LTC2309IF - 12-Bit 8-Ch SAR ADC, I2C, 5V | Analog Devices
N.º da peça: LTC2309IF ✓ Ativo| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $14.5 | $14,50 |
| 10 | $13.05 | $130,50 |
| 100 | $11.62 | $1.162,00 |
| 500 | $10.45 | $5.225,00 |
| 1.000 | $9.5 | $9.500,00 |
LTC2309IF Visão geral
A SAR ADC is a successive-approximation-register analog-to-digital converter that performs bit-by-bit conversion using a binary search across an internal capacitive DAC; this architecture delivers deterministic latency, excellent DC accuracy, and very low power consumption compared to pipeline or delta-sigma ADCs. The LTC2309 belongs to the data-converter IC hierarchy: ADC -> successive-approximation ADC -> data acquisition IC -> mixed-signal semiconductor, and is intended for multi-channel sensor monitoring in space- and power-constrained embedded systems.
Key headline specifications include 12-bit resolution, 8 single-ended or 4 differential analog input channels, 1.3 microsecond conversion time per channel using an internal oscillator, an integrated 2.5V reference (10 ppm/C typical drift), I2C-compatible two-wire serial interface with standard (100 kHz), fast (400 kHz), and high-speed (3.4 MHz) mode support, and 300 microampere typical supply current at 1 ksps throughput. An external reference can also be driven into the REFIN pin for ratiometric or shared-rail designs.
Architecturally, the device combines an 8-to-1 input MUX, a low-charge-input SHA front end, a capacitive-charge-redistribution SAR core, and a 2.5V bandgap reference. The fully-differential topology rejects common-mode noise and supplies/wide, while the I2C interface supports two address-select pins (AD0, AD1) to place four LTC2309 devices on the same bus for up to 32 channels. Internal Burst and Nap modes plus the I2C power-down command keep average current well below the 300 microamp quiescent figure in duty-cycled applications.
Typical use cases include multi-cell battery monitoring in portable instruments, 4-20 mA industrial sensor conditioning, isolated thermocouple / RTD digitizers, multiplexed data-acquisition front ends, and automotive cabin-temperature or HVAC sensor reading. Pin-for-pin compatible parts make it straightforward to migrate to higher-resolution devices when system SNR headroom becomes a limiting factor.
When designing, place 1 microfarad ceramic bypass capacitors at REF and VDD, keep analog and digital grounds separated until they join under the ADC, and consider tying unused analog inputs to ground through 1 kilohm to minimize charge-injection crosstalk. This page synthesizes distributor stock, parametric alternatives, application circuits, and layout notes that are not assembled in the manufacturer datasheet.
Alternativas drop-in para LTC2309IF — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Variantes desta série
Modelos da mesma série compatíveis como drop-in com LTC2309IF (mesmo formato e footprint) — diferindo em Package, Number of Input Channels, Supply Current, Resolution, RoHS Status.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
LTC2309HF#PBF
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LTC2309CFE#PBF
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LTC2309IFE#PBF
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LTC2305
✅ Drop-In ⚠️ Especificações não verificadas📋 Alternativa de referência (fora do catálogo)
LTC2306
✅ Drop-In ⚠️ Especificações não verificadas📋 Alternativa de referência (fora do catálogo)
LTC2309IF Classificações máximas e características elétricas
| Resolução | 12 bit |
| Number of Input Channels | 8 single-ended / 4 differential |
| Architecture | SAR (Successive Approximation Register) |
| Conversion Time | 1.3 us per channel (typical) |
| Throughput Rate | up to 500 ksps (datasheet-dependent) |
| Supply Voltage (VDD) | 5 V single supply |
| Corrente de alimentação | 300 uA at 1 ksps (typical) |
| Digital Interface | I2C-compatible, standard / fast / high-speed modes |
| I2C Address Selection | 2 pins (AD0, AD1) - up to 4 devices on one bus |
| Internal Reference | 2.5 V, 10 ppm/C typical drift |
| External Reference Input (REFIN) | Yes, supports ratiometric operation |
| Sample-and-Hold | Fully differential, common-mode noise rejection |
| Analog Input Range | 0 V to VDD (unipolar); +/-VREF differential |
| Encapsulamento | 20-TSSOP (FE) |
| Operating Temperature Range (I grade) | -40 C to +85 C |
| Corrente de desligamento | Nap / I2C power-down supported |
| Status RoHS | Compliant (PBF suffix) |
Configuração de pinos do LTC2309IF
| Pino 1 | CH0 — Analog input channel 0 / positive differential input 0 |
| Pino 2 | CH1 — Analog input channel 1 / negative differential input 0 |
| Pino 3 | CH2 — Analog input channel 2 / positive differential input 1 |
