How do I choose the right resistance value (5K, 10K, 50K, 100K)?

Match R25 to your ADC or TEC controller input range. 10K is the de-facto default for all ATI TEC controllers. Use 50K or 100K to cut bias current in battery-powered designs; use 5K when you need lower source impedance into a noisy ADC.

What does the B value mean and which one should I choose?

B is the material constant linking resistance at two temperatures: R(T)=R25*exp(B*(1/T - 1/298.15)). B=3950K is the most common for 0 to +100C. B=3404K targets ~25C laser-diode and TEC applications. B=4066K and B=4177K are optimized for higher-temperature points such as battery hot-spot monitoring.

How does NTC accuracy compare to RTD and thermocouple?

Over 0 to +70C a 0.5% NTC beats Class-A Pt100 on both accuracy and sensitivity. Outside that window RTDs win on linearity and range. Thermocouples win only above +300C.

NTC Thermistor Selection Guide | Analog Technologies

Q: What do the T63, T65, T70 / T63S, T65S, T70S suffixes mean?

Each base part has up to three forms: bare leads (no suffix); T63/T65/T70 = same bead with factory-installed PFA insulating tubing over the leads (non-sealed at the bead); T63S/T65S/T70S = sealed at the bead for moisture protection. The number indicates the tubing size class. They share the same datasheet and electrical specifications.

Q: Radial, axial, or ring lug — how do I choose?

Radial (both leads same end) for through-hole PCB and thermal-well insertion. Axial (leads opposite ends) for inline sense between thermal pads. Ring lug to bolt directly to heat sinks and bus-bars with M2 or M3 hardware.

Q: Are ATI thermistors interchangeable with Vishay, EPCOS/TDK, or Murata?

Electrically yes — a 10K B=3950K ATI part can replace an equivalent Vishay (NTCLE), EPCOS/TDK (B57861), or Murata (NXFT) part without firmware changes. Verify bead diameter, lead pitch, and tubing length mechanically.

NTC Thermistor Selection Guide

All Analog Technologies NTC thermistors are glass encapsulated for near-zero long-term drift, a wider operating range (up to +300 °C), and smaller bead sizes than epoxy-coated equivalents. This guide consolidates 36 base part numbers covering 68 individual SKUs across radial, axial, and ring-lug form factors. They are the standard temperature-sense element behind ATI's TEC controllers, TEC modules, and laser drivers.

±0.05 °CPrecision @ 25 °C

0.55 mmMin. bead diameter

−55 to +300 °COperating range

≈ 0 DriftGlass encapsulation

68 SKUsIn this guide

Form Factor: R Radial Leaded | A Axial Leaded | L Ring Lug Assembly | Termination Suffixes (each base part may have up to 3 variants stacked in the table): base bare leads | T63 / T65 / T70 with PFA insulating tubing, non-sealed | T63S / T65S / T70S with PFA tubing, sealed at bead (moisture-proof)

Photo

Style

Part Number
(+ Variants)

Data-
sheet

Resistance
@ 25 °C

Bead Φ
(mm)

Operating
Temp. Range

Dissipation
Factor

B Value
@ 25 / 50 °C

In Stock
(per variant)

Buy Now
(per variant)

Φ0.55 mm — Radial Leaded (Glass Encapsulated)

ATH10KR55B3950K Bare leads

10K ± 1%

0.55 ± 0.2mm

−30°C to +300°C

0.25 mW/°C

3950K ± 1%

Φ0.8 mm — Radial Leaded (Glass Encapsulated)

