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Contents

README

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CD74HC4538NSR

Texas Instruments · Monostable Multivibrators · SO-16-208mil

CD74HC4538NSR from Texas Instruments, in a SO-16-208mil. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 1CX passive External timing capacitor connection for monostable 1; if CX is 0.5µF or more, a protection diode or 51Ω series resistor is recommended against power-down discharge into pin 2.
2 1RXCX passive Timing resistor/capacitor node for monostable 1, where RMIN is 5kΩ, maximum current into the pin must be 30mA, and τ = 0.7·RX·CX.
3 1R input Active-low reset for monostable 1, where a low level forces Q low and Q̄ high and unused resets must be terminated.
4 1A input Leading-edge trigger input for monostable 1 with Schmitt trigger action, and an unused A input must be tied to GND.
5 1B input Trailing-edge trigger input for monostable 1 with Schmitt trigger action, and an unused B input must be tied to VCC.
6 1Q output Buffered true output of monostable 1 (standard outputs rated for 10 LSTTL loads over temperature).
7 1Q̄ output Buffered complementary output of monostable 1 (standard outputs rated for 10 LSTTL loads over temperature).
8 GND power_in Ground reference; all voltages are referenced to this pin.
9 2Q̄ output Buffered complementary output of monostable 2 (standard outputs rated for 10 LSTTL loads over temperature).
10 2Q output Buffered true output of monostable 2 (standard outputs rated for 10 LSTTL loads over temperature).
11 2B input Trailing-edge trigger input for monostable 2 with Schmitt trigger action, and an unused B input must be tied to VCC.
12 2A input Leading-edge trigger input for monostable 2 with Schmitt trigger action, and an unused A input must be tied to GND.
13 2R input Active-low reset for monostable 2, where a low level forces Q low and Q̄ high and unused resets must be terminated.
14 2RXCX passive Timing resistor/capacitor node for monostable 2, where RMIN is 5kΩ, maximum current into the pin must be 30mA, and τ = 0.7·RX·CX.
15 2CX passive External timing capacitor connection for monostable 2; if CX is 0.5µF or more, a protection diode or 51Ω series resistor is recommended against power-down discharge into pin 14.
16 VCC power_in Supply voltage: 2V to 6V for HC types and 4.5V to 5.5V for HCT types.

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package SO-16-208mil
Category Logic ICs
Pins 16

