TSA7887ARZ - 12-bit 125ksps 2-ch SAR ADC | Silicon Labs SOIC-8
MPN: TSA7887ARZ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $2.99 | $29.90 |
| 100 | $2.45 | $245.00 |
| 500 | $2.1 | $1,050.00 |
| 1,000 | $1.85 | $1,850.00 |
TSA7887ARZ Overview
An ADC (analog-to-digital converter) is a data-acquisition integrated circuit that samples continuous analog voltages and converts each sample into a discrete digital code for processing by a microcontroller, DSP, or FPGA. Successive-approximation-register (SAR) ADCs use a binary-search algorithm against a precision DAC and reference to resolve one bit per clock cycle, achieving a deterministic conversion time of N cycles for N-bit resolution. This conversion topology sits in the broader hierarchy: ADC -> data converter -> mixed-signal IC -> semiconductor. SAR ADCs are prized for low latency, deterministic behavior, and absence of pipeline-latency artifacts.
Key features include 12-bit resolution with no missing codes, an integrated 2.5V reference, an SPI-/QSPI-/MICROWIRE-compatible serial interface, true-differential analog inputs, software-configurable unipolar/bipolar input ranges, and a hardware-power-down pin. The internal reference can be overdriven with an external source, simplifying ratiometric measurements such as bridge-sensor readings. An on-chip oscillator eliminates the need for an external clock source in cost-sensitive designs.
Architecturally, the TSA7887ARZ uses a charge-balancing switched-capacitor DAC front end that converts the input voltage into a digital code across 12 SAR clock cycles. The auto-calibration cycle corrects offset and gain errors on every conversion, eliminating drift across temperature and supply variations. Serial data is clocked out MSB-first and conforms to standard SPI modes, allowing direct connection to most modern microcontrollers without glue logic.
Typical applications include portable instrumentation, battery-powered data loggers, industrial process-control loops, sensor conditioning modules, and panel-meter front ends. The low power draw makes it particularly attractive for solar- or energy-harvesting systems where average current budget is critical. The integrated reference and 2-channel mux further reduce total BOM and PCB area in compact designs.
When designing with this part, ensure the analog supply is decoupled with a 1uF ceramic plus a 10uF bulk capacitor placed within 5 mm of the AVDD pin. Reference-pin decoupling is equally critical - a 0.1uF ceramic directly across REF should be used. Avoid switching digital traces under the analog front end to preserve SNR.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for TSA7887ARZ — 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 TSA7887ARZ (same form factor and footprint) — differing in Package, Resolution, Input Type, Data Interface, Number of Channels.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
TSA7887ARZ-REEL
✅ Drop-In✓ In Stock
$2.48 / Unit
View Datasheet →TSA7887ARMZ-REEL
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →TLV2545IDGKR
✅ Drop-In✓ In Stock
$2.33 / Unit
View Datasheet →TLV1504IDRG4
✅ Drop-In✓ In Stock
$2.74 / Unit
View Datasheet →TLC549CD
✅ Drop-In✓ In Stock
$1.02 / Unit
View Datasheet →TSA7887ARZ Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Number of Channels | 2 |
| Conversion Rate | 125 ksps |
| Architecture | SAR (Successive Approximation Register) |
| Data Interface | Serial (SPI/QSPI/MICROWIRE-compatible) |
| Number of Inputs | 1, 2 (differential or single-ended) |
| Analog Supply Voltage | 2.7 V to 5.25 V |
| Digital Supply Voltage | 2.7 V to 5.25 V |
| Input Voltage Range (Unipolar) | 0 V to VREF (with internal 2.5V ref) |
| Internal Reference | 2.5 V |
| Reference Type | Internal, can be overdriven externally |
| Power Consumption at 125 ksps | 3.2 mW (typical) |
| Power-Down Current | Sub-microamp (hardware PD pin) |
| Operating Temperature Range | -40C to +85C |
| Package | 8-pin SOIC (RZ), 150-mil narrow body |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| Grade | 'A' Grade, xIND (industrial) |
TSA7887ARZ Pin Configuration
| Pin 1 | VDD — Analog supply (2.7V to 5.25V) |
| Pin 2 | AIN1+ — Channel 1 positive analog input |
| Pin 3 | AIN1- — Channel 1 negative analog input |
| Pin 4 | AIN2+ — Channel 2 positive analog input |
| Pin 5 | GND — Ground |
| Pin 6 | REF — Reference voltage (decouple with 0.1uF ceramic) |
| Pin 7 | DOUT/CS — Serial data output / chip select |
| Pin 8 | SCLK/PD — Serial clock / hardware power-down |
Typical Applications
TSA7887ARZ is suitable for 7 applications: Portable Sensor Data Logger, Industrial Process Control Loop, Panel Meter and Instrumentation Front End, Energy-Harvested Sensor Nodes, Medical Point-of-Care Diagnostics, Automotive Sensor Conditioning, Building Automation and HVAC.