ATH5KR8B3950K Bare leads

5K ± 1%

0.8 ± 0.15mm

−40°C to +250°C

1.2 mW/°C

3950K ± 1%

ATH10KR8B Bare leads

ATH10KR8BT65 + T65 tubing

ATH10KR8BT65S + T65S sealed

10K ± 1%

0.8 ± 0.1mm

−55°C to +250°C

0.4 mW/K

3478K / 3492K *

120

129

ATH10KR8B3404K Bare leads

ATH10KR8B3404KT65 + T65 tubing

ATH10KR8B3404KT65S + T65S sealed

10K ± 1%

0.8 ± 0.15mm

−40°C to +200°C

1.2 mW/°C

3404K ± 1%

ATH10KR8B3950K0.5% Bare leads

10K ± 0.5%

0.8 ± 0.15mm

−40°C to +250°C

1.2 mW/°C

3950K ± 1%

ATH50KR8B3950K Bare leads

50K ± 1%

0.8 ± 0.1mm

−40°C to +300°C

0.6 mW/°C

3950K ± 1%

ATH50KR8B3950K0.5% Bare leads

50K ± 0.5%

0.8 ± 0.1mm

−40°C to +300°C

0.6 mW/°C

3950K ± 1%

360

ATH100KR8 Bare leads

ATH100KR8T63 + T63 tubing

ATH100KR8T63S + T63S sealed

100K ± 1%

0.8 ± 0.1mm

−55°C to +250°C

0.4 mW/K

4066K ± 1%

127

ATH100KR8B3950K Bare leads

100K ± 1%

0.8 ± 0.2mm

−40°C to +300°C

0.6 mW/°C

3950K ± 1%

ATH100KR8B3950K0.5% Bare leads

100K ± 0.5%

0.8 ± 0.2mm

−40°C to +300°C

0.6 mW/°C

3950K ± 1%

400

ATH230KR8B4177K Bare leads

230K ± 1%

0.8 ± 0.2mm

−40°C to +300°C

0.6 mW/°C

4177K ± 1%

Φ1.0 mm — Radial Leaded (Epoxy Encapsulated)

ATH10K1R0 Epoxy encapsulated

10K ± 1%

1.0 ± 0.1mm

−55°C to +250°C

0.5 mW/K

3478K ± 1%

1825

Φ1.25 mm — Radial Leaded (Glass Encapsulated)

ATH10K1R25 Bare leads

ATH10K1R25T70 + T70 tubing

ATH10K1R25T70S + T70S sealed

10K ± 1%

1.25 ± 0.03mm

−40°C to +270°C

1.0 mW/°C

3990K ± 1%

100

203

ATH100K1R25 Bare leads

ATH100K1R25T70 + T70 tubing

ATH100K1R25T70S + T70S sealed

100K ± 1%

1.25 ± 0.2mm

−40°C to +270°C

0.9 mW/°C

3990K ± 1%

945

Φ1.3 mm — Radial Leaded (Glass Encapsulated)

ATH5K1R3B3950K Bare leads

ATH5K1R3B3950KT65 + T65 tubing

ATH5K1R3B3950KT65S + T65S sealed

5K ± 1%

1.3 ± 0.2mm

−40°C to +250°C

0.9 mW/°C

3950K ± 1%

ATH10K1R3B3950K Bare leads

ATH10K1R3B3950KT65 + T65 tubing

ATH10K1R3B3950KT65S + T65S sealed

10K ± 1%

1.3 ± 0.2mm

−40°C to +250°C

0.9 mW/°C

3950K ± 1%

ATH10K1R3B3950K0.5% Bare leads

ATH10K1R3B3950K0.5%T65 + T65 tubing

ATH10K1R3B3950K0.5%T65S + T65S sealed

10K ± 0.5%

1.3 ± 0.2mm

−40°C to +250°C

0.9 mW/°C

3950K ± 1%

ATH20K1R3B3950K Bare leads

20K ± 1%

1.3 ± 0.2mm

−40°C to +250°C

1.4 mW/°C

3950K ± 1%

ATH30K1R3B3950K Bare leads

30K ± 1%

1.3 ± 0.2mm

−40°C to +250°C

1.4 mW/°C

3950K ± 1%

805

ATH50K1R3B3950K0.5% Bare leads

50K ± 0.5%

1.3 ± 0.2mm

−55°C to +250°C

0.9 mW/°C

3950K ± 1%

ATH100K1R3B3950K Bare leads

100K ± 1%

1.3 ± 0.2mm

−40°C to +300°C

0.4 mW/°C

3950K ± 1%

ATH100K1R3B3950K0.5% Bare leads

100K ± 0.5%

1.3 ± 0.2mm

−40°C to +250°C

0.9 mW/°C

3950K ± 1%

Φ1.8 mm — Axial Leaded (Glass Encapsulated)

