TPS61291DRVR Selection Guide: Low-Quiescent-Current Boost Converters for IoT and Wearables

Bottom Line: When selecting a low-quiescent-current boost converter for IoT sensors, wearables, or coin-cell-powered devices, prioritize bypass-mode Iq over peak efficiency. The TPS61291DRVR from Texas Instruments delivers an industry-leading 15 nA bypass-mode quiescent current, a 0.9 V–5 V input range compatible with single alkaline, NiMH, or Li-ion cells, and fixed output voltages (2.5 V, 3.0 V, 3.3 V) in a tiny 6-pin HVSON package — all at roughly $0.27 per unit. If your design draws less than 10 mA most of the time and peaks only briefly, the TPS61291 is the right choice; higher-Iq converters save pennies on the BOM while costing weeks of battery life.

Why Quiescent Current Is the Critical Parameter in Ultra-Low-Power Designs

Quiescent current (Iq) is the current consumed by the converter's control circuitry when the output load is zero or negligible. In always-on IoT nodes and wearables, the device spends 99 % of its life in sleep or standby, so Iq dominates the current budget far more than switching efficiency. A converter with 50 µA Iq versus 15 nA Iq wastes an additional 3.3 mAh per day from a coin cell — enough to cut battery life from 12 months to a few weeks. Always check the datasheet Iq spec at your supply voltage, not the typical figure at a favorable test condition.

Input Voltage Range: Matching the Battery Chemistry

The TPS61291DRVR accepts 0.9 V–5 V input, covering:

• Single alkaline AA/AAA: 1.5 V fresh, 0.9 V discharged — matches TPS61291's lower limit exactly.
• Single NiMH: 1.2 V nominal.
• CR2032 coin cell: 3.0 V nominal, down to 2.0 V end-of-life.
• Single Li-ion / LiPo: 4.2 V full, 3.0 V cutoff.

Converters limited to 1.8 V or 2.0 V minimum input (such as many standard TPS612xx parts) cannot extract full energy from a deeply discharged cell. When your application must run a cell to 0.9 V, the TPS61291's 0.9 V startup threshold is non-negotiable.

Output Voltage Options and the Bypass Mode Advantage

The TPS61291 family provides three fixed output options — 2.5 V, 3.0 V, and 3.3 V — selected by a logic pin (VSEL). When the input voltage already exceeds the target output, the device enters bypass mode through an internal pass transistor, eliminating switching losses entirely. During bypass, the converter draws only 15 nA. This behavior is fundamentally different from a conventional boost that continues oscillating at light load; it means a Li-ion cell powering a 3.0 V system through the TPS61291 can run with near-zero overhead until the cell drops below 3.0 V.

Switching Topology: Hysteretic Current-Mode Control

The TPS61291 uses hysteretic (bang-bang) current-mode control rather than fixed-frequency PWM. Hysteretic control has no oscillator and therefore:

• Eliminates a fixed quiescent current floor tied to oscillator bias.
• Naturally scales switching frequency with load — fewer cycles at light load means lower average Iq.
• Requires no external compensation network, reducing BOM complexity.

The trade-off is variable switching frequency (roughly 500 kHz–4 MHz depending on load and input/output conditions), which can complicate EMI filtering. Fixed-frequency alternatives like the TPS61220DCKR (2 MHz, up to 500 mA) are preferable when conducted EMI in a regulated band matters more than minimum current consumption.

Package and PCB Integration Considerations

The TPS61291DRVR is packaged in a 6-pin HVSON (0.8 mm pitch, 1.5 × 1.5 mm) — one of the smallest boost converter footprints available. Design considerations:

• Exposed pad: The thermal pad connects to GND. Solder it for mechanical stability and any minimal thermal path.
• Inductor: A 2.2 µH–4.7 µH ceramic-core inductor, 0402 or 0603 size, is typical. Keep the switching loop (inductor, diode/switch, input cap) as tight as possible.
• Input/Output capacitors: 10 µF ceramic (X5R or X7R) on both rails handles the hysteretic ripple adequately.
• Trace width: At 250 mA peak switch current, a 0.2 mm trace is marginal — use 0.3–0.4 mm or a polygon pour.

