TSA7887ARMZ - 12-Bit 125ksps 2-Ch SAR ADC | Silicon Labs
MPN: TSA7887ARMZ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.2 | $5.20 |
| 10 | $4.65 | $46.50 |
| 100 | $3.92 | $392.00 |
| 500 | $3.48 | $1,740.00 |
| 1,000 | $3.1 | $3,100.00 |
TSA7887ARMZ Overview
An SAR ADC (successive-approximation-register analog-to-digital converter) is a type of data converter that uses a binary-search algorithm against an internal capacitive DAC to resolve an analog input one bit per conversion clock cycle. It belongs to the broad family of analog-to-digital converters (ADCs), which itself is part of the data-converter hierarchy inside mixed-signal and signal-chain integrated circuits. The SAR architecture is favored over delta-sigma and pipeline ADCs when low-latency deterministic conversion, small package size, and moderate sample rates (tens to hundreds of ksps) are required, particularly in multiplexed multi-channel systems.
Key features of the TSA7887ARMZ include an internal 2.5V reference (selectable externally via the REF pin), a 2-channel analog input multiplexer, true 12-bit performance with no missing codes, a 125 ksps maximum throughput, low power dissipation (typically under 2.5 mW at 3V/100 ksps), and automatic power-down between conversions that drops supply current below 1 microampere. The device uses an external clock for the serial interface and supports both unipolar single-ended and pseudo-differential input configurations.
The device leverages a charge-redistribution SAR core with input transient suppression and an automatic input common-mode settling window, which makes it tolerant of source-impedance variations when channels are switched. Combined with the internal precision reference, this means the TSA7887ARMZ can replace an external ADC + reference + op-amp buffer chain in many space-constrained designs.
Typical applications include portable and battery-powered data loggers, industrial process-control sensor front-ends (thermocouple, RTD, strain-gauge bridges), handheld instrumentation, and multiplexed 4-20 mA loop monitors. Designers also use it in optical sensor modules and consumer battery chargers where periodic current/voltage telemetry is required.
When designing with this part, size the input RC network and reference bypass capacitors per the datasheet's application circuit - inadequate decoupling is the most common cause of last-2-LSB noise and gain drift in SAR circuits. Consider the MAX1276CTC+ from Maxim's family as a drop-in 8-pin MSOP alternative if higher conversion speed is needed.
This page synthesizes distributor pricing, drop-in MSOP-8 alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for TSA7887ARMZ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with TSA7887ARMZ (same form factor and footprint) — differing in Package, Architecture, Sampling Rate, Number of Channels, Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
TSA7887ARMZ-REEL
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →MAX1276CTC+T
✅ Drop-In✓ In Stock
$3.42 / Unit
View Datasheet →MAX1275ACTC+T
✅ Drop-In✓ In Stock
$4.75 / Unit
View Datasheet →MAX1295BCEI
✅ Drop-In✓ In Stock
$11.2 / Unit
View Datasheet →MAX157BEPA
✅ Drop-In✓ In Stock
$3.62 / Unit
View Datasheet →TSA7887ARMZ Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Number of Channels | 2 (single-ended) / 1 (pseudo-differential) |
| Sampling Rate | 125 ksps |
| Architecture | SAR (Successive Approximation Register) |
| Input Type | Single-ended, pseudo-differential |
| Analog Supply Voltage | 2.7 V to 5.25 V |
| Digital Supply Voltage | 2.7 V to 5.25 V |
| Internal Reference Voltage | 2.5 V |
| Reference Mode | Internal 2.5 V or external |
| Digital Interface | SPI / QSPI / MICROWIRE-compatible serial |
| Shutdown Current | < 1 µA |
| Operating Temperature | -40 °C to +85 °C |
| Package | 8-pin MSOP (RMZ) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Grade | Industry / xIND second source |
TSA7887ARMZ Pin Configuration
| Pin 1 | AIN1 / I.C. — Analog input channel 1 (or pseudo-differential negative input) |
| Pin 2 | REF / AIN0 — Internal 2.5V reference bypass / analog input channel 0 |
| Pin 3 | GND — Analog and digital ground |
| Pin 4 | CS — Active-low chip select for SPI interface |
| Pin 5 | SCLK — Serial clock input for SPI/QSPI/MICROWIRE |
| Pin 6 | DOUT — Serial data output (ADC conversion results) |
| Pin 7 | VDD — Analog and digital supply (2.7 V to 5.25 V) |
| Pin 8 | SHDN — Hardware shutdown, low = power-down (<1 uA) |
Typical Applications
TSA7887ARMZ is suitable for 7 applications: Battery-Powered Data Loggers, Industrial Process Control Sensor Front-Ends, Handheld Test & Measurement Instrumentation, Optical Sensor Modules, Consumer Battery Chargers, Multiplexed 4-20 mA Loop Monitors, Strain-Gauge Bridge Readout (Weigh Scales).
