TLC540IDWR - 8-Bit 75kSPS SAR ADC, 11-Input MUX, 20-SOIC | TI
MPN: TLC540IDWR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.4 | $6.40 |
| 10 | $5.78 | $57.80 |
| 100 | $5.12 | $512.00 |
| 500 | $4.62 | $2,310.00 |
| 1,000 | $4.05 | $4,050.00 |
TLC540IDWR Overview
A Successive-Approximation Register (SAR) ADC is a converter architecture that performs a binary search on the input voltage through an internal DAC, yielding one conversion in N clock cycles for an N-bit result. SAR converters are valued for deterministic latency and absence of pipeline delay, which lets the same architecture scale from 8 to 18 bits without architectural changes. Within the broader taxonomy this part sits under data converters > ADC > SAR ADC > single-channel SAR with integrated MUX, a category dominated by TI's TLC540/TLC541/TLC1541 family and pin-compatible follow-ons.
Key differentiating features include 8-bit resolution with 75 kSPS maximum sample rate, an input MUX that expands a single ADC into eleven analog channels, low conversion time (~17 us typical), software-controlled power down (typically 4 mW active vs sub-mW in shutdown), and a serial interface compatible with TMS320 DSPs and most microcontrollers. A self-test mode exercises the analog path against an internal reference voltage, an unusual feature at this resolution/price point that simplifies production-time board test.
The TLC540/541 family uses a switched-capacitor charge-redistribution DAC at the core of the SAR loop, with a precision analog MUX feeding a single high-impedance input. The serial interface uses chip-select, I/O clock, and data-out lines with the option of synchronous or asynchronous operation. Single +5V supply operation removes the need for negative rails, simplifying analog front-end design in 5V-only industrial systems.
Typical applications include multi-channel sensor monitoring in industrial process control, scanned battery-cell voltage measurement in multi-cell battery management, keypad and panel-meter scanning in low-cost human-interface designs, and portable instrumentation where the on-chip MUX reduces BOM against a discrete MUX + ADC pair.
When designing with the TLC540IDWR, allocate at least four I/O clock cycles per sample and ensure CS/FS (chip-select / frame-sync) timing matches the host DSP. A 0.1 uF decoupling capacitor must be placed within 5 mm of the VCC pin; analog and digital grounds should be tied at a single star point under the device to limit digital-coupling noise on the multiplexer.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, with values verified against TI's TLC540 datasheet and current DigiKey/Mouser stock as of 2026-10-15.
Drop-in alternatives for TLC540IDWR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with TLC540IDWR (same form factor and footprint) — differing in Architecture, Package, Resolution, Sample Rate.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
TLC540IDWRG4
✅ Drop-In📋 Reference alternative (not in catalog)
TLC540IDWG4
✅ Drop-In📋 Reference alternative (not in catalog)
TLC540IDW
✅ Drop-In📋 Reference alternative (not in catalog)
TLC541IDWR
✅ Drop-In📋 Reference alternative (not in catalog)
TLC1541CDWRG4
✅ Drop-In✓ In Stock
$2.74 / Unit
View Datasheet →TLC540IDWR Maximum Ratings & Electrical Characteristics
| Resolution | 8 bit |
| Sample Rate | 75 kSPS |
| Number of Inputs | 11 (single-ended) + 1 self-test (12-channel mux) |
| Architecture | SAR (Successive Approximation Register) |
| Data Interface | Serial (synchronous SPI-compatible, 3-state output) |
| Number of ADC Channels | 1 (with integrated MUX) |
| Supply Voltage | 4.75 V to 5.5 V (single +5 V supply) |
| Operating Temperature | -40 C to +85 C |
| Package | 20-SOIC (DW) |
| Mounting Type | Surface Mount |
| Self-Test Mode | Yes (built-in) |
| Software Power-Down | Yes |
| Channel MUX Type | On-chip 12-channel analog multiplexer |
| Reference | Internal (uses VCC as reference input) |
| RoHS Status | Compliant |
TLC540IDWR Pin Configuration
| Pin 1 | A0 — Analog input channel 0 (MUX input) |
| Pin 2 | A1 — Analog input channel 1 (MUX input) |
| Pin 3 | A2 — Analog input channel 2 (MUX input) |
| Pin 4 | A3 — Analog input channel 3 (MUX input) |
| Pin 5 | A4 — Analog input channel 4 (MUX input) |
| Pin 6 | A5 — Analog input channel 5 (MUX input) |
| Pin 7 | A6 — Analog input channel 6 (MUX input) |
| Pin 8 | A7 — Analog input channel 7 (MUX input) |
| Pin 9 | REF+ — Reference voltage (VCC used as reference input per datasheet) |
| Pin 10 | GND — Ground (analog and digital tied single-point) |
| Pin 11 | A8 — Analog input channel 8 (MUX input) |
| Pin 12 | A9 — Analog input channel 9 (MUX input) |
| Pin 13 | A10 — Analog input channel 10 (MUX input) |
| Pin 14 | SDO — Serial data output (3-state) |
| Pin 15 | I/O CLOCK — Serial interface clock input |
| Pin 16 | CS — Chip select (active low) / frame sync input |
| Pin 17 | MODE — Operating mode selection input |
| Pin 18 | VCC — +5 V supply |
| Pin 19 | TEST1 — Test pin 1 (factory use) |
| Pin 20 | TEST2 — Test pin 2 (factory use / self-test function) |
Typical Applications
TLC540IDWR is suitable for 6 applications: Multi-channel industrial process sensors, Battery-cell voltage monitoring (BMS front end), Digital panel meters and panel scanners, Portable instrumentation and data loggers, Keypad and switch-matrix scanning, Industrial sensor hubs / 4-20 mA loops.