Portable Sensor Data Logger
The TSA7887ARZ suits battery-powered data loggers for environmental and industrial sensor monitoring. The 12-bit resolution over the 0V to 2.5V internal reference range accommodates thermocouple-conditioned, thermistor, and ratiometric bridge sensor outputs after signal conditioning. At 3.2 mW full-speed power consumption and sub-microamp hardware power-down draw, the device can be duty-cycled between samples so the average current budget remains battery-friendly. The 125 ksps throughput headroom supports oversampling for noise reduction without compromising power budget; common practical sampling rates fall between 100 Hz and 10 kHz for slow sensor signals. The SPI mode 0-3 compatible serial output mates directly with MSP430, STM32, or EFM32 microcontrollers common in low-power designs.
Recommended
Industrial Process Control Loop
In 4-20 mA loop-powered process-control transmitters and PLC analog-input modules, the TSA7887ARZ digitizes conditioned analog signals with 12-bit precision. The 2-channel mux allows simultaneous monitoring of two sensor points (e.g., temperature and pressure) per ADC chip, reducing the active-component count on loop-powered boards where each milliamp counts. According to the datasheet, the 2.7V-5.25V supply range accepts the common 5V isolated rail and the rectified 3.3V loop voltage. The industrial -40C to +85C operating range supports outdoor and cabinet installations. The internal 2.5V reference eliminates drift-sensitive external references and accommodates ratiometric measurements if required for sensor linearization.
Recommended
Panel Meter and Instrumentation Front End
Digital panel meters and handheld DMM front ends benefit from the TSA7887ARZ integrated 2.5V reference and dual-channel mux. The 12-bit resolution yields 1 mV display step on a 4V full-scale, sufficient for industrial panel indicators measuring thermocouple, RTD-conditioned, or 4-20 mA shunt signals. The 125 ksps throughput allows fast autoranging sweep times and supports peak-hold capture in transient measurement applications. The integrated reference simplifies meter calibration and improves long-term drift characteristics compared to an external reference source. SPI serial output enables compact TFT or OLED display attachments that read conversion results directly without additional glue logic.
Recommended
Energy-Harvested Sensor Nodes
Energy-harvesting wireless sensor nodes (WSNs) for building automation, structural-health monitoring, or remote environmental sensing place strict average-current budgets on each component. The TSA7887ARZ sub-microamp power-down current and 3.2 mW active power suit harvester designs where a few-ampere-hour primary cell or thin-film solar cell drives weeks-to-months of operation. Per the datasheet, the internal reference and dual-channel mux reduce the BOM versus a higher-channel ADC plus external reference, shrinking the duty-cycled energy budget. The 2.7V minimum supply accepts single-cell Li-ion, LiSOCl2, or regulated 3.3V harvester rails.
Recommended
Medical Point-of-Care Diagnostics
Portable point-of-care diagnostic devices - such as handheld glucometers, pulse oximetry front ends, and bedside patient monitors - leverage the TSA7887ARZ low-power 12-bit ADC performance. The 0V to 2.5V input range directly digitizes photodiode current-to-voltage transimpedance amplifier outputs, electrical-impedance-spectroscopy excitation waveforms, and analog-conditioner outputs from bioelectric sensors. The 125 ksps throughput is more than sufficient for the 1-10 kHz effective band of most bioelectric signals. The integrated reference simplifies the safety-isolation design by reducing the number of supplies that need to be considered for creepage and clearance.
Recommended
Automotive Sensor Conditioning
In non-safety automotive body and chassis sensor conditioning - HVAC flap position, ride-height, oil-level, or interior light sensors - the TSA7887ARZ serves as a low-cost digitizing front end. The -40C to +85C operating range covers the cabin and under-hood compartment ranges for passenger vehicle applications; safety-critical powertrain and chassis functions require an AEC-Q100-qualified part. The 2.7V to 5.25V supply accepts common regulated 5V body-controller rails. The integrated reference and dual-channel mux allow two-axes sensor (e.g., tilt + vibration) measurement per chip, reducing the controller pin count.