ATH5K1R8B3950K Axial leads

5K ± 1%

1.8 ± 0.2mm

−55°C to +250°C

2 mW/°C

3950K ± 1%

150

ATH10K1R8B3950K Axial leads

10K ± 1%

1.8 ± 0.2mm

−55°C to +250°C

2 mW/°C

3950K ± 1%

200

ATH20K1R8B3950K Axial leads

20K ± 1%

1.8 ± 0.2mm

−55°C to +250°C

2 mW/°C

3950K ± 1%

200

ATH30K1R8B3950K Axial leads

30K ± 1%

1.8 ± 0.2mm

−55°C to +250°C

2 mW/°C

3950K ± 1%

200

ATH50K1R8B3950K Axial leads

50K ± 1%

1.8 ± 0.2mm

−55°C to +250°C

2 mW/°C

3950K ± 1%

200

ATH100K1R8B3950K Axial leads

100K ± 1%

1.8 ± 0.2mm

−55°C to +250°C

2 mW/°C

3950K ± 1%

200

10K Ring Lug Assemblies — Bolt-On Mounting

ATH10KB3404KL2A Bare leads

ATH10KB3404KL2AT65 + T65 tubing

ATH10KB3404KL2AT65S + T65S sealed

10K ± 1%

lead 0.15mm

−40°C to +200°C

1.2 mW/°C

3404K ± 1%

ATH10KBL2A Bare leads

ATH10KBL2AT65 + T65 tubing

ATH10KBL2AT65S + T65S sealed

10K ± 1%

lead 0.15mm

−55°C to +250°C

—

3492K ± 1%

109

266

ATH10KL2B Bare leads

ATH10KL2BT70 + T70 tubing

ATH10KL2BT70S + T70S sealed

10K ± 1%

lead 0.2mm; ring 2.18mm

−40°C to +270°C

—

3950K ± 1%

ATH10KL2C Bare leads

ATH10KL2CT70 + T70 tubing

ATH10KL2CT70S + T70S sealed

10K ± 1%

lead 0.2mm; ring 3.02mm

−40°C to +270°C

—

3950K ± 1%

100

ATH10KL2D Bare leads

ATH10KL2DT70 + T70 tubing

ATH10KL2DT70S + T70S sealed

10K ± 1%

lead 0.2mm

−40°C to +270°C

—

3950K ± 1%

100K Ring Lug Assemblies — Bolt-On Mounting

ATH100KL2A Bare leads

ATH100KL2AT63 + T63 tubing

ATH100KL2AT63S + T63S sealed

100K ± 1%

lead 0.15mm

−55°C to +250°C

—

4066K ± 1%

ATH100KL2B Bare leads

ATH100KL2BT70 + T70 tubing

ATH100KL2BT70S + T70S sealed

100K ± 1%

lead 0.2mm; ring 2.18mm

−40°C to +270°C

—

3950K ± 1%

ATH100KL2C Bare leads

ATH100KL2CT70 + T70 tubing

ATH100KL2CT70S + T70S sealed

100K ± 1%

lead 0.2mm; ring 3.02mm

−40°C to +270°C

—

3950K ± 1%

110

How to read this table: each row is one base part. If the part has multiple termination forms (bare / +T65 / +T65S etc.), the variants are stacked vertically inside the Part Number, Stock, and Buy columns — one line per form, sharing the same datasheet and electrical specs above. Click any part number to open its product page; click the Φ or stock column header to sort within each section group.

How to Choose an NTC Thermistor by Application

Laser Diode & TEC Cooling

Sub-millimeter beads with very low thermal mass let you stabilize laser-diode and pump-diode temperatures to better than ±0.005 °C with a precision TEC controller. The 0.55 mm and 0.8 mm radials are the workhorse for butterfly packages, TO-can mounts, and fiber-optic transceivers.

Fast response (~1 s in still air for Φ0.55)
Long-term drift ≤ 0.1 °C/year at 25 °C
Pairs with all ATI TEC controllers out of the box

Top picks: ATH10KR55B3950K ATH10KR8B ATH10K1R3B3950K

Medical, Wearable & Battery Pack

Glass-encapsulated, hermetically sealed beads survive autoclave, ETO, and gamma sterilization. The Φ0.8 mm and Φ1.25 mm radials provide 0.5 % absolute-tolerance variants for patient monitoring and Li-ion pack thermistors where end-of-line calibration is expensive.

0.5 % tolerance variants available
RoHS & REACH compliant glass body
PFA tubing options (T65, T65S, T70, T70S)

Top picks: ATH10KR8B3950K 0.5% ATH10K1R25T70S ATH100K1R25T70S

Industrial, HVAC & Power

Larger Φ1.3 mm and Φ1.8 mm axial beads handle higher dissipation, hold their calibration across −55 to +250 °C, and self-heat predictably. Ring-lug assemblies bolt directly to heat sinks, motor windings, and battery bus-bars without an extra thermal-paste step.

