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Analog Devices Inc. ADP3178JRZ-REEL7
- Part No.:
- ADP3178JRZ-REEL7
- Manufacturer:
- Analog Devices Inc.
- Category:
- Special Purpose Regulators
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
ADP3178JRZ-REEL7.pdf
- Description:
- 4-BIT PROG BUCK CONTROLLER
- Quantity:
- Payment:
- Shipping:
Inventory:1,000
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Product details
Overview
ADP3178JRZ-REEL7 from Analog Devices is a 4-bit programmable synchronous buck controller for CPU core voltage regulation, supporting 1.3 V to 2.05 V output via VID interface, featuring ADOPT™ active voltage positioning, ±0.8% total output accuracy over temperature, and integrated dual linear regulator controllers for auxiliary rails. It drives external N-channel MOSFETs in a constant off-time current-mode architecture optimized for Intel Pentium III and Celeron platforms.
For engineers reviewing the ADP3178JRZ-REEL7 datasheet, ADP3178JRZ-REEL7 pinout, ADP3178JRZ-REEL7 application, or ADP3178JRZ-REEL7 equivalent, key selection criteria include VID-programmable output range, crowbar overvoltage protection (120% trip), dual adjustable linear regulator control, CT-programmable off-time, and SOIC-16 package compatibility with motherboard power sequencing requirements.
Technical Context
The ADP3178JRZ-REEL7 implements a current-mode, constant off-time control architecture where switching frequency varies inversely with input-to-output voltage ratio; off-time is set by an external capacitor on the CT pin (e.g., 150 pF yields ~200 kHz at 1.7 V out). Its ADOPT™ technology dynamically adjusts output voltage as a function of load current to optimize transient response without requiring additional output capacitance.
It integrates two independent linear regulator controllers with externally adjustable feedback (via LRFB1/LRFB2), each driving an external N-channel MOSFET (LRDRV1/LRDRV2), enabling precise 1.0 V ±3% auxiliary rail generation. The device includes full-cycle current sensing (CS+/CS–), overvoltage crowbar (115–125% nominal trip), and UVLO (7.0 V threshold) with 1.0 V hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage Range | 1.3 V to 2.05 V, digitally programmed via 4-bit VID code (VID0–VID3); enables precise core voltage matching for Intel VRM-compliant processors. |
| Total Output Accuracy | ±0.8% over 0°C to 70°C; ensures stable CPU operation within tight VRM 8.4 voltage tolerance windows (±40 mV static, ±80 mV transient). |
| Crowbar Trip Point | 115–125% of nominal DAC voltage; provides hardware-level microprocessor protection against catastrophic overvoltage without external components. |
| Linear Regulator Feedback | Adjustable via external resistor dividers on LRFB1/LRFB2; supports user-defined auxiliary outputs (e.g., 1.0 V ±3%) for AGP/GTL rails. |
| CT Off-Time Control | Programmable 3.5–4.5 µs off-time (at 25°C, CT = 200 pF); determines switching frequency and enables optimization of efficiency vs. regulator size. |
| UVLO Threshold | 7.0 V ±0.25 V with 1.0 V hysteresis; prevents erratic startup/shutdown during brown-out conditions in 12 V supply domains. |
| Current Sense Threshold | 69–87 mV (load-dependent); sets peak inductor current limit and enables accurate overcurrent protection scaling with RSENSE. |
Pinout & Package
ADP3178JRZ-REEL7 is housed in a 16-lead SOIC (R-16A) package with standard 1.27 mm pitch, rated for 0°C to 70°C ambient operation and compatible with JEDEC MS-012AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VID0–VID3 (Pins 1–4) | Voltage Identification Inputs | Read 4-bit digital code from CPU to set DAC reference; internal 20–30 kΩ pull-up to 5.0–5.7 V enables logic-high default when open. |
| LRFB1 / LRFB2 (Pins 5, 12) | Linear Regulator Feedback Inputs | High-impedance (0.3–1 µA) inputs for external resistor dividers; enable precise adjustment of auxiliary rail voltages (e.g., 1.0 V). |
| LRDRV1 / LRDRV2 (Pins 6, 11) | Linear Regulator Gate Drivers | Push-pull outputs driving external N-MOSFET gates; support fast transient response for auxiliary supplies independent of main buck operation. |
| CS– / CS+ (Pins 7–8) | Current Sense Differential Inputs | Monitor output current via sense resistor; CS– also serves as error amplifier inverting input for voltage regulation loop. |
| GND (Pin 9) | Power Ground Reference | Low-impedance return path for synchronous MOSFET sources and current sense circuitry; critical for noise immunity and crowbar reliability. |
| DRVH / DRVL (Pins 14–15) | High-Side / Low-Side MOSFET Drivers | 12 V-tolerant gate drivers with 6 Ω output resistance and 80 ns transition time; support N-channel FETs in synchronous buck topology. |
