Texas Instruments CD40109BPW

Overview

CD40109BPW from Texas Instruments is a quad low-to-high (and high-to-low) CMOS level shifter IC with independent dual-supply operation (VCC and VDD), enabling bidirectional voltage translation across 3 V to 18 V logic domains. It supports unrestricted power-up sequencing, operates with VCC > VDD for high-to-low shifting, and delivers rail-to-rail output swing from –0.5 V to VDD + 0.5 V. Used in mixed-voltage microcontroller interfacing and legacy bus bridging.

For engineers reviewing the CD40109BPW datasheet, CD40109BPW pinout, CD40109BPW application, or CD40109BPW equivalent, key selection criteria include independent supply sequencing tolerance, bidirectional level-shifting capability without external components, wide operating temperature range (–55°C to +125°C), and TSSOP-16 packaging for space-constrained industrial control designs.

Technical Context

The CD40109BPW implements four independent CMOS-based level-shifting channels, each with separate input and output stages referenced to distinct supply rails (VCC for inputs, VDD for outputs). Its architecture eliminates bootstrapping or charge-pump requirements, allowing safe hot-plug operation where VCC or VDD may be applied in any order.

Each channel supports input signal swings from VSS to ≥0.7×VCC and tolerates input voltages exceeding both VCC and VDD within absolute maximum ratings. Output drive capability is specified for capacitive loads up to 50 pF with typical propagation delay of 120 ns at 5 V VCC/VDD and 50 pF load.

Key Specifications

Pinout & Package

TSSOP-16 (PW) package: 4.4 mm × 5.0 mm body, 0.65 mm lead pitch, 1.2 mm max height, RoHS-compliant NIPDAU finish, MSL Level-1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar level-shifting applications.

Compared with SN74LVC4245APWR and TXS0104EPWR, the CD40109BPW uniquely supports asymmetric 3 V–18 V dual-rail operation, unrestricted supply sequencing, and true push-pull rail-to-rail outputs - making it the only option among the three for high-voltage industrial control and mixed-domain hot-plug systems.

Availability

CD40109BPW is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and mixed-voltage sensor interface applications requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD40109BPW includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The CD40109B series belongs to TI's legacy CMOS logic portfolio, designed specifically for robust, sequence-tolerant voltage translation in harsh environments where reliability and supply flexibility outweigh speed requirements.

FAQ

What is the maximum allowable voltage difference between VCC and VDD for CD40109BPW?

The CD40109BPW permits VCC and VDD to differ by up to 15 V, provided both remain within their respective absolute maximum ratings (3 V to 18 V each). For example, VCC = 3.3 V and VDD = 18 V is valid. This asymmetry enables direct interfacing between low-voltage microcontrollers and high-voltage industrial buses without external level-shifting circuitry. The CD40109BPW maintains correct logic translation and output drive integrity across this full differential range.

Does CD40109BPW require external pull-up or pull-down resistors on its inputs or outputs?

No, the CD40109BPW does not require external pull-up or pull-down resistors. Its CMOS input structure has high impedance and defined switching thresholds (≥0.7×VCC for high-level recognition), while its push-pull output stage actively drives both logic states to rail-to-rail levels (–0.5 V to VDD + 0.5 V). This eliminates passive components needed by open-drain translators like TXS0104EPWR, simplifying layout and improving noise immunity in CD40109BPW-based designs.

Can CD40109BPW operate with VCC greater than VDD, and what is the functional impact?

Yes, CD40109BPW fully supports VCC > VDD operation and functions as a high-to-low level shifter in that mode. When VCC = 12 V and VDD = 3.3 V, for instance, the device translates 12 V input signals down to 3.3 V-compatible outputs while preserving timing integrity and noise margins. This bidirectional capability - enabled by independent supply referencing - is intrinsic to the CD40109BPW architecture and requires no configuration changes or external circuitry.

What is the recommended PCB layout practice for CD40109BPW's VSS pins?

All four VSS pins (pins 3, 6, 12, 15) must be connected to a low-impedance ground plane using short, wide traces. TI's TSSOP-16 land pattern specifies a continuous solder mask-defined exposed metal pad beneath the package body - this should be tied directly to the main system ground plane via multiple thermal vias (minimum 4×0.3 mm diameter) to minimize ground bounce and ensure stable operation under fast switching. Failure to properly decouple VSS increases propagation delay variation and may cause output instability in CD40109BPW applications.

Is CD40109BPW compatible with modern 1.8 V logic systems?

No, CD40109BPW is not compatible with 1.8 V logic systems. Its minimum VCC and VDD rating is 3 V, and its input high-level threshold is defined as ≥0.7×VCC - meaning at VCC = 3 V, the minimum valid high input is 2.1 V. A 1.8 V logic high (typically ~1.35 V) falls below this threshold and will not register reliably. For 1.8 V interfaces, alternatives such as TXS0104EPWR or SN74AVCH4T245 are appropriate; CD40109BPW targets 3 V and above domains exclusively.