PCA9517DG4 - 2-Channel 400kHz I2C Level Translator | Texas Instruments
Référence : PCA9517DG4 ✓ ActifPCA9517DG4 Présentation
An I2C level translator, also called a voltage-level translator, is an interface IC placed between two bidirectional open-drain buses. The PCA9517 belongs to the I2C buffer/repeater hierarchy, where it combines bidirectional buffering, voltage-level translation, and bus-segmentation functions. Its two-channel architecture allows SDA and SCL to cross independently between a low-voltage domain and a higher-voltage domain while preserving I2C clock stretching and SMBus-compatible operation.
Key features include two bidirectional channels, operation from 0.9 V on the low side to 5.5 V on the high side, a maximum I2C bus speed of 400 kHz, and compatibility with both I2C and SMBus systems. The buffered channels can extend usable bus reach by isolating capacitance accumulated on the source side from the destination side. A quoted propagation delay of 170 ns and input capacitance of 6 pF are important when selecting pull-up resistors and evaluating timing margins.
The PCA9517 uses bidirectional buffers rather than unidirectional voltage-level shifters. Because I2C and SMBus signals are open-drain and pulled up externally, each translated channel can conduct in either direction. This makes the device suitable for a host controller operating at a lower voltage communicating with sensors, memory devices, or expansion components whose pull-up network uses a higher supply voltage. The manufacturer describes the PCA9517 as a CMOS and BiCMOS integrated circuit for these applications.
Typical uses include voltage adaptation between 1.8 V, 2.5 V, 3.3 V, and 5 V logic domains; isolating a long or heavily loaded I2C branch; and extending communication between a microcontroller and higher-voltage sensors or EEPROMs. Because both SDA and SCL require translation, the complete two-channel arrangement keeps data and clock voltage domains aligned.
Designers must provide correct pull-up resistors on each side of the translator and account for the 170 ns propagation delay when calculating the maximum operating frequency. The 8-SOIC package is also used by the PCA9515A, while Texas Instruments' TCA9517 is identified as a comparable dual bidirectional I2C buffer. Review device-specific enable behavior, bus capacitance, and logic thresholds before finalizing a replacement.
This page organizes the PCA9517DG4 specifications, replacement candidates, application guidance, and design considerations into one engineering-focused reference. It also distinguishes the published 0.9 V low-side capability from the 2.7 V to 5.5 V high-side range and identifies package and functional differences that matter when reusing an existing PCB.
Alternatives de remplacement direct pour PCA9517DG4 — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec PCA9517DG4 (même facteur de forme et même empreinte) — différant par Package, Function, Number of Channels, RoHS Status.
TCA9517DR
✅ Remplacement directContactez-nous pour le prix
Voir la fiche technique →PCA9515ADR
✅ Remplacement directContactez-nous pour le prix
Voir la fiche technique →PCA9517DG4 Spécifications
| Channel Count | 2 channels |
| Bus Compatibility | I2C bus and SMBus |
| Maximum I2C Bus Frequency | 400 kHz |
| Low-Side Minimum Supply Voltage | 0.9 V |
| High-Side Supply Voltage Range | 2.7 V to 5.5 V |
| Overall Supply Voltage Range | 2.7 V to 5.5 V |
| Buffer Direction | Bidirectional |
| Delay Time | 170 ns |
| Capacité d'entrée | 6 pF |
| Courant d'alimentation | 5 mA |
| Device Type | Level-translating I2C bus repeater |
| Logic Type | I2C logic |
| Integrated Circuit Technology | CMOS and BiCMOS |
| Boîtier | 8-SOIC (0.154 inch, 3.90 mm width) |
| Type de montage | Surface mount |
Guide de configuration des broches du PCA9517DG4 8-soic (0.154 inch, 3.90 mm width)
Configuration des broches du PCA9517DG4 (boîtier 8-soic (0.154 inch, 3.90 mm width)). La numérotation des broches, les fonctions et les schémas de connexion sont définis dans la fiche technique du fabricant. Consultez-la pour l'empreinte exacte et les directives de soudage.
Aucune donnée de brochage détaillée disponible pour PCA9517DG4.
Consultez la fiche technique pour la configuration complète des broches.
Applications typiques
PCA9517DG4 convient pour 6 applications: Low-Voltage Controller to 5 V Peripheral Bus, I2C Bus Extension, SMBus Voltage Adaptation, Mixed-Voltage Sensor Interface, EEPROM and Memory Bus Isolation, Multi-Domain Control Module.
Low-Voltage Controller to 5 V Peripheral Bus
The PCA9517DG4 fits between a low-voltage controller and a 3.3 V or 5 V I2C peripheral bus when the two sides cannot share one pull-up voltage. Its low-side operation extends down to 0.9 V, while the high side accepts 2.7 V to 5.5 V, allowing SDA and SCL to cross voltage domains without unidirectional level shifters. The two bidirectional channels preserve clock stretching and SMBus-compatible behavior. Keep pull-up networks separate on each side, account for the quoted 170 ns delay, and verify the attached peripheral's absolute voltage limits.