| Pino 4 | CH3 — Analog input channel 3 / negative differential input 1 |
| Pino 5 | CH4 — Analog input channel 4 / positive differential input 2 |
| Pino 6 | CH5 — Analog input channel 5 / negative differential input 2 |
| Pino 7 | CH6 — Analog input channel 6 / positive differential input 3 |
| Pino 8 | CH7 — Analog input channel 7 / negative differential input 3 |
| Pino 9 | GND — Ground reference |
| Pino 10 | REF — Internal 2.5V reference output; bypass with 1 uF |
| Pino 11 | REFIN — External reference input (tie to REF when using internal) |
| Pino 12 | VDD — 5V analog supply |
| Pino 13 | NC — Not connected (per datasheet) |
| Pino 14 | COM — Common input for single-ended conversion (tie to analog mid-supply or ground) |
| Pino 15 | AD0 — I2C address select bit 0 |
| Pino 16 | AD1 — I2C address select bit 1 |
| Pino 17 | NC — Not connected (per datasheet) |
| Pino 18 | NC — Not connected (per datasheet) |
| Pino 19 | SDA — I2C bidirectional serial data |
| Pino 20 | SCL — I2C serial clock input |
Aplicações típicas
LTC2309IF é adequado para 6 aplicaçãos: Multi-Cell Battery Pack Monitoring, Industrial 4-20 mA Loop Sensor Digitizer, Isolated Thermocouple / RTD Acquisition Front End, Portable Multi-Sensor Data Logger, HVAC Zone Temperature and Air-Quality Module, Automotive Cabin Sensor Hub.
Multi-Cell Battery Pack Monitoring
The LTC2309IF's eight single-ended analog inputs map directly onto an 8-cell Li-ion battery stack, allowing one ADC to digitize every cell voltage plus pack current with 12-bit resolution and 1.3 microsecond conversion time. The internal 2.5V reference (10 ppm/C typical drift) tracks cell voltage across the full charge/discharge curve without external buffering, while I2C high-speed mode (3.4 MHz) lets a low-cost microcontroller sweep all eight cells faster than the BMS protection loop requires. Typical system accuracy is well within 1 LSB per cell across -40C to +85C, and Nap/Power-Down modes drop quiescent current into the nanoampere range between sweeps.
Recomendado
Industrial 4-20 mA Loop Sensor Digitizer
The eight 12-bit channels of the LTC2309IF let designers replace four to eight discrete single-channel ADCs in a 4-20 mA loop-conditioning front end, slashing both board area and BOM cost. Each channel pairs with a 250 ohm sense resistor and an op-amp buffer so the LTC2309IF's 0 to VDD input range maps linearly to the full 4-20 mA span; the fully differential sample-and-hold circuit rejects common-mode noise injected along long factory-floor cabling. Industrial-grade -40C to +85C operation supports outdoor cabinet installations without additional thermal management, and I2C addresses AD0/AD1 let four LTC2309IF devices share one isolated I2C isolator channel for up to 32 sensor inputs.
Recomendado
Isolated Thermocouple / RTD Acquisition Front End
When used in cold-junction-compensated thermocouple or 3-wire RTD modules, the LTC2309IF delivers 12-bit conversion with the 2.5V internal reference supplying the excitation bridge - simplifying the analog front end. The four differential input pairs handle bipolar thermocouple voltages directly, while spare single-ended channels can read the cold-junction sensor (diode or NTC) at the same temperature resolution. The 1.3 microsecond conversion time keeps scan latency below the IEC 60584 update interval, and the I2C interface easily crosses a digital isolator such as the ADuM1251 for the required 5 kV reinforced isolation.
Recomendado
Portable Multi-Sensor Data Logger
Portable data loggers typically combine temperature, humidity, pressure, and accelerometer outputs at low duty cycle, where the LTC2309IF's 300 microampere typical supply current at 1 ksps and its Nap / Power-Down modes dominate the energy budget calculation. Up to eight analog transducers connect to a single IC, eliminating the digital channel count pressure that would otherwise force a higher-power microcontroller. The internal 2.5V reference removes the need for a separate reference IC, and the I2C bus needs only two microcontroller pins - critical when only a small Cortex-M0+ device is used.
Recomendado
HVAC Zone Temperature and Air-Quality Module
An HVAC zone controller reads multiple NTC thermistor chains, airflow sensors, and CO2 analog front ends; the LTC2309IF's eight 12-bit channels consolidate these signals while the internal reference simplifies factory calibration. The I2C interface daisy-chains additional zone tiles through two AD0/AD1 pins per chip, supporting up to four zones from a single MCU I2C controller. Industrial-grade -40C to +85C operation handles plenum-mounted electronics, and the wide common-mode input range of the differential SHA rejects long thermocouple runs picking up 60 Hz mains noise.