Multi-channel industrial process sensors
The TLC540IDWR is designed for industrial scanning of multiple analog sensors. Its 11-input MUX lets a single ADC handle up to eleven thermocouples, strain gauges, or 4-20 mA conditioned signals in sequence. At 75 kSPS, it can complete a full 11-channel scan in less than 147 microseconds - tight, but adequate for slow-varying process signals. Compared with discrete MUX + ADC solutions, this TI part eliminates the BOM cost of an external analog switch and the layout complexity of matching trace impedances. Design tip: when interfacing to noisy industrial environments, add an RC anti-aliasing filter at each AIN pin (10 kohm + 1 nF gives 16 kHz cutoff).
Recommended
Battery-cell voltage monitoring (BMS front end)
The TLC540IDWR fits BMS analog front ends that sample multi-cell battery stacks. Each cell voltage (1-5 V range) feeds one of the 11 MUX channels, and the ADC's 5 V supply doubles as the reference - simple, low-BoM. The -40 C to +85 C industrial temperature grade covers automotive and outdoor under-hood conditions. Compared with discrete sampling, the integrated MUX trims footprint to one SOIC-20 plus a few passives. Caveat: for high-accuracy BMS systems requiring 1 mV resolution, the 8-bit quantization gives about 19.5 mV granularity, so a 10-/12-bit ADC like TI ADS7828 may be a better fit.
Recommended
Digital panel meters and panel scanners
In digital panel meters and voltmeter scanners, the TLC540IDWR's on-chip MUX lets one chip scan up to 11 inputs sequentially and report back via SPI. The 8-bit result is fast enough for human-readable numeric displays (LCD or 7-segment) without the display perceivably flickering. The serial interface connects directly to most MCU GPIO without glue logic, simplifying the meter-board layout. Compared with dedicated panel-meter ADCs, this TI part offers more flexibility for firmware-led channel selection. Pinout: with the SOIC-20 footprint and known pin assignments from the datasheet, hand-solder rework is straightforward for serviceability.
Recommended
Portable instrumentation and data loggers
Portable data loggers use the TLC540IDWR to scan vibration, temperature, or pressure sensors at sub-kHz rates. The SAR architecture has deterministic latency - one conversion per N clock cycles - making timing calculations straightforward and avoiding the pipeline-delay confusion of higher-speed pipeline ADCs. Software-controlled power-down lets the ADC sleep between scans, drawing microamps and extending battery life. Compared with delta-sigma ADCs of similar speed, the SAR core of this TI part uses no precision analog filter, so settling time after channel switching is short - fast multi-channel scanning without wait states.
Recommended
Keypad and switch-matrix scanning
The TLC540IDWR's MUX can scan an analog key matrix of up to 11 keys/resistive ladder taps by digitizing the resulting voltage. The 8-bit resolution is sufficient for key-press quantization in human-interface panels. Compared with a discrete key-row/column scan via GPIO, this approach eliminates the debounce and wetting issues of mechanical switches - a pressed key produces a stable analog voltage rather than a bouncy logic pulse. Self-test mode can be used during boot to verify the ADC's analog path without external stimuli, simplifying production test fixtures.
Recommended
Industrial sensor hubs / 4-20 mA loops
Industrial 4-20 mA current loops are typically converted to 1-5 V via a 250-ohm sense resistor and scanned by an ADC. The TLC540IDWR can digitize up to eleven of these conditioned voltages through its MUX, sharing a single ADC across many sensors. The serial interface keeps the analog section physically distant from digital noise by using a single data line plus clock rather than parallel traces. Compared with designing an external MUX + ADC solution, the TI part reduces board space, ensures MUX-to-ADC matching, and trims cost. Recommended practice: condition each 4-20 mA loop with a single-stage RC filter (1 kohm + 100 nF) for anti-aliasing, and choose resistor values that put normal-operation voltages in the linear region of the ADC's input range (typically 10-90% of 5 V).
