Resistor SMD codes and designators

# Resistor SMD codes

## The 3-digit code

Standard-tolerance SMD resistors are marked with a simple 3-digit code. The first two numbers will indicate the significant digits, and the third will be the multiplier, telling you the power of ten to which the two significant digits must be multiplied (or how many zeros to add). Resistances of less than 10 ohms do not have a multiplier, the letter ‘R’ is used instead to indicate the position of the decimal point.

### 3-digit code examples:

220 = 22 × 100 (1) = 22Ω (not 220Ω!)
471 = 47 × 101 (10) = 470Ω
102 = 10 × 102 (100) = 1000Ω or 1kΩ
3R3 = 3.3Ω

## EIA-96

Recently, a new coding system (EIA-96) has appeared on 1% SMD resistors. It consists of a three character code: the first 2 numbers will tell us the 3 significant digits of the resistor value (see the lookup table below) and the third marking (a letter) will indicate the multiplier.

01Y = 100 × 0.01 = 1Ω
68X = 499 × 0.1 = 49.9Ω
76X = 604 × 0.1 = 60.4Ω
01A = 100 × 1 = 100Ω
29B = 196 × 10 = 1.96kΩ
01C = 100 × 100 = 10kΩ

Decode tables:

 Code Value Code Value Code Value Code Value 01 100 25 178 49 316 73 562 02 102 26 182 50 324 74 576 03 105 27 187 51 332 75 590 04 107 28 191 52 340 76 604 05 110 29 196 53 348 77 619 06 113 30 200 54 357 78 634 07 115 31 205 55 365 79 649 08 118 32 210 56 374 80 665 09 121 33 215 57 383 81 681 10 124 34 221 58 392 82 698 11 127 35 226 59 402 83 715 12 130 36 232 60 412 84 732 13 133 37 237 61 422 85 750 14 137 38 243 62 432 86 768 15 140 39 249 63 442 87 787 16 143 40 255 64 453 88 806 17 147 41 261 65 464 89 825 18 150 42 267 66 475 90 845 19 154 43 274 67 487 91 866 20 158 44 280 68 499 92 887 21 162 45 287 69 511 93 909 22 165 46 294 70 523 94 931 23 169 47 301 71 536 95 953 24 174 48 309 72 549 96 976
 Code Multiplier Z 0.001 Y or R 0.01 X or S 0.1 A 1 B or H 10 C 100 D 1000 E 10000 F 100000

## Power rating

To find out the approximative power rating of your SMD resistor, measure its length and width. A few commonly used package dimensions with the corresponding typical power ratings are presented in the table below. Use this table as a guide only, and always consult the component’s datasheet for the exact value.

 Package Size in inches (L×W) Size in mm (L×W) Power rating 0201 0.024” × 0.012” 0.6 mm × 0.3 mm 1/20W 0402 0.04” × 0.02” 1.0 mm × 0.5 mm 1/16W 0603 0.063” × 0.031” 1.6 mm × 0.8 mm 1/16W 0805 0.08” × 0.05” 2.0 mm × 1.25 mm 1/10W 1206 0.126” × 0.063” 3.2 mm × 1.6 mm 1/8W 1210 0.126” × 0.10” 3.2 mm × 2.5 mm 1/4W 1812 0.18” × 0.12” 4.5 mm x 3.2 mm 1/3W 2010 0.20” × 0.10” 5.0 mm × 2.5 mm 1/2W 2512 0.25” × 0.12” 6.35 mm × 3.2 mm 1W

## Temperature coefficient

GLOBAL TC CODE HISTORICAL TC CODE TEMPERATURE COEFFICIENT
Z T-16 5 ppm/°C
Y T-13 10 ppm/°C
X T-10 15 ppm/°C
E T-9 25 ppm/°C
H T-2 50 ppm/°C
K T-1 100 ppm/°C
L T-0 150 ppm/°C
N T-00 200 ppm/°C
Created: March 31, 2015, 9:21 a.m.
Modified: Jan. 23, 2017, 2:59 a.m.