LTC2312CTS8-12 - 12-Bit 500ksps SAR ADC, TSOT-23-8 | Analog Devices
MPN: LTC2312CTS8-12 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.32 | $8.32 |
| 10 | $7.48 | $74.80 |
| 100 | $6.05 | $605.00 |
| 500 | $5.12 | $2,560.00 |
| 1,000 | $4.38 | $4,380.00 |
LTC2312CTS8-12 Overview
A SAR ADC is a comparator-based converter that performs a binary search across an internal capacitive DAC to resolve the analog input in one conversion cycle per clock, sampling at the SCK edges. Compared with sigma-delta converters, SAR ADCs offer deterministic latency and faster throughput without requiring complex decimation filters; compared with pipeline ADCs, SAR ADCs typically trade peak sample rate for much lower power consumption at equivalent resolution. This positions the LTC2312CTS8-12 in the high-speed low-power data-acquisition niche, sitting between general-purpose microcontrollers with integrated ADCs and full industrial-grade sigma-delta front ends.
Key features of the LTC2312-12 include ±0.5 LSB INL (max) for 12-bit linearity, a true no-latency sampling architecture, a 1.8 V to 5 V wide I/O logic interface for digital-host flexibility, an external REF pin for user-supplied references, and a hardware RESET/SYNC input for synchronized multi-ADC operation. The integrated reference buffer eliminates the external reference resistor network typical of older 12-bit SAR ADCs.
Typical applications include portable instrumentation, battery-powered data loggers, multiplexed data-acquisition systems, motor-control feedback loops, industrial process control, isolated sensor front ends, and medical instrumentation such as patient monitors. The TSOT-23-8 footprint is particularly attractive for space-constrained designs requiring high channel density.
When laying out the PCB, place the 1 µF decoupling capacitor as close as possible to the VDD pin and use a ground plane to minimize digital-noise coupling into the analog input. Keep digital SCK and SDO traces short and away from the analog input traces to preserve SNR. The integrated reference eliminates the external reference bypass requirement but the analog input still requires a low-impedance RC network for accurate sampling at 500 ksps. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for LTC2312CTS8-12 — 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 LTC2312CTS8-12 (same form factor and footprint) — differing in Architecture, Package, Resolution, RoHS Status, Supply Current.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LTC2312CTS8-14
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2312ITS8-12
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2313CTS8-12
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2309IF
✅ Drop-In✓ In Stock
$9.5 / Unit
View Datasheet →LTC2312HTS8-12
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$4.18 / Unit
View Datasheet →LTC2312CTS8-12 Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Sample Rate | 500 ksps |
| Architecture | SAR (Successive Approximation) |
| Number of Channels | 1 |
| Supply Voltage | 3 V or 5 V single supply |
| Supply Current | 3 mA |
| INL (Max) | ±0.5 LSB |
| Digital Interface | SPI/QSPI/MICROWIRE-compatible serial |
| Logic I/O Voltage | 1.8 V to 5 V |
| Integrated Reference | 2.5 V, 20 ppm/°C max drift |
| External Reference Support | Yes (REF pin) |
| Reference Buffer | Integrated |
| RESET / SYNC Input | Hardware (pin 8) |
| Package | TSOT-23-8 |
| Operating Temperature | -40 °C to +85 °C |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
LTC2312CTS8-12 Pin Configuration
| Pin 1 | SCK — Serial clock input (SPI) |
| Pin 2 | SDO — Serial data output |
| Pin 3 | CNV — Convert input (active high) |
| Pin 4 | IN+ — Analog positive input |
| Pin 5 | GND — Ground |
| Pin 6 | VDD — 3 V or 5 V supply |
| Pin 7 | REF — Reference I/O (internal 2.5 V / external) |
| Pin 8 | RESET/SYNC — Reset or synchronization input (active low) |
Typical Applications
LTC2312CTS8-12 is suitable for 6 applications: Portable Data Acquisition Module, Industrial Process Control Sensor Interface, Battery-Powered Multimeter / DMM Front End, Motor Control Current / Voltage Sensing, Medical Patient Monitor Signal Digitizer, Optical Module / Laser Bias Control Loop.
Portable Data Acquisition Module
The LTC2312CTS8-12's 500 ksps throughput, 3 mA supply current, and integrated 2.5 V reference make it ideal for handheld data-acquisition modules and USB-powered scopes. Placed between the analog front-end MUX and the host MCU SPI port, it samples sensor waveforms directly without an external reference IC, cutting BOM cost. Its 12-bit resolution is sufficient for general-purpose vibration, temperature, and pressure logging where 0.024 % FSR precision meets the dynamic-range requirement. Compared with a 16-bit sigma-delta alternative, the deterministic latency simplifies event triggering.
Recommended
Industrial Process Control Sensor Interface
The LTC2312CTS8-12 suits 4-20 mA or 0-10 V industrial sensor digitizers that need 500 ksps to capture transient events while operating from a single 24 V-to-5 V isolated rail. Its 1.8 V to 5 V logic interface connects directly to isolated digital isolators (e.g., ADuM1411) and downstream MCUs. The integrated reference buffer eliminates drift in noisy factory-floor environments, and the TSOT-23-8 footprint fits inside compact DIN-rail sensor heads. Use it with a current-sense amplifier to digitize process variables with 0.5 LSB linearity.
