AS1521-T - 10-Bit 300ksps 8-Ch SAR ADC | ams OSRAM
MPN: AS1521-T ✓ نشطAS1521-T نظرة عامة
An SAR ADC is a type of analog-to-digital converter that uses a binary-search algorithm through an internal capacitive DAC and a single high-speed comparator to resolve an input voltage to within one least-significant bit. The SAR topology is prized for its deterministic latency - one conversion per acquisition cycle, no pipeline delay - and its excellent DC accuracy with no missing codes. As a member of the data-converter family, the AS1521 sits in the broader hierarchy of analog ICs -> ADC -> SAR ADC -> low-power multi-channel ADC, serving signal-chain applications where size, power, and AC linearity dominate.
Key features include true-differential analog inputs with software-configurable unipolar/bipolar ranges (0V to VREF or ±VREF), an external reference pin (up to VDD), a serial clock up to 4 MHz that yields 300 ksps throughput, and a 2-wire shutdown mode that drops supply current to 1 µA. The 20-pin TSSOP package is 4.4 mm wide with 0.65 mm pitch, providing a small footprint while remaining hand-solderable for prototyping.
The AS1521 uses a charge-redistribution DAC with an inherent sample-and-hold on each analog input, eliminating the need for external track-and-hold amplifiers. The architecture delivers ±0.5 LSB INL and ±0.5 LSB DNL across the full operating range, with 71 dB SINAD at 100 kHz input to maintain AC quality. Internal power-on reset and a low-noise internal reference buffer further simplify BOM.
Typical applications include portable industrial sensor interfaces (4-20 mA loop digitizers, thermocouple inputs), battery-powered data loggers, handheld instruments, isolated multi-channel monitoring, optical module diagnostics, and remote IoT sensor nodes. The wide supply range also makes it well-suited for USB-powered or 3.3 V microcontroller-resident designs.
When designing, place 0.1 µF ceramic bypass capacitors within 5 mm of the AVDD and DVDD pins and keep analog inputs routed away from switching clocks. Use a low-impedance external reference (REF5040 or equivalent) when absolute accuracy matters more than cost, since the internal reference is trimmed but not characterized for high-precision work.
This page synthesizes distributor stock levels, drop-in pin-compatible alternatives across brands, and practical decoupling/layout notes not collected in any single manufacturer document.
بدائل مباشرة لـ AS1521-T — نفس الحزمة، متوافق دبوس بدبوس. تُستثنى القطع ذات الحزم المختلفة التي تتطلب تعديل PCB.
الطرازات في هذه السلسلة
طرازات من نفس السلسلة متوافقة تمامًا مع AS1521-T (نفس عامل الشكل والبصمة) — يختلف في Package, Sampling Rate, Data Interface, Input Type, Number of Input Channels.
AS1520-T
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←AS1521
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
ADS8508IBDWRG4
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←ADS7822PG4
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←ADS7824PG4
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←ADS7825UE4
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←AS1521-T الحدود القصوى والخصائص الكهربائية
| الدقة | 10 bit |
| Architecture | SAR (Successive Approximation Register) |
| Number of Channels | 8 single-ended / 4 differential |
| معدل أخذ العينات | 300 ksps |
| Input Type | Differential, Pseudo-Differential, Single-Ended |
| Supply Voltage (Single) | 2.7 V to 5.25 V |
| Supply Current (Full Speed) | 1.1 mA typical |
| Power Consumption | 3.6 mW at 3 V, 300 ksps |
| تيار الإيقاف | 1 µA |
| الواجهة | SPI / QSPI / MICROWIRE compatible |
| Maximum Serial Clock | 4 MHz |
| INL (اللاخطية التكاملية) | ±0.5 LSB (max) |
| DNL (Differential Nonlinearity) | ±0.5 LSB (max, no missing codes) |
| SINAD at 100 kHz Input | 71 dB |
| درجة حرارة التشغيل | -40 °C to +85 °C |
| العلبة | 20-TSSOP, 4.4 mm body width |
| نوع التركيب | Surface Mount |
| Reference Type | External (REF pin) |
| حالة RoHS | Compliant |
تكوين أطراف AS1521-T
| دبوس 1 | CH0 — Analog input channel 0 |
