CD40106B — Hex Schmitt-Trigger Inverter

Overview

The CD40106B (CD40106) is a monolithic CMOS integrated circuit containing six independent inverting buffer gates with Schmitt-trigger inputs. Each gate functions as an inverter with built-in input hysteresis that discriminates between positive-going ( $V_T+$ ) and negative-going ( $V_T-$ ) threshold voltages.

With a wide operating supply voltage range from $3.0\text{V}$ to $18.0\text{V}$ DC and typical input hysteresis of $0.9\text{V}$ at $5\text{V}$ ( $2.3\text{V}$ at $10\text{V}$ , $3.5\text{V}$ at $15\text{V}$ ), the CD40106B converts slowly changing, noisy, or corrupted analog signals into sharp, jitter-free square digital waveforms. It is a cornerstone component for 12V automotive sensors, switch debouncing, and low-frequency multi-channel RC oscillators in modular synthesizers.

Quick reference


Supply Voltage Range (`VDD`)	3.0 V to 18.0 V DC (20.0 V maximum rating)
Logic Family	Standard CMOS 4000B Series
Inverters Count	6 Independent Schmitt-Trigger Inverters ( $Y = \overline{A}$ )
Hysteresis Voltage ( $V_H$ )	$0.9\text{ V}$ typ at $5\text{V}$ , $2.3\text{ V}$ typ at $10\text{V}$ , $3.5\text{ V}$ typ at $15\text{V}$
Positive Threshold ( $V_T+$ )	$2.9\text{ V}$ typ at $5\text{V}$ ( $5.8\text{ V}$ typ at $10\text{V}$ )
Negative Threshold ( $V_T-$ )	$1.9\text{ V}$ typ at $5\text{V}$ ( $3.9\text{ V}$ typ at $10\text{V}$ )
Propagation Delay ( $t_{pd}$ )	$140\text{ ns}$ typ at $V_{DD} = 10\text{V}$ ( $280\text{ ns}$ at $5\text{V}$ )
Package Options	14-pin DIP / SOIC-14 / TSSOP-14

Pinout (DIP-14 Package)

text

             ┌───┴───┐
          1A 1│ 1   14│ VDD
          1Y 2│       │13 6A
          2A 3│       │12 6Y
          2Y 4│CD40106B 11 5A
          3A 5│       │10 5Y
          3Y 6│       │9  4A
         VSS 7│       │8  4Y
             └───────┘

Pin	Name	Type	Description
1	`1A`	Schmitt Input	Inverter 1 Input
2	`1Y`	Digital Output	Inverter 1 Output ( $1Y = \overline{1A}$ )
3	`2A`	Schmitt Input	Inverter 2 Input
4	`2Y`	Digital Output	Inverter 2 Output
5	`3A`	Schmitt Input	Inverter 3 Input
6	`3Y`	Digital Output	Inverter 3 Output
7	`VSS`	Power	Ground / Negative Supply reference (0 V)
8	`4Y`	Digital Output	Inverter 4 Output
9	`4A`	Schmitt Input	Inverter 4 Input
10	`5Y`	Digital Output	Inverter 5 Output
11	`5A`	Schmitt Input	Inverter 5 Input
12	`6Y`	Digital Output	Inverter 6 Output
13	`6A`	Schmitt Input	Inverter 6 Input
14	`VDD`	Power	Positive Supply Voltage (+3.0 V to +18.0 V DC)

Function Table

Input A	Output Y ( $\overline{A}$ )
Low ( $L < V_T-$ )	High ( $H$ )
High ( $H > V_T+$ )	Low ( $L$ )

Specifications

Parameter	Symbol	Min	Typ	Max	Unit	Conditions
Supply Voltage	$V_{DD}$	3.0	—	18.0	V	Operating DC range
Positive Threshold Voltage	$V_T+$	2.2	2.9	3.6	V	$V_{DD} = 5\text{V}$
Negative Threshold Voltage	$V_T-$	1.3	1.9	2.4	V	$V_{DD} = 5\text{V}$
Hysteresis Voltage	$V_H$	0.3	0.9	1.6	V	$V_T+ - V_T-, V_{DD} = 5\text{V}$
Output Sink Current	$I_{OL}$	0.51	1.0	—	mA	$V_{DD} = 5\text{V}, V_{OUT} = 0.4\text{V}$
Output Source Current	$I_{OH}$	-0.51	-1.0	—	mA	$V_{DD} = 5\text{V}, V_{OUT} = 4.6\text{V}$
Propagation Delay	$t_{PLH}, t_{PHL}$	—	140	280	ns	$V_{DD} = 10\text{V}, C_L = 50\text{ pF}$
Quiescent Device Current	$I_{DD}$	—	0.02	1.0	µA	$V_{DD} = 5\text{V}, 25^\circ\text{C}$

Typical Applications

1. Simple Single-Gate RC Square Wave Oscillator

Because CMOS inputs have virtually infinite input impedance, an RC oscillator can be built using a single resistor and capacitor without loading effects:

text

            ┌─────[ R = 100kΩ ]─────┐
            │                       │
            ├───► [Pin 1: 1A]       │
            │       CD40106B        ├────► Square Wave Clock Output
            │     [Pin 2: 1Y] ──────┘
        [ C = 100nF ]
            │
           GND

Frequency is approximately $f \approx \frac{1}{0.8 \times R \times C}$ .

Common mistakes

Leaving unused inverter inputs floating: Even with Schmitt triggers, floating CMOS inputs float near intermediate voltages and trigger internal switching noise and excess power draw. Connect all unused inputs to VSS (GND) or VDD.
Assuming 74HC speed: The CD40106B has a propagation delay of $\sim 140\text{ ns}$ at $10\text{V}$ ( $280\text{ ns}$ at $5\text{V}$ ), compared to $15\text{ ns}$ for the 74HC14. Use the 74HC14 for high-frequency applications ( $> 5\text{ MHz}$ ).

Notes

Pin-Compatible Equivalents: 74HC14 (CMOS 2-6V high speed), 74HCT14 (TTL-compatible), 74LS14 (Bipolar TTL), HEF40106B.

Interface	6x Independent Schmitt-Trigger NOT Gates (1A->1Y, 2A->2Y, 3A->3Y, 4A->4Y, 5A->5Y, 6A->6Y)
Supply	3–18 V
Package	14-pin DIP / SOIC-14 / TSSOP-14