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter Symbol Min Typ Max Unit Conditions Page
Supply voltage range (HC types) VCC 2 6 V HC types 4
Operating temperature range TA -55 125 °C 4
Input rise and fall time, reset input tr, tf 1000 ns VCC = 2 V 4
Input rise and fall time, reset input tr, tf 500 ns VCC = 4.5 V 4
Input rise and fall time, reset input tr, tf 400 ns VCC = 6 V 4
External timing resistor RX 5 kΩ Note 4 4
DC supply voltage VCC -0.5 7 V 4
DC input diode current IIK -20 20 mA VI < -0.5 V or VI > VCC + 0.5 V 4
DC output diode current IOK -20 20 mA VO < -0.5 V or VO > VCC + 0.5 V 4
DC output source or sink current per output pin IO -25 25 mA VO > -0.5 V or VO < VCC + 0.5 V (as printed) 4
DC VCC or ground current ICC -50 50 mA 4
Maximum junction temperature 150 °C 4
Maximum storage temperature range -65 150 °C 4
Package thermal impedance, NS (SOP) package θJA 64 °C/W NS (SOP) package; JESD 51-7 4
High level input voltage VIH 1.5 V VCC = 2 V; -55°C to 125°C 4
High level input voltage VIH 3.15 V VCC = 4.5 V; -55°C to 125°C 4
High level input voltage VIH 4.2 V VCC = 6 V; -55°C to 125°C 4
Low level input voltage VIL 0.5 V VCC = 2 V; -55°C to 125°C 4
Low level input voltage VIL 1.35 V VCC = 4.5 V; -55°C to 125°C 4
Low level input voltage VIL 1.8 V VCC = 6 V; -55°C to 125°C 4
High level output voltage, CMOS loads VOH 1.9 V VI = VIH or VIL; IO = -0.02 mA; VCC = 2 V; -55°C to 125°C 4
High level output voltage, CMOS loads VOH 4.4 V VI = VIH or VIL; IO = -0.02 mA; VCC = 4.5 V; -55°C to 125°C 4
High level output voltage, CMOS loads VOH 5.9 V VI = VIH or VIL; IO = -0.02 mA; VCC = 6 V; -55°C to 125°C 4
High level output voltage, TTL loads VOH 3.7 V VI = VIH or VIL; IO = -4 mA; VCC = 4.5 V; -55°C to 125°C 4
High level output voltage, TTL loads VOH 5.2 V VI = VIH or VIL; IO = -5.2 mA; VCC = 6 V; -55°C to 125°C 4
Low level output voltage, CMOS loads VOL 0.1 V VI = VIH or VIL; IO = 0.02 mA; VCC = 2 V; -55°C to 125°C 5
Low level output voltage, TTL loads VOL 0.4 V VI = VIH or VIL; IO = 4 mA; VCC = 4.5 V; -55°C to 125°C 5
Input leakage current A, B, R II -1 1 µA VI = VCC or GND; VCC = 6 V; -55°C to 125°C 5
Input leakage current RXCX II -0.5 0.5 µA VCC = 6 V; -55°C to 125°C; Note 6 5
Quiescent device current ICC 160 µA VI = VCC or GND; IO = 0; VCC = 6 V; -55°C to 125°C 5
Active device current ICC 1 mA Q = High & pins 2, 14 at VCC/4; VI = VCC or GND; IO = 0; VCC = 6 V; -55°C to 125°C 5
Input pulse width, A or B tWH, tWL 120 ns VCC = 2 V; -55°C to 125°C 6
Input pulse width, A or B tWH, tWL 24 ns VCC = 4.5 V; -55°C to 125°C 6
Input pulse width, A or B tWH, tWL 20 ns VCC = 6 V; -55°C to 125°C 6
Input pulse width, R tWL 120 ns VCC = 2 V; -55°C to 125°C 6
Input pulse width, R tWL 24 ns VCC = 4.5 V; -55°C to 125°C 6
Input pulse width, R tWL 20 ns VCC = 6 V; -55°C to 125°C 6
Reset recovery time tREC 5 ns VCC = 2 V; -55°C to 125°C 6
Propagation delay A, B to Q tPLH 375 ns CL = 50 pF; VCC = 2 V; -55°C to 125°C 7
Propagation delay A, B to Q tPLH 75 ns CL = 50 pF; VCC = 4.5 V; -55°C to 125°C 7
Propagation delay A, B to Q tPLH 64 ns CL = 50 pF; VCC = 6 V; -55°C to 125°C 7
Propagation delay R to Q tPHL 375 ns CL = 50 pF; VCC = 2 V; -55°C to 125°C 7
Propagation delay R to Q tPHL 75 ns CL = 50 pF; VCC = 4.5 V; -55°C to 125°C 7
Propagation delay R to Q tPHL 64 ns CL = 50 pF; VCC = 6 V; -55°C to 125°C 7
Output transition time tTLH, tTHL 110 ns CL = 50 pF; VCC = 2 V; -55°C to 125°C 7
Output transition time tTLH, tTHL 22 ns CL = 50 pF; VCC = 4.5 V; -55°C to 125°C 7
Output transition time tTLH, tTHL 19 ns CL = 50 pF; VCC = 6 V; -55°C to 125°C 7
Output pulse width τ 0.595 0.805 ms VCC = 5 V; RX = 10 kΩ, CX = 0.1 µF; CL = 50 pF; -55°C to 125°C 7
Output pulse width match -1 1 % Same package 7

CAD (KiCad official)

  • Symbol: CD74HC4538NSR
  • Footprint: Adom_Gen:Texas_Instruments_CD74
  • 3D model: SO-16-208mil (KiCad packages3D, STEP)
  • 3D model files: cd74hc4538nsr-etched.step / cd74hc4538nsr-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); cd74hc4538nsr.step / cd74hc4538nsr.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Texas Instruments datasheet (28 pp, sha256 bf04c5a1ae827107, retrieved 2026-10-18, tier: manufacturer)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-5-5 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF