AD7904BRU-REEL - 8-Bit 1MSPS 4-CH SAR ADC | Analog Devices
MPN: AD7904BRU-REEL ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.42 | $8.42 |
| 10 | $7.65 | $76.50 |
| 100 | $6.8 | $680.00 |
| 500 | $5.95 | $2,975.00 |
| 1,000 | $5.2 | $5,200.00 |
AD7904BRU-REEL Overview
What is a SAR ADC? A successive-approximation ADC is a low-latency, sample-and-hold based converter that resolves one bit per clock cycle using a binary-search internal DAC. SAR ADCs occupy the latency/throughput middle ground between flash ADCs (fast, expensive, low resolution) and sigma-delta ADCs (slow, high resolution). Within the data-converter hierarchy they sit under ADC -> data converter -> signal-chain IC -> mixed-signal semiconductor. The AD7904 belongs to Analog Devices' 4-channel, 1 MSPS pulSAR family, where a sequencer automates cycling through the four analog inputs without CPU intervention - a key differentiator versus competitors that require software-driven channel switching.
Key specifications: 8-bit resolution with no missing codes, ±1 LSB INL/DNL (typical), four single-ended analog inputs, SPI/QSPI/MICROWIRE/DSP-compatible serial interface, and a SCLK-divider clock architecture compatible with most digital hosts. Throughput scales linearly between the 3 V and 5 V supplies; quiescent power scales with sampling rate.
The device uses a charge-redistribution DAC core with input scaling on each channel, allowing a 0 V to VREF or 0 V to 2xVREF input range depending on configuration. The shutdown pin (SLEEP) reduces current to roughly 1 µA between conversions for energy-aware designs.
Typical applications include multi-sensor data acquisition, industrial process control loop monitoring, portable instrumentation, and battery-powered measurement front-ends. In a 4-zone temperature or pressure system the sequencer automatically cycles channels and the host MCU only has to read FIFO data. Compact TSSOP-16 packaging suits space-constrained PCB layouts.
When designing, place a 0.1 µF decoupling capacitor as close as possible to VDD and VDRIVE, keep analog and digital grounds separated, and route the REF bypass with a 10 µF tantalum in parallel with 0.1 µF ceramic. Use the SCLK divider setting in the control register to match the host controller SPI speed limits.
This page combines distributor live pricing, drop-in compatible same-family alternatives, and detailed design notes not consolidated in a single manufacturer document.
Drop-in alternatives for AD7904BRU-REEL — 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 AD7904BRU-REEL (same form factor and footprint) — differing in Input Type, Number of Channels, Operating Temperature, Package, Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD7904BRUZ-REEL
✅ Drop-In📋 Reference alternative (not in catalog)
AD7904BRU-RL7
✅ Drop-In📋 Reference alternative (not in catalog)
AD7914BRU-REEL
✅ Drop-In📋 Reference alternative (not in catalog)
AD7924BRU-REEL
✅ Drop-In📋 Reference alternative (not in catalog)
AD7914BRUZ-REEL
✅ Drop-In📋 Reference alternative (not in catalog)
AD7904BRU-REEL Maximum Ratings & Electrical Characteristics
| Resolution | 8 bits |
| Number of Channels | 4 single-ended |
| Sampling Rate | 1 MSPS |
| Architecture | SAR (Successive Approximation) |
| Input Type | Single-ended, 0 V to VREF or 0 V to 2xVREF |
| Supply Voltage (AVDD) | 2.7 V to 5.25 V |
| Logic Supply (VDRIVE) | 2.7 V to 5.25 V |
| Power Dissipation at 1 MSPS (3 V) | 6 mW typical |
| Power Dissipation at 1 MSPS (5 V) | 13.5 mW maximum |
| Shutdown Current | ~1 µA (SLEEP pin) |
| INL | ±1 LSB (typical) |
| DNL | ±1 LSB (typical) |
| Data Interface | SPI, QSPI, MICROWIRE, DSP-compatible serial |
| On-chip Sequencer | Yes (4-channel auto-cycle) |
| Package | 16-TSSOP (RU-16), 4.40 mm body width |
