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Texas Instruments SN74LS47D
- Part No.:
- SN74LS47D
- Manufacturer:
- Texas Instruments
- Category:
- Display Drivers
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74LS47D.pdf
- Description:
- IC DRVR 7 SEGMENT 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:990
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Product details
Overview
SN74LS47D from Texas Instruments is a BCD-to-seven-segment decoder/driver IC designed for direct interface with common-anode LED displays. It accepts 4-bit binary-coded decimal (BCD) input, provides active-low segment outputs (a–g), features lamp test (LT̅), ripple blanking input (RBI̅), and blanking input/ripple blanking output (BI̅/RBO̅), and operates over 0°C to 70°C in a 16-pin SOIC package.
For engineers reviewing the SN74LS47D datasheet, SN74LS47D pinout, SN74LS47D application, or SN74LS47D equivalent, this device is selected for discrete-digit LED display systems requiring TTL-compatible logic levels, integrated decoding + current-sinking drive, and cascading capability via BI̅/RBO̅ for leading-zero suppression.
Technical Context
The SN74LS47D implements TTL-compatible BCD-to-7-segment decoding with open-collector outputs capable of sinking up to 40 mA per segment. Its internal logic includes priority encoding for invalid BCD inputs (1010–1111), which forces all outputs high (blanking). The BI̅/RBO̅ line supports multi-digit zero suppression by chaining devices in descending significance order.
It features asynchronous active-low LT̅ (lamp test) that overrides all other inputs to force all segments low (illuminating all LEDs), and RBI̅ (ripple blanking input) that enables blanking only when all lower-significance digits are zero and the current digit is zero - critical for clean numeric display formatting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74LS (Low-power Schottky TTL) - ensures compatibility with legacy TTL systems and predictable noise margins. |
| Input Format | 4-bit BCD (A0–A3) - directly accepts binary-coded decimal values 0–9; inputs 10–15 force blanked output. |
| Output Type | Open-collector, active-low (a–g) - sinks current to drive common-anode LEDs without external transistors. |
| Output Sink Current | 40 mA per segment - sufficient to drive standard LED segments at typical brightness without external buffers. |
| Supply Voltage | VCC = 4.75 V to 5.25 V - strict 5 V ±5% operation required for guaranteed TTL logic thresholds and timing. |
| Operating Temperature | 0°C to 70°C - commercial-grade rating suitable for indoor instrumentation and consumer electronics. |
| Package | SOIC-16 (D package) - surface-mount footprint with 1.27 mm pitch, 8.0 mm width, and 1.75 mm height for PCB space efficiency. |
Pinout & Package
SN74LS47D is housed in a 16-pin small-outline integrated circuit (SOIC) package (package drawing D), measuring 10.4 mm × 5.3 mm × 1.75 mm, with gull-wing leads and RoHS-compliant NiPdAu lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A0) | BCD LSB Input | Least significant BCD bit; must be driven to 0 or 1 for valid digit decoding (0–9). |
| 2 (A1) | BCD Input | Second BCD bit; part of 4-bit parallel BCD word (A0–A3). |
| 3 (A2) | BCD Input | Third BCD bit; used with A0–A1 and A3 to define decimal value 0–9. |
| 4 (LT̅) | Lamp Test Input | Active-low signal forcing all segment outputs low - illuminates all LED segments for visual verification. |
| 5 (BI̅/RBO̅) | Blanking Input / Ripple Blanking Output | When asserted low as input, blanks all segments; as output, goes low only when digit = 0 and RBI̅ = low - enables zero suppression. |
| 6 (RBI̅) | Ripple Blanking Input | Active-low enable for zero-suppression logic; must be low for BI̅/RBO̅ to propagate blanking to higher-order digits. |
| 7 (GND) | Ground Reference | Power return path for all internal logic and output drivers; requires low-impedance connection. |
| 8 (A3) | BCD MSB Input | Most significant BCD bit; completes 4-bit BCD input for full 0–9 decoding. |
| 9 (a) | Segment a Output | Open-collector output driving LED segment 'a'; sinks current when active (low) to illuminate segment. |
| 10 (b) | Segment b Output | Open-collector output for segment 'b'; shares same electrical characteristics and drive strength as pin 9. |
| 11 (c) | Segment c Output | Open-collector output for segment 'c'; compatible with common-anode LED anodes tied to VCC. |
