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Texas Instruments LM3370SDX-4221/NOPB
- Part No.:
- LM3370SDX-4221/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-WFDFN Exposed Pad
- Datasheet:
-
LM3370SDX-4221/NOPB.pdf
- Description:
- IC REG BUCK 1.8V/3.3V DL 16WSON
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM3370SDX-4221/NOPB from Texas Instruments is a dual synchronous step-down DC-DC converter with I²C-controlled dynamic voltage scaling, delivering 600 mA per channel at fixed output voltages of 1.8 V (VOUT1) and 3.3 V (VOUT2). It operates from a single 2.7 V–5.5 V input rail (e.g., Li-Ion or 3.3 V/5 V fixed supply), features 2 MHz fixed-frequency PWM switching, 180° out-of-phase buck operation for input ripple reduction, and internal synchronous rectification. It is used in baseband and application processors requiring independent, dynamically adjustable core and I/O power rails.
For engineers reviewing the LM3370SDX-4221/NOPB datasheet, LM3370SDX-4221/NOPB pinout, LM3370SDX-4221/NOPB application, or LM3370SDX-4221/NOPB equivalent, key selection criteria include confirmed dual-buck topology with I²C programmability, verified 1.8 V / 3.3 V default output configuration, validated 2.2 µH inductor + 4.7 µF/10 µF capacitor design requirements, and WSON-16 package compatibility with thermal performance (θJA = 26°C/W).
Technical Context
The LM3370SDX-4221/NOPB implements two independent voltage-mode synchronous buck regulators sharing a common 2 MHz oscillator but operating 180° out of phase to minimize input current ripple. Each channel integrates PFET and NFET power switches with RDS(ON) values of 390 mΩ (PFET) and 240 mΩ (NFET) in WSON package, enabling high efficiency across 0–600 mA load range.
Its I²C interface supports real-time control of output voltage (within family-defined ranges), PFM/PWM mode selection, spread-spectrum modulation for EMI reduction, and POR threshold trimming. The device includes dedicated enable pins (EN1/EN2), analog feedback inputs (FB1/FB2), open-drain POR outputs (nPOR1/nPOR2), and separate power grounds (PGND1/PGND2) for optimal noise isolation between channels.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Configuration | Dual independent buck converters: VOUT1 = 1.8 V (±3.5% FB accuracy), VOUT2 = 3.3 V (±3.5% FB accuracy) |
| Input Voltage Range | 2.7 V to 5.5 V - supports single-cell Li-Ion, NiMH/NiCd, or fixed 3.3 V/5 V rails without external LDO pre-regulation |
| Max Output Current | 600 mA per channel - sufficient for low-power application processors and FPGA I/O banks |
| Switching Frequency | 2.0 MHz (typ.) - enables use of compact 2.2 µH shielded inductors and reduces size of input/output filtering |
| Control Interface | I²C-compatible (400 kHz max) - allows dynamic voltage scaling, mode selection, and spread-spectrum activation without additional GPIOs |
| Thermal Performance | θJA = 26°C/W (WSON-16 on 4-layer board) - supports continuous 600 mA operation at TA ≤ 60°C with standard PCB layout |
| Protection Features | Cycle-by-cycle current limit (1200 mA typ.), thermal shutdown (150°C), under-voltage lockout, soft-start, and independent POR monitoring per output |
Pinout & Package
The LM3370SDX-4221/NOPB is packaged in a 4 mm × 5 mm × 0.8 mm, 16-lead non-pullback WSON (Package Number NHR0016B), optimized for space-constrained portable applications. Thermal pad exposed on bottom enhances heat dissipation.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| VIN2 | Buck 2 input power supply | Accepts 2.7–5.5 V; must be ≥ VOUT2 + 1 V for stable regulation at full load |
| SW2 | Buck 2 switch node | Connects to 2.2 µH inductor; requires low-ESR ceramic output capacitor (10 µF) at VOUT2 |
| PGND2 | Buck 2 power ground return | Must be routed separately from SGND and PGND1 to avoid noise coupling into feedback path |
| VDD | Signal supply input | Must be ≥ max(VIN1, VIN2); powers internal logic, I²C interface, and POR circuitry |
| SGND | Signal ground reference | Reference for FB1/FB2, SDA/SCL, EN1/EN2, nPOR1/nPOR2; connect to clean analog ground plane |
| PGND1 | Buck 1 power ground return | Separate return path for Buck 1 inductor current; ties to thermal pad for thermal conduction |
| SW1 | Buck 1 switch node | Connects to 2.2 µH inductor; requires low-ESR ceramic output capacitor (10 µF) at VOUT1 |
| VIN1 | Buck 1 input power supply | Accepts 2.7–5.5 V; must be ≥ VOUT1 + 1 V (e.g., ≥ 2.8 V for 1.8 V output) |
| FB1 | Buck 1 feedback input | Resistive divider sets VOUT1; internal 0.8 V reference; ±3.5% tolerance over temp and line |
| SDA | I²C data line | Open-drain; requires 2 kΩ pull-up to VDD; supports read/write of voltage, mode, and POR registers |
| SCL | I²C clock line | Open-drain; requires 2 kΩ pull-up to VDD; 400 kHz max frequency per I²C Fast-mode spec |