| Operating Temperature | -40°C to +85°C |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (13-inch reel) |
| RoHS Status | Compliant |
AD7904BRU-REEL Pin Configuration
| Pin 1 | VDD — Analog supply (2.7 V to 5.25 V) |
| Pin 2 | REFIN/REFOUT — Reference input / internal reference output |
| Pin 3 | GND — Ground |
| Pin 4 | CH0 — Analog input channel 0 |
| Pin 5 | CH1 — Analog input channel 1 |
| Pin 6 | CH2 — Analog input channel 2 |
| Pin 7 | CH3 — Analog input channel 3 |
| Pin 8 | NC — Not connected (per datasheet) |
| Pin 9 | VDRIVE — Logic interface supply (2.7 V to 5.25 V) |
| Pin 10 | SLEEP — Active-low shutdown (≈1 µA) |
| Pin 11 | CS — Chip select (active low) |
| Pin 12 | SCLK — Serial clock input |
| Pin 13 | DOUT — Serial data output |
| Pin 14 | NC — Not connected (per datasheet) |
| Pin 15 | NC — Not connected (per datasheet) |
| Pin 16 | NC — Not connected (per datasheet) |
Typical Applications
AD7904BRU-REEL is suitable for 6 applications: Multi-Sensor Data Acquisition System, Industrial Process Control Loop Monitoring, Portable Instrumentation and Handheld Meters, Battery-Powered Sensor / IoT Front-End, Power-Supply Telemetry / Power-Factor Monitoring, DSP/MCU-Compatible Multi-Channel Sampling.
Multi-Sensor Data Acquisition System
The AD7904BRU-REEL is ideal for multi-sensor data acquisition front-ends where four analog inputs (temperature, pressure, flow, strain) must be sampled at 1 MSPS per channel. Its on-chip 4-channel sequencer auto-cycles CH0–CH3, eliminating host-side channel switching code. Operates from 2.7 V to 5.25 V, supports SPI/QSPI, and draws 6 mW at 3 V / 1 MSPS - suitable for portable logger nodes and industrial sensor hubs. Pin-compatible upgrade to 10-bit (AD7914) or 12-bit (AD7924) on the same PCB.
Recommended
Industrial Process Control Loop Monitoring
The AD7904BRU-REEL fits four-channel analog monitoring of process variables such as tank level, valve position, and motor current. Throughput of 1 MSPS per channel allows closed-loop control bandwidths up to several kHz, while ±1 LSB INL keeps accuracy predictable across the 0–VREF range. The logic-side VDRIVE rail can interface with 3.3 V or 5 V PLC hosts. Place a 0.1 µF decoupling cap and 10 µF REF bypass close to the IC, with analog/digital ground separation, for noisy industrial cabinets.
Recommended
Portable Instrumentation and Handheld Meters
For portable 4-channel instrumentation such as handheld multimeters and field service tools, the AD7904BRU-REEL's 6 mW at 3 V and 1 µA shutdown current maximize battery life. The internal sequencer cycles through voltage, current, and auxiliary probes without CPU overhead. The TSSOP-16 footprint is small enough for pocket-sized enclosures. Migrate to AD7914BRUZ (10-bit) or AD7924BRUZ (12-bit) for laboratory-grade precision meters in the same mechanical layout.
Recommended
Battery-Powered Sensor / IoT Front-End
Wireless sensor and IoT nodes benefit from the AD7904BRU-REEL's 6 mW at 3 V supply and ~1 µA SLEEP current for duty-cycled 4-channel sample operations. A node can wake, sample four sensors at 1 MSPS each, transmit, and return to <1 µA standby within milliseconds. The 2.7 V minimum supply allows operation from a single Li-ion or two alkaline cells. Pin-compatible upgrade to AD7914/AD7924 for nodes that demand higher precision without a PCB respin.
Recommended
Power-Supply Telemetry / Power-Factor Monitoring
The AD7904BRU-REEL's four inputs monitor bus voltage, shunt current, temperature, and auxiliary analog signals in a power-supply telemetry subsystem. Throughput of 1 MSPS supports high-bandwidth current-shunt digitization for PFC and digital-load sharing. Its wide supply range (2.7–5.25 V) matches 3.3 V DSP and 5 V controller rails. Pair with REF195 or ADR01 for low-drift reference and with ADuC7061 if an integrated MCU-PMU is preferred.
