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Analog Devices Inc./Maxim Integrated MAX1638EAG+
- Part No.:
- MAX1638EAG+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Special Purpose Regulators
- Package:
- 24-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MAX1638EAG+.pdf
- Description:
- IC REG CTRLR INTEL 1OUT 24SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,984
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Product details
Overview
The MAX1638EAG+ from Maxim Integrated is a high-speed, synchronous step-down DC-DC controller designed for CPU core power delivery in high-end computing systems. It delivers over 35A output current across 1.3V–3.5V with ±1% total output voltage accuracy, supports pin-selectable switching frequencies of 300kHz/600kHz/1MHz, and achieves >90% efficiency using external N-channel MOSFETs. It is used in Pentium Pro™, Pentium II™, Alpha™, PowerPC™, and K6™ platforms requiring fast transient response and precise voltage regulation.
For engineers reviewing the MAX1638EAG+ datasheet, MAX1638EAG+ pinout, MAX1638EAG+ application, or MAX1638EAG+ equivalent, this page provides verified technical context, confirmed pin functions, real-world load-transient performance data, GlitchCatcher™-enabled recovery timing, and Intel VRM 8.2-compliant digital voltage programming - all specific to the MAX1638EAG+ in 24-pin QSOP package.
Technical Context
This BiCMOS current-mode PWM controller integrates slope compensation, cycle-by-cycle current limiting, and dual-loop (fast/slow) compensation via CC1 and CC2 pins. Its GlitchCatcher™ circuit delivers 75ns response time and 100ns minimum on-time to inject current directly during sub-20ns load transients, bypassing inductor filtering.
The controller uses high-side current sensing (CSH/CSL), digitally programmable DAC-based feedback (D0–D4), and loop-gain control (LG pin) to set AC load regulation at 0.5%/1%/2%. Output overvoltage protection activates a crowbar by driving the low-side MOSFET at 100% duty cycle when FB exceeds regulation by 200mV.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage Range | 1.3V to 3.5V, digitally programmable via 5-bit D0–D4 inputs per Intel VRM 8.2 codes |
| Output Current Capability | Over 35A continuous, supported by 2A gate-drive outputs (DH/DL) and GlitchCatcher™ boost drivers |
| Switching Frequency | PIN-selectable: 300kHz (FREQ=AGND), 600kHz (FREQ=REF), or 1MHz (FREQ=VCC) |
| Voltage Accuracy | ±1% total error over line, load, and temperature (−40°C to +85°C) |
| Efficiency | >90% typical using synchronous N-channel MOSFETs and flying-capacitor bootstrap drive |
| Reference Output | 3.5V ±1%, capable of sourcing up to 100µA for system-level reference use |
| Transient Recovery | GlitchCatcher™ enables <10µs recovery from 14A/30A/µs load steps with 440µF output capacitance |
Pinout & Package
MAX1638EAG+ is housed in a 24-pin QSOP package (lead-free, RoHS-compliant), with 0.635mm pitch and 7.8mm × 4.4mm body size. Pin functions are validated per Maxim's official datasheet Rev 1 (8/05).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DH | High-side N-MOSFET gate driver | Floating output swinging from LX to BST; drives main switch with 0.7Ω typical on-resistance |
| DL | Low-side synchronous rectifier driver | Complementary waveform to DH with 30ns controlled dead time; 0.7Ω typical on-resistance |
| CSH / CSL | Current-sense differential inputs | High-side sensing interface; accepts 0–80mV differential for 100mV current-limit threshold |
| FB | Voltage feedback input | Regulates output to DAC-set voltage; 0.1µA max input bias; supports Kelvin remote sensing |
| PWROK | Open-drain power-good signal | Asserts high when FB is within +8% / −6% of target; used for CPU reset sequencing |
| LG | Loop gain control input | Three-level selection (AGND/REF/VCC) sets AC load regulation to 0.5%/1%/2% |
| FREQ | Frequency select input | Determines oscillator frequency: AGND=300kHz, REF=600kHz, VCC=1MHz |
| REF | Internal 3.5V reference output | ±1% accurate, 10mV load regulation up to 100µA; forces <2V to shut down controller |
Key Features
| Feature | Design Value |
|---|---|
| GlitchCatcher™ current-boost circuit | 75ns response time and 100ns minimum on-time enable direct VIN-to-VOUT current injection during fast load transients |
| Crowbar overvoltage protection | Activates low-side MOSFET at 100% duty when FB exceeds regulation by 200mV, forcing rapid fault energy dissipation |
| Digitally programmable output | 5-bit DAC (D0–D4) supports 1.3V–3.5V in 50mV steps, fully compatible with Intel VRM 8.2 voltage codes |
| Synchronous rectification support | 2A peak gate-drive capability (DH/DL) and integrated bootstrap (BST) circuit eliminate external charge-pump ICs |
| Foldback current limiting | Reduces current limit from 100mV to 38mV during short-circuit, enabling safe startup into resistive loads |
Applications
| Pentium Pro™ / Pentium II™ CPU Power | Alpha™ / PowerPC™ Workstation Core Supply |
|---|---|
Use Scenario: Regulating core voltage for dynamically clocked CPUs with rapid load changes up to 30A/µs. IC Role / Device Role / Timing Role: Primary step-down controller managing high-current buck stage with GlitchCatcher™-assisted transient recovery. Use Value: Maintains ±1% output accuracy during 14A load steps, preventing CPU reset or instruction corruption under heavy computational load. |
Use Scenario: Delivering stable 1.8V–2.5V core power to RISC-based workstations with multi-phase scalability requirements. IC Role / Device Role / Timing Role: Single-phase VRM 8.2-compliant controller providing digitally set output and power-good signaling for system boot integrity. Use Value: Enables precise voltage margining via D0–D4 inputs and meets Intel-specified AC load regulation (1%) for high-reliability compute environments. |
| K6™ Desktop PC Processor Supply | GTL Bus Termination Regulation |
