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Texas Instruments TCA9801DGKT
- Part No.:
- TCA9801DGKT
- Manufacturer:
- Texas Instruments
- Category:
- Translators, Level Shifters
- Package:
- Datasheet:
-
TCA9801DGKT.pdf
- Description:
- IC TRANSLTR BIDIRECTIONAL 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,667
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Product details
Overview
TCA9801DGKT from Texas Instruments is a dual-channel bidirectional I²C/SMBus level-translating buffer with integrated B-side current source (1.1 mA typical), supporting 0.8 V–3.6 V on A-side and 1.65 V–3.6 V on B-side, ultra-low quiescent current (23 µA total at 1.8 V), and true buffering without static voltage offset-used in server backplanes to isolate high-speed I²C segments across mixed-voltage domains.
For engineers reviewing the TCA9801DGKT datasheet, TCA9801DGKT pinout, TCA9801DGKT application, or TCA9801DGKT equivalent, key selection criteria include B-side current-source strength (1.1 mA), bus capacitance limit (400 pF), propagation delay (75–260 ns), powered-off high-impedance A-side pins, and absence of external B-side pull-up resistors.
Technical Context
The TCA9801DGKT implements true bidirectional buffering-not pass-FET translation-using an internal current source on the B-side to detect bus contention and eliminate static voltage offsets. This architecture enables sub-0.3 V VOL on both sides (0.13 V on A-side, 0.26 V on B-side) and supports clock stretching and multi-master arbitration without signal degradation.
No power sequencing dependency exists: VCCA may be less than, equal to, or greater than VCCB. The EN input is active-high, referenced to VCCA, with internal 150–450 kΩ pull-up; disabling EN halts data forwarding but leaves the B-side current source enabled if VCCB is powered.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| A-side supply range | 0.8 V to 3.6 V - enables direct interface with low-voltage processors (e.g., 0.8 V I/O cores) without level-shifter cascading |
| B-side supply range | 1.65 V to 3.6 V - supports standard I²C slaves (1.8 V, 2.5 V, 3.3 V) while eliminating external B-side pull-ups |
| B-side current source | 1.1 mA typical ±25% - sets rise time and bus drive capability; matches 400 pF max load at 400 kHz SMBus operation |
| Max SCL frequency | 400 kHz - full compatibility with Fast-mode I²C and SMBus 2.0/3.0 timing requirements |
| VOL (A-side) | 0.13 V max at 6 mA - ensures reliable low-level recognition by 1.2 V–1.8 V receivers with tight VIL thresholds |
| VOL (B-side) | 0.26 V max - eliminates false-low detection when interfacing with legacy 3.3 V slaves having 0.3×VCC VIL |
| Total quiescent current | 23 µA at 1.8 V/1.8 V - enables always-on I²C monitoring in battery-backed systems without measurable drain |
Pinout & Package
Package: VSSOP-8 (DGK), 3.00 mm × 3.00 mm body, 0.65 mm pitch, thermally enhanced for industrial ambient (–40°C to +125°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VCCA | A-side supply input | Reference for SDAA, SCLA, and EN logic; powers A-side I/O circuitry and internal control logic |
| 2 SCLA | A-side serial clock I/O | Connects to master clock line; requires external pull-up to VCCA even if unused |
| 3 SDAA | A-side serial data I/O | Connects to master data line; requires external pull-up to VCCA even if unused |
| 4 GND | Ground reference | Common return for all internal circuits; must be low-impedance connection to system ground plane |
| 5 EN | Active-high enable input | Referenced to VCCA; logic high enables bidirectional translation; internal 150–450 kΩ pull-up to VCCA |
| 6 SDAB | B-side serial data I/O | Connects to slave data line; no external pull-up allowed-internal current source provides bias |
| 7 SCLB | B-side serial clock I/O | Connects to slave clock line; no external pull-up allowed-internal current source provides bias |
| 8 VCCB | B-side supply input | Reference for SDAB, SCLB, and internal current source; powers B-side output drivers and detection circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Integrated B-side current source | 1.1 mA typical eliminates need for external B-side pull-up resistors and improves rise time on capacitive buses |
