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Analog Devices Inc. ADM1022ARQ
- Part No.:
- ADM1022ARQ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Sensor and Detector Interfaces
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
ADM1022ARQ.pdf
- Description:
- LOW-COST PC TEMPERATURE MONITOR
- Quantity:
- Payment:
- Shipping:
Inventory:12,255
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Product details
Overview
ADM1022ARQ from Analog Devices is a low-cost PC temperature monitor and fan controller ASIC with dual remote diode sensing (D1+/D1–, D2+/D2–), on-chip bandgap temperature sensor, 8-bit DAC for analog fan speed control (FAN_SPD), and dual voltage monitors (VCC, VMON) for brownout detection. It operates from 3.0 V to 5.5 V, delivers ±3°C internal sensor accuracy, and interfaces via SMBus at up to 400 kHz - used in network servers and microprocessor-based office equipment for hardware thermal protection.
For engineers reviewing the ADM1022ARQ datasheet, ADM1022ARQ pinout, ADM1022ARQ application, or ADM1022ARQ equivalent, key selection considerations include its 16-lead QSOP package, open-drain interrupt/reset outputs (INT, RST1, RST2), programmable dual-diode channel configuration, fault-tolerant fan control logic, and SMBus address flexibility via ADD/NTEST_OUT pin.
Technical Context
The ADM1022ARQ integrates two independent temperature measurement channels: one dedicated (D1+/D1–) and one reconfigurable (D2+/D2– as diode input or THERM/GPI), each using switched-current ΔVBE sensing with 1°C resolution and ±5°C external accuracy. Its 8-bit DAC drives FAN_SPD with 0–2.5 V output range, ±5% total unadjusted error, and supports external op-amp buffering for fan motor control.
It implements dual independent reset generators: RST1 triggered by VCC falling below 2.925 V (50 mV hysteresis), and RST2 asserted on VMON undervoltage, MR assertion, or RST1 activity - both with 140–560 ms timeout. The SMBus interface uses 7-bit addressing with ADD/NTEST_OUT determining A1/A0 bits at power-up, supporting up to three device addresses on one bus.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 3.0 V to 5.5 V - enables direct compatibility with 3.3 V and 5 V system rails without level-shifting. |
| Internal Temp Accuracy | ±3°C - ensures reliable ambient temperature monitoring for system-level thermal management decisions. |
| External Diode Accuracy | ±5°C - supports accurate CPU/dual-processor die temperature tracking using standard substrate transistors. |
| SMBus Clock Frequency | Up to 400 kHz - allows high-speed register read/write for real-time thermal feedback loops. |
| DAC Output Range | 0 V to 2.5 V - provides full-scale analog control signal for external fan driver circuits (e.g., op-amp + MOSFET). |
| Reset Threshold (VCC) | 2.925 V ±75 mV - triggers RST1 during brownout to hold system in reset until stable supply resumes. |
| Package Type | 16-Lead QSOP (RQ-16) - surface-mount footprint compatible with automated PCB assembly and moderate thermal dissipation (θJA = 105°C/W). |
Pinout & Package
ADM1022ARQ is housed in a 16-lead QSOP (RQ-16) package, 3.9 mm × 4.9 mm body, 1.0 mm nominal height, gull-wing leads, 0.65 mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FAN_OFF (Pin 1) | Open-drain digital output | Asserts low to request immediate fan shutdown independent of DAC-controlled speed - used for emergency thermal shutdown. |
| MR (Pin 2) | Manual reset input | Pulled up internally (20 kΩ); active-low assertion forces RST2 and initiates 140–560 ms reset timeout - enables board-level reset coordination. |
| RST1 (Pin 3) | Bidirectional open-drain I/O | Auto-asserts during VCC brownout; can be driven externally as system reset input - supports shared reset bus architectures. |
| GND (Pin 4) | Power and signal ground | Common reference for all analog measurements, DAC output, and digital I/O - requires low-impedance connection to minimize noise coupling. |
| VCC (Pin 5) | Main power supply input | Primary 3.0–5.5 V rail powering core logic, ADC, and internal bandgap reference - also monitored for first reset generator. |
| VMON (Pin 6) | Analog voltage monitor input | Second independent brownout detector input - allows monitoring of auxiliary supply (e.g., +12 V regulator output via resistor divider). |
| RST2 (Pin 7) | Open-drain reset output | OR-combined assertion from VMON undervoltage, MR activation, or RST1 activity - provides fail-safe system reset signaling. |
| FAN_SPD/NTEST_IN (Pin 8) | Configurable analog output / test input | 8-bit DAC output (0–2.5 V) for fan speed; pulled low at power-up to prevent inadvertent NAND test mode - requires 4.7 kΩ external pull-down. |
| D1– (Pin 9) | Remote diode negative input | Current sink node for dedicated D1 channel - biased above GND by internal diode to reject ground noise in noisy PCB environments. |
| D1+ (Pin 10) | Remote diode positive input | Current source node for dedicated D1 channel - paired with D1– to measure ΔVBE of CPU-integrated transistor or discrete diode. |
| D2–/THERM (Pin 11) | Reconfigurable analog input / digital output | Programmable as second diode negative input or active-low overtemperature flag - enables dual-CPU monitoring or hardware trip signaling. |
