My Inquiry
My Account
Analog Devices Inc. AD7825BN
- Part No.:
- AD7825BN
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 24-DIP (0.300", 7.62mm)
- Datasheet:
-
AD7825BN.pdf
- Description:
- IC ADC 8BIT 4CH 2MSPS 24-DIP
- Quantity:
- Payment:
- Shipping:
Inventory:7,472
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
AD7825BN from Analog Devices is a high-speed, 4-channel, 8-bit parallel-output analog-to-digital converter (ADC) with 2 MSPS throughput, 420 ns conversion time, on-chip 2.5 V reference, and track-and-hold - designed for DSP front ends and subsampling in mobile communication systems.
For engineers reviewing the AD7825BN datasheet, AD7825BN pinout, AD7825BN application, or AD7825BN equivalent, this page delivers verified technical context, real-world interface behavior, channel selection logic, power-down timing, and design-meaningful specifications - all confirmed for the AD7825BN variant in 24-lead PDIP package.
Technical Context
The AD7825BN implements an 8-bit half-flash architecture: a 4-bit coarse flash stage followed by a 4-bit fine flash stage, achieving full conversion in ≤420 ns. It uses a single falling edge of CONVST to initiate conversion and enter hold mode, with automatic power-down triggered by low CONVST at EOC assertion.
Channel selection is performed via dedicated A0/A1 address inputs (not written to), enabling immediate multiplexer switching without register access. The VMID pin allows analog input span centering across AGND–VDD, supporting both 0 V–2.5 V (5 V supply) and 0 V–2 V (3 V supply) ranges with ±0.75 LSB INL and ±0.75 LSB DNL.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 8-bit straight binary output - ensures compatibility with standard 8-bit microprocessor data buses without bit-shifting or format conversion. |
| Max Throughput | 2 MSPS - supports real-time sampling of baseband signals up to 10 MHz full-power bandwidth (FPBW) for subsampling applications. |
| Conversion Time | 420 ns max - defines minimum inter-conversion interval; enables >2.38 million conversions/sec in burst mode with proper timing margin. |
| INL / DNL | ±0.75 LSB max each - guarantees monotonicity and no missing codes over −40°C to +85°C, critical for closed-loop control accuracy. |
| Supply Range | 3 V ±10% or 5 V ±10% - dual-voltage operation allows direct integration into mixed-supply systems without level-shifting circuitry. |
| On-chip Reference | 2.5 V ±50 mV (2% tolerance) - eliminates external reference component count; usable as VREF IN/OUT with optional decoupling. |
| Power-Down Current | 5 μA max - reduces idle power by >99.9% vs. 12 mA active current, enabling battery-sensitive portable instrumentation designs. |
Pinout & Package
AD7825BN is supplied in a 24-lead, 0.3" wide plastic dual in-line package (PDIP). Pin functions are validated per Analog Devices Rev. C datasheet Figure 4 and Table 4.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN1–VIN4 | Analog Input Channels | Four single-ended inputs; default range 0 V–2.5 V (5 V supply) or 0 V–2 V (3 V supply); span centered via VMID. |
| A0, A1 | Channel Address Inputs | Direct hardware-selectable channel index (0–3); no write cycle needed - simplifies FPGA/microcontroller interface logic. |
| CONVST | Convert Start / Power-Down Control | Falling edge initiates conversion and hold; sampled at EOC high to auto-enter power-down if low - enables event-driven low-power operation. |
| PD | Power-Down Enable | Active-low pin (AD7825BN-specific); forces deep sleep independent of CONVST state - used for system-level power gating. |
| EOC | End-of-Conversion Output | Active-low pulse (≥70 ns wide); asserts interrupt or latches data without external timing logic - supports standalone use. |
| CS, RD | Parallel Interface Controls | Enable data bus access only when both low; compatible with 8051, PIC, and ADSP-21xx processors per datasheet interfacing guides. |
| DB0–DB7 | 8-Bit Parallel Data Outputs | High-impedance when CS/RD inactive; drive CMOS levels (VOH ≥2.4 V @ 3 V, ≥4 V @ 5 V) - directly interfaces standard logic families. |
| VREF IN/OUT | Reference I/O | Supplies or accepts 2.5 V reference; internal 2.5 V ref available here; decoupling to AGND recommended for noise immunity. |
| VMID | Input Span Center Voltage | Sets midpoint of analog input range; default = 1.25 V (5 V) or 1.0 V (3 V); allows offset compensation for single-supply op amp drivers. |
Key Features
