SMD code N91
Marking codes are not standardised, and the same code is reused by unrelated makers for unrelated parts. Below is every part in our tables printed with it, and any printed with a code that is easy to misread as it, from the manufacturers' own marking tables and published code lists.
N91 on a chip capacitor
910 pF
910 pF capacitor
The n is both the decimal point and the unit: 910 pF.
Check it with a meter
Lift one end and measure it on a capacitance range. A good one reads close to 910 pF. In circuit the meter also sees everything connected across it, so the reading means little until it is out. A failed one usually reads near 0 Ω, or a steady low resistance, on the ohms range, often from a crack. On the board a shorted capacitor shorts its whole rail. A failed reading does not change what to fit: the marking still says 910 pF.
On a transistor or diode body (SOT-23, SOT-343, SOT-23-5), N91 is a part code instead. Those parts are listed below.
5 parts are printed N91
Not sure which one you have?
Answer up to 4 quick questions and these 5 parts are ranked, with a meter test that settles it. It works on a dead part too.
HE61CN3901MRSOT-233 pins, Heermicr SemicconductorSOT-233 pinsHeermicr Semicconductor
- What it is
- Voltage supervisor
- Maker
- Heermicr Semicconductor
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 3.9V±1%, +Reset ODO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
HE7039MNM5R1SOT-23-55 pins, Heermicr SemicconductorSOT-23-55 pinsHeermicr Semicconductor
- What it is
- Voltage supervisor
- Maker
- Heermicr Semicconductor
- Package
- SOT-23-5
- Pins
- 5
- Details
- Voltage detector IC: 3.9V±1%, +Reset ODO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
HE7039MNNR1SOT-233 pins, Heermicr SemicconductorSOT-233 pinsHeermicr Semicconductor
- What it is
- Voltage supervisor
- Maker
- Heermicr Semicconductor
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 3.9V±1%, +Reset ODO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
HE7039MNPR1SOT-893 pins, Heermicr SemicconductorSOT-893 pinsHeermicr Semicconductor
- What it is
- Voltage supervisor
- Maker
- Heermicr Semicconductor
- Package
- SOT-89
- Pins
- 3
- Details
- Voltage detector IC: 3.9V±1%, +Reset ODO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
SO642SOT-233 pins, SGS-Thomson MicroelectronicsSOT-233 pinsSGS-Thomson Microelectronics
- What it is
- Not recorded
- Maker
- SGS-Thomson Microelectronics
- Package
- SOT-23
- Pins
- 3
- Details
- npn Vce 300V
- Source
- Published code list
Is it dead? The meter test is below: This part.
Is it dead? One meter test per kind
Parts of the same kind are tested the same way, so each test is here once. Each part above points to its own.
Integrated circuit
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
- A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
- Supply present, output stuck: failed, or its load has.
- On the board:
- A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
- Compare:
- The surest reference is the same IC on a working board, measured pin by pin.
- Watch for:
- Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
This part
Diode range and ohms range, part lifted.
Working, it reads
Depends on what it is. The datasheet, or an identical part, says.
Dead, it reads
- Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
- Open between every pair of pins: failed open, or a part that reads open when working.
- On the board
- this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
- Compare:
- If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Printed with a code easy to misread as N91
One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.
Did you find your part?
Open this in the search to correct a character or try another package.