For lower-density boards where 0402 passives are a challenge, the TPS61291DRVT (same die, SOT-23-6 equivalent footprint) offers a slightly larger landing pattern.

Recommended Products Comparison Table

Product	Iq (bypass / active)	Vin Range	Vout Options	Peak Switch Current	Package	Best For
TPS61291DRVR	15 nA / ~4 µA	0.9–5 V	2.5/3.0/3.3 V fixed	250 mA	6-pin HVSON	Coin cell, AA, ultra-low-power IoT
TPS61291DRVT	15 nA / ~4 µA	0.9–5 V	2.5/3.0/3.3 V fixed	250 mA	6-pin SOT-23	Same as DRVR, hand-solderable proto
TPS61220DCKR	~18 µA	0.7–5.5 V	Adjustable	500 mA	6-pin SC-70	Higher-current IoT nodes, adjustable rail
TPS610995DRVR	800 nA	0.7–5.5 V	Adjustable	300 mA	6-pin HVSON	Balance between Iq and flexibility
TPS610992YFFR	800 nA	0.7–5.5 V	Adjustable	300 mA	6-pin DSBGA	Smallest footprint, advanced packaging

Alternatives from Other Vendors

Analog Devices / Maxim MAX17222: Ultra-low 300 nA Iq, 0.4 V–5.5 V input, adjustable output, 50 mA peak — best for sub-50 mA coin-cell nodes where input can dip below 0.9 V.

Microchip MCP1640: ~19 µA Iq, 0.65 V–5.5 V input, adjustable or fixed output, 400 mA peak. Suitable when moderate quiescent is acceptable and a wider device ecosystem (MPLAB support, long-term supply guarantee) is valued.

Renesas ISL9120: ~45 µA Iq, synchronous, 1.8 V–5.5 V input, adjustable, 1.5 A — targets higher-power portable devices where efficiency at 100 mA+ matters more than nA-level standby.

None of these alternatives match TPS61291's 15 nA bypass-mode Iq. If your system genuinely spends most of its time in deep sleep and only wakes for brief sensor reads, the TPS61291 family's bypass mode is a competitive advantage that no other device at this price point matches as of 2025.

Selection Decision Flowchart

Use this decision logic to choose the right low-Iq boost converter:

1. Does your battery voltage ever drop below 0.9 V?

   • Yes → Consider MAX17222 (0.4 V min) or Microchip MCP1640 (0.65 V min).
   • No → Continue.

2. Is your average load current under 50 mA with brief peaks?

   • Yes → TPS61291DRVR is likely optimal.
   • No (100 mA+ sustained) → Consider TPS610995DRVR (800 nA Iq, 300 mA) or TPS61220DCKR (500 mA peak, adjustable).

3. Do you need an adjustable output voltage?

   • Yes → TPS610995DRVR or TPS610992YFFR (both adjustable, 800 nA Iq).
   • No → TPS61291DRVR covers 2.5 V, 3.0 V, or 3.3 V fixed rails.

4. Is PCB space the primary constraint?

   • Yes → TPS610992YFFR (1.56 × 0.77 mm DSBGA) or TPS61291DRVR (1.5 × 1.5 mm HVSON).
   • No → TPS61291DRVT (SOT-23-6) simplifies hand assembly.

5. Is EMI compliance in a narrow frequency band required?

   • Yes → TPS61220DCKR (fixed 2 MHz PWM, easier to filter).
   • No → TPS61291 hysteretic control is acceptable.

Common IoT and Wearable Use Cases

Bluetooth Low Energy (BLE) beacon: A CR2032 powers a Nordic nRF52 (3.3 V, ~1.5 mA average). The TPS61291DRVR bypasses when the cell is full, switches only when the cell drops below 3.3 V, and maintains 15 nA overhead the rest of the time — extending battery life by 20–40 % compared to a 50 µA-Iq alternative.

Environmental sensor node: A pair of AA cells (3.0 V combined) runs an MCU + humidity sensor that wakes every 60 seconds. Average current is 8 µA. The TPS61291's bypass mode ensures the converter itself contributes only 15 nA to this budget.

Medical patch wearable: A 120 mAh LiPo (3.7–4.2 V nominal) powers a 3.3 V ECG front-end. The converter operates in bypass for most of the discharge cycle; the hysteretic boost engages only near end-of-life.

