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Analog Devices Inc./Maxim Integrated MAX8505EEE+
- Part No.:
- MAX8505EEE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX8505EEE+.pdf
- Description:
- IC REG BUCK ADJ 3A 16QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,386
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Product details
Overview
MAX8505EEE+ from Maxim Integrated is a synchronous step-down DC-DC regulator with integrated high- and low-side N-channel MOSFETs, delivering up to 3A output current at 0.8V–0.85×VIN across 2.6V–5.5V input. It operates at selectable 500kHz or 1MHz switching frequency, features ±1% output voltage accuracy over load/line/temperature, and includes open-drain Power-OK (POK) monitoring - used in FPGA core supplies and server chipset rails.
For engineers reviewing the MAX8505EEE+ datasheet, MAX8505EEE+ pinout, MAX8505EEE+ application, or MAX8505EEE+ equivalent, key selection considerations include its dual-frequency enable via CTL pin, in-regulation soft-start limiting output-voltage dip during microprocessor power-on, ceramic-capacitor compatibility, and thermal-overload/short-circuit protection for rugged industrial power delivery.
Technical Context
The MAX8505EEE+ employs current-mode PWM control with slope compensation to stabilize the inner loop and prevent subharmonic oscillation at duty cycles >50%. Its transconductance error amplifier (60–160 µS) drives the COMP pin, where external RC compensation sets loop bandwidth without requiring complex type-II/III networks.
It integrates dual current-limit thresholds: ~6A peak (high-side) and ~3.8A valley (low-side), enabling robust overload handling. The POK circuit monitors FB voltage against ±12% window (0.704V–0.896V) with 25–100µs fault delay to suppress chatter, and asserts open-drain low when out-of-regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3A continuous - supports FPGA core or ASIC I/O rail loads without external current boosting |
| Input Voltage Range | 2.25V–5.5V - extends down to 2.25V with bias supply on VCC, enabling single-supply operation from Li-ion or 3.3V rails |
| Output Voltage Range | 0.8V to 0.85×VIN - adjustable via external resistor divider on FB, supporting 1.2V CPU cores and sub-1V SoC domains |
| Switching Frequency | Selectable 500kHz or 1MHz - higher frequency enables smaller 1µH inductor and 47µF ceramic output capacitor |
| Output Accuracy | ±1% over load/line/temperature - ensures stable voltage margin for 1.2V ±3% FPGA core requirements |
| Power-OK Threshold | FB = 0.8V ±12% - provides reliable system reset signaling without external comparator circuitry |
| Thermal Shutdown | 170°C junction with 20°C hysteresis - enables self-recovering pulsed operation under sustained overload |
Pinout & Package
MAX8505EEE+ is housed in a 16-pin QSOP package (4.9mm × 6mm footprint) with exposed pad for thermal enhancement. Pin assignments are validated per Maxim's official pin description table and typical operating circuit.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1,3,14,16 LX | Inductor switch node | Four paralleled pins connect to inductor; internal high-/low-side MOSFETs switch here - must be shorted externally and bypassed to PGND with 3300pF |
| 2,4 IN | Main power input | Dual pins accept 2.25V–5.5V input; require two 22µF ceramic bypass caps to GND - shared routing reduces impedance |
| 5 BST | Bootstrap supply | Connects 0.1µF cap to LX; bootstraps high-side gate drive above VIN - requires external Schottky diode from IN |
| 6 VCC | Low-side gate drive & bias supply | Decoupled via 10Ω + 0.1µF to GND - separates noisy switching return from analog ground |
| 7 POK | Open-drain Power-OK output | Pulls low when FB exits 0.704V–0.896V window; needs external pull-up to ≤5.5V for system monitoring |
| 8 CTL | Frequency select / enable | GND = shutdown; ≥0.8×VCC = 1MHz; 0.55–0.7×VCC = 500kHz - enables dynamic frequency scaling for efficiency optimization |
| 9 COMP | Loop compensation node | Connects series RC to GND; pulled to GND during UVLO/shutdown - sets bandwidth and phase margin |