Battery-Powered Data Loggers
The TSA7887ARMZ excels in battery-powered data loggers because of its 12-bit SAR precision, <1 µA auto power-down current between conversions, and 2.5 mW active dissipation at 3V/100 ksps. Packaged in a 3 mm x 3 mm MSOP-8, it occupies minimal PCB area, leaving more room for the battery and BLE module. The internal 2.5V reference eliminates a separate reference IC, shrinking the BOM. For example, in a remote environmental sensor running on a single CR2032 coin cell, the TSA7887ARMZ can settle a single conversion in 8 µs, return to <1 µA standby, and achieve multi-year battery life. Designers should pair it with low-power MCUs like TI MSP430 or Silicon Labs' own EFM32 family. Performance tip: bypass AVDD with a 1 µF X7R ceramic plus a 0.1 µF HF cap placed within 2 mm of the supply pin to avoid last-2-LSB gain drift.
Recommended
Industrial Process Control Sensor Front-Ends
In industrial process-control loops reading thermocouples, RTDs, and 4-20 mA current loops, the TSA7887ARMZ delivers the 12-bit resolution and 125 ksps throughput needed for the typical 4 Hz to 10 kHz control loop. Its 2-channel mux allows simultaneous monitoring of a process variable and a diagnostic point - for instance temperature plus supply current. The internal 2.5V reference ratiometrically rejects supply drift, while the SPI/QSPI/MICROWIRE-compatible serial port interfaces directly to most industrial MCUs. Performance consideration: front-end protection with TVS diodes and isolated signal chains (e.g. using ISO7241 isolators) preserves the ADC's input range. The 8-pin MSOP footprint keeps the front-end compact within DIN-rail-mounted I/O modules.
Recommended
Handheld Test & Measurement Instrumentation
Handheld multimeters, oscilloscope probes, and field calibration tools benefit from the TSA7887ARMZ's low power draw and 2-channel input. Its SAR architecture provides deterministic low-latency conversion - no pipeline delay - making single-shot acquisitions of AC line voltages and RF envelope detectors clean and repeatable. The 2.5V internal reference supports true 2.5V full-scale inputs, simplifying per-channel scaling. The 3 mm x 3 mm MSOP-8 package suits highly miniaturized handheld form factors like clamp meters and optical tachometers. Battery-life benefit: with auto power-down between conversions, the ADC contributes negligibly to standby drain on a Li-ion-powered handheld. Calibrate once per shift using an external 4.096V reference override on the REF pin.
Recommended
Optical Sensor Modules
Optical sensor modules - ambient light sensors, colorimeters, and proximity detectors - frequently require a small fast ADC for translating photodiode current into a digital code. The TSA7887ARMZ's 12-bit resolution across two channels lets the module digitize both the sensor signal and an LED drive-current monitor simultaneously. Its low noise floor and small MSOP-8 package support the tight form factor of wearable or smartphone-embedded modules. Performance tip: drive the photodiode through a transimpedance amplifier (TIA) and DC-cancel any ambient by chopping the LED; the TSA7887ARMZ settles within 8 µs - fast enough for 10 kHz synchronized sampling.
Recommended
Consumer Battery Chargers
In smart consumer battery chargers (Li-ion, NiMH, lead-acid), the TSA7887ARMZ monitors charge voltage and current via two analog channels, providing closed-loop telemetry to the charger MCU. With 12-bit resolution, the device can resolve sub-10 mV on a 5V scale - enough for accurate CC/CV charge-transition detection. The internal 2.5V reference is ratiometric to a 5V USB rail when used with a precision divider, eliminating a separate reference. Power dissipation is modest enough that even 1 A-capable chargers stay within thermal envelope. Application tip: pair with a low-side current-sense amplifier (e.g. INA180) and route both signals to the 2 channels of the TSA7887ARMZ for fully digital telemetry.
Recommended
Multiplexed 4-20 mA Loop Monitors
Programmable Logic Controllers (PLCs) and process-control remote I/O modules handle dozens of 4-20 mA current loops per board. The TSA7887ARMZ is well suited as a per-board low-cost 12-bit ADC for these loops; while most PLCs prefer higher-density 16-channel SAR converters, the TSA7887ARMZ covers distributed I/O nodes that require only 2 channels each. The MSOP-8 footprint keeps per-channel PCB density low, and the internal reference simplifies ratiometric conversion from a 250 Ω sense resistor. Performance tip: place a 250 Ω ±0.1% precision resistor in series with each loop and buffer with a low-offset op-amp before the ADC input to maintain 12-bit integrity across temperature.