| VCC (Pin 13) | Main Supply Input | Accepts 4.5–12.6 V; powers internal bias, oscillator, and drivers; diode-OR'd with 5 VSB/12 V in motherboard designs for seamless standby operation. |
| COMP (Pin 16) | Error Amplifier Output | Compensation node for voltage loop; connects to RC network for stability tuning; 3.0 V max output limits current comparator threshold. |
| CT (Pin 10) | Oscillator Timing Capacitor | Connects to ground; charges at 150 µA to set fixed off-time; value directly determines operating frequency and light-load behavior. |
Key Features
| Feature | Design Value |
|---|---|
| ADOPT™ Active Voltage Positioning | Dynamically lowers output voltage under increasing load to maintain optimal transient headroom-enables minimum output capacitance while meeting Intel VRM 8.4 step-load specs. |
| Integrated Dual Linear Regulator Controllers | Two independent, externally adjustable regulators (via LRFB1/LRFB2) eliminate need for discrete LDOs; support 1.0 V ±3% rails for AGP/GTL with high bandwidth load-step response. |
| Hardware Crowbar Protection | Turns on low-side MOSFET if output exceeds 120% nominal voltage-protects CPU without external circuitry; resets automatically at ~50% nominal voltage. |
| VID-Programmable Core Voltage | Direct interface to Intel CPU VID bus; supports 16 discrete voltages from 1.30 V to 2.05 V in 50 mV steps-ensures compliance with Pentium III/Celeron power delivery requirements. |
| Constant Off-Time Current-Mode Control | Eliminates need for slope compensation; provides inherent stability across wide VIN/VOUT ratios and simplifies loop compensation versus voltage-mode controllers. |
Applications
| Desktop CPU Core Power Supply | Server Board Auxiliary Rail Generation |
|---|---|
Use Scenario: Generating 1.7 V @ 15 A for a 750 MHz Pentium III processor on ATX motherboard with VRM 8.4 compliance. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-side/low-side N-MOSFET switching, VID decoding, and active voltage positioning. Use Value: Achieves ±40 mV static and ±80 mV transient voltage tolerance using only five Rubycon ZA-series output capacitors (ESR < 5 mΩ), enabled by ADOPT™. | Use Scenario: Providing 1.0 V AGP rail and 1.0 V GTL+ reference rail on dual-processor server board with strict sequencing requirements. IC Role / Device Role / Timing Role: Dual linear regulator controller generating auxiliary supplies synchronized to main buck startup and maintaining regulation during 5 VSB-only standby mode. Use Value: Eliminates two discrete LDOs; linear regulators remain active during VCC UVLO, ensuring Intel-specified 3.3 V tracking and rail ordering without external sequencers. |
| Notebook Docking Station Power Management | Industrial Embedded x86 Module Supply |
Use Scenario: Supporting hot-plug CPU voltage scaling in docking station with dynamic load changes up to 20 A/µs di/dt. IC Role / Device Role / Timing Role: Core voltage controller with crowbar protection and fast current-sense loop (50 ns response) to handle rapid transients from GPU/CPU co-location. Use Value: Crowbar activation within 400 ns prevents CPU latch-up during sudden overvoltage events; ADOPT™ reduces required bulk capacitance by 35% versus passive positioning. | Use Scenario: Powering fanless x86 SBC with extended thermal envelope (0°C to 70°C) requiring long-term stability and no derating. IC Role / Device Role / Timing Role: Main DC-DC controller with ±0.8% accuracy over full temperature range and UVLO hysteresis preventing cycling near brown-out thresholds. Use Value: Maintains VRM-spec compliance across industrial temperature range without recalibration; SOIC-16 package supports automated optical inspection and reflow compatibility. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADP3158JRZ-REEL7 | Fixed 2.5 V / 1.8 V linear regulator outputs; identical buck control, VID range, and ADOPT™ engine. | Targeted for legacy Pentium III designs requiring fixed auxiliary rails; lacks external adjustability of ADP3178JRZ-REEL7. | Select ADP3158JRZ-REEL7 only when auxiliary rail voltages are strictly 2.5 V and 1.8 V-no resistor divider needed. |
| ISL6522CRZ-T | Intel VRM 8.5-compliant; 6-bit VID (0.0125 V steps), higher accuracy (±0.5%), but no integrated linear regulator controllers. | Requires external LDOs or discrete regulators for auxiliary rails; designed for newer Pentium 4 platforms with tighter voltage resolution. | Choose ISL6522CRZ-T when upgrading to VRM 8.5 and needing finer VID resolution-but add external regulators for AGP/GTL rails. |
Compared with ADP3158JRZ-REEL7, ADP3178JRZ-REEL7 offers design flexibility through adjustable linear regulator outputs, while ISL6522CRZ-T provides enhanced VID resolution and accuracy at the cost of increased BOM count for auxiliary supplies.