| D2+/GPI (Pin 12) | Reconfigurable analog input / digital input | Programmable as second diode positive input or general-purpose logic input - supports external fan enable or status polling via Status Register Bit 4. |
| ADD/NTEST_OUT (Pin 13) | Address select / test output | Three-state input (GND/VCC/open) setting SMBus A1/A0 bits at power-up - allows up to three ADM1022ARQ devices on same bus without address conflict. |
| INT (Pin 14) | Open-drain interrupt output | Asserts low when any programmed limit (temp/voltage) is violated - enables OS-level thermal event handling without polling. |
| SCL (Pin 15) | SMBus clock input | Master-generated clock signal (≤400 kHz) synchronizing all serial transactions - requires external pull-up resistor (typically 2.2–10 kΩ). |
| SDA (Pin 16) | SMBus bidirectional data | Open-drain data line shared across SMBus slaves - requires external pull-up; supports START/STOP, ACK/NACK, and byte transfers per SMBus spec. |
Key Features
| Feature | Design Value |
|---|---|
| Dual remote diode sensing | Enables simultaneous monitoring of two CPUs or processor cores using standard substrate transistors - no external components required beyond routing. |
| On-chip bandgap temperature sensor | Provides accurate ambient temperature measurement without external sensor - eliminates BOM cost and placement complexity for system-level thermal awareness. |
| Fault-tolerant fan control | Automatically forces full-speed fan operation if hardware temperature trip points are exceeded - prevents thermal runaway even if software fails. |
| Two independent voltage monitors | Supports brownout detection on main VCC and auxiliary VMON rails - enables robust power sequencing and supply integrity validation in multi-rail systems. |
| SMBus-compatible serial interface | Reduces pin count and simplifies integration into PIIX4/ICH-class host controllers - supports standard System Management Bus protocols including Read Byte and block transfers. |
Applications
| Server Thermal Monitoring | Desktop PC Hardware Management |
|---|---|
Use Scenario: Real-time CPU die temperature tracking in dual-processor rack-mounted servers with redundant cooling. IC Role / Device Role / Timing Role: Dual-channel remote diode sensor and fan speed controller - measures D1+/D1– (CPU1) and D2+/D2– (CPU2), drives fans via FAN_SPD DAC, asserts INT on overtemp. Use Value: Enables dynamic fan speed adjustment based on actual processor junction temperatures - reduces acoustic noise and power consumption while maintaining safe thermal margins. | Use Scenario: Motherboard-level thermal supervision in consumer desktop PCs with single-core Pentium III processors. IC Role / Device Role / Timing Role: On-chip ambient sensor + single remote diode channel (D1+/D1–) + dual voltage monitors - reports ambient and CPU temperature, detects +3.3 V/+12 V rail faults. Use Value: Provides BIOS-accessible thermal data and automatic reset assertion during power supply instability - improves system reliability and user experience during voltage sags. |
| Office Equipment Thermal Protection | Test Instrument Environmental Control |
Use Scenario: Overtemperature safeguard in laser printer engine controllers where ambient temperature rises rapidly during print cycles. IC Role / Device Role / Timing Role: Ambient temperature monitor (on-chip sensor) + programmable THERM output (Pin 11) - triggers FAN_OFF when ambient exceeds setpoint, forcing immediate fan activation. Use Value: Prevents thermal damage to fuser assemblies and imaging drums by initiating forced-air cooling before critical thresholds are breached. | Use Scenario: Calibration-stable temperature monitoring in benchtop multimeters and oscilloscopes operating across 0°C–50°C ambient range. IC Role / Device Role / Timing Role: High-accuracy (±3°C) on-chip sensor + low-drift 8-bit DAC - compensates internal reference drift and controls thermoelectric cooler (TEC) bias current. Use Value: Maintains measurement accuracy over environmental temperature swings without requiring external calibration - reduces service intervals and field recalibration costs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar temperature monitor and fan controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM92CIMX | Single remote diode channel only; no VMON input; 12-bit ADC (vs. ADM1022ARQ's 8-bit); SMBus-only interface (no GPI/THERM pins) | Lacks dual-diode support and voltage monitoring - suitable for simpler single-CPU systems without auxiliary rail supervision | Select LM92CIMX when higher temperature resolution (0.0625°C) is prioritized over dual-sensor capability and brownout detection. |
| MAX6657ASA+ | Integrated 10-bit ADC; supports only on-chip sensor (no remote diode inputs); includes internal EEPROM for nonvolatile limit storage | No remote sensing capability - limited to ambient temperature monitoring only; no fan control DAC or reset outputs | Choose MAX6657ASA+ for cost-sensitive embedded applications needing only local temperature logging with persistent configuration storage. |
Compared with LM92CIMX and MAX6657ASA+, the ADM1022ARQ uniquely combines dual remote diode sensing, on-chip temperature measurement, dual voltage monitoring, and analog fan control in a single 16-pin QSOP - making it the only option among the three capable of full hardware thermal management in dual-processor server platforms.
