My Inquiry
My Account
Texas Instruments SN74CBT3257DBQR
- Part No.:
- SN74CBT3257DBQR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
SN74CBT3257DBQR.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,323
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74CBT3257DBQR from Texas Instruments is a 4-bit 1-of-2 FET multiplexer/demultiplexer in SSOP-16 (DBQ) package, featuring 5 Ω typical on-state resistance, TTL-compatible control inputs (VIH = 2 V, VIL = 0.8 V), and propagation delay as low as 0.25 ns at VCC = 5 V. It serves as a bidirectional analog/digital signal switch in bus isolation and data routing applications.
For engineers reviewing the SN74CBT3257DBQR datasheet, SN74CBT3257DBQR pinout, SN74CBT3257DBQR application, or SN74CBT3257DBQR equivalent, key selection criteria include on-resistance matching across channels, OE/S-controlled channel selection timing, bidirectional signal integrity at 5 V logic levels, and thermal performance in SSOP-16 (θJA = 90°C/W).
Technical Context
The SN74CBT3257DBQR implements four independent single-pole double-throw (SPDT) FET switches, each selectable via shared S (select) and OE (output enable) control lines. Each switch connects one A-terminal to either B1 or B2 based on S state when OE is low.
It operates with no internal level-shifting circuitry-signal paths are passive, bidirectional, and rail-to-rail compatible within VCC = 4 V to 5.5 V. Control logic uses standard TTL thresholds, and all unused inputs must be tied to VCC or GND per TI SCBA004 guidance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| On-state resistance (ron) | 5 Ω typical at VCC = 4.5 V, 30 mA - ensures minimal voltage drop and signal attenuation in high-speed digital or analog switching paths. |
| Propagation delay (tpd) | 0.25 ns typical at VCC = 5 V, CL = 50 pF - enables sub-nanosecond signal routing for high-frequency bus applications. |
| Supply voltage range | 4 V to 5.5 V - compatible with standard 5 V TTL/CMOS systems without level translation. |
| Input voltage thresholds | VIH = 2 V, VIL = 0.8 V - guarantees reliable recognition of TTL logic levels across temperature (−40°C to 85°C). |
| Channel capacitance (Cio(OFF)) | 4 pF typical at B port with OE = VCC - limits crosstalk and maintains signal integrity during channel disable. |
| Supply current (ICC) | 3 μA typical at VCC = 5.5 V - supports ultra-low static power in always-on signal path management. |
Pinout & Package
SN74CBT3257DBQR is housed in a 16-pin Shrink Small-Outline Package (SSOP-DBQ), 3.9 mm × 4.9 mm body, 1.75 mm max height, 0.65 mm lead pitch. Pin 1 index located at top-left corner with beveled edge marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 13, 14, 15, 16 | B1/B2 port terminals (1B1–4B1, 1B2–4B2) | Four pairs of bidirectional switch outputs; each pair connects to corresponding A terminal when selected by S and enabled by OE. |
| 7, 10, 11, 12 | A port terminals (1A–4A) | Four bidirectional input/output channels; connected to selected B1 or B2 path depending on S and OE states. |
| 8 | GND | Ground reference for all switch and logic circuitry; required for proper on-resistance and timing behavior. |
| 9 | VCC | Positive supply (4–5.5 V); powers internal control logic and defines switch conduction voltage range. |
| 16 | OE | Active-low output enable; when high, all switches disconnect (high-impedance state); when low, S determines B1/B2 routing. |
| 15 | S | Select control; low → A = B1, high → A = B2 (only active when OE = low). |
Key Features
| Feature | Design Value |
|---|---|
| Low on-state resistance | 5 Ω typical ensures <50 mV drop at 10 mA, preserving logic margins and analog signal fidelity. |
| TTL-compatible control interface | VIH = 2 V / VIL = 0.8 V eliminates need for external level shifters in mixed-voltage 5 V systems. |
| Bidirectional signal path | No direction pin required; signals flow equally well from A→B or B→A, simplifying PCB routing in bus arbitration. |
| Fast switching speed | 0.25 ns tpd at 5 V enables use in >1 GHz data paths where propagation skew must be minimized. |
| Low off-capacitance | 4 pF Cio(OFF) minimizes capacitive loading on inactive channels, reducing crosstalk in dense multiplexed buses. |
