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Texas Instruments LMR70503TMX/NOPB
- Part No.:
- LMR70503TMX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WFBGA, DSBGA
- Datasheet:
-
LMR70503TMX/NOPB.pdf
- Description:
- IC REG BUCK BST ADJ 270MA 8DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:7,920
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Product details
Overview
LMR70503TMX/NOPB from Texas Instruments is a buck-boost DC-DC converter IC generating adjustable negative output voltage (–0.9 V to –5.5 V) from a 2.8 V to 5.5 V input, featuring 320 mA switch current limit, 500 kHz minimum switching frequency, and internal soft start - used in op-amp biasing, data converter rails, and LCD bias supplies.
For engineers reviewing the LMR70503TMX/NOPB datasheet, LMR70503TMX/NOPB pinout, LMR70503TMX/NOPB application, or LMR70503TMX/NOPB equivalent, this page delivers verified technical context, validated pin functions, confirmed operating ranges, and real-world design implications - all specific to the LMR70503TMX/NOPB thin DSBGA package with 8 bumps.
Technical Context
The LMR70503TMX/NOPB implements peak current mode control with a fixed 500 kHz minimum switching frequency to avoid audible noise, dynamically reducing peak inductor current-not frequency-at light loads to maintain regulation. It integrates a high-side MOSFET with 1.1 Ω typical RDS(on) at 2.8 V and uses ground-referred EN and FB pins for simplified system-level sequencing.
Its operation includes three distinct load regimes: (1) no-load/very-light-load with TON-MIN clamping and active dummy load, (2) light-load with constant-frequency/variable-peak-current control, and (3) heavy-load with fixed peak current (320 mA) and frequency modulation - all coordinated by internal UVLO (2.55 V rise), thermal shutdown (165 °C), and soft-start/soft-off discharge circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8 V to 5.5 V - supports single-cell Li-ion, USB, and 3.3 V/5 V rails without external pre-regulation. |
| Output Voltage Range | –0.9 V to –5.5 V - programmable via external resistor divider on FB/VREF; enables precision negative bias for analog signal chains. |
| Switch Current Limit | 320 mA (typical) - sets maximum inductor peak current; defines absolute load capability under worst-case VIN/VOUT conditions. |
| Minimum Switching Frequency | 500 kHz (typical) - prevents audio-band oscillation; ensures EMI filtering compatibility and predictable layout behavior. |
| Reference Voltage | 1.19 V (typical) - stable internal VREF at FB node; determines output setpoint accuracy and feedback divider design margin. |
| Shutdown Supply Current | 1 µA (max) - enables ultra-low-power standby in battery-critical systems; measured with EN = 0 V. |
| UVLO Threshold | 2.55 V (rising), 0.13 V hysteresis - prevents erratic startup during brown-out; ensures reliable enable only above functional VIN. |
Pinout & Package
Tiny 8-bump thin DSBGA package: 0.84 mm × 1.615 mm × 0.6 mm - optimized for space-constrained portable and wearable PCBs with minimal thermal mass.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power supply input | Connects to 2.8–5.5 V source; powers internal circuitry and high-side MOSFET; must be present before EN assertion. |
| GND | Analog ground reference | Common return for internal bias circuits; not tied to VOUT potential - enables ground-referenced EN/FB interface. |
| SW | Switch node | Drain of internal high-side MOSFET; requires low-inductance Schottky diode cathode placement to minimize ringing. |
| VOUT | Negative output terminal | Delivers regulated –0.9 V to –5.5 V; connects to anode of external Schottky diode and output capacitor bank. |
| EN | Enable input | Active-high, GND-referenced control; rising threshold 1.05–1.2 V; must remain below VIN at all times. |
| FB | Feedback input | Compares divided VOUT against internal VREF (1.19 V); sets output voltage via RT/RB resistor network. |
| VREF | Reference voltage output | 1.19 V (typ) buffered reference; connects to bottom resistor (RB) of feedback divider; drives ≤100 kΩ load. |
Key Features
| Feature | Design Value |
|---|---|
| No external compensation required | Internal loop compensation eliminates need for external RC networks - reduces BOM count and layout sensitivity. |
| Ground-referred enable and feedback | EN and FB referenced to GND (not VOUT) - simplifies control logic interfacing and eliminates level-shifting components. |
| Integrated soft start and soft off | Controlled ramp-up/ramp-down of VOUT during enable/disable - prevents inrush current and output voltage overshoot. |
| Internal dummy load for light-load regulation | Automatically engages when output voltage exceeds regulation due to TON-MIN limitation - maintains stability down to zero load. |
| Thermal shutdown with hysteresis | Shuts down at 165 °C (typ), restarts at 155 °C (typ) - protects against sustained overtemperature without cycling. |
Applications
| Op-Amp Negative Rail Generation | Data Converter Bias Supply |
|---|---|
|
Use Scenario: Providing symmetric ±VREF rails for rail-to-rail op-amps in precision sensor front-ends. IC Role / Device Role / Timing Role: Generates stable, low-noise –2.5 V or –5.0 V bias from a 3.3 V system rail using external feedback resistors. Use Value: Enables full-scale input swing and minimizes offset drift - critical for 16-bit+ SAR ADC drivers and instrumentation amplifiers. |
Use Scenario: Supplying negative reference voltage for dual-supply ADCs/DACs in medical imaging and test equipment. IC Role / Device Role / Timing Role: Delivers tightly regulated –3.3 V or –5.5 V with <1% line/load regulation across temperature. Use Value: Reduces code-dependent errors and improves SNR by suppressing power-supply-induced harmonic distortion. |
| LCD Panel Biasing | Portable Instrument Negative Supply |
|