Industrial wireless sensor: A 3.6 V lithium thionyl-chloride primary (ER14250) powers an ISM-band radio. The TPS61291 handles the 3.0 V → 3.3 V boost near end-of-life without continuous switching overhead. Search FindMyChip for compatible boost converters to compare pricing across 200+ verified distributors.

Sourcing and Supply Chain Notes

The TPS61291DRVR is catalogued by Texas Instruments and available through authorized channels. FindMyChip aggregates inquiry-only inventory across 200+ verified distributors, enabling competitive price discovery — especially useful for mid-volume production runs (1,000–50,000 units) where spot pricing varies significantly. The DRVR (tape-and-reel, 3000-unit reel) suits SMT production; the DRVT (smaller reel or tube) suits prototyping. Both are RoHS-compliant and rated for –40 °C to +85 °C industrial operation.

For multi-sourcing strategies or EOL risk mitigation, the TPS610995DRVR or TPS61220DCKR are functionally close alternatives to keep on your AVL. Request a quote on FindMyChip to compare verified distributor pricing in real time.

FAQ

What is the difference between TPS61291DRVR and TPS61291DRVT? Both parts share the same silicon die and electrical specifications — 15 nA bypass-mode Iq, 0.9 V–5 V input, 250 mA peak switch current, fixed 2.5/3.0/3.3 V output. The DRVR is packaged in a 6-pin HVSON (1.5 × 1.5 mm) on a 3,000-unit tape-and-reel, suited for automated SMT pick-and-place in production. The DRVT is the SOT-23-6 equivalent, compatible with 0.95 mm pitch footprints common in prototype layouts and available in smaller reel quantities.

Can the TPS61291 power a 3.3 V MCU from a single AA battery? Yes. A fresh AA delivers 1.5 V; the TPS61291 boosts this to 3.3 V. As the cell discharges to 0.9 V, the converter continues to regulate — extracting nearly 100 % of the cell's available capacity. Peak output current is 250 mA, sufficient for most MCU + radio startup transients. Verify your peak current requirement against the TI datasheet (SLVSCD4) for the specific input voltage scenario.

How does bypass mode reduce battery drain? When Vin ≥ Vout, the TPS61291 activates an internal pass FET (P-channel bypass switch), connecting input to output directly without switching. The control circuit enters a deep-sleep state drawing only 15 nA. No inductor or capacitor switching occurs, so there are no gate-drive losses or switching losses — only the FET's on-resistance (Rdson) and resistive drop across the conduction path. For a Li-ion cell above 3.3 V powering a 3.3 V rail, bypass mode is effectively the lowest-loss topology possible.

What inductor is recommended for TPS61291? TI recommends a 2.2 µH to 4.7 µH shielded ferrite inductor with DCR ≤ 0.5 Ω and saturation current ≥ 400 mA. Suitable parts include Murata LQM21PNR47MGSD (2.2 µH, 0805, Isat 500 mA) or TDK MLZ2012M2R2WT (2.2 µH, 0805). Unshielded inductors are acceptable if the switching node is not adjacent to a sensitive analog input, but shielded types reduce EMI by 10–15 dB in the 1–5 MHz range.

Is TPS61291 AEC-Q100 qualified? No. The TPS61291 is rated for –40 °C to +85 °C commercial/industrial range (Grade 2 equivalent) but is not listed as AEC-Q100 qualified by TI as of 2025. For automotive applications requiring AEC-Q100 Grade 1 (–40 °C to +125 °C), TI's TPS61299 or TPS61240 families with AEC-Q100 qualification are the appropriate replacements.

Conclusion

The TPS61291DRVR is the benchmark low-quiescent-current boost converter for coin-cell IoT and wearable designs as of 2025: 15 nA bypass-mode Iq, 0.9 V startup, fixed-voltage simplicity, and a sub-$0.30 price point. Its hysteretic control architecture and bypass mode together minimize both active and standby losses in a 1.5 × 1.5 mm footprint. For adjustable output requirements at slightly higher Iq (800 nA), consider the TPS610995DRVR or TPS610992YFFR from the same TI family.

Search FindMyChip to compare real-time pricing across verified distributors, or request a quote for volume pricing on the TPS61291DRVR and alternatives.