Recommended
Strain-Gauge Bridge Readout (Weigh Scales)
Compact digital weighing scales and force gauges often pair a 4-arm Wheatstone bridge load cell with a low-power 12-bit ADC. The TSA7887ARMZ's 2 channels allow simultaneous reading of the bridge output (after amplification) and a temperature sensor for compensation. Its auto power-down between conversions keeps average current draw below 5 mW on a 5V USB-C powered scale, even at 100 conversions per second. The 2.5V internal reference can be overdriven by an external ratiometric 1.024V or 2.5V low-drift reference like the MAX6129 for higher-precision applications. Design tip: select an instrumentation amplifier (e.g. INA333) with low offset drift to preserve the TSA7887ARMZ's 12-bit noise-free resolution across the 0-3 mV/V bridge output range.
Recommended
Recommended Products Summary
Engineering reference data for TSA7887ARMZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TSA7887ARMZ-REEL | MAX1276CTC+T | MAX1275ACTC+T | MAX1295BCEI | MAX157BEPA |
|---|---|---|---|---|---|---|
| Brand | Silicon Labs | Silicon Labs | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | MSOP-8 (RMZ) | MSOP-8 (RMZ) - same | TDFN-12 - similar small SMD | MSOP-10 - same family, slightly larger | QSOP-28 - larger | PDIP-8 - through-hole |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 10 bits |
| Sampling Rate | 125 ksps | 125 ksps | 200 ksps | 225 ksps | 250 ksps | 200 ksps |
| Number of Channels | 2 | 2 | 12 | 8 | 12 | 2 |
| Internal Reference Voltage | 2.5 V | 2.5 V | 2.5 V | 4.096 V | 2.5 V | 2.5 V |
| Supply Voltage Range | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 3 V to 3.6 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 2.7 V to 5.25 V |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | 0 °C to +70 °C | 0 °C to +70 °C | -40 °C to +85 °C | -40 °C to +85 °C |
| Shutdown Current | < 1 µA | < 1 µA | 1 µA | 5 µA | 5 µA | 10 µA |
Key Differentiators
- Lowest shutdown current in class (< 1 µA) (vs MAX157BEPA)
- True 12-bit, no-missing-codes performance (vs MAX157BEPA)
- MSOP-8 footprint with internal 2.5V reference (vs MAX1295BCEI)
Design Notes
Bypass AVDD and DVDD with a 1 µF X7R ceramic plus a 0.1 µF HF ceramic placed within 2 mm of the supply and GND pins. SAR ADCs draw transient currents on each conversion clock edge; inadequate decoupling is the most common cause of last-2-LSB noise and apparent gain drift. For battery-powered designs, route the chip select (CS) high between conversions to allow the internal auto power-down to drop supply current below 1 µA.
Keep the analog input traces short, symmetric, and routed over a single continuous ground plane. Avoid routing digital lines (CS, SCLK, DOUT) parallel to AIN0/AIN1, which couples digital switching transients into the analog front-end. Place the reference bypass capacitor (1 µF minimum, 10 µF preferred for very high source-impedance sensors) directly across the REF pin to GND. Recommendation: use a 4-layer PCB with separate analog and digital ground planes tied only at the ADC GND pin.
Do not exceed the 2.7V-5.25V absolute maximum ratings on AVDD; reverse-polarity protection is not built in. The SHDN pin must be tied high through a pull-up resistor if unused, otherwise the part can latch in shutdown after power-up. The REF pin is not ratiometric to VDD unless overdriven by an external reference; for ratiometric applications, drive AVDD with the sensor excitation voltage and overdrive REF externally. Always issue a complete SPI read (with dummy SCLK cycles) to clock out the latest conversion result before initiating the next acquisition.
Source impedance above the datasheet's 1 kΩ maximum degrades AC performance and increases crosstalk between channels because the SAR ADC's input sample-and-hold cannot fully settle. For high-impedance sensors (such as pH probes or reference electrodes), buffer the input with a CMOS-input op-amp (e.g. OPA2333 or LMP7704) before the ADC input. When using a pseudo-differential configuration, keep the negative input ground return short and shared with the ADC GND pin to avoid ground-loop noise pickup on the 12-bit conversion.
Compliance Information
RoHS compliant per Silicon Labs product declaration. REACH SVHC compliant per EU regulatory filings. Lead-free reflow-compatible packaging. Not AEC-Q100 qualified (use automotive-grade alternatives from TI or ADI for vehicle applications). Halogen-free status unknown from verified web data; consult manufacturer datasheet.
