Answer: The LM1117MP-ADJ/NOPB is TI’s adjustable 800 mA LDO in a 4-pin SOT-223 (DCY), rated for 0 to 125 °C junction temperature. It holds 1.25 V from OUT to ADJ, drops out at 1.3 V max at 800 mA and wants a ≥10 µF tantalum output capacitor with 0.3–22 Ω ESR. For sub-zero use, order the LM1117IMP-ADJ/NOPB (−40 °C). (TI SNOS412Q §7, §9.2; Package Option Addendum.)
Key specifications
| Parameter | Value | Condition | Source |
|---|---|---|---|
| Reference voltage VREF | 1.238 / 1.25 / 1.262 V | IOUT = 10 mA, VIN − VOUT = 2 V, TJ = 25 °C | §7.5 Electrical Characteristics, p.5 |
| VREF, full range | 1.225 – 1.27 V | 10–800 mA, 1.4 V ≤ VIN − VOUT ≤ 10 V, TJ 0–125 °C | §7.5, p.5 |
| Dropout voltage | 1.2 typ / 1.3 max V | IOUT = 800 mA (max over 0–125 °C); output 100 mV below nominal | §7.5, p.6, note 4 |
| Current limit | 800 min / 1200 typ / 1500 max mA | VIN − VOUT = 5 V, TJ = 25 °C | §7.5, p.6 |
| Minimum load current (ADJ) | 1.7 typ / 5 max mA | VIN = 15 V; max over 0–125 °C | §7.5, p.6 |
| Line regulation (ADJ) | 0.035 % typ / 0.2 % max | IOUT = 10 mA, 1.5 V ≤ VIN − VOUT ≤ 13.75 V | §7.5, p.5 |
| Load regulation (ADJ) | 0.2 % typ / 0.4 % max | VIN − VOUT = 3 V, 10–800 mA | §7.5, p.5 |
| Adjust pin current | 60 typ / 120 max µA | Max over 0–125 °C | §7.5, p.6 |
| Ripple rejection | 75 typ / 60 min dB | 120 Hz, VIN − VOUT = 3 V, 1 Vpp ripple | §7.5, p.6 |
| Input voltage | 15 V recommended max; 20 V absolute max | VIN to GND | §7.3 and §7.1, p.4 |
| Junction temperature (LM1117) | 0 to 125 °C | Recommended operating; LM1117I is −40 to 125 °C | §7.3, p.4 |
| RθJA / RθJC(top) / RθJB, SOT-223 (DCY) | 61.6 / 42.5 / 10.4 °C/W | JEDEC board model | §7.4 Thermal Information, p.4 |
| Output capacitor | ≥ 10 µF tantalum, ESR 0.3–22 Ω; 22 µF tantalum when CADJ is used | — | §9.2.2.1.3, p.15 |
| Orderable / marking | LM1117MP-ADJ/NOPB, Active, 1000-unit small reel, marking N03A | SOT-223 (DCY) 4 pins, 0–125 °C | Package Option Addendum |
Pinout (SOT-223, DCY)
| Pin | Name | Note |
|---|---|---|
| 1 | ADJ/GND | Adjust input on this part |
| 2 | VOUT | |
| 3 | VIN | |
| 4 (tab) | VOUT | TI counts the tab as pin 4 |
Source: Table 6-1, p.3. TI lists VOUT as “2, 4” for SOT-223, so the tab is officially part of the output net. Do not tie it to ground copper.
The capacitor window is the main design constraint
TI asks for at least 10 µF tantalum on the output, with ESR between 0.3 Ω and 22 Ω (§9.2.2.1.3). That lower bound matters:
- A modern X5R/X7R ceramic has an ESR of a few milliohms, well below 0.3 Ω. A bare MLCC output is outside TI’s stated window.
- If you must use ceramics, add series resistance to land inside 0.3–22 Ω, or put a small tantalum or aluminium-polymer part in parallel, and check the transient response on the bench.
- Once ADJ is bypassed with CADJ, TI increases the requirement to 22 µF tantalum on the output (§9.2.2.1.3).
- On the input, TI suggests 10 µF tantalum “for almost all applications” (§9.2.2.1.1).