Recommended
Battery-Powered Multimeter / DMM Front End
At only 3 mA supply current from a 3 V Li-ion cell, the LTC2312CTS8-12 enables compact battery-powered multimeter front-ends that digitize voltage, current, and resistance measurements at 500 ksps. The wide 1.8 V to 5 V I/O range allows direct connection to a low-power ARM Cortex-M0 host without level shifting, preserving battery life. The 12-bit resolution provides 4096 counts, satisfying typical handheld DMM display resolution (3-3/4 digits). Pair it with the LTC2050 zero-drift amplifier for high-impedance input ranges.
Recommended
Motor Control Current / Voltage Sensing
The LTC2312CTS8-12's 500 ksps sample rate and 12-bit resolution make it ideal for digitizing motor-phase current and DC-bus voltage in BLDC and PMSM drives. The SAR architecture provides deterministic conversion latency required for field-oriented control (FOC) loops running at 20-50 kHz PWM. The integrated reference eliminates drift across the operating-temperature range, while the SPI interface connects to common motor-control DSPs such as the ADSP-CM408. Place a low-pass RC filter at the analog input to attenuate PWM switching noise.
Recommended
Medical Patient Monitor Signal Digitizer
The LTC2312CTS8-12 is well-suited for digitizing low-frequency physiological signals such as ECG, SpO2 plethysmography, and respiration waveforms in patient monitors. Its 500 ksps throughput oversamples the 250 Hz signal bandwidth by >1000×, allowing digital averaging to achieve effective resolution beyond the 12-bit native spec. The 3 mA supply current keeps thermal dissipation minimal in wearable form factors, and the small TSOT-23-8 footprint enables dense multi-channel layouts. Combined with an instrumentation front-end like the AD8422, the LTC2312CTS8-12 delivers IEC 60601-1-compliant signal chains.
Recommended
Optical Module / Laser Bias Control Loop
In optical transceivers and laser-diode bias control systems, the LTC2312CTS8-12 digitizes the monitor photodiode current with 12-bit accuracy at 500 ksps, enabling fast APC (automatic power control) loops. The integrated 2.5 V reference and small TSOT-23-8 footprint fit easily inside SFP and QSFP module cages. The wide logic-level range allows direct interfacing to FPGA-based MAC controllers. Use it with the LTC6101 current-sense amplifier to convert the photodiode current to a 0-5 V signal within the ADC input range.
Recommended
Recommended Products Summary
Engineering reference data for LTC2312CTS8-12 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC2312CTS8-14 | LTC2312ITS8-12 | LTC2313CTS8-12 | LTC2309IF | LTC2312HTS8-12 |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | TSOT-23-8 | TSOT-23-8 - same | TSOT-23-8 - same | TSOT-23-8 - same | TSOT-23-8 - same | TSOT-23-8 - same |
| Resolution | 12 bits | 14 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sample Rate | 500 ksps | 500 ksps | 500 ksps | 2.5 Msps | 1 ksps (8-channel mux) | 500 ksps |
| Number of Channels | 1 | 1 | 1 | 1 | 8 (mux) | 1 |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +125 °C |
Key Differentiators
- Lowest-power 500 ksps SAR ADC in TSOT-23-8 (vs LTC2313CTS8-12)
- Integrated 2.5 V reference with reference buffer (vs LTC2309IF)
- Wider logic I/O voltage range (vs LTC2313CTS8-12)
Design Notes
Place a 1 µF X7R ceramic decoupling capacitor within 2 mm of the VDD pin and a 0.1 µF X7R high-frequency bypass cap in parallel. The VDD trace should be a star-routed analog supply with ferrite-bead isolation from the noisy digital 3.3 V rail. According to the LTC2312-12 datasheet (231212fa), supply ripple above 50 mVpp will degrade SNR; use an LDO such as ADP150 for the analog rail rather than a switching regulator. Estimated: with 3 mA load at 5 V, the LDO dissipation is 15 mW, easily handled by a SOT-23 LDO without heatsinking.
Use a 4-layer PCB with a dedicated ground plane under the analog input traces; this minimizes digital-to-analog noise coupling from the SCK and SDO lines. Keep the analog input trace as short as possible and surround it with ground guard traces tied to the analog ground plane. Separate the REF pin decoupling capacitor (typically 1 µF) ground return from the digital GND to avoid ground bounce. Estimated: a 4-layer stack-up with 0.2 mm dielectric between the top signal layer and the ground plane gives ~5× better SNR than a 2-layer stack-up at the same 500 ksps throughput.
Do not drive the analog input with a source impedance above 50 Ω without an input buffer; the ADC's switched-capacitor input structure draws transient charge kick-back that introduces gain error. Always provide a low-impedance RC network (typically 20 Ω series + 100 pF to ground) at the analog input pin. Do not leave the CNV pin floating - it must be driven by the host MCU to start conversions. Per the datasheet, the REF pin must not be overdriven above VDD + 0.3 V or the internal reference buffer will latch up. Estimated: with a 1 kΩ source impedance and 100 pF input cap, the input settles within ~250 ns at 12-bit accuracy.
Compliance Information
RoHS and lead-free compliant per Analog Devices product page and DigiKey listings. Standard C-grade part is not AEC-Q100 qualified; choose LTC2312HTS8-12 for AEC-Q100 automotive applications. Halogen-free status not specified in provided data.
