TPS61251DSGR - 3.5MHz Boost Converter for Battery Backup | Texas Instruments
MPN: TPS61251DSGR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.92 | $1.92 |
| 10 | $1.68 | $16.80 |
| 100 | $1.32 | $132.00 |
| 500 | $1.08 | $540.00 |
| 1,000 | $0.91 | $910.00 |
TPS61251DSGR Overview
A boost converter is a type of switched-mode DC-DC converter whose output voltage is higher than its input voltage. In the broader power-management taxonomy, a boost (or step-up) converter sits beside buck, boost-buck, and SEPIC topologies; all belong to the voltage-regulator IC family, which is itself a sub-category of power-management ICs (PMICs). Boost converters are commonly used in portable products where a single-cell Li-Ion, Li-polymer, or 3-cell NiMH source must be boosted to 3.3V, 3.45V, 5V, or higher rails for downstream loads.
The TPS61251DSGR accepts inputs from 2.3V to 6V and produces an adjustable output of up to 6.5V typical, with the input-current limit programmable via a single external resistor. Operating at a fixed 3.5-MHz switching frequency, the device supports small 1-uH inductors, reducing total solution area. Efficiency peaks at 92% under typical loads; the integrated snooze mode drops quiescent current when the backup source is fully charged, preserving stored energy. Protection features include adjustable input-current limit, thermal shutdown, and over-voltage protection.
The architecture pairs a current-mode PWM controller with a low-RDS(on) synchronous power stage and a precision current-sense amplifier for the adjustable constant-current limit. The high switching frequency pushes the ripple noise above the audio band, simplifying filtering. Programmable soft-start and the snooze-mode pin allow designers to tune startup behavior and standby losses for ultra-low-power sleep states.
Typical applications include backup power for solid-state drives (SSD), hold-up supplies in industrial meters and e-meters, portable medical devices, wireless IoT sensor nodes, and SSD caching modules. The wide input range suits USB-on-the-go (OTG) boost requirements as well. For designers evaluating alternatives, the TPS61251DSGR occupies the same 2x2 mm footprint as TI's other DSG-package parts, allowing PCB reuse across similar backup or general-purpose boost rails.
When designing with this part, choose an input capacitor rated for the worst-case RMS ripple and a 1-uH shielded inductor with low DC resistance to preserve efficiency at 1.5 A. The ILIM resistor sets the constant-current regulation point for capacitor charging - verify this value matches the backup-capacitor manufacturer's recommended charge profile to avoid premature aging.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for TPS61251DSGR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with TPS61251DSGR (same form factor and footprint) — differing in Input Voltage Range, Output Voltage, Package, Topology.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
TPS61251DSGT
✅ Drop-In📋 Reference alternative (not in catalog)
TPS61240DRVT
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$0.92 / Unit
View Datasheet →TPS61251DSGR Maximum Ratings & Electrical Characteristics
| Topology | Boost (step-up) DC-DC converter |
| Switching Frequency | 3.5 MHz (typical) |
| Output Current | 1.5 A (peak switch current) |
| Peak Efficiency | 92% (at typical operating point) |
| Input Voltage Range | 2.3 V to 6 V |
| Output Voltage | Adjustable, up to 6.5 V (typical) |
| Input Current Limit Accuracy | ±10% |
| Adjustable Input Current Limit | Yes (via external resistor) |
| Snooze Mode | Yes (integrated, pin-controlled) |
| Soft-Start | Programmable |
| Thermal Shutdown | Yes |
| Over-Voltage Protection | Yes |
| Package | WSON-8 (DSG) 2x2 mm |
| Operating Temperature Range | -40 C to +85 C |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
TPS61251DSGR Pin Configuration
| Pin 1 | VIN — Input supply voltage (2.3 V to 6 V) |
| Pin 2 | GND — Ground |
| Pin 3 | EN/SNOOZE — Enable and snooze-mode control input |
| Pin 4 | ILIM — Adjustable input current-limit programming pin (resistor to GND) |
| Pin 5 | FB — Feedback input for output voltage regulation |
| Pin 6 | VOUT — Regulated output voltage |
| Pin 7 | SW — Inductor switching node |
| Pin 8 | PGND — Power ground |
Typical Applications
TPS61251DSGR is suitable for 7 applications: SSD Hold-Up / Cache Flush Backup, Industrial E-Meter / Smart Meter Hold-Up Supply, Portable Medical Device Backup Power, Wireless IoT Sensor / Solid-State Drive Cache Node, POS Terminal / Cash-Register Hold-Up, USB OTG / 5 V Boost from Single Li-Ion, Automotive Infotainment / Cluster Ride-Through.