| nPOR1 | Buck 1 power-on-reset output | Open-drain active-low; asserts when VOUT1 < 94% of target; requires 100 kΩ pull-up |
| nPOR2 | Buck 2 power-on-reset output | Open-drain active-low; asserts when VOUT2 < 94% of target; requires 100 kΩ pull-up |
| EN1 | Buck 1 enable input | Active-high; logic high ≥ 1.0 V enables Buck 1; can be controlled independently of EN2 for sequencing |
| EN2 | Buck 2 enable input | Active-high; logic high ≥ 1.0 V enables Buck 2; supports staggered startup via GPIO or I²C |
| FB2 | Buck 2 feedback input | Resistive divider sets VOUT2; same internal reference and tolerance as FB1 |
Key Features
| Feature | Design Value |
|---|---|
| I²C-controlled dynamic voltage scaling | Enables real-time adjustment of VOUT1 (1.0–2.0 V in 50 mV steps) and VOUT2 (1.8–3.3 V in 100 mV steps) to match processor DVFS states |
| 180° out-of-phase buck timing | Reduces peak input current by ~30% and cuts input capacitor RMS current, allowing smaller 4.7 µF input caps |
| Automatic PFM/PWM mode switching | Maintains >85% efficiency down to 1 mA load via ultra-low IQ_PFM (34 µA typ. both channels), eliminating need for external enable control |
| Spread-spectrum modulation | Reduces peak EMI by >10 dB in 30–100 MHz band via I²C-enabled dithering of 2 MHz switching frequency |
| Independent POR with trimmable thresholds | nPOR1/nPOR2 provide system-level reset assertion at 94% VOUT (default), configurable to 70% or 85% for margin testing or brownout recovery |
| Internal synchronous rectification | Eliminates external Schottky diodes; achieves >92% peak efficiency at 600 mA with 2.2 µH/10 µF design |
Applications
| Baseband Processor Core Power | Application Processor I/O Supply |
|---|---|
Use Scenario: Powering ARM9/ARM11 core voltage (VDD_CORE) in cellular handsets or GPS modules where battery life and thermal density are critical. IC Role / Device Role / Timing Role: Dual-buck regulator providing tightly regulated 1.8 V core rail with dynamic scaling and independent 3.3 V I/O rail for memory interface. Use Value: Enables processor DVFS via I²C, reducing average core power by up to 40% during idle; 180° phase shift lowers input cap stress and extends battery runtime. | Use Scenario: Supplying configurable I/O voltage (VDD_IO) for multi-standard connectivity SoCs (e.g., Wi-Fi + Bluetooth + GPS) requiring 1.8 V or 3.3 V logic levels. IC Role / Device Role / Timing Role: Dual-channel DC-DC delivering stable 3.3 V I/O rail while supporting dynamic reconfiguration of auxiliary domain voltages via I²C. Use Value: Eliminates need for discrete LDOs or multiple single-buck ICs; spread-spectrum mode meets FCC Class B radiated emissions limits without added shielding. |
| FPGA Configuration & I/O Banks | Low-Power DSP Audio Subsystem |
Use Scenario: Powering Spartan-6 or iCE40 FPGA core (1.2 V) and I/O banks (1.8 V/3.3 V) in portable instrumentation or edge AI accelerators. IC Role / Device Role / Timing Role: Dual synchronous buck supplying VCCINT and VCCIO with independent enable/control for safe power sequencing during configuration. Use Value: Independent EN1/EN2 pins allow FPGA core to power up before I/O banks; POR outputs feed FPGA INIT_B for hardware reset coordination. | Use Scenario: Delivering clean, low-noise 1.8 V core and 3.3 V analog supply to TI C5000/C6000-series DSPs in voice-enabled wearables or hearing aids. IC Role / Device Role / Timing Role: Dual buck converter with forced PWM mode support to suppress switching noise in audio signal chain paths. Use Value: Forced PWM mode eliminates PFM-induced low-frequency ripple (<20 kHz), preventing audible artifacts in DAC/ADC paths without sacrificing light-load efficiency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62400DRCT | Fixed 1.2 V / 3.3 V outputs; no I²C interface; 2.25 MHz switching; 600 mA per channel; 3 mm × 3 mm QFN-16 | Lacks dynamic voltage scaling and spread-spectrum; suitable only for static voltage systems | Select when I²C control is unnecessary and board area is constrained - smaller footprint but no firmware-based optimization |
| RT8059ZSP | 1.8 V / 3.3 V fixed outputs; I²C-compatible; 1.5 MHz switching; 600 mA per channel; 4 mm × 4 mm WQFN-16 | Lower switching frequency increases inductor size; no POR outputs; different I²C register map and timing | Select when thermal budget allows larger inductors and system firmware already supports RT series register definitions |
Compared with TPS62400DRCT and RT8059ZSP, the LM3370SDX-4221/NOPB uniquely combines I²C-programmable voltage scaling, spread-spectrum EMI reduction, and dual independent POR signals - making it optimal for battery-powered systems requiring coordinated power management and regulatory compliance without external supervision logic.
