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Texas Instruments SN74LS90N — Discrete Semiconductors

SN74LS90N Decade Counter, 42 MHz, 14-DIP – TI 74LS

MPNSN74LS90N
End of Life

Texas Instruments 74LS series, SN74LS90N, IC DECADE COUNTER 14-DIP. Asynchronous reset, negative-edge triggered, 42 MHz count rate, 4.75 V–5.25 V supply, 0°C to 70°C, 14-PDIP.

$2.88Ref. price · indicative, final on quote
Packaging14-DIP (0.300", 7.62mm)
RoHSROHS3 Compliant
Series74LS
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

SN74LS90N specifications
ParameterValue
Series74LS
Logic typeCounter, Decade
Trigger typeNegative Edge
MountingThrough Hole
Supply voltage4.75 V ~ 5.25 V
Operating temperature0°C ~ 70°C
ResetAsynchronous
PackageTube
DirectionUp
Count rate42 MHz
Case14-DIP (0.300\", 7.62mm)
Number of elements1
Number of bits per element4

Product details

Asynchronous reset — clears without waiting for a clock edge

The reset is asynchronous, meaning the counter clears immediately when the reset line is asserted — no need to wait for the next clock edge. That's useful for power-on reset circuits or emergency clears in a divider chain, but it also means the reset input must be free of glitches or properly debounced in noisy environments. The part is a single-element, 4-bit counter; one package gives you one decade stage.

Commercial temperature grade — indoor, controlled environments only

It belongs in benchtop instruments, office equipment, or appliance control boards.

TI still manufactures this part, so there is no last-time-buy clock ticking.

Frequently asked questions

How fast can the SN74LS90N count?

The maximum count rate is 42 MHz. It will reliably divide or count clock signals up to that frequency.

What is the pinout of SN74LS90N?

The SN74LS90N comes in a 14-pin PDIP. The standard 74LS90 pinout includes clock A (pin 14), clock B (pin 1), reset inputs R0(1) and R0(2) (pins 2, 3), reset inputs R9(1) and R9(2) (pins 6, 7), and outputs QA–QD (pins 8–11). Consult the TI datasheet for the full connection diagram.