10K and 100K with M2 / M3 ring-lug options
Operating range up to +300 °C (Φ0.8 mm glass)
PFA-tubed or bare leads

Top picks: ATH10K1R8B3950K ATH10KBL2A ATH100KL2A

NTC Thermistor vs. RTD vs. Thermocouple — Quick Comparison

Parameter	NTC Thermistor (this page)	Pt100 / Pt1000 RTD	Type-K / T Thermocouple
Typical accuracy	±0.05 to ±0.1 °C	±0.1 to ±0.3 °C	±1 to ±2.5 °C
Useful range	−55 to +300 °C	−200 to +850 °C	−200 to +1700 °C
Sensitivity	~−4 %/°C (very high)	~+0.385 %/°C	~40 µV/°C
Response time (small bead)	0.3 – 2 s in still air	3 – 10 s	1 – 5 s
Cost	$	$$ – $$$	$ – $$
Linearity	Highly non-linear (Steinhart–Hart)	Near-linear	Near-linear (with CJC)
Best for	Precision local sensing, laser/TEC, medical, battery	Process control, wide range	Furnaces, exhaust, extreme heat

Parameter

NTC Thermistor (this page)

Pt100 / Pt1000 RTD

Type-K / T Thermocouple

Typical accuracy

±0.05 to ±0.1 °C

±0.1 to ±0.3 °C

±1 to ±2.5 °C

Useful range

−55 to +300 °C

−200 to +850 °C

−200 to +1700 °C

Sensitivity

~−4 %/°C (very high)

~+0.385 %/°C

~40 µV/°C

Response time (small bead)

0.3 – 2 s in still air

3 – 10 s

1 – 5 s

Cost

$$ – $$$

$ – $$

Linearity

Highly non-linear (Steinhart–Hart)

Near-linear

Near-linear (with CJC)

Best for

Precision local sensing, laser/TEC, medical, battery

Process control, wide range

Furnaces, exhaust, extreme heat

Frequently Asked Questions

What do the T63, T65, T70 / T63S, T65S, T70S suffixes mean? Why are they stacked?

Each base part number (e.g. ATH10KR8B) has up to three physical forms sharing the same electrical specs: bare leads (no suffix); T63 / T65 / T70 = PFA insulating tubing factory-fitted over the leads, non-sealed at the bead; T63S / T65S / T70S = the same tubing but sealed at the bead for moisture protection or sterilization. The digits indicate the tubing size class. Because the electrical spec and the datasheet are identical across all three forms, this guide groups them in one row — you'll see each variant's stock count and Buy Now buttons stacked vertically in the right-hand columns.

How do I pick the right resistance value (5K, 10K, 50K, 100K)?

Match the thermistor's R₂₅ to the input range of your ADC or controller. 10 kΩ is the de-facto default and is supported by every ATI TEC controller and most microcontroller reference designs. Use 50 k or 100 k when bias current must be sub-microamp (battery-powered sensors, self-heating-sensitive measurements). Use 5 k when you need lower source impedance into a noisy ADC or to reduce cable pickup.

What does the B value (B25/85, B25/100) mean and which one should I choose?

B is the material constant linking resistance at two temperatures: R(T) = R₂₅·exp(B·(1/T − 1/298.15)). A higher B means a steeper resistance change per °C — better resolution at the cost of dynamic range. B = 3950 K is the common choice for 0 to +100 °C work; 3404 K targets ~25 °C laser-diode and TEC applications; 4066 K and 4177 K are optimized for higher-temperature points such as battery-pack hot-spot monitoring.

Radial, axial, or ring lug — how do I choose the form factor?

Radial (both leads exiting the same end) is the standard for through-hole PCB mounting and for inserting into a thermal well next to a laser diode or TEC. Axial (leads on opposite ends) is preferred when the bead must sit between two thermal pads or when you wick-solder it inline with a sense wire. Ring-lug assemblies have an M2 or M3 brass lug factory-attached to the leads — bolt them directly to a heat sink, motor housing, or battery bus-bar.

Are ATI thermistors interchangeable with Vishay, EPCOS/TDK, or Murata NTCs?

Electrically, yes — an ATH10KR8B3950K can replace a 10 kΩ / B = 3950 K part from Vishay (NTCLE), EPCOS/TDK (B57861), or Murata (NXFT) without firmware changes, because the resistance-vs-temperature table is industry-standard. Mechanically, double-check the bead diameter, lead pitch, and tubing length against your footprint. ATI's 0.5 %-tolerance variants are typically 1–2 grades tighter than the equivalent catalog part.

How does NTC accuracy compare to an RTD or thermocouple?

Over a 0 to +70 °C window, a 0.5 %-tolerance NTC beats a Class-A Pt100 RTD on both accuracy (±0.05 °C vs ±0.15 °C) and sensitivity (4 %/°C vs 0.385 %/°C). Outside that window the RTD's linearity and wider range win. Thermocouples are last on accuracy and first on temperature range — choose one only when the sense point exceeds +300 °C.