Design notes
- ADJ bypass sizing. The CADJ impedance at the ripple frequency must be below R1: 1/(2π f CADJ) < R1. TI’s example is R1 = 124 Ω at 120 Hz → CADJ > 11 µF (§9.2.2.1.2, eq. 1). At 100 Hz (50 Hz mains, full-wave), the same R1 needs 1/(2π × 100 × 124) = 12.8 µF or more.
- Light-load headroom. The adjustable LM1117 needs only 5 mA worst case to stay in regulation (§7.5), half the 10 mA that the AMS1117 specifies. With R1 = 240 Ω (5.2 mA) the divider alone just covers it; R1 = 124 Ω (10 mA) leaves margin.
- Remote sensing. Tie R1 straight to the OUT pin and return R2 at the load’s ground (§8.3.1). TI’s example: R1 = 125 Ω at the load with 0.05 Ω of line resistance makes the line look four times worse for a 5 V output.
- Thermal. 61.6 °C/W is a JEDEC-board figure (§7.4). From 5 V to 3.3 V at 0.5 A (0.85 W), the rise is about 52 °C. On a small board, expect a higher number.
- Protection diode. Not needed normally; the internal diode survives 10–20 A microsecond surges. TI recommends an external output-to-input diode only with ≥1000 µF on the output and an input that can be shorted instantly (§8.4.1).
Pitfalls specific to LM1117MP-ADJ
- Using the MP version in cold environments. LM1117 (no “I”) is specified for TJ 0–125 °C only (§7.3). Below 0 °C, order LM1117IMP-ADJ/NOPB (marking N03B).
- A ceramic-only output. It sits below the 0.3 Ω ESR floor; see the window above.
- Comparing dropout figures across vendors 1:1. TI defines dropout as the point where the output has fallen 100 mV (note 4), while AMS uses a 1 % change. The 1.3 V numbers are not measured the same way.
- Reading “800 mA” as the current limit. 800 mA is the minimum current limit at 25 °C and 5 V of headroom (§7.5). The typical is 1.2 A, so the part can deliver more than its rating into a fault.
- Driving it at 20 V. 20 V is the absolute maximum; the recommended limit is 15 V (§7.3).
Part numbers (information only)
| Orderable | Package / quantity | TJ | Marking |
|---|---|---|---|
| LM1117MP-ADJ/NOPB | SOT-223 (DCY), 1000 small T&R | 0 to 125 °C | N03A |
| LM1117MPX-ADJ/NOPB | SOT-223 (DCY), 2000 large T&R | 0 to 125 °C | N03A |
| LM1117IMP-ADJ/NOPB | SOT-223 (DCY), 1000 small T&R | −40 to 125 °C | N03B |
Source: Package Option Addendum, SNOS412Q. All three are listed as Active. Status at the time of reading; check TI for current status.
FAQ
- Can I use a ceramic output capacitor with the LM1117? Not on its own. TI requires an output capacitor ESR between 0.3 Ω and 22 Ω (§9.2.2.1.3), and ceramics are far below 0.3 Ω.
- What is the difference between LM1117MP-ADJ and LM1117IMP-ADJ? Temperature: MP is rated for TJ 0–125 °C, IMP for −40 to 125 °C (§7.3). The markings are N03A and N03B.
- What does /NOPB mean? It is TI’s lead-free (Pb-free) suffix; the addendum lists these parts with SN lead finish and RoHS “Yes”.
- What is the minimum load for the adjustable LM1117? 1.7 mA typical, 5 mA maximum (§7.5).
- Is the LM1117 a drop-in for the AMS1117? Same SOT-223 pin order, but check the capacitor ESR window, temperature grade and 800 mA rating. See the equivalents page.
Related (internal links)
- AMS1117 equivalents comparison
- AMS1117-ADJ (SOT-223)
- LD1117S33TR
- CJT1117B-ADJ
- AMS1117-ADJ resistor calculator (same 1.25 V reference)
- Capacitor types
- Linear voltage regulators
Sources (retrieved 2026-10-26)
- Texas Instruments, LM1117 800-mA Low-Dropout Linear Regulator, SNOS412Q (revised January 2023): https://www.ti.com/lit/ds/symlink/lm1117.pdf — including the Package Option Addendum at the end of the PDF.
Disclaimer
Values are copied from TI SNOS412Q, read on 26 Oct 2026; worked numbers are our arithmetic. TI marks the Application and Implementation section as not part of the component specification. Verify against the current datasheet and TI product page before production.
Reviewed by: Jasper · Updated: 2026-10-26