| No static voltage offset | Enables true bidirectional buffering with sub-0.3 V VOL on both sides-prevents lock-up with low-VIL receivers |
| Powered-off high-impedance A-side pins | SCLA/SDAA enter Hi-Z when VCCA or VCCB falls below UVLO-allows safe hot-plug of A-side master without bus contention |
| Back-power protection | All I²C pins include protection circuitry preventing current flow into VCCA/VCCB-enables safe operation during partial power-down |
| Independent supply rails | VCCA and VCCB may be powered in any sequence or at different voltages-removes system-level sequencing constraints |
Applications
| Server Backplane I²C Isolation | Industrial Sensor Hub Interface |
|---|---|
|
Use Scenario: Isolating 0.8 V FPGA management controller I²C bus from 3.3 V temperature/power sensors on a multi-rack server backplane. IC Role / Device Role / Timing Role: Bidirectional level-translating repeater enabling clock/data translation between mismatched voltage domains while preserving SMBus timing integrity. Use Value: Eliminates external B-side pull-ups and reduces board space by 30% vs discrete resistor networks; maintains 400 kHz operation under 300 pF bus load. |
Use Scenario: Interfacing a 1.8 V microcontroller to multiple 2.5 V and 3.3 V analog sensor ICs in a factory-floor vibration monitor with strict EMI limits. IC Role / Device Role / Timing Role: Dual-channel I²C buffer providing galvanic separation between controller and sensor clusters, supporting clock stretching during ADC conversions. Use Value: Sub-0.3 V VOL prevents false-low errors in noisy industrial environments; ultra-low 23 µA quiescent current extends battery life in portable units. |
| PC UEFI Firmware Configuration Bus | Power-Sensitive IoT Node |
|
Use Scenario: Extending the I²C bus from a 1.2 V UEFI firmware engine to 3.3 V PMICs and thermal diodes across a high-density motherboard. IC Role / Device Role / Timing Role: Level-shifting repeater enabling voltage-domain bridging without violating Intel Platform Environment Control Interface (PECI) timing margins. Use Value: Propagation delay ≤260 ns ensures setup/hold compliance for 400 kHz SMBus writes; EN pin allows runtime isolation during firmware updates. |
Use Scenario: Connecting a 0.9 V ultra-low-power MCU to 1.8 V environmental sensors in a solar-powered edge node requiring 10-year battery life. IC Role / Device Role / Timing Role: Always-on I²C translator maintaining bus connectivity during MCU sleep cycles, with powered-off A-side pins preventing leakage. Use Value: 23 µA total quiescent current minimizes standby drain; B-side current source enables fast wake-up response without pull-up resistor warm-up delay. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C level-translating buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TCA9802DGKT | Higher B-side current source (2.2 mA typical) supports >400 pF bus loads and faster rise times at 3.3 V | Better suited for high-capacitance industrial backplanes (>350 pF) or 1 MHz custom I²C extensions | Select when bus capacitance exceeds 300 pF or when driving long traces with >20 cm length |
| TCA9800DGKT | Lower B-side current source (0.54 mA typical) reduces power consumption but limits max bus capacitance to ~200 pF | Optimized for ultra-low-power wearable sensors where <10 µA standby current is critical | Select only for sub-200 pF buses and systems requiring minimum ICCB (<20 µA at 1.8 V) |
Compared with TCA9802DGKT and TCA9800DGKT, the TCA9801DGKT delivers optimal balance of drive strength (1.1 mA), power efficiency (23 µA), and bus capacitance support (400 pF), making it the default choice for mainstream server, PC, and industrial I²C isolation where design margin and component count reduction are prioritized.
Availability
TCA9801DGKT is available at Aetrix Electronics and suitable for server backplanes, industrial sensor hubs, PC UEFI configuration buses, and power-sensitive IoT nodes requiring stable component supply across extended product lifecycles.
Supply support for TCA9801DGKT 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, designing and manufacturing analog, embedded processing, and digital signal processing technologies since 1930.