Recommended
Building Automation and HVAC
Building automation controllers, room-thermostat boards, and HVAC damper-actuator electronics all use the TSA7887ARZ to digitize analog temperature, humidity, air-quality, and pressure sensors. The 12-bit resolution over the 2.5V reference provides 0.6 mV LSB, sufficient for 0.1C-resolution thermistor and platinum-RTD front ends after signal conditioning. The 2.7V minimum supply draws from common 3.3V or 5V regulated rails powered from the 24VAC HVAC bus. According to the datasheet, the SPI output directly drives the popular STM32 and PIC microcontrollers used on modern thermostat mainboards.
Recommended
Recommended Products Summary
Engineering reference data for TSA7887ARZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TSA7887ARZ-REEL | TSA7887ARMZ-REEL | TLV2545IDGKR | TLV1504IDRG4 | TLC549CD |
|---|---|---|---|---|---|---|
| Package | 8-SOIC (RZ) | 8-SOIC (RZ) - same | 8-SOIC (RZ) - same | 8-MSOP (DGK) - same compact footprint | 8-SOIC (DRG4) - same | 8-SOIC (D) - same |
| Brand | Silicon Labs | Silicon Labs (same) | Silicon Labs (same) | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 10 bits | 8 bits |
| Sample Rate | 125 ksps | 125 ksps | 125 ksps | 200 ksps | 200 ksps | 40 ksps |
| Input Channels | 2 (mux) | 2 (mux) | 2 (mux) | 5 (mux) | 4 (mux) | 1 |
| Architecture | SAR | SAR | SAR | SAR | SAR | SAR |
| Internal Reference | 2.5V | 2.5V | 2.5V | 4.096V | External only | External only |
| Supply Voltage | 2.7V to 5.25V | 2.7V to 5.25V | 2.7V to 5.25V | 2.7V to 5.5V | 2.7V to 5.5V | 3.0V to 6.0V |
| Interface | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE |
Key Differentiators
- Integrated 2.5V reference - reduces BOM (vs TLC549CD)
- Dual-channel analog input mux (vs TLC549CD)
- Higher resolution at comparable speed (vs TLV1504IDRG4)
- Lower power draw at full speed (vs TLV2545IDGKR)
- SPI modes 0-3 with no configuration bits (vs TLV2545IDGKR)
Design Notes
Place the analog supply decoupling capacitors (one 10uF ceramic bulk plus one 0.1uF X7R ceramic) within 5 mm of the AVDD pin. Place a separate 0.1uF ceramic directly across the REF pin to the analog ground plane. According to the manufacturer datasheet, the reference decoupling is critical to achieving 12-bit noise performance. Avoid running digital clock or serial-interface traces beneath the analog input or reference pin footprint to minimize digital-noise coupling into the high-impedance front end.
Estimated: at 125 ksps sampling rate with a 12-bit SAR front end, the analog input source impedance should be kept below approximately 1 kohm to preserve full conversion accuracy. The internal switched-capacitor DAC draws transient charge from the analog source during the acquisition phase. According to the Silicon Labs datasheet, an input RC-frontend (typically 100 ohm in series with the AIN+ line, plus the recommended capacitor to GND) reduces kickback transients and improves THD at full 12-bit resolution.
Do not enable SPI mode-3 timing if the host MCU defaults to mode 0 without verifying SCLK-to-CS edge relationship. The TSA7887ARZ samples data on the configured edge; mismatched mode can yield zero-shifted output. Also, the hardware power-down pin is asynchronous - deasserting it waits one conversion cycle before settling, so the first post-wakeup conversion should be discarded in firmware. Per the datasheet, the auto-calibration cycle runs at the end of each conversion; allow 24 acquisition-clock cycles between sample-trigger and read.
At 125 ksps continuous sampling with 5V supply, the TSA7887ARZ dissipates approximately 3.2 mW. The 8-SOIC (RZ) package has a theta_JA around 110 C/W on a 1-oz 2-layer board. Estimated: continuous-conversion junction temperature rise is approximately 0.4 C above ambient, well within the 125C absolute maximum. No heatsinking is required. In enclosed IO-Link or HVAC enclosures, however, ensure the input sensor dissipation and ADC dissipation combined remain within board thermal limits.
Use the hardware power-down pin to duty-cycle the ADC between sample bursts. According to the manufacturer datasheet, full power-down drops supply current to under 1uA, allowing the average converter current to be reduced by 100-1000x in low-duty-cycle sensor applications. A typical firmware pattern is: wake the ADC, perform N conversions, store results, re-enter power-down. Time the wake-to-ready interval (typically 1-2 microseconds) into the overall sampling budget.
Compliance Information
Industrial -40C to +85C grade only - no AEC-Q100 automotive qualification. RoHS and lead-free status confirmed on Silicon Labs product page and DigiKey listing. For halogen-free status, see Silicon Labs material declaration.