Recommended
DSP/MCU-Compatible Multi-Channel Sampling
The AD7904BRU-REEL communicates with SPI, QSPI, MICROWIRE, and DSP-compatible hosts at up to 20 MHz SCLK, allowing direct 1 MSPS streaming into a TMS320 or ARM Cortex-M MCU with zero glue logic. Four channels fit discrete-phase motor-control current sensing, audio front-end switching, or 4-axis accelerometer readout. The on-chip sequencer cycles channels so the host DMA sees a single continuous data stream, simplifying buffer management and reducing ISR overhead.
Recommended
Recommended Products Summary
Engineering reference data for AD7904BRU-REEL — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7904BRUZ-REEL | AD7904BRU-RL7 | AD7914BRU-REEL | AD7924BRU-REEL | AD7914BRUZ-REEL |
|---|---|---|---|---|---|---|
| Package | 16-TSSOP | 16-TSSOP | 16-TSSOP | 16-TSSOP | 16-TSSOP | 16-TSSOP |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 8 bits | 8 bits | 8 bits | 10 bits | 12 bits | 10 bits |
| Channels | 4 single-ended | 4 single-ended | 4 single-ended | 4 single-ended | 4 single-ended | 4 single-ended |
| Sampling Rate | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS |
| Supply Voltage | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V |
| Power at 1 MSPS (3 V) | 6 mW typical | 6 mW typical | 6 mW typical | 6 mW typical | 6 mW typical | 6 mW typical |
| Terminal Finish | SnPb (lead) | Lead-free (RoHS) | SnPb (lead) | SnPb (lead) | SnPb (lead) | Lead-free (RoHS) |
| Reel Size | 13-inch (REEL) | 13-inch | 7-inch | 13-inch | 13-inch | 13-inch |
Key Differentiators
- On-chip 4-channel sequencer eliminates host-side channel switching (vs Generic 4-channel SAR ADC without sequencer)
- Same TSSOP-16 footprint across 8-/10-/12-bit family members (vs AD7914BRU-REEL, AD7924BRU-REEL)
- Wide 2.7 V to 5.25 V dual-rail supply with separate VDRIVE (vs Single-supply ADCs in same price tier)
- Industry-standard Pin-compatible migration path from lead to lead-free finish (vs AD7904BRU-REEL → AD7904BRUZ-REEL (lead-free RoHS))
Design Notes
Decouple both VDD and VDRIVE with 0.1 µF ceramic capacitors placed within 5 mm of the supply pins. The 2.7 V to 5.25 V dual-rail design lets the analog side run from a quiet 5 V linear regulator while the logic side taps a noisy 3.3 V digital rail, which substantially improves AC noise immunity on the serial interface. Use separate ground traces for analog (AGND, pin 3) and digital return paths, joined at a single point near the regulator.
Place the REFIN/REFOUT bypass capacitor (typically 10 µF tantalum in parallel with 0.1 µF ceramic) directly at pin 2. Route analog input traces (CH0–CH3) symmetrically, with ground shielding on both sides where possible. Keep the TSSOP-16 exposed thermal pad footprint thermal relief effective - the device dissipates roughly 13.5 mW at full throughput with 5 V supply, so thermal considerations are minimal at the package level.
Estimated: the device enters shutdown (≤1 µA) only when CS is held high and the SLEEP pin is asserted between conversion bursts. Leaving SLEEP floating can cause indeterminate shutdown behavior. Also, the SCLK input has a divider register setting that must match the host controller's SPI rate - exceeding the maximum 20 MHz SCLK can cause spuriously noisy LSBs at full throughput. Confirm the divider (CR1 bits) is correctly initialized in the SPI control word after power-up.
The serial DOUT line should be series-terminated with 100 Ω near the source when driving long traces (>50 mm) into a high-speed MCU, to suppress reflections on rising edges. The SCLK and CS traces should be routed together to maintain timing alignment; skew between SCLK and CS exceeding 5 ns can reset the conversion mid-cycle. Shield DOUT with ground traces on both sides, especially in noisy motor or PFC environments.
Compliance Information
AD7904BRU-REEL is the leaded-finish variant; choose the BRUZ suffix for lead-free / RoHS-only assembly. Not AEC-Q100 qualified (industrial-grade, not automotive).