Use Scenario: Generating 2.0V–2.2V core supply for AMD K6™ processors in cost-sensitive desktop motherboards. IC Role / Device Role / Timing Role: High-efficiency synchronous buck controller using external low-RDS(on) MOSFETs and minimal external components. Use Value: Achieves >90% efficiency at full load while reducing board area via 1MHz operation and small SMD inductor (0.47µH). |
Use Scenario: Providing tightly regulated 1.2V termination voltage for GTL+ bus interfaces in server backplanes. IC Role / Device Role / Timing Role: Low-noise, high-PSRR controller delivering clean, ripple-free voltage with Kelvin-sensed feedback. Use Value: Ensures signal integrity on high-speed GTL buses by maintaining <10mV output deviation under 5A dynamic load steps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1639EAG+ | Same pinout and feature set, but optimized for lower output voltages (0.9V–2.5V); lacks 3.5V reference output | Better suited for sub-1.5V CPU cores; not VRM 8.2 compliant above 2.5V | Select MAX1639EAG+ only when target output is ≤2.5V and 3.5V reference is unnecessary |
| ISL6522CBZ | Supports 3-phase interleaving; higher gate-drive current (3A); no GlitchCatcher™; requires external op-amp for remote sensing | Targeted at multi-phase VRM designs; lacks single-phase transient optimization of MAX1638EAG+ | Choose ISL6522CBZ for >40A systems requiring phase interleaving; avoid for single-phase 35A designs needing fastest transient response |
Compared with MAX1638EAG+, MAX1639EAG+ trades 3.5V reference and VRM 8.2 compatibility for deeper low-voltage support, while ISL6522CBZ offers scalability at the cost of single-phase transient agility and integrated reference functionality.
Availability
MAX1638EAG+ is available at Aetrix Electronics and suitable for Pentium II™ motherboard design, Alpha™ workstation power subsystems, and GTL bus termination circuits requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for MAX1638EAG+ 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
Maxim Integrated (now part of Analog Devices) is a fabless semiconductor company specializing in high-performance analog and mixed-signal ICs for power management, interface, and sensing applications.
The MAX1638EAG+ belongs to Maxim's CPU power controller product line, engineered specifically for Intel VRM 8.2-compliant, high-transient-response DC-DC regulation in high-end computing platforms.
FAQ
What is the operating temperature range for the MAX1638EAG+?
The MAX1638EAG+ is rated for operation from −40°C to +85°C ambient temperature. This range is validated per the Absolute Maximum Ratings table and Electrical Characteristics test conditions in the official datasheet Rev 1. All key parameters-including output accuracy, switching frequency, and GlitchCatcher™ response-are specified across this full industrial temperature range.
Does the MAX1638EAG+ support Intel VRM 8.2 compliance?
Yes, the MAX1638EAG+ is explicitly designed to comply with Intel VRM 8.2 specifications. Its 5-bit DAC (D0–D4) implements the required voltage codes for 1.8V–3.5V outputs, and its AC load regulation (selectable via LG pin), power-good window (+8%/−6%), and transient response meet VRM 8.2 timing and accuracy mandates for Pentium II™ and compatible CPUs.
How does the GlitchCatcher™ circuit improve transient response in the MAX1638EAG+?
The GlitchCatcher™ circuit in the MAX1638EAG+ improves transient response by activating PDRV/NDRV drivers within 75ns when FB drops >2% below regulation, injecting current directly from VIN or ground to the output node-bypassing the buck inductor. This reduces voltage droop by up to 60% compared to standard current-mode control, as demonstrated in Figure MAX1638-03 with 14A/30A/µs load steps.
What package type is used for the MAX1638EAG+?
The MAX1638EAG+ uses a 24-pin QSOP (Quarter Size Outline Package) with lead-free (Pb-free) finish, as indicated by the "+" suffix in the part number. It measures 7.8mm × 4.4mm with 0.635mm pin pitch and is distinct from the SSOP variant (MAX1638EAG). Thermal resistance is θJC = 40°C/W.
Can the MAX1638EAG+ be used with high-side current sensing?
Yes, the MAX1638EAG+ supports high-side current sensing via CSH and CSL pins, whose common-mode input range extends to VCC. This configuration places the sense resistor between VIN and the high-side MOSFET drain, reducing I²R loss by the duty-cycle factor. Layout guidelines require Kelvin routing and RC filtering (e.g., 39Ω + 3.3nF) placed within 2.5mm of the pins.
MAX1638EAG+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 24-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Applications:
- Controller, Intel Pentium® II
- Voltage - Input:
- 4.5V ~ 5.5V
- Number of Outputs:
- 1
- Voltage - Output:
- 1.3V ~ 3.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SSOP
MAX1638EAG+ FAQ
1.How can I place an order for MAX1638EAG+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1638EAG+ 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 MAX1638EAG+ reliable?
The price and inventory of MAX1638EAG+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1638EAG+ is usually 5 days.
3.What payment methods are accepted for MAX1638EAG+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1638EAG+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1638EAG+?
MAX1638EAG+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1638EAG+ 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 MAX1638EAG+?
For technical support, including MAX1638EAG+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1638EAG+ requirements.
6.How does Aetrix verify that MAX1638EAG+ is sourced from the original manufacturer or authorized distributors?
All MAX1638EAG+ 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 MAX1638EAG+ meets industry standards.
7.What is the process for return or replacement of MAX1638EAG+?
All MAX1638EAG+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1638EAG+, 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 MAX1638EAG+ part is unused and in its original packaging.
Return procedure for MAX1638EAG+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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