlternativesMAX189BC/D Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Number of Inputs | 1 single-ended |
| Conversion Type | SAR (Successive Approximation) |
| Input Voltage Range | 0 V to 5 V |
| Supply Voltage | +5 V (single supply) |
| Sampling Rate | 75 ksps maximum |
| Conversion Time | 8.5 us (typ) |
| Track/Hold Acquisition Time | 1.5 us (typ) |
| Internal Reference Voltage | 4.096 V (buffered) |
| Integral Nonlinearity (INL) | +/- 1 LSB (B grade) |
| Operating Current (active) | 1.5 mA (typ) |
| Shutdown Current | 2 uA (typ) |
| Serial Interface | SPI/QSPI/MICROWIRE-compatible, 3-wire |
| Package | Die (unpackaged bare die) |
| Temperature Grade | Commercial |
MAX189BC/D die (unpackaged bare die) Pin Configuration Guide
Pin configuration for MAX189BC/D (die (unpackaged bare die) package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for MAX189BC/D.
Refer to the datasheet for full pin configuration.
Typical Applications
MAX189BC/D is suitable for 7 applications: Portable Data Loggers, Battery-Powered Instrumentation, Industrial Process Control Front-Ends, Pen-Tablet Digitizers and Touch Sensing, Isolated Sensor Read-Out Stages, Hybrid Module and MCM Designs, Handheld Test and Measurement.
Portable Data Loggers
The MAX189BC/D fits portable data loggers because it draws only 1.5 mA in active mode and falls to 2 uA in hardware shutdown, extending battery life across multi-week acquisition campaigns. Its 12-bit resolution and 75 ksps throughput comfortably digitize slow-channel thermocouples, strain gauges, and 4-20 mA current loops used in field instrumentation. The internal 4.096V reference removes one or two external components, shrinking BOM cost for high-volume handheld units, while the SPI output saves microcontroller GPIO pins that are often scarce in compact logger designs.
Recommended
Battery-Powered Instrumentation
The MAX189BC/D is well matched to battery-powered digital multimeters, clamp meters, and isolated sensor read-out boards where the +5V rail is generated by a boost converter from a 3V cell. The part's 8.5 microsecond conversion time and 1.5 microsecond acquisition support rapid autoranging without inducing audible noise on the analog front-end. Duty-cycling via the SHDN pin lets the system sleep at 2 microamps between conversions, a critical capability for handheld instruments that must last months on a single AA cell.
Recommended
Industrial Process Control Front-Ends
Process-control analog front-ends that read 4-20 mA current loops or 0-5 V sensor outputs benefit from the MAX189BC/D's integral +/- 1 LSB linearity and 75 ksps throughput, which provides enough headroom for multiplexed multi-channel scanning. The integrated 4.096V reference removes the need for an external reference and saves panel space inside DIN-rail mounted controllers. The 3-wire SPI output cleanly interfaces to industrial MCUs such as the MAXQ or ARM Cortex-M families, enabling deterministic register reads under RTOS control without parallel-bus loading.
Recommended
Pen-Tablet Digitizers and Touch Sensing
The MAX189BC/D's 75 ksps sampling rate and 12-bit resolution capture stylus-tip pressure and position at human-handwriting speeds without aliasing, making it suitable for pen-tablet digitizers and consumer touch-control peripherals. The serial interface keeps the flex-cable count to three (CS, SCLK, DOUT), allowing clean routing between the sensor matrix and the host MCU. The 2-microamp shutdown mode lets the digitizer sleep between pen-down events, extending battery life in wireless tablets.
Recommended
Isolated Sensor Read-Out Stages
Isolated analog front-ends using digital isolators and a single isolated +5V rail pair cleanly with the MAX189BC/D, which presents only three digital signals to the isolator (CS, SCLK, DOUT). Compared with parallel-output ADCs, the MAX189BC/D's SPI interface cuts isolator channel count - and therefore BOM cost - by an order of magnitude. The internal 4.096V reference tolerates the warm-up drift common in isolated modules, and the 1.5 mA active current keeps the isolated-side supply budget under 10 mW even at full 75 ksps throughput.
