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Datasheet 3D Model

ST312RAM Series

Chip Inductors for Critical Applications

ST312RAM Series features ferrite construction for high current handling.
  • Higher inductance values than ceramic 0603 inductors.
  • Heavier gauge wire for low DCR.
  • Inductance values from 15 nH to 10 μH.
  • Matte tin over nickel over silver-platinum-glass frit terminations.

Looking for the commercial version of this part? See Coilcraft 0603AF Series
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Specifications

Electrical specifications at 25°C.

Part number 1 Inductance (nH) 2
(Tolerance: ±5%) 		Impedance typ (Ω)
@ 100 MHz 		Q min 3 SRF min (MHz) 4 DCR max (Ω) 5 Imax (A) Color code
ST312RAM15NJRZ 15 @ 7.9 MHz 10.0 10 @ 7.9 MHz 2800 0.023 1.2 Yellow
ST312RAM33NJRZ 33 @ 7.9 MHz 19.0 10 @ 7.9 MHz 1840 0.028 1.2 Red
ST312RAM39NJRZ 39 @ 7.9 MHz 23.0 13 @ 7.9 MHz 2200 0.115 0.60 Green
ST312RAM47NJRZ 47 @ 7.9 MHz 42.0 13 @ 7.9 MHz 2250 0.052 1.1 White
ST312RAM50NJRZ 50 @ 7.9 MHz 31.0 15 @ 7.9 MHz 1830 0.052 1.1 Violet
ST312RAM68NJRZ 68 @ 7.9 MHz 39.0 15 @ 7.9 MHz 1500 0.150 0.50 Gray
ST312RAM72NJRZ 72 @ 7.9 MHz 60.0 15 @ 7.9 MHz 1800 0.065 1.0 Blue
ST312RAM85NJRZ 85 @ 7.9 MHz 51.0 15 @ 7.9 MHz 1600 0.065 1.0 Brown
ST312RAM111JRZ 110 @ 7.9 MHz 70.0 12 @ 7.9 MHz 980 0.060 1.1 Red
ST312RAM121JRZ 120 @ 7.9 MHz 76.0 12 @ 7.9 MHz 920 0.089 0.90 Black
ST312RAM151JRZ 150 @ 7.9 MHz 89.0 15 @ 7.9 MHz 1050 0.093 0.85 Yellow
ST312RAM201JRZ 200 @ 7.9 MHz 120 15 @ 7.9 MHz 880 0.115 0.80 Green
ST312RAM241JRZ 240 @ 7.9 MHz 140 12 @ 7.9 MHz 720 0.120 0.70 Violet
ST312RAM271JRZ 270 @ 7.9 MHz 173 12 @ 7.9 MHz 600 0.220 0.55 Brown
ST312RAM361JRZ 360 @ 7.9 MHz 210 15 @ 7.9 MHz 700 0.210 0.55 Blue
ST312RAM391JRZ 390 @ 7.9 MHz 240 15 @ 7.9 MHz 700 0.300 0.50 Black
ST312RAM421JRZ 420 @ 7.9 MHz 250 11 @ 7.9 MHz 685 0.330 0.50 Red
ST312RAM471JRZ 470 @ 7.9 MHz 306 12 @ 7.9 MHz 460 0.370 0.48 Orange
ST312RAM561JRZ 560 @ 7.9 MHz 371 12 @ 7.9 MHz 400 0.490 0.42 Blue
ST312RAM601JRZ 600 @ 7.9 MHz 372 16 @ 7.9 MHz 540 0.552 0.36 Blue
ST312RAM681JRZ 680 @ 7.9 MHz 420 12 @ 7.9 MHz 420 0.460 0.36 Orange
ST312RAM821JRZ 820 @ 7.9 MHz 507 12 @ 7.9 MHz 260 0.580 0.34 Green
ST312RAM102JRZ 1000 @ 7.9 MHz 663 13 @ 7.9 MHz 320 0.840 0.32 Black
ST312RAM152JRZ 1500 @ 7.9 MHz 944 17 @ 7.9 MHz 330 1.300 0.22 Orange
ST312RAM222JRZ 2200 @ 7.9 MHz 5220 12 @ 2.5 MHz 65 1.100 0.25 Red
ST312RAM472JRZ 4700 @ 7.9 MHz 2100 12 @ 7.9 MHz 45 1.500 0.22 Yellow
ST312RAM103JRZ 10000 @ 2.5 MHz 1400 9 @ 2.5 MHz 30 4.500 0.10 Gray
Notes
  1. When ordering, please specify termination and screening codes: e.g. ST312RAM103JRZ.
  2. Inductance measured using a Coilcraft SMD-A fixture in an Agilent/ HP 4286A impedance analyzer or equivalent with Coilcraft-provided correlation pieces.
  3. Q measured at the same frequency as inductance using an Agilent/ HP 4291A with an Agilent/HP 16197A test fixture or equivalents.
  4. SRF measured using an Agilent/HP 8753ES network analyzer or equivalent and a Coilcraft SMD-D test fixture.
  5. DCR measured on a Keithley 580 micro-ohmmeter or equivalent and a Coilcraft CCF1010 test fixture.

Termination:

  • R = Matte tin over nickel over silver-platinum-glass frit.
  • Q = Tin-silver-copper (95.5/4/0.5) over tin over nickel over silver-platinum-glass frit. (Special order, added cost)
  • P = Tin-lead (63/37) over tin over nickel over silver-platinum-glass frit. (Special order, added cost)

Screening:

  • Z = Unscreened
  • H = Coilcraft CP-SA-10001 Group A
  • Screening performed to the document’s latest revision.
  • Lot qualification (Group B) available.
  • Custom testing also available.
  • Country of origin restrictions available; prefix options G or F.
Environmental
Ambient temperature range:
–40°C to +85°C with Irms current.
Storage temperature range:
Component: –55°C to +100°C.
Packaging: –55°C to +80°C.
Maximum part temperature:
+100°C (ambient + temp rise).
Failures in Time (FIT) / Mean Time Between Failures (MTBF):
See FIT/MTBF Calculations

Performance curves

L vs Frequency

L vs Frequency

Q vs Frequency

Q vs Frequency

Z vs Frequency

Z vs Frequency

Physical characteristics

st312ramd.gif
 
A max B max C max D ref E F G H I J  
0.071 0.044 0.036 0.015 0.030 0.013 0.034 0.040 0.025 0.025 inches
1,80 1,12 0,91 0,38 0,76 0,33 0,86 1,02 0,64 0,64 mm
Note: Dimensions are before optional solder application. For maximum overall dimensions including solder, add 0.0025 in / 0,064 mm to B and 0.006 in / 0,15 mm to A and C.

General specification

Core Material:
Ferrite
Weight:
4.3 – 5.7 mg
Packaging:
2000 per 7′′ reel; Paper tape: 8 mm wide, 1.0 mm thick, 4 mm pocket spacing.
Temperature coefficient of inductance:
+50 to +300 ppm/°C.

Soldering/Washing

Moisture Sensitivity Level (MSL):
1 (unlimited floor life at <30°C / 85% relative humidity).
Resistance to soldering heat:
Max three 40 second reflows at +260°C, parts cooled to room temperature between cycles.
Refer to Soldering Coilcraft Components before soldering.