BETASelected reference2.5 V nominal
A-grade 2.5 V shunt reference
LM4040 Specifications
Review LM4040 electrical specifications, operating conditions and package details.
Package view
Key specifications
A series resistor supplies both the external load and the shunt reference. If the load takes too much current, the reference falls out of regulation.
Initial A-grade accuracy±0.1 % at 25°C, 100 µA
Full-range minimum current65 µA guaranteed requirement
Industrial ambient range−40–85 °C
Package details
LM4040AIZ-2.5/NOPB · TO-92
| Property | Details |
|---|---|
| Manufacturer | Texas Instruments |
| Part number | LM4040AIZ-2.5/NOPB |
| Package | TO-92 |
| Connections | 3 pins |
| Mounting | Through-hole |
| Lead pitch | 1.27 mm · straight leads |
| Package code | LP |
| Thermal reference | θJA 166°C/W under TI reference conditions; mounting dependent |
Selected parts and package maps
A-grade 2.5 V industrial devices
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Through-hole order | LM4040AIZ-2.5/NOPB | TO-92 LP; straight leads |
| SMD order | LM4040AIM3-2.5/NOPB | SOT-23 DBZ; body code R2A |
| TO-92 front-view pins | 1 DNC; 2 cathode; 3 anode | Flat face toward viewer |
| SOT-23 top-view pins | 1 cathode; 2 anode; 3 DNC | DNC must float or connect to anode |
| Active terminals | Cathode and anode | No adjustment or enable input |
| Selected accuracy / temperature | A grade / I range | Not C, D, E or automotive limits |
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The TO-92 manufacturer drawing is a bottom view; the page labels its viewing orientation.
Reference voltage and temperature
IR=100 µA unless noted
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Nominal breakdown voltage | 2.5 V | Reverse operation |
| Initial A-grade error | ±2.5 mV maximum | ±0.1%; 25°C |
| Full-temperature A-grade error | ±19 mV maximum | −40 to 85°C; 2.481–2.519 V |
| Average temperature coefficient | ±100 ppm/°C maximum | Full specified temperature span |
| Typical temperature coefficient | ±15 ppm/°C | 100 µA or 1 mA |
| Typical coefficient at 10 mA | ±20 ppm/°C | Characterization, not a maximum |
No specifications match. Try a parameter name or a unit.
Initial accuracy is not the complete overtemperature error.
Current range and impedance
Preserve current for both load and reference
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Minimum operating current at 25°C | 45 µA typical; 60 µA maximum | Use the maximum requirement for design |
| Minimum over full temperature | 65 µA maximum | Reference current after subtracting load |
| Maximum operating reverse current | 15 mA | Respect package heating |
| Reverse-current absolute maximum | 20 mA | Stress only |
| Forward-current absolute maximum | 10 mA | Not normal reference operation |
| Dynamic impedance | 0.3 Ω typical; 0.8 Ω maximum | IR1 mA, 120 Hz, AC current 10% of IR |
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A shunt reference draws the current left over by the load.
Noise and current regulation
Source test conditions retained
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Voltage change: IRmin to 1 mA | 0.3 mV typ.; 0.8 mV max. at 25°C | 1 mV maximum over temperature |
| Voltage change: 1–15 mA | 2.5 mV typ.; 6 mV max. at 25°C | 8 mV maximum over temperature |
| Wideband noise | 35 µV RMS typical | IR100 µA, 10 Hz–10 kHz |
| Long-term stability | 120 ppm typical | 1000 h; 25°C±0.1°C; IR100 µA |
| Thermal hysteresis | 0.08% typical | Manufacturer −40 to125°C cycle test |
| External stabilization capacitor | Not required | Capacitive loads tolerated; system filtering may still help |
No specifications match. Try a parameter name or a unit.
Typical noise and aging figures are not guaranteed maximum errors.
A 5 V to 2.5 V reference node
Calculated example, not a power regulator
Manufacturer specifications 7 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Feed resistor | 2.49 kΩ, 1%, ≥0.25 W | From 5 V source to cathode |
| Test load | 10 kΩ, 1%, ≥0.25 W | From cathode to anode/ground |
| Nominal feed current | (5−2.5)/2490=1.004 mA | Supplies load plus reference |
| Nominal load current | 2.5/10000=250 µA | 0.625 mW load power |
| Nominal reference current | 754 µA | 1.004 mA−250 µA |
| Nominal reference dissipation | 2.5×0.754 mA≈1.89 mW | Feed resistor dissipates approximately 2.51 mW |
| Worst-case low-source budget | At 4.75 V, VR2.519 V, RS+1%, RL−1%: IR≈633 µA | Still above 65 µA before additional system loads |
No specifications match. Try a parameter name or a unit.
A high-impedance measurement input is preferable to a heavy load.
Temperature and physical installation
Board-dependent thermal metrics
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Ambient operating range | −40 to85°C | Selected industrial temperature grade |
| Maximum junction temperature | 125°C | Use the operating and power-derating guidance |
| TO-92 θJA | 166°C/W | TI thermal-information reference board |
| SOT-23 θJA | 291.9°C/W | TI thermal-information reference board |
| Reference loss at 15 mA | 37.5 mW nominal | 2.5 V×15 mA |
| Layout | Short reference and return paths | Keep load-return drops out of sensitive measurements |
No specifications match. Try a parameter name or a unit.
Thermal resistance depends on assembly; older lead-length estimates are not interchangeable with reference-board metrics.
Connections by function
Select a pin for its function, connection guidance and electrical notes.