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Analog Devices Inc./Maxim Integrated MAX1821EBC
- Part No.:
- MAX1821EBC
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Special Purpose Regulators
- Package:
- 10-WFBGA, CSPBGA
- Datasheet:
-
MAX1821EBC.pdf
- Description:
- IC REG LINEAR WCDMA 600MA BUCK
- Quantity:
- Payment:
- Shipping:
Inventory:2,644
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Product details
Overview
MAX1821EBC from Maxim Integrated is a fixed-output, synchronous step-down DC-DC buck regulator optimized for powering microprocessor cores and power amplifiers in battery-powered WCDMA handsets. It delivers 600mA guaranteed output current with 1MHz PWM switching, 150mV dropout at full load (including external inductor RDC), and supports fixed output voltages set via external resistive divider from 1.25V to 5.5V. Its 3×4 UCSP package enables compact mobile designs.
For engineers reviewing the MAX1821EBC datasheet, MAX1821EBC pinout, MAX1821EBC application, or MAX1821EBC equivalent, key selection criteria include its fixed-feedback architecture (FB pin), 1.25V reference voltage accuracy (±2%), 180µA quiescent current in skip mode, and compatibility with ceramic output capacitors without external Schottky diodes.
Technical Context
The MAX1821EBC implements a slope-compensated current-mode PWM controller capable of 0%–100% duty-cycle operation, enabling true low-dropout regulation down to input voltages within 150mV of the output. Its internal P-channel high-side switch (0.3Ω typ) and N-channel synchronous rectifier eliminate external diode losses and support efficient light-load operation via automatic pulse-skipping.
It uses an internal 1MHz oscillator (SYNC pin tied to GND per ordering code EBC), features a 1.25V ±2% FB reference with <50nA input bias, and includes undervoltage lockout (2.35V typ) and thermal shutdown protection. The device operates across –40°C to +85°C and requires no minimum load in forced-PWM mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 600mA guaranteed - sufficient to power RF PA stages or microprocessor cores without derating at +85°C. |
| Input Voltage Range | 2.6V to 5.5V - compatible with single-cell Li-ion (3.0–4.2V) and dual-cell alkaline/NiMH (up to 3.6V) battery inputs. |
| Output Voltage Range | 1.25V to 5.5V (programmable via FB divider) - supports common core rails (1.2V, 1.5V, 1.8V, 2.5V, 3.3V) and analog subsystems. |
| Quiescent Current | 180µA (typ) in skip mode - extends battery life in standby by minimizing idle power draw. |
| Dropout Voltage | 150mV at 600mA - includes internal MOSFET RDS(on) and external inductor RDC, enabling regulation near battery end-of-life. |
| Switching Frequency | 1MHz (internal oscillator) - allows use of small 4.7µH inductors and 4.7µF ceramic output capacitors. |
| Reference Accuracy | 1.25V ±2% (VFB) - ensures tight output regulation across temperature and line/load conditions. |
Pinout & Package
MAX1821EBC is housed in a 3×4 mm chip-scale package (UCSP™) with 10 terminals. Pin assignments are identical between MAX1820 and MAX1821 UCSP variants per datasheet Pin Description table.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SKIP | PWM/Skip-mode control input | Logic high (BATT) forces constant-frequency PWM; logic low (GND) enables automatic pulse-skipping at light loads. |
| COMP | Compensation node | Connects to RC network (82kΩ + 330pF to GND) to stabilize loop response and prevent oscillation. |
| FB | Feedback sense input | Regulates to 1.25V; sets output voltage via resistor divider between VOUT and GND. |
| GND | Analog ground reference | Low-impedance return path for error amplifier and internal bias circuits. |
| PGND | Power ground | Separate return for high-current LX switching path to minimize noise coupling into control circuitry. |
| LX | Switch node | Connects to inductor; carries high di/dt current during switching - requires short, low-inductance PCB routing. |
| BATT | Main supply input | 2.6–5.5V input; bypassed to PGND with ≥10µF low-ESR capacitor to suppress ripple and supply transients. |
| SHDN | Active-low shutdown control | Pulls to GND to reduce supply current to 0.1µA and place output in high-impedance state. |
| SYNC | External clock synchronization input | Must be connected to GND for MAX1821EBC (no sync capability); unused pin in this variant. |
| REF | Internal reference bypass | Connect 0.047µF capacitor to GND to filter reference noise and improve PSRR. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed-output programmability | 1.25V to 5.5V via external resistor divider on FB pin - eliminates need for DAC or digital interface in cost-sensitive applications. |
| Synchronous rectification | Integrated N-channel MOSFET replaces Schottky diode - improves efficiency by >5% at 300mA and reduces thermal stress. |
| 100% duty-cycle operation | Enables regulation down to VIN = VOUT + 150mV - critical for maintaining core voltage as Li-ion battery discharges from 4.2V to 3.0V. |
| Low-quiescent-current skip mode | 180µA typical supply current at light loads - extends standby time in handheld devices with intermittent processing bursts. |
| Robust protection suite | Includes undervoltage lockout (2.35V), thermal shutdown, and cycle-by-cycle current limiting - prevents damage during brownout or overload events. |
Applications
| WCDMA Power Amplifier Supply | Microprocessor Core Rail |
|---|---|
Use Scenario: Powers linear RF power amplifier in 3G WCDMA handset during transmit bursts, requiring fast transient response and stable voltage under dynamic load. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 2.8V/3.3V to PA stage; handles 0–600mA load steps with <30µs settling time. Use Value: 150mV dropout ensures PA remains powered down to 3.0V battery voltage; 1MHz switching minimizes EMI near RF front-end. | Use Scenario: Supplies voltage to ARM9 or similar embedded processor core in portable instrumentation or industrial controller. IC Role / Device Role / Timing Role: Main core supply with tight 1.25V ±2% reference accuracy and low-noise operation via REF bypass capacitor. Use Value: Synchronous rectification and 180µA skip-mode IQ enable >100-hour battery life in sleep mode with periodic wake-up cycles. |
| Digital Camera Image Sensor Bias | PCMCIA/CardBus Interface Rail |
Use Scenario: Provides clean, low-noise 2.5V bias to CMOS image sensor during exposure and readout phases. IC Role / Device Role / Timing Role: Low-ripple buck converter with ceramic output capacitor support; COMP compensation stabilizes against sensor's pulsed current draw. Use Value: 1MHz switching avoids interference with sensor pixel clock harmonics; 0.1µA shutdown current preserves battery during camera standby. | Use Scenario: Generates 3.3V interface rail for PCMCIA or CardBus peripheral in ruggedized field equipment. IC Role / Device Role / Timing Role: High-reliability DC-DC converter with wide 2.6–5.5V input range to accommodate varying host supply conditions. Use Value: Undervoltage lockout (2.35V) prevents erratic behavior during hot-swap insertion; UCSP package withstands mechanical shock in portable form factors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | 3MHz switching frequency, 300mA output, 1.8–6.5V input, 0.6–5.5V output; smaller 1.2×1.6mm DSBGA package | Higher frequency enables smaller passives but lower max current; less suitable for 600mA PA loads | Select when board space is constrained and load current ≤300mA; verify loop stability with ceramic output caps. |
| ADP2119ACPZ-R7 | 1.2MHz switching, 600mA output, 2.3–5.5V input, 0.6–5.5V output; integrated soft-start, ±1.5% FB accuracy | Higher FB accuracy and soft-start improve power sequencing; no SYNC pin, same UCSP footprint | Prefer for systems requiring tighter output tolerance or controlled startup ramp; pin-compatible replacement with minor layout review. |
Compared with MAX1821EBC, TPS62231DRYR trades current capability for size and frequency, while ADP2119ACPZ-R7 matches output current and input range but adds soft-start and improved reference accuracy-making it suitable for sequenced power domains where MAX1821EBC's simpler control scheme is unnecessary.