| Feature | Design Value |
|---|---|
| 420 ns conversion time | Enables maximum DSP processing time per sample in real-time systems - critical for adaptive filtering and modulation/demodulation pipelines. |
| Hardware channel selection (A0/A1) | Eliminates software register writes for channel change - reduces latency and CPU overhead in multi-sensor acquisition systems. |
| Automatic power-down on CONVST low | Reduces average power without external control logic - ideal for burst-mode sensing where conversion intervals exceed 500 ns. |
| VMID-adjustable input span | Compensates for system-level DC offsets and enables rail-to-rail input utilization with single-supply signal conditioning amplifiers. |
| On-chip 2.5 V reference (±2%) | Removes need for external precision reference IC - cuts BOM cost and board area while maintaining SNR ≥48 dB at 30 kHz input. |
Applications
| Disk Drive Read Channel | Mobile Baseband Subsampling |
|---|---|
Use Scenario: Digitizing PRML (Partial Response Maximum Likelihood) analog waveforms from magnetic head preamplifiers at ~20–40 MSPS effective rate via undersampling. IC Role / Device Role / Timing Role: ADC front end capturing high-frequency analog read signals; operates at 2 MSPS with 10 MHz FPBW to alias Nyquist-zone 3–4 signals into baseband. Use Value: Enables compact, low-power read channel design without external anti-alias filter - leverages AD7825BN's −70 dB channel-to-channel isolation to suppress adjacent track crosstalk. |
Use Scenario: Sampling IF signals in GSM/EDGE transceivers using bandpass sampling to avoid image-reject mixers. IC Role / Device Role / Timing Role: High-speed digitizer for 100–200 MHz IF bands; uses 2 MSPS sampling to fold desired channel into DC–1 MHz baseband. Use Value: Achieves >48 dB SNR at 30 kHz input while maintaining −65 dB IMD - meets ETSI spectral mask requirements for adjacent channel leakage ratio (ACLR). |
| DSP-Based Motor Control | Portable Data Acquisition |
Use Scenario: Simultaneous sampling of current, voltage, and position feedback in servo drives with real-time vector control loop closure. IC Role / Device Role / Timing Role: Multi-channel ADC feeding TI C2000 or ADSP-21xx DSPs; channels selected via A0/A1 during PWM dead-time intervals. Use Value: 420 ns conversion + 200 ns track-and-hold acquisition enables <1 µs total latency - supports 20 kHz PWM carrier frequencies with precise phase alignment. |
Use Scenario: Battery-powered handheld oscilloscope or vibration analyzer requiring low standby power and fast wake-on-event response. IC Role / Device Role / Timing Role: Primary digitizer with automatic power-down between triggers; CONVST edge-triggered acquisition synchronized to external sensor interrupt. Use Value: 5 µA power-down current extends battery life to >100 hours; EOC pulse directly clocks FPGA sample buffer - eliminates polling overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit, multi-channel, parallel-interface ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7822BN | 1-channel version in 20-lead PDIP; identical core architecture, timing, and reference but no A0/A1 pins or PD pin. | Used where single-input monitoring suffices (e.g., power supply telemetry); lacks multiplexing and dedicated power-down control. | Select AD7822BN only when channel count and PD pin are unnecessary - saves PCB space but removes multi-signal capability. |
| AD7829BN | 8-channel version in 28-lead PDIP; adds A2 pin and VIN5–VIN8; same conversion time, reference, and power specs. | Required for systems needing >4 analog inputs (e.g., multi-phase motor control, multi-sensor IoT nodes); larger footprint and routing complexity. | Choose AD7829BN when expanding beyond four channels; verify layout accommodates 28-pin spacing and additional analog trace isolation. |
Compared with AD7822BN and AD7829BN, the AD7825BN uniquely balances channel count (4), package size (24-pin PDIP), and feature set (A0/A1 + PD) - making it optimal for mid-complexity embedded acquisition where space and signal count are constrained but flexibility is required.
Availability
AD7825BN is available at Aetrix Electronics and suitable for disk drive read channels, mobile communication subsampling, and DSP-based motor control requiring stable component supply across industrial temperature range (−40°C to +85°C).
Supply support for AD7825BN includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.