SSD Hold-Up / Cache Flush Backup
The TPS61251DSGR's 3.5-MHz switching frequency, 1.5-A peak switch current, and adjustable input-current limit (±10%) make it a strong fit for solid-state-drive (SSD) backup-power modules. A typical SSD holds DRAM write-back buffers that must be flushed to NAND within milliseconds of an unexpected input loss. The TPS61251DSGR sits between the 3.3 V rail and a 1 F to 4 F backup super-capacitor, regulating constant-charge current via its ILIM pin so the super-cap never receives damaging inrush. The high 3.5-MHz frequency pushes ripple above the AM band, avoiding interference with the SSD's radio-adjacent circuits. Its 8-pin WSON (DSG) 2x2 mm footprint fits inside constrained SSD enclosures, and the integrated snooze mode minimizes standby losses once the super-cap is topped up.
Recommended
Industrial E-Meter / Smart Meter Hold-Up Supply
In smart-meter designs, line-power outages require continued metering and data logging for several seconds before the meter resets. The TPS61251DSGR boosts a 2.3-6 V input to a 3.3 V or 5 V backup rail and charges a large super-capacitor through its programmable current limit. The 92% peak efficiency minimizes thermal rise in the meter enclosure, and the snooze-mode function reduces quiescent current draw once the cap is full, preserving hold-up energy for the next outage. The WSON-8 2x2 mm footprint is small enough to retrofit into legacy meter PCBs and meets industrial temperature-grade requirements at -40 C to +85 C operation.
Recommended
Portable Medical Device Backup Power
Battery-powered patient monitors, infusion pumps, and handheld diagnostic tools demand uninterrupted operation across battery hot-swap or brownout events. The TPS61251DSGR's wide 2.3-6 V input range accepts a single-cell Li-Ion or Li-polymer source, while its adjustable constant-current limit ensures the backup super-capacitor is charged within thermal-safe limits for medical-grade reliability. The 3.5-MHz switching frequency keeps EMI outside the ECG / EEG bandwidth, a critical requirement when sensitive analog front-ends share the same board. Integrated thermal shutdown and over-voltage protection support IEC 60601-style safety reviews.
Recommended
Wireless IoT Sensor / Solid-State Drive Cache Node
IoT sensor nodes with local cache, edge AI, or radio retransmission require short-duration hold-up when their primary energy source - coin cell, harvested, or battery - is interrupted. The TPS61251DSGR charges a small super-cap from the battery rail and supplies 3.3 V to the radio and MCU during outages. Programmable soft-start protects inrush-sensitive energy-harvesting sources, while the snooze mode reduces standby losses so the buffered energy is available months later. The 2x2 mm WSON package and 1-uH inductor requirement allow tiny 20x20 mm sensor board layouts.
Recommended
POS Terminal / Cash-Register Hold-Up
Point-of-sale terminals must preserve transaction logs and complete card-present EMV cycles even if the AC-DC brick drops out briefly. The TPS61251DSGR charges a 1 F to 4.5 F super-cap on the 12 V input rail through its programmable ILIM pin and supplies 5 V to the EMV/PCI controller during the 50-200 ms hold-up window. The 92% efficiency preserves energy as heat, important for the enclosed POS environment where case temperature is regulated. The WSON-8 footprint leaves room for the printer, display, and Ethernet ports on the same PCB.