| دبوس 2 | CH1 — Analog input channel 1 |
| دبوس 3 | CH2 — Analog input channel 2 |
| دبوس 4 | CH3 — Analog input channel 3 |
| دبوس 5 | CH4 — Analog input channel 4 |
| دبوس 6 | GND — Analog ground |
| دبوس 7 | REF — External reference voltage input |
| دبوس 8 | AVDD — Analog supply voltage |
| دبوس 9 | DVDD — Digital supply voltage |
| دبوس 10 | DGND — Digital ground |
| دبوس 11 | CSN — Chip select (active low) |
| دبوس 12 | DIN — Serial data input |
| دبوس 13 | DOUT — Serial data output |
| دبوس 14 | SCLK — Serial clock input |
| دبوس 15 | CH5 — Analog input channel 5 |
| دبوس 16 | CH6 — Analog input channel 6 |
| دبوس 17 | CH7 — Analog input channel 7 |
| دبوس 18 | SHDN — Shutdown control (active low) |
| دبوس 19 | COM — Common reference for single-ended inputs |
| دبوس 20 | NC — Not connected (per datasheet) |
التطبيقات النموذجية
AS1521-T مناسب لـ 7 التطبيقs: Portable Battery-Powered Data Logger, Industrial 4-20 mA Loop Sensor Interface, Optical Module Diagnostics and Monitoring, Handheld Test and Measurement Instrument, Remote IoT Sensor Node, USB-Powered Data Acquisition Module, Isolated Multi-Channel Voltage Monitoring.
Portable Battery-Powered Data Logger
The AS1521-T fits portable battery-powered data loggers because its 3.6 mW power dissipation at 300 ksps and 1 µA shutdown current extend coin-cell runtime by 5-10x versus 8-channel ADCs that draw 10+ mW. With 8 single-ended inputs, it digitizes four thermocouple pairs or eight 4-20 mA loop sensors without an external mux, while its SPI interface uses only 4 MCU pins, leaving GPIOs free for SD card and LCD control.
موصى به
Industrial 4-20 mA Loop Sensor Interface
The AS1521-T is well-matched to multi-channel 4-20 mA loop digitizers: its differential input mode rejects common-mode noise from long industrial cable runs (typically 50-60 Hz), and its 0V-to-REF input range maps directly to the 4-20 mA signal after a 250 ohm sense resistor. The 300 ksps throughput allows sampling all 8 channels at 37.5 kHz each, exceeding the Nyquist requirement for 4-20 mA loop signals by 100x with headroom for over-sampling filtering.
موصى به
Optical Module Diagnostics and Monitoring
Optical transceivers (SFP/QSFP modules) require multi-channel temperature, laser-bias, and received-power monitoring - an ideal use case for the AS1521-T. Its 8 single-ended inputs can monitor bias current, TEC voltage, output power, and case temperature simultaneously, while the SPI bus shares pins with the module's existing I2C/SPI management interface. The 2.7-5.25 V supply range covers both 3.3 V module rails and 5 V host-side designs.
موصى به
Handheld Test and Measurement Instrument
The AS1521-T is suitable for handheld multimeters and oscilloscope front-ends due to its small 20-pin footprint, low power consumption that supports 9 V battery operation via an LDO, and 10-bit resolution adequate for 3.5-digit display readout. The serial interface streams conversion results to a microcontroller or direct-drive LCD driver without bus contention, and the wide -40 to +85 °C operating range supports field use in extreme conditions.
موصى به
Remote IoT Sensor Node
The AS1521-T powers remote IoT sensor nodes by digitizing multiple sensors (temperature, humidity, pressure, gas) on a single chip with SPI connectivity to LoRa or BLE SoCs. Its 1 µA shutdown mode is critical for duty-cycled sensor nodes that sample every 60 seconds - the device spends >99.9% of its life in shutdown, drawing negligible current. The wide supply range allows direct Li-ion battery operation without a separate regulator.
موصى به
USB-Powered Data Acquisition Module
The AS1521-T is well-suited to USB-powered multi-channel DAQ modules that digitize audio, vibration, or strain-gauge signals at the 5 V USB rail. Its 5.25 V maximum supply rating accommodates USB voltage directly, eliminating the need for an LDO and reducing BOM cost. The 300 ksps aggregate throughput supports 8 channels at 37.5 kHz each - sufficient for audio-bandwidth (20 kHz) vibration analysis with 2x oversampling.