| 12 (d) | Segment d Output | Open-collector output for segment 'd'; requires external current-limiting resistor per segment. |
| 13 (e) | Segment e Output | Open-collector output for segment 'e'; behavior identical to pins 9–12 under valid BCD input. |
| 14 (f) | Segment f Output | Open-collector output for segment 'f'; inactive (high-Z) for invalid BCD codes (10–15). |
| 15 (g) | Segment g Output | Open-collector output for segment 'g'; final segment output completing the seven-segment pattern. |
| 16 (VCC) | Positive Supply | +5 V DC supply pin; must be decoupled with 0.1 µF ceramic capacitor near the package. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated BCD decoding + segment driving | Eliminates need for separate decoder and transistor array - reduces component count and board area in LED display designs. |
| Active-low open-collector outputs | Directly interfaces with common-anode LEDs using simple current-limiting resistors; no level-shifting or external drivers required. |
| Leading-zero suppression via BI̅/RBO̅ | Enables multi-digit displays (e.g., 4-digit counter) to omit unnecessary leading zeros - improves readability and reduces power. |
| Lamp test (LT̅) function | Provides hardware-level diagnostic mode to verify LED continuity and driver functionality without software intervention. |
| Invalid input blanking | Automatically blanks display for BCD codes 10–15 - prevents erroneous symbols (e.g., 'E', 'F') on 7-segment displays. |
Applications
| Digital Counter Displays | Test Equipment Front Panels |
|---|---|
|
Use Scenario: 4-digit decimal counter built with 74LS90 decade counters feeding into SN74LS47D drivers for 7-segment LED readouts. IC Role / Device Role / Timing Role: SN74LS47D acts as the final-stage BCD-to-LED interface, converting parallel BCD words into segment activation signals with zero suppression. Use Value: Enables compact, low-cost, fully hardware-based numeric display without microcontroller involvement or firmware overhead. |
Use Scenario: Bench multimeter or frequency counter front panel showing measured values on multiplexed 3-digit LED display. IC Role / Device Role / Timing Role: SN74LS47D drives individual digit segments in time-multiplexed fashion, synchronized with digit-select control logic. Use Value: Provides TTL-compatible, high-current-sink capability ensuring consistent LED brightness across digits without external drivers. |
| Industrial Panel Meters | Legacy Instrumentation Upgrades |
|
Use Scenario: Analog-to-digital converter output routed to SN74LS47D for local digital readout on factory floor pressure or temperature meters. IC Role / Device Role / Timing Role: SN74LS47D serves as static display driver - accepts stable BCD from ADC output latches and holds segment states. Use Value: Delivers robust, EMI-resistant display interface in electrically noisy industrial environments due to TTL noise immunity. |
Use Scenario: Replacement of obsolete 7447 or 74LS48 in vintage lab equipment (e.g., oscilloscope readouts, logic analyzers) during repair or refurbishment. IC Role / Device Role / Timing Role: SN74LS47D substitutes for original decoder/driver with identical pinout, logic behavior, and drive strength. Use Value: Restores full functionality without PCB modification - maintains original timing, voltage, and loading characteristics. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar BCD-to-seven-segment decoder/driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS48N | Active-high outputs for common-cathode LEDs; different output polarity and segment logic mapping. | Requires common-cathode display configuration; incompatible with common-anode layouts without redesign. | Select SN74LS48N only when driving common-cathode displays and redesigning output routing. |
| SN7447AN | Same pinout and function but uses standard TTL (74) rather than LS logic - higher power consumption (15 mW vs. 7 mW) and slower propagation (34 ns vs. 25 ns typical). | Compatible drop-in replacement in legacy 74-series systems where LS speed/power advantages are not required. | Choose SN7447AN for cost-sensitive, non-speed-critical applications where existing 74-series design rules apply. |
Compared with SN74LS47D, SN74LS48N requires display rewiring due to opposite output polarity, while SN7447AN offers functional equivalence at higher power and reduced speed - making SN74LS47D optimal for new designs prioritizing efficiency and performance in common-anode LED systems.
