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Texas Instruments UA9638ACD
- Part No.:
- UA9638ACD
- Manufacturer:
- Texas Instruments
- Category:
- Drivers, Receivers, Transceivers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
UA9638ACD.pdf
- Description:
- IC TRANSCEIVER 2/0 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,491
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Product details
Overview
UA9638ACD from Texas Instruments is a dual high-speed differential line driver compliant with EIA/TIA-422-B, operating from a single 5V supply, driving 50Ω loads up to 15Mbps, with TTL/CMOS-compatible inputs and output short-circuit protection - used in factory automation and smart grid communication links.
For engineers reviewing the UA9638ACD datasheet, UA9638ACD pinout, UA9638ACD application, or UA9638ACD equivalent, this page delivers verified electrical specs, SOIC-8 package details, functional pin roles, real-world use cases, and two validated alternative parts for industrial serial interface design.
Technical Context
The UA9638ACD implements two independent Schottky-clamped differential drivers optimized for baseband data transmission over twisted-pair cabling. Each channel accepts single-ended TTL/CMOS logic inputs and produces complementary outputs (Y/Z) with matched propagation delay (10–20 ns) and low skew (≤1 ns).
It operates across 0°C to 70°C with 4.75–5.25V supply tolerance, delivers ±50mA output drive capability, maintains 2V differential output magnitude into 100Ω, and features input clamp diodes and thermal-limited power dissipation (464 mW at 70°C in SOIC).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.75–5.25 V - ensures stable operation under standard 5V rail tolerances without external regulation |
| Data Rate | Up to 15 Mbps - supports high-speed RS-422-style point-to-point or multi-drop industrial links |
| Differential Output Voltage | 2 V (min) into 100Ω - meets EIA/TIA-422-B minimum swing for noise-immune reception |
| Propagation Delay | 10–20 ns - enables precise timing alignment in synchronous serial systems |
| Output Skew | ≤1 ns - minimizes inter-channel timing mismatch critical for dual-channel synchronization |
| Input Compatibility | TTL and CMOS - allows direct interfacing with microcontrollers, FPGAs, and legacy logic without level-shifting |
| Short-Circuit Protection | −50 to −150 mA per output - prevents latch-up or damage during cable fault conditions |
Pinout & Package
UA9638ACD is supplied in an 8-pin SOIC (D) package measuring 4.9 mm × 6 mm with 1.27 mm lead pitch and 1.75 mm max height.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 1) | Power Supply Input | 5V positive rail connection - must be decoupled locally to suppress switching noise |
| 1A (Pin 2) | Channel 1 Data Input | Single-ended TTL/CMOS logic input controlling Channel 1 differential output pair |
| 2A (Pin 3) | Channel 2 Data Input | Single-ended TTL/CMOS logic input controlling Channel 2 differential output pair |
| GND (Pin 4) | Ground Reference | Common return path for supply and signal currents - requires low-impedance PCB connection |
| 2Z (Pin 5) | Channel 2 Inverting Output | Negated differential output for Channel 2 - paired with 2Y to form balanced RS-422 signal |
| 2Y (Pin 6) | Channel 2 Non-Inverting Output | True differential output for Channel 2 - forms 180° phase complement to 2Z |
| 1Z (Pin 7) | Channel 1 Inverting Output | Negated differential output for Channel 1 - paired with 1Y for noise-rejecting transmission |
| 1Y (Pin 8) | Channel 1 Non-Inverting Output | True differential output for Channel 1 - provides full-swing complementary signal to 1Z |
Key Features
| Feature | Design Value |
|---|---|
| EIA/TIA-422-B Compliance | Guarantees interoperability with industry-standard differential receivers like UA9637A in noise-prone environments |
| Schottky-Clamped Transistors | Reduces propagation delay to ≤20 ns while maintaining TTL-level input thresholds and fast edge rates |
| Input Clamp Diodes | Protects against transient overvoltage on 1A/2A inputs without requiring external TVS components |
| 50Ω Load Drive Capability | Enables direct termination matching on PCB traces or cables - eliminates need for external current boosters |
| Thermal Derating Support | SOIC package rated for 464 mW at 70°C - enables reliable operation in unventilated industrial enclosures |
Applications
| Factory Automation | Smart Grid Communications |
|---|---|
|
Use Scenario: High-noise PLC-to-remote I/O module data links over 100+ meter twisted-pair wiring in manufacturing cells. IC Role / Device Role / Timing Role: Dual differential driver converting controller-side TTL signals into robust RS-422 outputs for noise-immune transmission. Use Value: 15 Mbps rate and 2 V differential swing ensure error-free communication despite EMI from motors and VFDs. |
Use Scenario: Substation RTU to intelligent electronic device (IED) telemetry using shielded twisted-pair in outdoor utility cabinets. IC Role / Device Role / Timing Role: Dual-channel line driver enabling simultaneous status reporting and command feedback over shared physical layer. Use Value: Matched channel delay (<1 ns skew) preserves time-critical sequence integrity in protection relay coordination. |
| ATM/Cash Counter Interfaces | AC Servo Motor Drives |
|
Use Scenario: Secure cash dispensing module communication with main controller inside tamper-resistant ATM chassis. IC Role / Device Role / Timing Role: Isolates sensitive control logic from noisy power stages via differential signaling with local ground separation. Use Value: Short-circuit protection prevents latch-up during connector hot-plug events common in field service operations. |
Use Scenario: Position feedback loop between servo amplifier and encoder in closed-loop motion control systems. IC Role / Device Role / Timing Role: Transmits quadrature A/B and index signals from incremental encoders with minimal jitter. Use Value: 10 ns typical propagation delay ensures sub-microsecond timing accuracy required for 100 kHz encoder update rates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual differential line driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS9638 | Pin-compatible, identical pinout and function; same EIA-422-B compliance and 15 Mbps rating | No temperature range difference - both rated 0°C to 70°C; DS9638 uses older process but matches UA9638ACD performance | Select DS9638 only if legacy sourcing or cross-manufacturer BOM flexibility is required |
| SN75ALS191 | Faster switching (5 ns typ propagation delay), higher drive strength (±100 mA), but no short-circuit protection | Requires external current limiting for fault conditions; suited for ultra-low-jitter applications where robustness is secondary | Choose SN75ALS191 when timing precision outweighs fault tolerance - not drop-in replacement |
Compared with DS9638 and SN75ALS191, UA9638ACD uniquely balances EIA-422-B compliance, integrated short-circuit protection, and SOIC-8 manufacturability - making it optimal for cost-sensitive, reliability-critical industrial interfaces where layout space and fault resilience matter.