Recommended
Hybrid Module and MCM Designs
Because the MAX189BC/D ships as a bare die, it integrates naturally into hybrid modules and multi-chip modules (MCMs) where space and parasitic inductance are at a premium. Designs targeting medical imaging probes, downhole oil-drilling sensors, and aerospace instrumentation place the MAX189BC/D die alongside an op-amp die and reference die in a single ceramic substrate, eliminating the bond-wire inductance of a packaged part. Designers working in this space will value the matched 4.096V reference and SPI-compatible serial output, both of which simplify cross-die interconnections on the substrate.
Recommended
Handheld Test and Measurement
The MAX189BC/D's combination of 12-bit resolution, 75 ksps sampling, and 1.5 mA active current suits handheld oscilloscope-style probes and signal-conditioner modules where low weight and long battery life are mandatory. The integrated track/hold and 4.096V reference simplify the analog signal chain to a resistor-divider, op-amp buffer, and the ADC itself, which keeps the front-end BOM under a dozen components. Designers targeting portable test instruments can use the SPI interface to stream captured samples to an OLED display and on-board memory without taxing the host microcontroller.
Recommended
Recommended Products Summary
Engineering reference data for MAX189BC/D — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX189CC/D | MAX189AC/D | MAX187BC/D | MAX187BCPA |
|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | Die (bare die) | Die (bare die) - same | Die (bare die) - same | Die (bare die) - same | 8-pin PDIP - same family, packaged |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate | 75 ksps | 75 ksps | 75 ksps | 75 ksps | 75 ksps |
| Integral Nonlinearity | +/- 1 LSB (B grade) | +/- 1 LSB (C grade) | +/- 1/2 LSB (A grade) | +/- 1 LSB | +/- 1 LSB |
| Output Interface | Serial (SPI) | Serial (SPI) | Serial (SPI) | Parallel (12-bit) | Parallel (12-bit) |
| Internal Reference | 4.096 V buffered | 4.096 V buffered | 4.096 V buffered | 4.096 V buffered | 4.096 V buffered |
| Supply Voltage | +5 V | +5 V | +5 V | +5 V | +5 V |
Key Differentiators
- Bare-die format enables hybrid and MCM integration (vs MAX187BCPA)
- Lower-cost +/-1 LSB INL versus A-grade precision (vs MAX189AC/D)
- SPI serial output minimizes isolator channel count (vs MAX187BC/D)
Design Notes
Decouple VDD with a 0.1 uF ceramic capacitor placed within 2 mm of the die bond pad, and add a 10 uF bulk capacitor at the supply entry to the MCM or hybrid substrate. The MAX189BC/D draws 1.5 mA active and 2 uA in shutdown, so the bulk capacitor value is set by the worst-case burst-conversion current rather than the average. Estimated: at 75 ksps with 8.5 us per conversion, the maximum RMS ripple on the supply stays under 5 mV if the bulk capacitor is mounted within 5 mm of the VDD pad.
Separate the analog ground (AGND) and digital ground (DGND) on the substrate and tie them together at a single point near the GND bond pad. Keep digital traces (CS, SCLK, DOUT) routed away from the AIN and REF pads to avoid capacitive coupling that appears as input-sampling kickback. For die-level assembly, minimize bond-wire length on the AIN node to keep track/hold acquisition accurate at 1.5 us.
Do not drive SHDN faster than the data-sheet maximum slew rate, otherwise the internal bias recovery may corrupt the first conversion. Always issue a dummy conversion after wake-up from shutdown before reading a meaningful sample. The internal reference requires the REF cap pin to be bypassed with at least 4.7 uF; reducing this capacitor degrades reference stability and ADC linearity.
When using long PCB or flex-cable runs, place a 100 ohm series resistor at the SCLK and DOUT drivers near the source to dampen transmission-line ringing. The MAX189BC/D's SPI inputs are not 5V tolerant if the controller runs at 3.3 V, so confirm the Vih threshold against the controller's VOH. Estimated: with a 100 ohm series resistor and 10 pF load, the SCLK edge rate stays below 5 ns/V into the ADC pin.
Compliance Information
RoHS and lead-free per Maxim product page. Not AEC-Q100 qualified - the MAX189 is commercial temperature grade. Bare-die parts are typically not halogen-free tested in the same way as packaged parts; consult factory for specific requirements.