| 10 FB | Voltage feedback input | Regulates to 0.8V; external resistive divider sets output - low 0.1µA bias current minimizes divider error |
| 11 REF | Soft-start timing reference | Capacitor here sets ramp time (32ms/µF); goes to 0V in shutdown - prevents inrush into downstream logic |
| 12 GND | Analog ground | Reference for REF, FB, COMP - must tie to PGND at single point to avoid noise coupling |
| 13,15 PGND | Power ground | High-current return for LX switches; connects to GND at star point - critical for EMI and thermal performance |
Key Features
| Feature | Design Value |
|---|---|
| Integrated dual MOSFETs | Eliminates external high-/low-side FETs and drivers - reduces BOM count and layout area by >30% vs discrete controllers |
| In-regulation soft-start | Active voltage regulation during startup limits output dip when microprocessors exit undervoltage lockout - prevents false resets |
| Ceramic/polymer capacitor support | Stable with low-ESR/ESL ceramics (e.g., 47µF X5R) - avoids electrolytic bulk caps and improves transient response |
| Adjustable switching frequency | 500kHz/1MHz selection via CTL pin - allows trade-off between efficiency (lower fSW) and component size (higher fSW) |
| ±1% output accuracy | Maintains tight regulation across -40°C to +85°C - meets stringent core voltage tolerances for 28nm/16nm SoCs |
| Comprehensive protection | Includes current-limit, short-circuit, thermal-overload, and UVLO - enables unattended operation in telecom and storage systems |
Applications
| FPGA Core Supply | Server Chipset Rail |
|---|---|
Use Scenario: Powers 1.2V core of Xilinx Artix-7 or Intel Cyclone V FPGA during configuration and active logic operation. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering regulated 1.2V/3A with fast transient response to handle logic switching currents. Use Value: In-regulation soft-start prevents voltage dip when FPGA exits reset, ensuring reliable configuration loading without reboots. |
Use Scenario: Supplies 1.8V I/O or 1.05V memory controller rail in dual-socket x86 server motherboards. IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator with POK signaling for BIOS power sequencing and health monitoring. Use Value: ±1% accuracy maintains JEDEC-compliant voltage margins under full load and temperature swing, reducing system-level validation risk. |
| RAID Controller Power | Network Processor I/O |
Use Scenario: Generates 3.3V or 2.5V auxiliary supply for RAID-on-chip (ROC) ASICs in enterprise storage enclosures. IC Role / Device Role / Timing Role: Compact 4.9mm × 6mm regulator with thermal shutdown protecting against airflow failure in dense 2U chassis. Use Value: Dual current-limit architecture handles bursty disk spin-up loads without latch-off, improving system uptime. |
Use Scenario: Delivers 1.2V to 1.5V I/O banks of multi-core network processors (e.g., Marvell ARMADA XP) in 10G Ethernet line cards. IC Role / Device Role / Timing Role: Fast-transient-response buck converter synchronized to system clock via CTL pin for noise-sensitive SerDes lanes. Use Value: 1MHz operation enables <100ns POK response to output faults - critical for deterministic packet processing failover. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54331DR | 3A, 5.5V–36V input, fixed 570kHz fSW, no POK, ±2% accuracy | Lacks Power-OK output and ±1% accuracy - requires external monitoring circuitry for safety-critical rails | Choose when wide-input range (e.g., 12V intermediate bus) outweighs need for precision and fault signaling |
| RTQ2132BGQW | 3A, 2.7V–17V input, 600kHz/1.2MHz selectable, ±1.5% accuracy, POK with hysteresis | Higher input range and POK hysteresis improve noise immunity, but larger 3mm × 3mm QFN footprint vs QSOP | Prefer when board space allows QFN and system requires wider VIN tolerance with robust POK behavior |
Compared with TPS54331DR and RTQ2132BGQW, MAX8505EEE+ offers tighter ±1% regulation, integrated POK without hysteresis (simpler interface), and QSOP packaging suited for through-hole prototyping or legacy layouts - making it optimal for compact, precision 3.3V/5V-input FPGA and server applications.