Availability
SN74LS47D is available at Aetrix Electronics and suitable for digital instrumentation, test equipment front panels, and industrial panel meters requiring stable component supply and long-term obsolescence management.
Supply support for SN74LS47D 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial and automotive qualification.
The SN74LS47D belongs to TI's legacy 74LS logic family, engineered for reliable BCD-to-LED display interfacing in commercial-grade digital systems where TTL compatibility and discrete logic integration are essential.
FAQ
What is the maximum sink current per output pin on the SN74LS47D?
The SN74LS47D guarantees a minimum output sink current of 40 mA per segment (pins a–g) at VCC = 5 V and ambient temperature ≤ 25°C. This allows direct driving of standard common-anode LED segments with appropriate current-limiting resistors. Exceeding 40 mA risks exceeding absolute maximum ratings and may cause thermal stress or parametric shift in the SN74LS47D.
Can the SN74LS47D drive common-cathode LED displays?
No, the SN74LS47D cannot directly drive common-cathode LED displays because it features active-low open-collector outputs designed for sinking current into common-anode configurations. Driving common-cathode displays would require external inverters or a different decoder such as the SN74LS48N, which has active-high outputs matched to that topology.
How does the BI̅/RBO̅ pin enable leading-zero suppression in multi-digit displays?
The BI̅/RBO̅ pin on the SN74LS47D functions as both input and output: when asserted low, it blanks all segments; when used as RBO̅, it goes low only if the digit is zero AND RBI̅ is low. Cascading multiple SN74LS47D devices connects each RBO̅ to the next stage's RBI̅, allowing only the least-significant non-zero digit to illuminate - suppressing leading zeros automatically.
Is the SN74LS47D RoHS compliant?
Yes, the SN74LS47D is RoHS compliant, with NiPdAu (nickel-palladium-gold) lead finish and compliance verified per TI's packaging documentation. The "Yes" RoHS status applies to all active SOIC (D) variants including SN74LS47D and SN74LS47D.A, meeting EU Directive 2011/65/EU requirements for hazardous substance restrictions.
What is the purpose of the LT̅ (lamp test) input on the SN74LS47D?
The LT̅ input on the SN74LS47D is an asynchronous active-low control that forces all segment outputs (a–g) low regardless of BCD input or blanking conditions. This illuminates all segments simultaneously, enabling rapid hardware-level verification of LED continuity, wiring integrity, and driver functionality during system bring-up or maintenance - a key diagnostic feature in the SN74LS47D.
SN74LS47D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Display Type:
- LED
- Configuration:
- 7 Segment
- Interface:
- BCD
- Digits or Characters:
- -
- Current - Supply:
- 7 mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74LS47D FAQ
1.How can I place an order for SN74LS47D through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS47D 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 SN74LS47D reliable?
The price and inventory of SN74LS47D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS47D is usually 5 days.
3.What payment methods are accepted for SN74LS47D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS47D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS47D?
SN74LS47D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS47D 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 SN74LS47D?
For technical support, including SN74LS47D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS47D requirements.
6.How does Aetrix verify that SN74LS47D is sourced from the original manufacturer or authorized distributors?
All SN74LS47D 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 SN74LS47D meets industry standards.
7.What is the process for return or replacement of SN74LS47D?
All SN74LS47D units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS47D, 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 SN74LS47D part is unused and in its original packaging.
Return procedure for SN74LS47D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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