LP2950-3.3 Reference Tables, Pins & Specifications

Pin reference

Signal names, electrical functions and connection guidance

TO-92

Physical pin numbers3 pins

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LP2950-3.3 pin functions and connections
Signal	Type	Function & connection
OUT	Regulated rail	Fixed 3.3 V output; an external stability capacitor is required. Connection guidance Connect to the load and 10 µF output capacitor; return both to GND. TO-92 pin 1; TO-252 pin 3. Use the selected package map.
GND	Common return	Reference and bias-current return for the regulator. Connection guidance Join input return, output capacitor and load grounds locally. Pin 2 in both packages; TO-252 exposed tab is also GND.
IN	Supply input	Supply input for the protected series-pass stage. Connection guidance Use +5 V in the example and local 1 µF bypass. TO-92 pin 3; TO-252 pin 1. Maximum operating input 30 V; allow design margin.

C-grade fixed 3.3 V parts

Manufacturer-referenced values6 parameters

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Parameter	Value	Conditions / notes
Through-hole order	LP2950CZ-3.3/NOPB	TO-92 LP; straight-lead bulk footprint
SMD order	LP2950CDT-3.3/NOPB	TO-252 NDP; formed outer leads and grounded tab
TO-92 physical pins	OUT1 · GND2 · IN3	Flat face toward viewer, leads down
TO-252 physical pins	IN1 · GND2 · OUT3	Front face, leads down; tab is GND
Accuracy grade	C: ±1% initial	AC-grade values are not substituted
Extra controls	No shutdown or error-output lead	These belong to the related LP2951

Verify order suffix and lead form before fabrication.

Temperature and headroom remain essential

Manufacturer-referenced values6 parameters

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Parameter	Value	Conditions / notes
Nominal output	3.3 V	Fixed internally; no external divider
Recommended input range	2.3–30 V family range	3.3 V regulation additionally needs dropout headroom
Maximum input stress	30 V	Do not design at the stress limit
Output-current class	100 mA	Adequate voltage headroom and cooling required
Junction operating temperature	−40–125°C	Device junction, not ambient
Minimum external load	Not required for LP2950 regulation	Capacitor stability requirements still apply

A 2.3 V input cannot produce a regulated 3.3 V output.

3.3 V option; source conditions retained

Manufacturer-referenced values7 parameters

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Parameter	Value	Conditions / notes
Output at 25°C	3.267–3.333 V	Nominal 3.3 V
Output at −25 to 85°C	3.251–3.350 V	Manufacturer specified range
Output over full temperature	3.234–3.366 V	−40 to 125°C
Across 100 µA–100 mA load	3.221–3.379 V	Full-temperature limit
Temperature coefficient	50 ppm/°C typical; 150 max.	Output-voltage drift
Line regulation at 25°C	0.04% typical; 0.2% max.	Input from VOUT(nom)+1 V to 30 V
Load regulation at 25°C	0.1% typical; 0.2% max.	Load from 100 µA to 100 mA

AC-grade limits are tighter; this page deliberately uses the selected C-grade specification.

Load and temperature change both

Manufacturer-referenced values6 parameters

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Parameter	Value	Conditions / notes
Dropout at 100 µA load, 25°C	50 mV typical; 80 mV max.	150 mV maximum over full temperature
Dropout at 100 mA load, 25°C	380 mV typical; 450 mV max.	600 mV maximum over full temperature
Ground current at 100 µA load	75 µA typical; 120 µA max. at 25°C	140 µA maximum over full temperature
Ground current at 100 mA load	8 mA typical; 12 mA max. at 25°C	14 mA maximum over full temperature
Short-circuit current	160 mA typical; 200 mA max. at 25°C	220 mA maximum over full temperature; not a load rating
Full-load example headroom	At least 0.6 V for the full-temperature dropout limit	Allow additional tolerance and ripple margin

Dropout is measured when output falls 100 mV below its nominal operating value.

Capacitance alone is not enough

Manufacturer-referenced values6 parameters

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Parameter	Value	Conditions / notes
3.3 V minimum output capacitor	2.2 µF	Observe the stability-versus-ESR curves
Illustrated output capacitor	10 µF tantalum, ≥10 V	Choose ESR in the recommended stable region across temperature
ESR guidance for 2.2 µF	Approximately 0.05–5 Ω	TI application guidance; larger capacitors have their own curves
Ceramic output capacitor	May need 0.1–2 Ω series resistance	Use X5R/X7R and check effective capacitance after DC bias
Local input bypass	1 µF	Particularly for batteries or long supply wiring
Example COUT polarity	Positive to OUT; negative to GND	Check voltage rating and startup behavior

10 µF helps mitigate some startup/short-recovery overshoot. It is not a guarantee for arbitrary source impedance or capacitor ESR.

Manufacturer thermal-board conditions

Manufacturer-referenced values6 parameters

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Parameter	Value	Conditions / notes
TO-92 θJA	157.4°C/W	TI reference board; actual assembly varies
TO-252 θJA	51.3°C/W	High-K board with 12 thermal vias
TO-252 θJC(bottom)	2.2°C/W	Grounded exposed tab
Total regulator dissipation	(VIN−VOUT)×ILOAD + VIN×IGND	Ground current cannot always be ignored
Example 10 mA pass loss	(5−3.3)×0.010 = 17 mW	Add 5×IGND at the actual load
Illustrative full-load total	170 mW + 40 mW = 210 mW	5 V input, 100 mA load, typical 8 mA ground current

Thermal resistance is not an intrinsic promise of available output current.

A modest test load with clear returns

Manufacturer-referenced values6 parameters

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Parameter	Value	Conditions / notes
Supply / input bypass	5 V / 1 µF	Common GND return
Nominal output	3.3 V	Actual output follows the C-grade limits
Test load	330 Ω, ≥0.25 W	3.3/330 = 10 mA
Load dissipation	3.3²/330 = 33 mW	Nominal calculation
Output capacitor	10 µF, ≥10 V, ESR verified	Local placement between OUT and GND
Pass-stage loss	17 mW	Does not include load-dependent ground current

Calculated illustration; not measured waveforms or an executable simulation.