Availability
ADP3178JRZ-REEL7 is available at Aetrix Electronics and suitable for desktop motherboard development, server power subsystems, embedded x86 computing modules, and industrial docking station designs requiring stable component supply and long-lifecycle support.
Supply support for ADP3178JRZ-REEL7 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, serving precision instrumentation, industrial automation, communications, and computing markets.
The ADP3178JRZ-REEL7 belongs to Analog Devices' CPU power controller product line, engineered specifically for Intel VRM-compliant core voltage regulation with integrated auxiliary rail management and robust transient protection.
FAQ
What is the primary function of the ADP3178JRZ-REEL7 in a motherboard power system?
The ADP3178JRZ-REEL7 serves as the main synchronous buck controller for CPU core voltage regulation, decoding VID signals to set 1.3–2.05 V output, implementing ADOPT™ active voltage positioning for transient response, and managing two external N-MOSFETs. It also controls two auxiliary linear regulators via LRFB1/LRFB2 and LRDRV1/LRDRV2, making ADP3178JRZ-REEL7 a complete single-chip solution for Pentium III/Celeron power delivery.
How does the ADP3178JRZ-REEL7 implement overvoltage protection, and what triggers it?
The ADP3178JRZ-REEL7 uses an integrated crowbar function that activates when the regulated output exceeds 115–125% of the nominal VID-set voltage-e.g., >2.07 V for a 1.7 V setting. Upon detection, it forces DRVL high to turn on the low-side MOSFET, shorting the output to ground until voltage drops to ~50% of nominal. This hardware-level protection requires no external components and responds within 400 ns, safeguarding the CPU from destructive overvoltage events.
Can the linear regulator outputs of the ADP3178JRZ-REEL7 be configured for voltages other than 1.0 V?
Yes-the ADP3178JRZ-REEL7's linear regulator outputs are fully adjustable via external resistor dividers connected to LRFB1 and LRFB2. While the typical application uses 1.0 V ±3%, the feedback network can be scaled to generate any voltage between ~0.8 V and VCC – 1.5 V, provided the external N-MOSFET and layout support the target current and thermal requirements. This flexibility distinguishes ADP3178JRZ-REEL7 from the fixed-output ADP3158JRZ-REEL7.
What is the role of the CT pin on the ADP3178JRZ-REEL7, and how is its value selected?
CT sets the constant off-time via an external capacitor to ground; charging current is 150 µA (typical), and off-time ends when CT reaches 3.0 V. For example, a 150 pF capacitor yields ~3.3 µs off-time, resulting in ~200 kHz switching at 1.7 V output. CT value must be chosen based on target frequency, input voltage, and load dynamics-larger values reduce frequency and improve light-load efficiency but increase output ripple. ADP3178JRZ-REEL7's CT pin enables predictable frequency scaling without loop compensation changes.
Does the ADP3178JRZ-REEL7 support power sequencing with standby supplies like 5 VSB?
Yes-ADP3178JRZ-REEL7 is designed for seamless sequencing with standby rails. Its VCC pin can be diode-OR'd between 5 VSB and 12 V, allowing linear regulators to activate as soon as VCC rises above ~1 V-even before UVLO (7.0 V) is reached-ensuring Intel-compliant 3.3 V tracking during standby. The main buck controller remains disabled until VCC exceeds UVLO, providing clean separation between auxiliary rail enablement and core voltage ramp-up in ADP3178JRZ-REEL7 systems.
ADP3178JRZ-REEL7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Applications:
- Controller, Intel Pentium® III
- Voltage - Input:
- 5V
- Number of Outputs:
- -
- Voltage - Output:
- 1.3V ~ 2.05V
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
ADP3178JRZ-REEL7 FAQ
1.How can I place an order for ADP3178JRZ-REEL7 through Aetrix?
Please submit a Request for Quotation (RFQ) for ADP3178JRZ-REEL7 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 ADP3178JRZ-REEL7 reliable?
The price and inventory of ADP3178JRZ-REEL7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADP3178JRZ-REEL7 is usually 5 days.
3.What payment methods are accepted for ADP3178JRZ-REEL7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADP3178JRZ-REEL7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADP3178JRZ-REEL7?
ADP3178JRZ-REEL7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADP3178JRZ-REEL7 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 ADP3178JRZ-REEL7?
For technical support, including ADP3178JRZ-REEL7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADP3178JRZ-REEL7 requirements.
6.How does Aetrix verify that ADP3178JRZ-REEL7 is sourced from the original manufacturer or authorized distributors?
All ADP3178JRZ-REEL7 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 ADP3178JRZ-REEL7 meets industry standards.
7.What is the process for return or replacement of ADP3178JRZ-REEL7?
All ADP3178JRZ-REEL7 units undergo pre-shipment inspection (PSI). If there is an issue with ADP3178JRZ-REEL7, 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 ADP3178JRZ-REEL7 part is unused and in its original packaging.
Return procedure for ADP3178JRZ-REEL7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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