Applications
| PCI Bus Isolation | Memory Address Multiplexing |
|---|---|
Use Scenario: Isolating PCI address/data lines between two bus masters to prevent contention during handoff. IC Role / Device Role / Timing Role: Bidirectional SPDT switch controlled by system arbitration logic (S/OE) to route signals only when master is granted access. Use Value: 5 Ω Ron and 0.25 ns tpd maintain signal integrity across full PCI 33 MHz timing budget while enabling clean bus ownership transitions. |
Use Scenario: Sharing a single address bus among multiple memory banks using time-multiplexed addressing. IC Role / Device Role / Timing Role: 4-bit demux routes common address lines to Bank A (B1) or Bank B (B2) under microcontroller S/OE control. Use Value: Rail-to-rail analog switching preserves address bit voltage levels across banks, eliminating level-shift errors in multi-bank decoding. |
| Test Equipment Signal Routing | Legacy I/O Expansion |
Use Scenario: Reconfigurable signal path in automated test equipment connecting DUT pins to measurement instruments. IC Role / Device Role / Timing Role: Four independent SPDT switches allow dynamic reassignment of probe points without mechanical relays. Use Value: 4 pF off-capacitance prevents loading of high-impedance instrument inputs; 5 Ω Ron avoids gain error in precision voltage measurements. |
Use Scenario: Adding parallel I/O capability to microcontrollers with limited GPIO, using shared data lines and bank-select logic. IC Role / Device Role / Timing Role: Acts as 4-bit data bus expander, toggling between two peripheral sets via S/OE from MCU control pins. Use Value: TTL-compatible inputs simplify direct connection to 5 V MCUs; low ICC (3 μA) avoids measurable impact on system standby current. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET multiplexer/demultiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3384DBQR | Higher drive strength (±128 mA), 3.3 V–5 V supply, 3.5 Ω Ron, but requires VCC ≥ 4.5 V for guaranteed 5 V operation. | Supports higher-current loads (e.g., terminated transmission lines) but less tolerant of marginal 4 V supplies. | Choose when driving heavier capacitive loads or requiring tighter Ron matching across temperature. |
| 74LVC1G3157GW,125 | Single-channel, 1.65–5.5 V supply, 6 Ω Ron, smaller XSON-6 package, lower ICC (0.1 μA), but lacks 4-bit integration. | Requires four devices for equivalent functionality; better for space-constrained single-line routing than consolidated bus switching. | Choose for ultra-low-power, discrete-channel applications where board area outweighs integration benefit. |
Compared with SN74CBT3257DBQR, SN74CBTD3384DBQR delivers lower Ron and higher current capability at the cost of tighter supply constraints, while 74LVC1G3157GW,125 trades integration for extreme miniaturization and quiescent current reduction-neither is pin-compatible, and both require layout revision.
Availability
SN74CBT3257DBQR is available at Aetrix Electronics and suitable for PCI bus isolation, memory address multiplexing, test equipment signal routing, and legacy I/O expansion requiring stable component supply and long-term industrial availability.
Supply support for SN74CBT3257DBQR 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, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
The SN74CBT3257DBQR belongs to TI's CBT (Crossbar Bus Transceiver) logic family, designed specifically for high-speed, low-distortion analog/digital signal routing in 5 V systems with strict timing and impedance requirements.
FAQ
What is the maximum operating temperature range for the SN74CBT3257DBQR?
The SN74CBT3257DBQR is rated for operation from −40°C to +85°C ambient temperature. This range is validated per TI's recommended operating conditions and supported by thermal characterization (θJA = 90°C/W for DBQ package). The device maintains specified on-resistance, propagation delay, and logic thresholds across this full industrial temperature span, making SN74CBT3257DBQR suitable for deployment in non-temperature-controlled enclosures and outdoor industrial hardware.