Availability
ADM1022ARQ is available at Aetrix Electronics and suitable for network servers, desktop PCs, and microprocessor-based office equipment requiring stable component supply and long-term industrial availability.
Supply support for ADM1022ARQ 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.
The ADM1022ARQ belongs to Analog Devices' hardware monitoring IC product line, designed specifically for thermal and power integrity supervision in x86-based computing platforms - emphasizing SMBus integration, fault-tolerant response, and minimal external component count.
FAQ
What is the primary function of the ADM1022ARQ in a PC motherboard design?
The ADM1022ARQ serves as a dedicated hardware thermal and power supervisor - measuring up to two remote diode temperatures (e.g., CPU cores), monitoring ambient temperature via its on-chip sensor, detecting brownout conditions on VCC and VMON rails, generating reset signals (RST1/RST2), and controlling fan speed via its 8-bit DAC output (FAN_SPD). In motherboard designs, ADM1022ARQ offloads thermal management from the BIOS or EC, enabling faster, deterministic responses to overtemperature or undervoltage events without software intervention.
How does the ADM1022ARQ achieve accurate remote temperature measurement despite PCB noise?
The ADM1022ARQ uses a switched-current ΔVBE sensing technique that rejects absolute VBE variation and common-mode noise - measuring voltage difference between two precisely controlled diode bias currents. Its D– inputs include internal bias diodes to lift the remote sensor's negative terminal above ground, reducing ground-loop errors. Layout guidance recommends parallel D+/D– routing with guard traces, 0.1 µF bypassing, and optional 1000 pF filtering - all validated to maintain ±5°C accuracy even with 100 mVp-p supply noise, as shown in TPC 2 and TPC 3 of the ADM1022ARQ datasheet.
Can the ADM1022ARQ control more than one fan, and how is fan speed adjusted?
The ADM1022ARQ provides a single analog fan speed output (FAN_SPD) - an 8-bit DAC generating 0–2.5 V - which must be interfaced with external driver circuitry (e.g., op-amp + MOSFET or bipolar transistor) to drive a fan. While ADM1022ARQ itself controls only one fan channel, its FAN_OFF pin (Pin 1) offers independent on/off gating, and its INT and THERM outputs can trigger secondary fan controllers. Fan speed is adjusted by writing 8-bit values (0x00–0xFF) to the Analog Output Register via SMBus; 0x00 yields 0 V (minimum speed), 0xFF yields 2.5 V (maximum speed), with linear interpolation between.
What SMBus address options are supported by the ADM1022ARQ, and how is the address selected?
The ADM1022ARQ supports three SMBus slave addresses determined by the logic state of the ADD/NTEST_OUT pin (Pin 13) at power-up: grounded → 0x2C, open-circuit → 0x2E (default), connected to VCC → 0x2D. These correspond to 7-bit addresses 0101100, 0101110, and 0101101 respectively - with the R/W bit appended during transaction. Address selection occurs only at power-on reset; changing ADD during operation has no effect until next power cycle. This allows up to three ADM1022ARQ devices on the same SMBus without address collision.
Does the ADM1022ARQ require external components for basic operation, and what are the critical ones?
Yes - the ADM1022ARQ requires several external components for reliable operation: a 4.7 kΩ pull-down resistor on FAN_SPD/NTEST_IN (Pin 8) to prevent unintended NAND test mode; external pull-up resistors on SDA and SCL (typically 2.2–10 kΩ); 0.1 µF ceramic bypass capacitor between VCC and GND; and optional 1000 pF filter capacitor between D+ and D– for noisy environments. For fan control, external op-amp and transistor circuitry (e.g., Figure 5c in datasheet) is mandatory - ADM1022ARQ does not drive fans directly. No external crystal or timing components are needed, as all timing is internally generated.
ADM1022ARQ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Temperature Sensor
- Input Type:
- Logic
- Output Type:
- Analog
- Current - Supply:
- 2.6 mA
- Operating Temperature:
- 0°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QSOP
ADM1022ARQ FAQ
1.How can I place an order for ADM1022ARQ through Aetrix?
Please submit a Request for Quotation (RFQ) for ADM1022ARQ 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 ADM1022ARQ reliable?
The price and inventory of ADM1022ARQ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADM1022ARQ is usually 5 days.
3.What payment methods are accepted for ADM1022ARQ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADM1022ARQ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADM1022ARQ?
ADM1022ARQ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADM1022ARQ 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 ADM1022ARQ?
For technical support, including ADM1022ARQ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADM1022ARQ requirements.
6.How does Aetrix verify that ADM1022ARQ is sourced from the original manufacturer or authorized distributors?
All ADM1022ARQ 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 ADM1022ARQ meets industry standards.
7.What is the process for return or replacement of ADM1022ARQ?
All ADM1022ARQ units undergo pre-shipment inspection (PSI). If there is an issue with ADM1022ARQ, 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 ADM1022ARQ part is unused and in its original packaging.
Return procedure for ADM1022ARQ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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