Availability
MAX1821EBC is available at Aetrix Electronics and suitable for WCDMA cellular phone power amplifiers, microprocessor core supplies, and digital camera image sensor biasing requiring stable component supply across extended production lifecycles.
Supply support for MAX1821EBC 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 semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.
The MAX1820/MAX1821 product line was designed specifically for high-efficiency, space-constrained battery-powered RF and portable computing systems-emphasizing low dropout, synchronous rectification, and minimal external component count.
FAQ
What is the correct connection for the SYNC pin on MAX1821EBC?
The SYNC pin on MAX1821EBC must be connected to GND. This variant lacks external synchronization capability and relies solely on its internal 1MHz oscillator. Leaving SYNC floating or connecting it to any voltage other than GND may cause erratic switching behavior or failure to regulate. The MAX1821EBC datasheet explicitly states that SYNC must be grounded for proper operation.
Can MAX1821EBC operate with a 2.5V input voltage?
No, MAX1821EBC cannot reliably operate with a 2.5V input. Its absolute minimum input voltage is 2.6V, and its undervoltage lockout triggers below 2.35V (typ). At 2.5V, the device may fail to start or drop out of regulation under load. For 2.5V systems, consider alternatives like the ADP2119ACPZ-R7 (2.3V min) or verify actual battery discharge profile to ensure sustained ≥2.6V operation.
What is the maximum output voltage achievable with MAX1821EBC using external resistors?
The maximum output voltage for MAX1821EBC is 5.5V, limited by its absolute maximum input rating and internal circuitry. When setting higher outputs (e.g., 5.0V), ensure the input voltage remains ≥5.5V to maintain regulation margin and avoid dropout. The FB pin reference is fixed at 1.25V, so output is calculated as VOUT = 1.25V × (1 + R1/R2), with practical limits imposed by power dissipation and stability.
Does MAX1821EBC require an external Schottky diode?
No, MAX1821EBC does not require an external Schottky diode. It integrates a synchronous N-channel rectifier that replaces the external diode, reducing conduction losses and improving efficiency by up to 8% at medium loads. This also eliminates reverse recovery noise and simplifies PCB layout-confirmed in the datasheet's "No External Schottky Diode Required" feature list.
How does MAX1821EBC behave during battery voltage sag below 2.6V?
When input voltage sags below the 2.35V (typ) undervoltage lockout threshold, MAX1821EBC disables switching, turns off internal MOSFETs and reference, and places the output in high-impedance state. Output voltage collapses, and supply current drops to <1µA. Once input rises above the UVLO threshold with 1% hysteresis, MAX1821EBC resumes regulation with internal soft-start behavior to limit inrush current.
MAX1821EBC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 10-WFBGA, CSPBGA
- Packaging:
- Bulk
- Product Status:
- Active
- Applications:
- Converter, DDR
- Voltage - Input:
- 2.6V ~ 5.5V
- Number of Outputs:
- 1
- Voltage - Output:
- 1.25V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-UCSP (2.02x1.54)
MAX1821EBC FAQ
1.How can I place an order for MAX1821EBC through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1821EBC 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 MAX1821EBC reliable?
The price and inventory of MAX1821EBC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1821EBC is usually 5 days.
3.What payment methods are accepted for MAX1821EBC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1821EBC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1821EBC?
MAX1821EBC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1821EBC 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 MAX1821EBC?
For technical support, including MAX1821EBC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1821EBC requirements.
6.How does Aetrix verify that MAX1821EBC is sourced from the original manufacturer or authorized distributors?
All MAX1821EBC 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 MAX1821EBC meets industry standards.
7.What is the process for return or replacement of MAX1821EBC?
All MAX1821EBC units undergo pre-shipment inspection (PSI). If there is an issue with MAX1821EBC, 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 MAX1821EBC part is unused and in its original packaging.
Return procedure for MAX1821EBC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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