The TCA9801DGKT belongs to TI's I²C level-shifting buffer family, engineered specifically for robust, low-power, mixed-voltage I²C/SMBus domain isolation in servers, networking equipment, and industrial automation systems.
FAQ
What is the maximum bus capacitance supported by the TCA9801DGKT?
The TCA9801DGKT supports up to 400 pF on the B-side (SDAB/SCLB), as specified in the Electrical Characteristics table under CBUS parameter. Exceeding this limit degrades rise time and may cause timing violations at 400 kHz operation. The A-side (SDAA/SCLA) has no defined capacitance limit. For designs approaching 400 pF, verify tr/tf and tPHL/tPLH using the values in Section 7.6 of the TCA9801DGKT datasheet.
Can external pull-up resistors be used on the B-side pins (SDAB/SCLB) of the TCA9801DGKT?
No-external pull-up resistors must not be connected to SDAB or SCLB. The TCA9801DGKT integrates a 1.1 mA current source on the B-side to provide pull-up functionality and ensure proper low-level detection via IILC. Adding external resistors violates the IEXT-I specification (≤200 µA), risks false-low interpretation, and may prevent external devices from meeting the required 500 µA IILC contention current.
Does the TCA9801DGKT require power supply sequencing between VCCA and VCCB?
No-the TCA9801DGKT imposes no power sequencing requirements. VCCA may be powered before, after, or simultaneously with VCCB, and VCCA may be less than, equal to, or greater than VCCB. This flexibility is enabled by independent UVLO thresholds (0.3–0.8 V for VCCA; 1.2–1.6 V for VCCB) and isolated internal circuitry, simplifying system power architecture design.
What happens to the A-side pins (SCLA/SDAA) when VCCA is unpowered but VCCB remains active?
When VCCA falls below its UVLO threshold (≤0.55 V), the SCLA and SDAA pins enter a high-impedance state per the Powered-Off High Impedance feature. They remain electrically isolated and safe for continued I²C communication on the B-side. This behavior enables hot-swap capability for A-side masters without disrupting downstream slave operation or causing bus contention.
How does the TCA9801DGKT handle clock stretching and multi-master arbitration?
The TCA9801DGKT fully supports clock stretching and multi-master arbitration by propagating SCL transitions bidirectionally with minimal added delay (tPHL ≤250 ns, tPLH ≤260 ns) and preserving signal integrity during handoff events. Its true buffering architecture-without static voltage offset-prevents overshoot and ensures clean low-to-high transitions, critical for reliable arbitration resolution in systems with multiple I²C masters.
TCA9801DGKT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Translator Type:
- Voltage Level
- Channel Type:
- Bidirectional
- Number of Circuits:
- 1
- Channels per Circuit:
- 2
- Voltage - VCCA:
- 0.8 V ~ 3.6 V
- Voltage - VCCB:
- 1.65 V ~ 3.6 V
- Input Signal:
- -
- Output Signal:
- -
- Output Type:
- Non-Inverted
- Data Rate:
- -
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Features:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
TCA9801DGKT FAQ
1.How can I place an order for TCA9801DGKT through Aetrix?
Please submit a Request for Quotation (RFQ) for TCA9801DGKT on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for TCA9801DGKT reliable?
The price and inventory of TCA9801DGKT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TCA9801DGKT is usually 5 days.
3.What payment methods are accepted for TCA9801DGKT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TCA9801DGKT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TCA9801DGKT?
TCA9801DGKT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TCA9801DGKT order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for TCA9801DGKT?
For technical support, including TCA9801DGKT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TCA9801DGKT requirements.
6.How does Aetrix verify that TCA9801DGKT is sourced from the original manufacturer or authorized distributors?
All TCA9801DGKT products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TCA9801DGKT meets industry standards.
7.What is the process for return or replacement of TCA9801DGKT?
All TCA9801DGKT units undergo pre-shipment inspection (PSI). If there is an issue with TCA9801DGKT, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The TCA9801DGKT part is unused and in its original packaging.
Return procedure for TCA9801DGKT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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