Availability
UA9638ACD is available at Aetrix Electronics and suitable for factory automation, smart grid telemetry, and AC servo motor drives requiring stable component supply and long-term industrial lifecycle support.
Supply support for UA9638ACD 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 leader delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
The UA9638ACD belongs to TI's legacy high-speed interface line - designed specifically for robust, low-cost differential data transmission in electrically noisy industrial environments.
FAQ
What is the operating temperature range of the UA9638ACD?
The UA9638ACD is characterized for operation from 0°C to 70°C ambient temperature. This commercial-grade range aligns with typical industrial control cabinet environments and matches the specification of companion devices like the UA9637A receiver. The SOIC package's thermal resistance (RθJA = 116.7°C/W) supports reliable operation within this range when proper PCB copper area is used for heat dissipation. UA9638ACD does not support extended or automotive temperature grades.
Does the UA9638ACD require external termination resistors?
Yes, the UA9638ACD requires external 100Ω termination resistors across each differential pair (e.g., between 1Y and 1Z, and between 2Y and 2Z) at the receiver end to prevent signal reflections and ensure signal integrity at 15 Mbps. The device itself does not integrate termination; its 2V differential output voltage is specified into a 100Ω load, confirming that external termination is part of the intended system design. UA9638ACD outputs are not internally terminated.
Is the UA9638ACD pin-compatible with the DS9638?
Yes, the UA9638ACD is fully pin-compatible with the DS9638 - sharing identical SOIC-8 or PDIP-8 pinouts, terminal functions, and electrical behavior. Both devices implement the same dual-driver architecture, meet EIA/TIA-422-B, and operate from 5V. This interchangeability is explicitly stated in the UA9638ACD datasheet Feature section and confirmed by TI's packaging documentation. UA9638ACD can replace DS9638 without PCB changes.
What is the maximum capacitive load the UA9638ACD can drive reliably?
The UA9638ACD is characterized for CL = 15 pF in switching tests (td(OD), tt(OD)), and its 20 ns max transition time assumes this load. While not explicitly rated beyond 15 pF, practical designs with up to 30–40 pF (including PCB trace capacitance and receiver input capacitance) maintain 15 Mbps operation when combined with proper termination and controlled impedance routing. Exceeding this may degrade edge rate and increase jitter. UA9638ACD performance degrades predictably beyond 15 pF, requiring layout optimization.
Can the UA9638ACD be used with 3.3V logic inputs?
Yes, the UA9638ACD accepts 3.3V logic inputs because its VIH (min) is 2.0V and VIL (max) is 0.8V under recommended operating conditions - well within the VOH/VOL ranges of standard 3.3V CMOS outputs. However, the device itself requires a 5V supply (4.75–5.25V); it does not operate from 3.3V. So while 3.3V controllers can directly drive UA9638ACD inputs, the UA9638ACD must be powered separately from a 5V rail.
UA9638ACD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Driver
- Protocol:
- RS422, RS485
- Number of Drivers/Receivers:
- 2/0
- Duplex:
- -
- Receiver Hysteresis:
- -
- Data Rate:
- -
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
UA9638ACD FAQ
1.How can I place an order for UA9638ACD through Aetrix?
Please submit a Request for Quotation (RFQ) for UA9638ACD 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 UA9638ACD reliable?
The price and inventory of UA9638ACD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UA9638ACD is usually 5 days.
3.What payment methods are accepted for UA9638ACD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UA9638ACD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UA9638ACD?
UA9638ACD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UA9638ACD 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 UA9638ACD?
For technical support, including UA9638ACD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UA9638ACD requirements.
6.How does Aetrix verify that UA9638ACD is sourced from the original manufacturer or authorized distributors?
All UA9638ACD 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 UA9638ACD meets industry standards.
7.What is the process for return or replacement of UA9638ACD?
All UA9638ACD units undergo pre-shipment inspection (PSI). If there is an issue with UA9638ACD, 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 UA9638ACD part is unused and in its original packaging.
Return procedure for UA9638ACD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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