موصى به
Isolated Multi-Channel Voltage Monitoring
The AS1521-T fits isolated multi-channel voltage monitoring in power-supply sequencers and battery management systems where multiple rail voltages need digitizing through an isolation barrier. Its 8 inputs monitor 8 separate rails with a single SPI link to the MCU side of the isolator, halving the number of expensive digital isolator channels versus per-channel ADCs. Its 71 dB SINAD ensures accurate rail-voltage readings even in noisy switching-converter environments.
موصى به
ملخص المنتجات الموصى بها
بيانات مرجعية هندسية لـ AS1521-T — المقارنة وإرشادات التصميم ومعلومات الامتثال.
دليل الاختيار
المقارنة مع البدائل
| المعامل | هذا المنتج | AS1520-T | AS1521 | ADS8508IBDWRG4 | ADS7822PG4 | ADS7824PG4 | ADS7825UE4 |
|---|---|---|---|---|---|---|---|
| Brand | ams OSRAM | ams OSRAM | ams OSRAM | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 20-TSSOP | 20-TSSOP - same | 20-TSSOP - same | 20-SOIC - same 20-pin, different body | 8-PDIP | 28-SOIC | 20-SOIC |
| Resolution | 10 bit | 10 bit | 10 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Channels | 8 single-ended / 4 differential | 8 single-ended / 4 differential | 8 single-ended / 4 differential | 8 single-ended | 1 single-ended | 4 single-ended | 4 single-ended |
| Sampling Rate | 300 ksps | 400 ksps | 300 ksps | 200 ksps | 200 ksps | 200 ksps | 200 ksps |
| Supply Voltage | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 4.75 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 4.75 V to 5.25 V |
| Interface | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | Parallel |
| Power Consumption | 3.6 mW at 3 V | 4.5 mW at 3 V | 3.6 mW at 3 V | 10 mW at 5 V | 1.5 mW at 3 V | 3 mW at 3 V | 15 mW at 5 V |
| 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 +85 °C | -40 °C to +85 °C |
أبرز الفروقات
- Lowest power 8-channel 10-bit SAR ADC in 20-TSSOP (مقابلADS8508IBDWRG4)
- 8 channels in a smaller footprint than competitors (مقابلADS7825UE4)
- Single-supply 2.7V operation versus 5V-only competitors (مقابلADS8508IBDWRG4)
- Faster sampling than most 12-bit TI alternatives (مقابلADS7822PG4 / ADS7824PG4)
ملاحظات التصميم
Place 0.1 µF ceramic bypass capacitors (X7R or X5R dielectric) within 5 mm of both AVDD and DVDD pins. A bulk 10 µF tantalum or aluminum-polymer capacitor at the supply input provides the inrush current required by the internal charge-redistribution DAC during each conversion. Tie AVDD and DVDD to the same supply rail in single-supply designs, but route them separately on the PCB to prevent digital switching noise from coupling into the analog domain.
Route analog input traces as differential pairs with matched lengths to minimize common-mode noise pickup. Keep a continuous ground plane under the analog traces and place a ground guard ring around sensitive analog input pins (CH0-CH7) to prevent digital crosstalk. The 20-TSSOP 0.65 mm pitch is suitable for 4-layer boards with 0.1 mm trace-and-space rules, but for high-impedance source designs consider a guard-driven analog ground plane on layer 2.
Use a low-impedance external reference (e.g., REF5040, MAX6126) when absolute accuracy matters, because the internal reference is trimmed but not specified for high-precision applications. Add a 1 µF ceramic bypass capacitor on the REF pin within 3 mm of the IC, and use a separate analog ground return for the reference current to avoid ground bounce from digital currents polluting the reference voltage. Estimated: at 300 ksps, the reference current spikes to ~1 mA at each conversion edge.
Do not leave unused analog inputs floating - tie them to COM or AVDD/2 to prevent leakage-induced accuracy drift. The shutdown pin (SHDN, pin 18) must be tied high through a 100 kΩ pull-up if shutdown is not used, otherwise the device may enter shutdown mode intermittently. When operating at sample rates below 50 ksps, insert an external anti-aliasing RC filter (typically 1 kΩ and 100 pF) before each analog input to limit broadband noise.
معلومات الامتثال
RoHS compliant per ams-OSRAM product page. Industrial temperature grade only (-40 to +85 °C); not AEC-Q100 qualified - automotive applications should use AS1521-Q1 variant if available.