Availability
LM3370SDX-4221/NOPB is available at Aetrix Electronics and suitable for baseband processor core power, FPGA I/O bank supply, and low-power DSP audio subsystems requiring stable component supply, long-term lifecycle assurance, and consistent parametric performance across production batches.
Supply support for LM3370SDX-4221/NOPB 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-efficiency DC-DC conversion for portable and industrial applications.
The LM3370 belongs to TI's portable power management portfolio, designed specifically for ultra-low-voltage, multi-rail power delivery in space- and battery-constrained devices such as smartphones, wearables, and IoT edge nodes.
FAQ
What are the default output voltages configured for the LM3370SDX-4221/NOPB?
The LM3370SDX-4221/NOPB is factory-configured with VOUT1 = 1.8 V and VOUT2 = 3.3 V. These values are set by internal resistor networks and confirmed in TI's ordering information table. The I²C interface allows dynamic reprogramming within the device's supported ranges (1.0–2.0 V for VOUT1, 1.8–3.3 V for VOUT2), but the default 1.8 V / 3.3 V pairing is fixed for this specific part number.
Does the LM3370SDX-4221/NOPB require external catch diodes?
No, the LM3370SDX-4221/NOPB does not require external catch diodes. It integrates synchronous rectification using internal NFETs for both buck channels, eliminating conduction losses and heat generation associated with external Schottky diodes. This is explicitly stated in the "Internal Synchronous Rectification for High Efficiency" feature and confirmed in the functional block diagram and typical application circuit.
Can the LM3370SDX-4221/NOPB operate with only one output enabled?
Yes, the LM3370SDX-4221/NOPB supports independent channel control. EN1 and EN2 are separate logic inputs, allowing Buck 1 (1.8 V) to be active while Buck 2 (3.3 V) remains disabled, or vice versa. The datasheet confirms this in the "Independent enable pin for each output allows for simple and effective power sequencing" description and pin function table.
What is the purpose of the nPOR1 and nPOR2 pins on the LM3370SDX-4221/NOPB?
The nPOR1 and nPOR2 pins on the LM3370SDX-4221/NOPB are open-drain power-on-reset outputs that assert low when their respective output voltage falls below 94% of target (default threshold). They provide hardware reset signaling to microcontrollers or FPGAs, ensuring system stability during power-up or brownout events. Each pin requires a 100 kΩ pull-up resistor to VDD per the pin descriptions.
Is the LM3370SDX-4221/NOPB pin-compatible with other variants in the LM3370 family?
Yes, all LM3370 variants - including LM3370SDX-4221/NOPB, LM3370SD-4221, and LM3370TLX-3806/NOPB - share identical pinouts for their respective packages (WSON-16 or DSBGA-20). The WSON-16 version maintains consistent pin numbering and function mapping across all SD/SDX suffixes, enabling drop-in replacement for different voltage options without PCB redesign.
LM3370SDX-4221/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.8V, 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 600mA
- Frequency - Switching:
- 2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-WSON (5x4)
LM3370SDX-4221/NOPB FAQ
1.How can I place an order for LM3370SDX-4221/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3370SDX-4221/NOPB 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 LM3370SDX-4221/NOPB reliable?
The price and inventory of LM3370SDX-4221/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3370SDX-4221/NOPB is usually 5 days.
3.What payment methods are accepted for LM3370SDX-4221/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3370SDX-4221/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3370SDX-4221/NOPB?
LM3370SDX-4221/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3370SDX-4221/NOPB 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 LM3370SDX-4221/NOPB?
For technical support, including LM3370SDX-4221/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3370SDX-4221/NOPB requirements.
6.How does Aetrix verify that LM3370SDX-4221/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3370SDX-4221/NOPB 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 LM3370SDX-4221/NOPB meets industry standards.
7.What is the process for return or replacement of LM3370SDX-4221/NOPB?
All LM3370SDX-4221/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3370SDX-4221/NOPB, 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 LM3370SDX-4221/NOPB part is unused and in its original packaging.
Return procedure for LM3370SDX-4221/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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