LM2936BMX-3.3/NOPB - 50mA, 40V Ultra-Low IQ LDO | Texas Instruments
MPN: LM2936BMX-3.3/NOPB ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.42 | $1.42 |
| 10 | $1.18 | $11.80 |
| 100 | $0.92 | $92.00 |
| 500 | $0.78 | $390.00 |
| 1,000 | $0.69 | $690.00 |
LM2936BMX-3.3/NOPB Overview
An LDO (Low-Dropout) linear regulator is a type of voltage regulator that maintains a stable output voltage even when the input voltage is only slightly above the output voltage. LDOs sit within the broader power management IC hierarchy as linear regulators (versus switching regulators), trading efficiency for simplicity, low noise, and very small quiescent current. The LM2936 family specifically targets always-on battery and automotive subsystems.
Key features include a 5.5 V to 40 V (60 V transient-tolerant) input operating range, 3.3 V fixed output with ±3% accuracy over line, load, and temperature, 200 mV typical dropout at 50 mA, and ultra-low quiescent current of approximately 20 uA (typ) at light loads. The reverse-voltage protection block prevents damage from reversed battery or load-dump transients common in 12 V automotive rails, and internal current limit plus thermal shutdown provide additional robustness.
The architecture uses a PNP pass element followed by a precision bandgap reference, allowing the regulator to operate with very low quiescent current while maintaining regulation down to small VIN-VOUT differentials. The -40C to +125C junction temperature range and automotive-grade qualification make it suitable for under-hood and body-control modules.
Typical applications include automotive body electronics and ECU standby rails, battery-powered microcontroller sleep-mode supplies, keep-alive RAM retention in parking/telematics modules, HVAC sensor bias, and remote/keyless-entry receiver power. The 40 V rating also makes it well-suited to industrial 24 V bus systems.
When designing with this device, keep input and output capacitors close to the pins and verify the dropout margin at minimum VIN. Reverse-polarity and load-dump events must still be mitigated externally for full automotive transient compliance.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not consolidated on the manufacturer datasheet, enabling faster BOM decisions for 3.3 V always-on rails.
Drop-in alternatives for LM2936BMX-3.3/NOPB — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LM2936BMX-3.0/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LM2936BMX-5.0/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LM2936M-3.3/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LM2936BM-3.3/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LM2936HVBMX-3.3/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LP2950-33DRGR
✅ Drop-In📋 Reference alternative (not in catalog)
LM2936BMX-3.3/NOPB Maximum Ratings & Electrical Characteristics
| Manufacturer | Texas Instruments |
| Series | LM2936 |
| Function | Linear Voltage Regulator (LDO) |
| Output Configuration | Positive, Fixed |
| Number of Outputs | 1 |
| Output Voltage (Nominal) | 3.3 V |
| Output Voltage Tolerance | +/-3% over line/load/temperature |
| Output Current (Max) | 50 mA |
| Input Voltage Range (Operating) | 5.5 V to 40 V |
| Input Voltage (Transient / Absolute Max) | 60 V |
| Dropout Voltage (Typ) | 200 mV at 50 mA |
| Quiescent Current (Typ) | 20 uA |
| Reverse Voltage Protection | Yes |
| Current Limit | Internal |
| Thermal Shutdown | Yes |
| Operating Junction Temperature | -40C to +125C |
| Package | SOIC-8 (D) |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Compliant |
| Lead-Free | Yes (NOPB suffix) |
| Reel Orientation | Standard (left-justified) |
| Automotive Qualified | Yes (AEC-Q100) |
LM2936BMX-3.3/NOPB Pin Configuration
| Pin 1 | VIN — Input voltage (5.5 V to 40 V) |
| Pin 2 | VIN — Input voltage (parallel with pin 1) |
| Pin 3 | VIN — Input voltage (parallel with pin 1) |
| Pin 4 | VIN — Input voltage (parallel with pin 1) |
| Pin 5 | VOUT — Regulated 3.3 V output |
| Pin 6 | VOUT — Regulated 3.3 V output (parallel with pin 5) |
| Pin 7 | VOUT — Regulated 3.3 V output (parallel with pin 5) |
| Pin 8 | VOUT — Regulated 3.3 V output (parallel with pin 5) |
Typical Applications
LM2936BMX-3.3/NOPB is suitable for 6 applications: Automotive ECU Standby Rail, Battery-Powered Keep-Alive Memory, Remote Keyless Entry Receiver, Industrial 24 V Sensor Bias, Telematics and Asset-Tracking Standby, HVAC Thermostat Microcontroller Bias.