Recommended
USB OTG / 5 V Boost from Single Li-Ion
USB On-The-Go (OTG) hosts often need a 5 V bus from a single Li-Ion cell (3.0-4.2 V). The TPS61251DSGR's adjustable output up to about 6.5 V supports 5 V USB OTG, peripheral power, and small display bias rails. The 1.5-A peak switch current and 92% efficiency meet USB-IF inrush-current expectations for peripheral plug-in events, while the small 1 uH inductor and 2x2 mm WSON keep the BOM footprint negligible in mobile-form-factor designs.
Recommended
Automotive Infotainment / Cluster Ride-Through
Automotive infotainment and instrument clusters need sub-second ride-through during cranking or accessory dropouts so the head unit does not reboot. The TPS61251DSGR boosts a 2.3-6 V (post-reverse-polarity and pre-regulator) rail into a backup super-cap that supports 3.3 V logic supplies. Its -40 C to +85 C operating range aligns with automotive interior grades, and its adjustable constant-current limit lets designers tune charge time to a specific super-cap and trigger window. PCB layout reuse is straightforward thanks to the small WSON-8 footprint.
Recommended
Recommended Products Summary
Engineering reference data for TPS61251DSGR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TPS61251DSGT |
|---|---|---|
| Brand | Texas Instruments | Texas Instruments |
| Package | WSON-8 (DSG) 2x2 mm | WSON-8 (DSG) 2x2 mm - same |
| Switching Frequency | 3.5 MHz | 3.5 MHz |
| Peak Switch Current | 1.5 A | 1.5 A |
| Peak Efficiency | 92% | 92% |
| Input Voltage Range | 2.3 V to 6 V | 2.3 V to 6 V |
| Snooze Mode | Yes | Yes |
| Reel Quantity | 3000 pcs (DSGR) | 250 pcs (DSGT) |
Key Differentiators
- Adjustable input current limit with ±10% accuracy for predictable backup-capacitor charging (vs Discrete boost + shunt-resistor current limit designs)
- Integrated snooze mode to preserve backup energy for the next hold-up event (vs Generic boost converters without standby optimization)
- 2x2 mm WSON-8 footprint with 3.5-MHz switching for small inductor and cap choices (vs Larger 1-2 MHz alternatives in TSSOP-10 or QFN-10 packages)
Design Notes
Estimated: At VIN = 3.3 V, VOUT = 5.0 V, IOUT = 0.5 A, the TPS61251DSGR delivers roughly 1.85 W (P_OUT) and the boost topology incurs switching and conduction losses. With 92% peak efficiency the device draws ~2.0 W from VIN, giving ~150 mW dissipation in the WSON-8 (theta_JA around 60-80 C/W on a small 1 oz copper pour). Confirm thermal performance with a board-level measurement, especially at 85 C ambient in enclosed e-meter or POS enclosures.
Place the 1-uH inductor and input/output ceramic capacitors within 5 mm of the SW, VIN, and VOUT pins to minimize parasitic loop inductance that would otherwise couple high-di/dt switching noise into feedback. Use a single ground-return star with PGND and GND tied at the thermal pad, and connect all grounds to the exposed thermal pad beneath the WSON-8 for both electrical and thermal conduction. Recommended 22 uF X5R ceramic input and output capacitors handle ripple under 1.5 A loads.
Do not omit the ILIM resistor - leaving the ILIM pin floating triggers the default minimum current limit and may starve backup-capacitor charging. Verify the ILIM value with the manufacturer datasheet equation rather than copying adjacent reference designs; lower current limits extend hold-up time but lengthen recharge between outages. Watch out for super-capacitor inrush: the adjustable current limit is the primary protection and must be designed below the super-cap manufacturer's absolute-max surge rating.
Route the FB trace away from the SW trace and the inductor to avoid noise coupling; a 4-5 mil trace guarded by a ground pour is recommended. Keep analog-sensitive functions such as feedback and snooze-mode control on the opposite side of the package from the switching node. Stitched ground vias around the WSON thermal pad reduce both ground bounce and junction-to-ambient thermal resistance for sustained hold-up operation.
Compliance Information
RoHS and REACH compliant per TI product page; WSON-8 packaging and lead-free finish. Not AEC-Q100 qualified - this part targets consumer, industrial, and SSD backup uses rather than under-the-hood automotive. Reach out to TI for -Q1 suffix variants if automotive grade is required.