Recommandé
I2C Bus Extension
Use the PCA9517DG4 as a repeatable boundary on an I2C segment whose accumulated capacitance would otherwise burden the controller or remote devices. Its bidirectional SDA and SCL buffers separate the source and destination bus sections, while the 400-kHz operating capability supports Fast-mode I2C communication. The quoted 6 pF input capacitance must be included when sizing pull-up resistors and estimating loading. Separate external pull-ups should establish valid logic levels in each voltage domain, and system timing must include the 170 ns propagation delay.
Recommandé
SMBus Voltage Adaptation
The PCA9517DG4 is appropriate for SMBus-compatible systems where a manager operates at one logic voltage and slave devices use another. Because the PCA9517 is an I2C/SMBus level-translating repeater, both SDA and SCL can be translated bidirectionally while retaining clock stretching. The 400-kHz limit defines the highest supported bus rate, and the 0.9 V low-side capability provides additional headroom for low-voltage managers. Confirm each side's pull-up voltage and the slave's allowable input range before deployment.
Recommandé
Mixed-Voltage Sensor Interface
The PCA9517DG4 can connect a low-voltage embedded controller to sensors, converters, or other instrumentation using a higher I2C pull-up voltage. Translating SDA and SCL together prevents the clock from remaining at one logic level while data crosses into another. Its 2.7 V to 5.5 V high-side range supports common 3.3 V and 5 V buses, while the low side can extend down to 0.9 V. Review sensor power sequencing, bus capacitance, and the translator's 170 ns delay when the sensor also imposes a clock-stretching limit.
Recommandé
EEPROM and Memory Bus Isolation
Placing the PCA9517DG4 between a controller and an I2C EEPROM or memory device can isolate the memory bus from capacitance on the controller-side segment. The buffered SDA and SCL paths maintain bidirectional communication, while separate pull-up networks let the EEPROM operate from 3.3 V or 5 V even when the controller uses a lower voltage. The device's 400-kHz capability covers common memory interfaces, but address setup, hold, and access timing still depend on the memory device. Validate timing with the 170 ns translator delay included.
Recommandé
Multi-Domain Control Module
The PCA9517DG4 is useful in a control module that combines a low-voltage processor rail with higher-voltage communications or expansion logic. Its two independent bidirectional channels translate both I2C clock and data, allowing the higher-voltage section to retain a conventional pull-up arrangement. This arrangement reduces the need for a processor pin to tolerate a higher bus voltage. Designers should confirm enable or power-sequencing requirements, use the manufacturer application circuit as a starting point, and preserve adequate timing margin around the 400-kHz operating ceiling.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour PCA9517DG4 — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | TCA9517DR | PCA9515ADR |
|---|---|---|---|
| Package | 8-SOIC (0.154 inch, 3.90 mm width) | 8-SOIC | 8-SOIC |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Channel Count | 2 channels | 2 channels | 2 channels |
| Buffer Direction | Bidirectional | Bidirectional | Bidirectional |
| Bus Compatibility | I2C bus and SMBus | I2C bus | I2C bus |
Principaux différenciateurs
- Lower low-side operating capability (vs TCA9517DR)
- Two complete bidirectional I2C channels (vs TCA9517DR)
- SMBus-compatible level translation (vs PCA9515ADR)
- SOIC footprint reuse (vs PCA9515ADR)
Notes de conception
Use separate pull-up networks for SDA and SCL on each side of the translator. Connecting both voltage domains to one pull-up supply defeats the level-shifting function and can expose the low-voltage devices to excessive voltage. Select resistor values from the capacitance of each isolated bus section and the required rise time. Because the PCA9517DG4 uses open-drain-compatible bidirectional buffering, each side must retain a valid passive pull-up.
Include the quoted 170 ns propagation delay when evaluating SCL timing, especially at the 400-kHz maximum rate. Calculate worst-case rise time from each bus section's total capacitance and pull-up resistance, and check clock-stretching behavior separately because the remote device may hold SCL low. Treat the translator as two independently loaded channels rather than assuming the source-side capacitance is completely hidden from the destination.
Place the PCA9517DG4 close to the boundary between low-voltage and high-voltage bus sections. Keep SDA and SCL routing lengths and topology similar to minimize propagation-time and capacitance differences between the two translated channels. Provide a solid ground reference, avoid long stubs into unused connectors, and place pull-up resistors near the devices that establish each domain's logic level. Follow the manufacturer recommended application circuit when reproducing the 8-SOIC footprint.
Confirm that both voltage domains can be powered in the sequence required by the attached controller and peripherals. The PCA9517DG4 supports low-side voltages down to 0.9 V and high-side voltages from 2.7 V to 5.5 V, but power-ramp behavior can affect bus logic if either side becomes active before its pull-up network is valid. Use the device enable or power-sequencing arrangement specified by the manufacturer for the selected system configuration.
Informations de conformité
The verified product and distributor listings do not explicitly state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status.