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Analog Devices Inc./Maxim Integrated MAX1977EEI-TG068
- Part No.:
- MAX1977EEI-TG068
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Special Purpose Regulators
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX1977EEI-TG068.pdf
- Description:
- IC REG LINEAR MAIN PWR SUP CNTLR
- Quantity:
- Payment:
- Shipping:
Inventory:2,000
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Product details
Overview
MAX1977EEI-TG068 from Maxim Integrated is a dual step-down switch-mode power-supply (SMPS) controller with integrated 5V/3.3V linear regulators, designed for notebook and subnotebook main power supplies. It delivers fixed 400kHz/500kHz switching frequencies, supports 4.5V–24V input, provides ±1.5% output voltage accuracy, and features Quick-PWM™ control with 100ns load-step response.
For engineers reviewing the MAX1977EEI-TG068 datasheet, MAX1977EEI-TG068 pinout, MAX1977EEI-TG068 application, or MAX1977EEI-TG068 equivalent, key selection criteria include its ultrasonic pulse-skipping mode (>25kHz), dual-mode feedback (fixed/adjustable), PGOOD signaling, and bootstrapped LDOs delivering 100mA each at 5V and 3.3V.
Technical Context
The MAX1977EEI-TG068 implements Maxim's proprietary Quick-PWM™ constant-on-time architecture without external current-sense resistors-relying instead on LX node sensing for current-limit detection. Its dual PWM controllers operate at fixed 400kHz (5V rail) and 500kHz (3.3V rail), enabling compact magnetics and high efficiency in thin-and-light portable systems.
It integrates two independent soft-start circuits, internal soft-stop discharge for negative-voltage prevention, and programmable fault protection via PRO pin. The device supports three operating modes-PWM (fixed frequency), idle (pulse-skipping), and ultrasonic (≥25kHz)-selected via SKIP pin, balancing EMI, audio noise, and light-load efficiency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 24V - supports 3–4-cell Li+ battery inputs and wide-input adapter operation. |
| Switching Frequencies | 400kHz (5V SMPS), 500kHz (3.3V SMPS) - enables smaller inductors and faster transient response. |
| Output Voltage Accuracy | ±1.5% - ensures stable core logic supply under line/load/temperature variation. |
| LDO Outputs | 5V/100mA and 3.3V/100mA - always-on, bootstrapped from SMPS outputs for low-noise auxiliary rails. |
| Load Step Response | 100ns - Quick-PWM™ architecture maintains regulation during CPU burst loads without external compensation. |
| Ultrasonic Mode | ≥25kHz minimum switching frequency - eliminates audible noise in speaker/headphone circuits. |
| PGOOD Threshold | −9.5% nominal output - provides reliable power-good assertion with 1% hysteresis for system sequencing. |
Pinout & Package
MAX1977EEI-TG068 is housed in a 28-pin QSOP package (5.0mm × 10.3mm, 0.635mm pitch), lead-free and RoHS-compliant, rated for −40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | N.C. | No internal connection - must be left floating or grounded per layout best practices. |
| 2 | PGOOD | Open-drain power-good signal - asserts low if either SMPS output deviates >10% from nominal. |
| 3 | ON3 | Enable input for 3.3V SMPS - supports delay-start sequencing when tied to REF. |
| 4 | ON5 | Enable input for 5V SMPS - allows independent or cascaded startup with ON3. |
| 5 | ILIM3 | Current-limit threshold adjust for 3.3V SMPS - default 100mV; adjustable 50–300mV via voltage divider. |
| 6 | SHDN | Shutdown control - pulls device into 6µA quiescent state when below 1.0V trip level. |
| 7 | FB3 | Feedback input for 3.3V SMPS - tied to GND for fixed output; resistor divider for adjustable 2.0–5.5V range. |
| 8 | REF | 2.000V precision reference - sources up to 100µA; used for biasing ILIM/TON/SKIP and sequencing. |
| 9 | FB5 | Feedback input for 5V SMPS - identical dual-mode functionality as FB3. |
| 10 | PRO | Fault protection enable/disable - GND = overvoltage/undervoltage protection active; VCC = disabled. |
| 11 | ILIM5 | Current-limit threshold adjust for 5V SMPS - same scaling and logic as ILIM3. |
| 12 | SKIP | Operating mode select - GND = idle (pulse-skip), VCC = PWM, REF/floating = ultrasonic (≥25kHz). |
| 13 | TON | Frequency select - VCC = 400kHz/500kHz; GND = 200kHz/300kHz (not applicable to MAX1977 variant). |
| 14 | BST5 | Boost capacitor connection for 5V SMPS high-side driver - requires external 0.1µF ceramic capacitor. |
| 15 | LX5 | Inductor switch node for 5V SMPS - also serves as current-sense point in MAX1999 (not used in MAX1977). |
| 16 | DH5 | High-side gate driver output for 5V SMPS - swings between LX5 and BST5; drives N-channel MOSFET gate. |
| 17 | VCC | Analog supply input - powers internal circuitry; bypass with 0.1µF ceramic capacitor near pin. |