Recomendado
Automotive Cabin Sensor Hub
Cabin-air-quality, humidity, and seat-occupant sensors typically output analog signals that the LTC2309IF aggregates with one IC over the I2C bus. Although the LTC2309IF is industrial-grade (-40C to +85C), the LTC2309HF#PBF drop-in variant supports the extended automotive cabin range up to +125C and keeps the same AD0/AD1 address pinning. Total conversion latency of 1.3 microseconds per channel easily multiplexes through eight channels within the typical 10 ms CAN update interval, and the 12-bit resolution is adequate for thermal and gas-sensor conditioning without local ADC amplification.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para LTC2309IF — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | LTC2309HF#PBF | LTC2309CFE#PBF | LTC2309IFE#PBF | LTC2305 | LTC2306 |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 20-TSSOP (FE) | 20-TSSOP (FE) - same | 20-TSSOP (FE) - same | 20-TSSOP (FE) - same | 20-TSSOP (FE) - same | 20-TSSOP (FE) - same |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Number of Input Channels | 8 single-ended / 4 differential | 8 / 4 | 8 / 4 | 8 / 4 | 1 single-ended (reduced) | 2 single-ended (reduced) |
| Conversion Time | 1.3 us | 1.3 us | 1.3 us | 1.3 us | 1.3 us | 1.3 us |
| Digital Interface | I2C (Std/Fast/HS) | I2C (Std/Fast/HS) | I2C (Std/Fast/HS) | I2C (Std/Fast/HS) | I2C (Std/Fast/HS) | I2C (Std/Fast/HS) |
| Internal Reference | 2.5 V (10 ppm/C) | 2.5 V (10 ppm/C) | 2.5 V (10 ppm/C) | 2.5 V (10 ppm/C) | 2.5 V internal | 2.5 V internal |
| Supply Voltage | 5 V single supply | 5 V | 5 V | 5 V | 5 V | 5 V |
| Operating Temperature | -40C to +85C (I grade) | -40C to +125C (extended) | 0C to +70C (commercial) | -40C to +85C | -40C to +85C | -40C to +85C |
Principais diferenciais
- 8 single-ended channels in a 20-TSSOP with I2C, plus internal reference (vs LTC2305 (1-channel))
- Industrial temperature grade with pin-compatible extended-grade option (vs LTC2309CFE#PBF (commercial 0C to +70C))
- I2C high-speed mode (3.4 MHz) support alongside standard and fast modes (vs LTC2308 (12-bit, 8-ch, SPI))
Notas de projeto
Estimated: at 5V VDD and 1 ksps continuous sampling with all eight channels mux'd, average supply current is ~300 uA per the datasheet; this drops to single-digit uA between samples when commanded into Nap mode via the I2C power-down bit. Place a 0.1 uF X7R ceramic capacitor as close as practical (less than 5 mm trace) to the VDD pin, plus a 10 uF bulk bypass on the analog 5V rail. Split analog and digital ground returns under the IC and tie them only at the regulator's ground pad to prevent return-current noise from coupling into the reference.
Estimated: route the eight CHx analog input traces as parallel, length-matched tracks with a ground guard on both sides to minimize channel-to-channel crosstalk. Place a 1 uF X7R bypass capacitor directly between REF (pin 10) and the analog ground plane; the LTC2309 needs this cap to keep reference noise below 50 uVrms. Unused analog inputs should be tied to a defined voltage through 1 kilohm to minimize charge-injection leakage into active channels - typically the analog mid-supply or ground.
Estimated: most layout failures stem from (1) leaving REFIN floating instead of tying it to REF, which disables the internal reference and yields all-zero conversions; (2) sharing SDA/SCL pull-ups with high-current digital outputs, which couples switching transients into the ADC data; and (3) enabling differential mode without tying COM to analog mid-supply, which collapses the input dynamic range. The I2C SDA and SCL lines require 2 to 10 kilohm pull-ups to 5V; high-speed (3.4 MHz) mode additionally needs a 4 kilohm pull-up per the I2C specification.
Estimated: keep digital I2C traces at least 5 mm away from CH0-CH7 analog traces and use a continuous analog-ground pour under the TSSOP package. The exposed pad (pin 11 EP, when present) and the GND pin (pin 9) must both be soldered to that pour. For designs with >100 mV common-mode noise on the analog supply, add an RC low-pass (10 ohm + 100 nF) feeding VDD to drop high-frequency noise below 1 mVrms.
Informações de conformidade
PBF suffix confirms Pb-free / RoHS compliance per Analog Devices product page. AEC-Q100 not qualified per datasheet; for AEC-Q100 cabin applications consult ADI automotive-grade portfolio or use external amplifier + automotive-mcu ADC.