Use Scenario: Generating –1.5 V to –5.0 V gate drive voltages for STN/TN LCD displays in handheld meters. IC Role / Device Role / Timing Role: Supplies adjustable negative VEE rail with fast transient response to display refresh cycles. Use Value: Ensures consistent contrast ratio and eliminates ghosting - achieved via 500 kHz min frequency and low output ripple. |
Use Scenario: Creating compact, low-quiescent negative supply for battery-powered oscilloscopes and logic analyzers. IC Role / Device Role / Timing Role: Operates from single Li-ion cell (2.8–4.2 V) to deliver –5.0 V at up to 250 mA with 1 µA shutdown current. Use Value: Extends battery life >2× versus discrete charge-pump solutions while maintaining PCB area <3 mm². |
Equivalent & Alternatives
The following parts are listed as comparable options for similar negative-output buck-boost applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS60403DBVR | Charge-pump topology; fixed –3.3 V output; no inductor required; 60 mA max output. | Suitable only for low-current, low-noise applications where inductor-free design is mandatory. | Choose TPS60403DBVR if board space is extremely constrained and load ≤60 mA; avoid for >100 mA or adjustable-VOUT needs. |
| LMR62421XMF/NOPB | Step-down-only; positive output only; 2.7–5.5 V input; 2.4 A switch current; requires external compensation. | Cannot generate negative voltage; unsuitable for op-amp bias or LCD VEE without additional inverting stage. | LMR62421XMF/NOPB is not a functional alternative - only consider if redesigning for positive-only architecture with higher current. |
Compared with LMR70503TMX/NOPB, TPS60403DBVR offers smaller solution size but sacrifices output adjustability and current capability; LMR62421XMF/NOPB is incompatible for negative-rail generation and requires complete schematic revision.
Availability
LMR70503TMX/NOPB is available at Aetrix Electronics and suitable for op-amp biasing, data converter reference supplies, and LCD panel biasing requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial and medical electronics.
Supply support for LMR70503TMX/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 over 50 years of innovation in high-reliability power conversion solutions.
The LMR70503TMX/NOPB belongs to TI's SIMPLE SWITCHER® family, designed specifically for compact, easy-to-use DC-DC conversion in space- and noise-sensitive applications - emphasizing minimal external components and robust transient performance.
FAQ
What is the absolute maximum input voltage rating for the LMR70503TMX/NOPB?
The LMR70503TMX/NOPB has an absolute maximum VIN-to-GND rating of –0.5 V to 6.0 V. Exceeding 6.0 V risks permanent damage to the internal high-side MOSFET and control circuitry. Operation above 5.5 V violates recommended operating conditions and may cause premature failure or parametric shift.
Can the LMR70503TMX/NOPB generate –0.9 V output with 2.8 V input?
Yes, the LMR70503TMX/NOPB supports –0.9 V output across its full input range (2.8 V to 5.5 V). At 2.8 V input, it delivers –0.9 V with ≥100 mA load capability and maintains regulation via minimum-frequency operation and dummy-load activation - confirmed in Figure 13 and Table 1 of the datasheet.
Does the LMR70503TMX/NOPB require external compensation components?
No, the LMR70503TMX/NOPB features fully internal compensation - no external capacitors or resistors are needed on the COMP or SS pins. This is explicitly stated in the FEATURES section and validated by the "No External Compensation" bullet in the official datasheet (SNVS850A).
How does the LMR70503TMX/NOPB handle short-circuit conditions?
The LMR70503TMX/NOPB provides inherent short-circuit protection via peak current limiting (320 mA typical) and minimum off-time (TOFF-MIN) enforcement. During hard short, it cycles at minimum frequency with clamped peak current - preventing thermal runaway while maintaining safe junction temperatures per the datasheet's Short Circuit Protection section.
What is the purpose of the dummy load function in the LMR70503TMX/NOPB?
The dummy load in the LMR70503TMX/NOPB activates only at near-zero load when TON-MIN prevents further reduction of peak inductor current. It sinks excess charge from the output capacitor to prevent overvoltage - ensuring regulation stability down to 0 mA load without external circuitry, as detailed in the OPERATING DESCRIPTION section.
LMR70503TMX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 8-WFBGA, DSBGA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Negative
- Topology:
- Buck-Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.8V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- -0.9V
- Voltage - Output (Max):
- -5.5V
- Current - Output:
- 270mA (Switch)
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DSBGA
LMR70503TMX/NOPB FAQ
1.How can I place an order for LMR70503TMX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR70503TMX/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 LMR70503TMX/NOPB reliable?
The price and inventory of LMR70503TMX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR70503TMX/NOPB is usually 5 days.
3.What payment methods are accepted for LMR70503TMX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR70503TMX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR70503TMX/NOPB?
LMR70503TMX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR70503TMX/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 LMR70503TMX/NOPB?
For technical support, including LMR70503TMX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR70503TMX/NOPB requirements.
6.How does Aetrix verify that LMR70503TMX/NOPB is sourced from the original manufacturer or authorized distributors?
All LMR70503TMX/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 LMR70503TMX/NOPB meets industry standards.
7.What is the process for return or replacement of LMR70503TMX/NOPB?
All LMR70503TMX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LMR70503TMX/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 LMR70503TMX/NOPB part is unused and in its original packaging.
Return procedure for LMR70503TMX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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