| 18 | DL5 | Low-side gate driver output for 5V SMPS - sinks 3.3A / sources 1.7A; drives synchronous rectifier. |
| 19 | GND | Power and analog ground - single-point star grounding recommended for noise-sensitive SMPS design. |
| 20 | LX3 | Inductor switch node for 3.3V SMPS - current-sense point only in MAX1999; not used in MAX1977. |
| 21 | DH3 | High-side gate driver output for 3.3V SMPS - identical function and drive strength as DH5. |
| 22 | LDO3 | 3.3V linear regulator output - 100mA max; automatically boots from OUT3 when regulated. |
| 23 | DL3 | Low-side gate driver output for 3.3V SMPS - identical sink/source capability as DL5. |
| 24 | GND | Second ground terminal - improves thermal and noise performance in 28-pin QSOP layout. |
| 25 | LDO5 | 5V linear regulator output - 100mA max; boots from OUT5; includes undervoltage lockout (3.7–4.3V). |
| 26 | OUT3 | 3.3V SMPS regulated output - feeds system I/O, memory, and LDO3 bootstrap path. |
| 27 | OUT5 | 5V SMPS regulated output - powers USB, display, and LDO5 bootstrap path. |
| 28 | V+ | Main input supply - accepts 4.5–24V; powers SMPS controllers and internal regulators. |
Key Features
| Feature | Design Value |
|---|---|
| Quick-PWM™ control | 100ns load-step response without sense resistors - reduces BOM count and PCB area while maintaining stability. |
| Dual-mode feedback | Fixed (3.3V/5V) or adjustable (2.0–5.5V) outputs via FB pins - simplifies design reuse across multiple voltage requirements. |
| Ultrasonic pulse-skipping | Switching frequency held ≥25kHz in light-load mode - eliminates audible coil whine in portable audio systems. |
| Integrated bootstrapped LDOs | 5V/100mA and 3.3V/100mA always-on outputs - provide low-noise auxiliary rails without external regulators. |
| Programmable fault protection | PRO pin enables/disables overvoltage (±8–14%) and undervoltage (65–75%) shutdown - enhances system safety and debug flexibility. |
| Internal soft-start & soft-stop | 1.7ms ramp time and controlled output discharge - prevents inrush current and negative voltage spikes during power transitions. |
Applications
| Notebook Power Management | Subnotebook Main Supply |
|---|---|
Use Scenario: Primary power controller in 12–14″ clamshell notebooks powered by 3- or 4-cell Li+ batteries. IC Role / Device Role / Timing Role: Generates 5V and 3.3V main logic rails while sequencing LDOs and monitoring PGOOD for CPU reset assertion. Use Value: 400kHz/500kHz switching enables <10mm² total power stage footprint and meets Intel IMVP-IV timing margins. | Use Scenario: Compact main power solution in ultra-thin subnotebooks (<18mm profile) with tight thermal constraints. IC Role / Device Role / Timing Role: Dual SMPS controller with ultrasonic mode ensures silent operation during video playback and voice calls. Use Value: ≥25kHz pulse-skipping eliminates audible noise from inductors and capacitors without sacrificing light-load efficiency. |
| PDA System Power | Mobile Communication Device |
Use Scenario: Power management for handheld PDAs with ARM-based SoC, touchscreen, and SD card interface. IC Role / Device Role / Timing Role: Supplies 3.3V I/O and 5V peripheral rails; uses ON3/ON5 delay-start to sequence memory before processor. Use Value: Bootstrapped LDOs deliver clean 100mA auxiliary power without adding discrete regulators or increasing standby current. | Use Scenario: Main power controller in 3G/4G mobile hotspots and VoIP handsets requiring dual-rail support and low EMI. IC Role / Device Role / Timing Role: Regulates 5V USB host port and 3.3V baseband processor supply; SKIP pin selects PWM mode for RF section immunity. Use Value: Fixed-frequency PWM mode reduces conducted EMI in sensitive RF bands, easing EMC certification. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output SMPS controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1777EEI+ | 200kHz/300kHz switching frequencies; no TON pin; uses CS3/CS5 current-sense resistors. | Better suited for cost-sensitive, lower-frequency designs where size is less critical than efficiency at medium loads. | Select MAX1777EEI+ when optimizing for peak efficiency at 1–3A loads and board space is not constrained. |
| MAX1999EEI+ | Pin-selectable 200/300kHz or 400/500kHz; includes TON pin; supports both current-sense resistor and LX-sense modes. | Offers full frequency flexibility and dual-sensing options - ideal for platform reuse across thin-and-light and mainstream notebooks. | Choose MAX1999EEI+ when designing scalable platforms requiring one controller across multiple SKUs with varying performance targets. |
Compared with MAX1777EEI+ and MAX1999EEI+, the MAX1977EEI-TG068 delivers higher switching frequencies for smaller passive components and optimized light-load ultrasonic operation, making it the preferred choice for thermally constrained, noise-sensitive thin-and-light portable systems.