Availability
MAX8505EEE+ is available at Aetrix Electronics and suitable for FPGA core supplies, server chipset rails, and RAID controller power systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX8505EEE+ 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) designs precision analog and power management ICs for demanding industrial, computing, and communications applications.
The MAX8505 belongs to Maxim's high-efficiency synchronous buck regulator product line, engineered specifically for low-voltage, high-current digital loads such as microprocessor cores, ASICs, and FPGA I/O banks in space-constrained systems.
FAQ
What input voltage range does the MAX8505EEE+ support?
The MAX8505EEE+ operates from 2.25V to 5.5V input. With a separate 2.6V–5.5V bias supply on VCC, the main IN input can drop as low as 2.25V - enabling use with partially discharged Li-ion batteries or low-dropout post-regulated supplies. This extended range is confirmed in Absolute Maximum Ratings and Electrical Characteristics tables across -40°C to +85°C.
How is output voltage set on the MAX8505EEE+?
The MAX8505EEE+ uses a resistor divider from output to FB pin to set output voltage, referenced to an internal 0.8V bandgap (VREF). The formula is R2 = R3 × (VOUT/VREF − 1), with R3 recommended ≤50kΩ. FB regulation accuracy is ±1% over load, line, and temperature - verified in Electrical Characteristics tables with min/typ/max values at 0.791V–0.808V.
Does the MAX8505EEE+ support both 500kHz and 1MHz switching frequencies?
Yes, the MAX8505EEE+ supports both frequencies via the CTL pin: drive CTL to ≥0.8×VCC for 1MHz, to 0.55–0.7×VCC for 500kHz, or to GND for shutdown. Frequency stability is guaranteed across input voltage (2.6V–5.5V) and temperature (-40°C to +85°C), with typical values of 0.44–0.56MHz (500kHz mode) and 0.95–1.05MHz (1MHz mode) shown in Typical Operating Characteristics.
What protection features does the MAX8505EEE+ include?
The MAX8505EEE+ integrates current-limit (6A peak / 3.8A valley), short-circuit, thermal-overload (170°C shutdown with 20°C hysteresis), and VCC undervoltage lockout (2.2V–2.35V threshold). These are documented in Electrical Characteristics and Detailed Description sections, with fault behaviors like pulsed output during thermal events and automatic recovery after cooling.
Can the MAX8505EEE+ drive ceramic output capacitors?
Yes, the MAX8505EEE+ is explicitly designed for ceramic or polymer output capacitors - stated in Features and General Description. Its current-mode control with slope compensation ensures stability with low-ESR ceramics (e.g., 47µF X5R), eliminating need for electrolytics. This is validated by stable operation in Typical Operating Circuit and Transient Response waveforms using ceramic caps.
MAX8505EEE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.6V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 4.68V
- Current - Output:
- 3A
- Frequency - Switching:
- 500kHz, 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QSOP
MAX8505EEE+ FAQ
1.How can I place an order for MAX8505EEE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX8505EEE+ 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 MAX8505EEE+ reliable?
The price and inventory of MAX8505EEE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX8505EEE+ is usually 5 days.
3.What payment methods are accepted for MAX8505EEE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX8505EEE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX8505EEE+?
MAX8505EEE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX8505EEE+ 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 MAX8505EEE+?
For technical support, including MAX8505EEE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX8505EEE+ requirements.
6.How does Aetrix verify that MAX8505EEE+ is sourced from the original manufacturer or authorized distributors?
All MAX8505EEE+ 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 MAX8505EEE+ meets industry standards.
7.What is the process for return or replacement of MAX8505EEE+?
All MAX8505EEE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX8505EEE+, 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 MAX8505EEE+ part is unused and in its original packaging.
Return procedure for MAX8505EEE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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