Does the SN74CBT3257DBQR support bidirectional signal flow?
Yes, the SN74CBT3257DBQR supports fully bidirectional signal flow between A and B terminals without direction control pins. Its FET-based architecture provides symmetrical conduction characteristics-voltage and current pass equally well from A to B1/B2 or from B1/B2 to A. This enables SN74CBT3257DBQR to serve in applications like shared data buses, JTAG chain reconfiguration, and analog sensor multiplexing where signal origin changes dynamically.
Can unused control inputs on the SN74CBT3257DBQR be left floating?
No, unused control inputs on the SN74CBT3257DBQR must not be left floating. Per TI application report SCBA004, floating TTL-compatible inputs can cause increased ICC, erratic switching, or latch-up due to intermediate voltage states. All unused OE and S inputs must be tied directly to VCC or GND. For SN74CBT3257DBQR, tying OE high disables all channels safely; tying S to GND or VCC fixes the B1/B2 selection permanently if only one path is needed.
What is the significance of the "DBQR" suffix in SN74CBT3257DBQR?
The "DBQR" suffix in SN74CBT3257DBQR identifies the package type and packaging format: "DB" denotes the SSOP (Shrink Small-Outline Package) variant, "Q" indicates the QSOP (Quarter-size Small-Outline Package) dimensional variant per JEDEC MO-137AB, and "R" specifies tape-and-reel packaging (2,000 units per reel). This distinguishes SN74CBT3257DBQR from tube-packaged versions (e.g., SN74CBT3257DBR) and other packages like SOIC-D or TSSOP-PW.
How does the SN74CBT3257DBQR handle power supply decoupling?
The SN74CBT3257DBQR requires local 0.1 μF ceramic decoupling capacitance placed as close as possible to the VCC (pin 9) and GND (pin 8) pins. Due to its fast switching (0.25 ns tpd) and low on-resistance, transient current spikes during channel switching can induce supply noise; inadequate decoupling leads to increased ground bounce, timing jitter, or false switching. TI recommends placing the capacitor within 2 mm of the pins and using short, wide traces-this practice ensures stable operation of SN74CBT3257DBQR in high-speed multiplexing applications.
SN74CBT3257DBQR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Multiplexer/Demultiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- -
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
SN74CBT3257DBQR FAQ
1.How can I place an order for SN74CBT3257DBQR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3257DBQR 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 SN74CBT3257DBQR reliable?
The price and inventory of SN74CBT3257DBQR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3257DBQR is usually 5 days.
3.What payment methods are accepted for SN74CBT3257DBQR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CBT3257DBQR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74CBT3257DBQR?
SN74CBT3257DBQR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBT3257DBQR 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 SN74CBT3257DBQR?
For technical support, including SN74CBT3257DBQR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3257DBQR requirements.
6.How does Aetrix verify that SN74CBT3257DBQR is sourced from the original manufacturer or authorized distributors?
All SN74CBT3257DBQR 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 SN74CBT3257DBQR meets industry standards.
7.What is the process for return or replacement of SN74CBT3257DBQR?
All SN74CBT3257DBQR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3257DBQR, 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 SN74CBT3257DBQR part is unused and in its original packaging.
Return procedure for SN74CBT3257DBQR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74CBT3257DBQR Tags
-
SN74HC138DR
Texas Instruments
-
TC7SB3157CFU,LF(CT
Toshiba Semiconductor and Storage
-
74CBTLV3257PW,118
Nexperia USA Inc.
-
SN74CBTLV3257PWR
Texas Instruments
-
74CBTLV3257GUX
Nexperia USA Inc.
-
74HC154BQ,118
Nexperia USA Inc.
-
P3S0200GMX
NXP USA Inc.
-
SN74CB3Q3245PWR
Texas Instruments
-
SN74CB3Q3257RGYR
Texas Instruments
-
TCA9543APWR
Texas Instruments
-
TCA9546APWR
Texas Instruments
-
SN74HC138N
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