The AD7822/AD7825/AD7829 family was engineered for high-speed, low-power, microprocessor-compatible data acquisition - targeting real-time systems where conversion latency, channel flexibility, and supply voltage agility are critical.
FAQ
What is the maximum sampling frequency supported by the AD7825BN?
The AD7825BN supports a maximum throughput of 2 MSPS (million samples per second), with a guaranteed maximum conversion time of 420 ns. This allows sustained sampling at precisely 2 × 10⁶ conversions/sec when timing constraints (e.g., t13 ≥200 ns channel selection delay) are met. The AD7825BN maintains specified AC performance - including 48 dB SNR and −65 dB IMD - up to this rate under −40°C to +85°C conditions.
Does the AD7825BN require an external reference voltage?
No, the AD7825BN includes an on-chip 2.5 V reference with ±2% initial accuracy and 50 ppm/°C temperature coefficient, accessible at the VREF IN/OUT pin. This reference is sufficient for most applications; however, an external precision reference (e.g., AD780) can be connected to VREF IN/OUT to improve absolute accuracy if required. The AD7825BN operates correctly with or without external reference connection.
How does channel selection work on the AD7825BN?
Channel selection on the AD7825BN is performed exclusively via the A0 and A1 address inputs - no internal register write is needed. These pins are sampled on the falling edge of RD to select one of four analog inputs (VIN1–VIN4). This hardware-based method eliminates software overhead and ensures deterministic channel switching, making it ideal for time-critical applications like motor control commutation sequencing.
Can the AD7825BN operate from a 3 V supply?
Yes, the AD7825BN is fully specified for operation from 3 V ±10% (2.7 V to 3.3 V) as well as 5 V ±10% (4.5 V to 5.5 V). At 3 V, the input voltage range defaults to 0 V–2 V p-p, LSB size becomes 0.8 × VREF / 256, and logic thresholds adjust to VINH ≥2 V and VINL ≤0.4 V. All dynamic and DC specifications - including INL, DNL, SNR, and conversion time - are guaranteed across both supply ranges.
What is the purpose of the VMID pin on the AD7825BN?
The VMID pin on the AD7825BN sets the center voltage of the analog input range - allowing the 2 V (3 V supply) or 2.5 V (5 V supply) span to be positioned anywhere between AGND and VDD. With VMID unconnected, the default center is 1.0 V (3 V) or 1.25 V (5 V). Connecting VMID to an external voltage (e.g., from an op amp) compensates for system-level DC offsets and enables full utilization of single-supply driver amplifiers without clipping.
AD7825BN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Number of Bits:
- 8
- Sampling Rate (Per Second):
- 2M
- Number of Inputs:
- -
- Input Type:
- -
- Data Interface:
- Parallel
- Configuration:
- -
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 1
- Architecture:
- -
- Reference Type:
- -
- Voltage - Supply, Analog:
- -
- Voltage - Supply, Digital:
- -
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 24-PDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
AD7825BN FAQ
1.How can I place an order for AD7825BN through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7825BN on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for AD7825BN reliable?
The price and inventory of AD7825BN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7825BN is usually 5 days.
3.What payment methods are accepted for AD7825BN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7825BN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7825BN?
AD7825BN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7825BN order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for AD7825BN?
For technical support, including AD7825BN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7825BN requirements.
6.How does Aetrix verify that AD7825BN is sourced from the original manufacturer or authorized distributors?
All AD7825BN products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AD7825BN meets industry standards.
7.What is the process for return or replacement of AD7825BN?
All AD7825BN units undergo pre-shipment inspection (PSI). If there is an issue with AD7825BN, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The AD7825BN part is unused and in its original packaging.
Return procedure for AD7825BN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AD7825BN Tags
-
ADC081C021CIMKX/NOPB
Texas Instruments
-
MCP3021A5T-E/OT
Microchip Technology
-
TLA2024IRUGR
Texas Instruments
-
MCP3221A5T-E/OT
Microchip Technology
-
MCP3221A5T-I/OT
Microchip Technology
-
MCP3221A4T-E/OT
Microchip Technology
-
MCP3221A6T-E/OT
Microchip Technology
-
MCP3221A0T-E/OT
Microchip Technology
-
MCP3221A1T-E/OT
Microchip Technology
-
ADC121S021CIMFX/NOPB
Texas Instruments
-
MCP3001-I/MS
Microchip Technology
-
MCP3001-I/SN
Microchip Technology
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