Availability
MAX1977EEI-TG068 is available at Aetrix Electronics and suitable for notebook computers, subnotebook systems, PDAs, and 3–4-cell Li+ battery-powered devices requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature.
Supply support for MAX1977EEI-TG068 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 portable, industrial, and communications applications.
The MAX1777/MAX1977/MAX1999 product line was engineered specifically for multi-rail, battery-powered computing platforms-delivering quad-output power control with integrated sequencing, protection, and low-noise operation in a single 28-pin QSOP.
FAQ
What is the switching frequency configuration of the MAX1977EEI-TG068?
The MAX1977EEI-TG068 operates at fixed 400kHz for the 5V SMPS and 500kHz for the 3.3V SMPS. Unlike the MAX1999, it does not include a TON pin and cannot be reconfigured to lower frequencies. This fixed high-frequency operation minimizes inductor and capacitor size while supporting fast transient response required in modern notebook CPUs.
Does the MAX1977EEI-TG068 require external current-sense resistors?
No, the MAX1977EEI-TG068 does not require external current-sense resistors. It uses internal LX node sensing for current-limit detection, eliminating the need for sense resistors and associated power loss. This architecture is distinct from the MAX1777 (which requires CS3/CS5 resistors) and aligns with Maxim's Quick-PWM™ implementation for improved efficiency and reduced BOM count.
How does the MAX1977EEI-TG068 manage power sequencing between its outputs?
The MAX1977EEI-TG068 supports flexible power sequencing via ON3 and ON5 enable pins. Connecting ON3 or ON5 to the REF pin initiates delay-start sequencing-ensuring the 5V rail reaches regulation before enabling the 3.3V rail (or vice versa). This eliminates cross-conduction risk and satisfies strict SoC power-up requirements without external timers or supervisors.
What is the role of the SKIP pin on the MAX1977EEI-TG068?
The SKIP pin on the MAX1977EEI-TG068 selects the operating mode: GND enables idle (pulse-skipping) mode for highest light-load efficiency; VCC enables fixed-frequency PWM mode to reduce EMI; and leaving it floating or connecting to REF activates ultrasonic mode (≥25kHz), which suppresses audible noise in audio-sensitive applications like notebooks and VoIP handsets.
Can the MAX1977EEI-TG068's LDO outputs operate independently of the SMPS rails?
No-the 5V and 3.3V LDO outputs (LDO5 and LDO3) are bootstrapped from their respective SMPS outputs (OUT5 and OUT3). They only regulate when the corresponding SMPS rail is active and within specification (e.g., OUT5 > 4.43V for LDO5 to engage). If an SMPS shuts down due to fault or disable, its LDO output drops out, ensuring coordinated power loss across related subsystems.
MAX1977EEI-TG068 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-SSOP (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Applications:
- Controller, Notebook Power System
- Voltage - Input:
- 4.5V ~ 24V
- Number of Outputs:
- 4
- Voltage - Output:
- 2V ~ 3.3V, 5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QSOP
MAX1977EEI-TG068 FAQ
1.How can I place an order for MAX1977EEI-TG068 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1977EEI-TG068 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 MAX1977EEI-TG068 reliable?
The price and inventory of MAX1977EEI-TG068 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1977EEI-TG068 is usually 5 days.
3.What payment methods are accepted for MAX1977EEI-TG068?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1977EEI-TG068 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1977EEI-TG068?
MAX1977EEI-TG068 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1977EEI-TG068 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 MAX1977EEI-TG068?
For technical support, including MAX1977EEI-TG068 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1977EEI-TG068 requirements.
6.How does Aetrix verify that MAX1977EEI-TG068 is sourced from the original manufacturer or authorized distributors?
All MAX1977EEI-TG068 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 MAX1977EEI-TG068 meets industry standards.
7.What is the process for return or replacement of MAX1977EEI-TG068?
All MAX1977EEI-TG068 units undergo pre-shipment inspection (PSI). If there is an issue with MAX1977EEI-TG068, 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 MAX1977EEI-TG068 part is unused and in its original packaging.
Return procedure for MAX1977EEI-TG068:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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