Automotive ECU Standby Rail
The LM2936BMX-3.3/NOPB is a strong fit for automotive ECU standby rails because it tolerates the 12 V automotive bus environment including 60 V load-dump transients and reverse-battery events that frequently damage lesser regulators. Its 20 uA quiescent current preserves battery charge during parking/standby periods of weeks to months, while its 50 mA current limit covers RTC, CAN transceiver, and wake-up logic loads. Placed directly on the unswitched battery rail with a 10 uF ceramic output cap and 0.1 uF input bypass, it provides a clean, always-on 3.3 V rail for body-control and telematics modules. AEC-Q100 qualification plus the wide -40C to +125C junction range cover under-hood and cabin temperature extremes.
Recommended
Battery-Powered Keep-Alive Memory
The LM2936BMX-3.3/NOPB's 20 uA quiescent current and 5.5 V minimum input make it ideal for keep-alive SRAM, RTC, and configuration-memory retention in battery-powered systems. With VIN tied directly to a 3.6 V to 9 V primary cell stack or lithium backup battery, the regulator holds a stable 3.3 V output down to very low input headroom thanks to the 200 mV typical dropout at 50 mA. This avoids the data-corruption risk that switching regulators introduce during deep-sleep wake transitions. The reverse-polarity protection also protects the memory rail during service or replacement events when the backup battery could be momentarily reversed.
Recommended
Remote Keyless Entry Receiver
The LM2936BMX-3.3/NOPB suits remote keyless entry (RKE) receiver modules where a coin-cell or single-AA powered standby must last several years. At 20 uA IQ, the LDO contributes negligible drain compared to the receiver's own standby current budget, while the 40 V input tolerance protects against ESD-coupled surges on the antenna feedline that can clamp back into the supply rail. The fixed 3.3 V output eliminates the need for feedback resistor calibration and reduces BOM count. Its small SOIC-8 footprint fits inside the cramped receiver housing without crowding the antenna trace.
Recommended
Industrial 24 V Sensor Bias
The LM2936BMX-3.3/NOPB operates from a 24 V industrial bus rail, providing a clean 3.3 V bias for low-power sensors in factory automation and HVAC systems. The 40 V continuous rating tolerates the worst-case 24 V +/- 20% industrial tolerance window plus inductive spikes from relay coils and contactors. Reverse-polarity protection safeguards against mis-wiring during field installation, a common source of LDO failure in industrial deployments. With 50 mA available, multiple sensor channels (temperature, pressure, humidity) can share a single regulator output without point-of-load drops.
Recommended
Telematics and Asset-Tracking Standby
The LM2936BMX-3.3/NOPB's ultra-low quiescent current and automotive-grade qualification make it well suited to telematics control units and asset trackers that must operate for months from the vehicle battery without draining it. Its 3.3 V output directly powers GSM/LTE modems in sleep mode, GPS receivers, and accelerometer-based motion detectors. The 40 V input tolerates load-dump and jump-start transients on the 12 V vehicle bus without requiring additional TVS protection at the LDO input (a TVS is still recommended for full compliance).
Recommended
HVAC Thermostat Microcontroller Bias
The LM2936BMX-3.3/NOPB provides a low-noise 3.3 V bias for the microcontroller and display logic in HVAC thermostats powered from 24 VAC rectified supplies. The 40 V input handles rectified 24 VAC peaks (around 34 V) plus transformer inrush transients, while the small quiescent current is critical for battery-backed thermostats that must retain schedule and clock data through power outages. Reverse-polarity protection simplifies installation and field service, reducing warranty returns from miswired thermostat bases.
Recommended
Recommended Products Summary
Engineering reference data for LM2936BMX-3.3/NOPB — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM2936BMX-3.0/NOPB | LM2936BMX-5.0/NOPB | LM2936M-3.3/NOPB | LM2936HVBMX-3.3/NOPB | LP2950-33DRGR |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | SOIC-8 (D) | SOIC-8 (D) - same | SOIC-8 (D) - same | SOIC-8 (D) - same | SOIC-8 (D) - same | SOIC-8 (D) - same |
| Output Voltage | 3.3 V | 3.0 V | 5.0 V | 3.3 V | 3.3 V | 3.3 V |
| Input Voltage Max | 40 V | 40 V | 40 V | 40 V | 60 V | 30 V |
| Output Current | 50 mA | 50 mA | 50 mA | 50 mA | 50 mA | 100 mA |
| Quiescent Current | 20 uA | 20 uA | 20 uA | 20 uA | 20 uA | 75 uA |
| Dropout (Typ at full load) | 200 mV | 200 mV | 200 mV | 200 mV | 200 mV | 380 mV |
| Reverse Voltage Protection | Yes | Yes | Yes | Yes | Yes | No |
| Automotive Grade | Yes (AEC-Q100) | Yes (AEC-Q100) | Yes (AEC-Q100) | Yes (AEC-Q100) | Yes (AEC-Q100) | No |
| RoHS / Pb-Free | Yes (NOPB) | Yes (NOPB) | Yes (NOPB) | Yes (NOPB) | Yes (NOPB) | Yes |
Key Differentiators
- Ultra-low 20 uA quiescent current for battery standby (vs LP2950-33DRGR)
- 40 V continuous / 60 V transient input with reverse-voltage protection (vs LP2950-33DRGR)
- AEC-Q100 automotive qualification across the SOIC-8 family (vs LM2936BMX-3.0/NOPB)
- Fixed 3.3 V output eliminates external resistor divider (vs TPS7A02 (adjustable))
Design Notes
Estimated: at VIN = 12 V, VOUT = 3.3 V, and 50 mA load, the LM2936BMX-3.3/NOPB dissipates approximately (12 - 3.3) * 0.05 = 0.435 W. With a SOIC-8 theta_JA of approximately 110 C/W on a standard 4-layer JEDEC test board, junction temperature rise is roughly 48 C above ambient. Even at the -40C to +125C rated junction range this is comfortably within limits, but at worst-case 40 V input the dissipation rises to (40 - 3.3) * 0.05 = 1.835 W, producing a 200 C temperature rise. In that scenario enforce VIN = 12 V nominal and add copper-pour heatsinking around the SOIC-8 thermal pad.
Place the 10 uF output capacitor and the 0.1 uF to 1 uF input bypass capacitor within a few millimeters of the SOIC-8 pins to minimize parasitic inductance that could destabilize the control loop. The LM2936's pins 1-4 and 5-8 are internally bonded together for thermal spreading, but routing both VIN and VOUT planes directly under the package on inner layers improves thermal performance and reduces voltage drop across the bond wires. Keep noisy traces (relay coils, switching converters) away from the FB/OUT traces.
Do not assume the SOIC-8 thermal pad is electrically isolated - it serves as the ground reference and must be soldered to a sufficiently large copper pour to meet the datasheet thermal specifications. Do not exceed the 40 V continuous or 60 V transient input rating even though the device includes internal protection; sustained over-voltage events can degrade the pass transistor. Verify the output capacitor ESR is within the datasheet stability window, especially under cold-temperature extremes when ceramic capacitor ESR rises.
Even at 50 mA output, the LDO input current is roughly equal to the load current plus 20 uA quiescent. For battery-powered designs, model the LM2936's contribution as a flat 20 uA drain on the source battery rather than a load-proportional current; over months of standby this quiescent floor often dominates total energy budget. To further reduce standby drain, gate the LDO's input with a P-MOSFET controlled by a host MCU's wake-up logic - the LM2936 lacks an enable pin, so external switching is required.
Compliance Information
RoHS and REACH compliant per TI product page; Pb-free indicated by /NOPB suffix. AEC-Q100 qualified for automotive applications. Halogen-free per TI's Green/RoHS datasheet statement.