Recommended
Recommended Products Summary
Engineering reference data for TLC540IDWR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TLC540IDWRG4 | TLC540IDWG4 | TLC540IDW | TLC541IDWR | TLC1541CDWRG4 |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 20-SOIC (DW) | 20-SOIC (DW) - same | 20-SOIC (DW) - same | 20-SOIC (DW) - same | 20-SOIC (DW) - same | 20-SOIC (DW) - same |
| Resolution | 8 bit | 8 bit (identical) | 8 bit (identical) | 8 bit (identical) | 8 bit (same core) | 10 bit (upgrade) |
| Sample Rate | 75 kSPS | 75 kSPS (identical) | 75 kSPS (identical) | 75 kSPS (identical) | 75 kSPS (same core) | 38 kSPS (lower) |
| Number of Inputs (MUX) | 11 external + 1 self-test | 11 + 1 (identical) | 11 + 1 (identical) | 11 + 1 (identical) | 11 + 1 (same core) | 11 + 1 (same MUX count) |
| Architecture | SAR | SAR (identical) | SAR (identical) | SAR (identical) | SAR (same) | SAR (same core, higher res) |
| Supply Voltage | +5 V (4.75-5.5 V) | +5 V (identical) | +5 V (identical) | +5 V (identical) | +5 V (same) | +5 V (same) |
| Data Interface | Serial SPI-compatible | Serial SPI-compatible (identical) | Serial SPI-compatible (identical) | Serial SPI-compatible (identical) | Serial (revised timing) | Serial DSP-style frame sync |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C (identical) | -40 C to +85 C (identical) | -40 C to +85 C (identical) | -40 C to +85 C (same) | 0 C to +70 C (commercial) |
| RoHS Compliance | Compliant | Compliant (Pb-free) | Compliant (Pb-free) | Compliant | Compliant | Compliant (Pb-free) |
Key Differentiators
- 11-input on-chip MUX eliminates external analog switch (vs Single-channel SAR ADCs (e.g., many older 8-bit ADCs without MUX))
- Pin-compatible 8-bit family with packaging/finish variants (vs Cross-brand replacements (e.g., non-TI alternatives))
- Industrial temperature grade plus on-chip self-test (vs Commercial-grade ADCs without self-test)
Design Notes
Estimated layout baseline for the TLC540IDWR: place a 0.1 uF decoupling ceramic within 5 mm of the VCC pin (pin 18) plus a 10 uF bulk electrolytic on the same supply trace. Tie analog and digital grounds at a single star point beneath the SOIC-20 footprint - not at the board edge. A floating ground or multiple-tie ground system introduces switching noise into the SAR comparator, degrading last-bit stability. Reserve a guard ring around each analog input trace (AIN0..AIN10) to reduce crosstalk from digital signals.
Estimated supply analysis: at +5 V VCC and typical 8 mA active current, the ADC draws roughly 40 mW active. Because VCC doubles as the SAR reference, supply noise (LDO ripple, GSM burst, switching-event ringing) translates directly into conversion noise. Place the TLC540IDWR downstream of a low-noise LDO such as a TLV1117-5, not on a switching rail sharing the same node with an MCU. Add a ferrite bead at the supply pin if the upstream rail is shared with other circuits.
Watch the SPI timing for the TLC540IDWR: I/O CLOCK must be valid for at least N clock cycles per conversion (N=14 internal cycles), and CS must be asserted before the first clock edge. Pulling CS high mid-conversion triggers an internal reset that drops the result. When migrating firmware from the TLC540 to the TLC541 or TLC1541, verify the register-map differences (especially around MODE pin and self-test selection) - those parts are pin-compatible at the silicon level but require firmware updates for control sequence.
Estimated anti-aliasing guidance: each MUX input should see a low-pass RC filter with -3 dB cutoff at one-tenth of the sampling frequency. With 75 kSPS throughput and ~11 channels scanned sequentially, effective per-channel rate is roughly 6.8 kHz; an R of 10 kohm and C of 2.2 nF gives a 7.2 kHz cutoff. This filter also acts as a front-end MUX transient-glitch suppressor - the MUX switching transients otherwise appear on the input pin for several microseconds. For systems in noisy industrial environments, add a series 1 kohm resistor at each AIN pin to limit input current during ESD events.
Compliance Information
RoHS compliant per TI part suffix conventions. Not AEC-Q100 qualified - this is an industrial-grade part (-40 C to +85 C). For automotive applications, consult TI's automotive-grade ADC portfolio. Lead-free (Pb-free) reflow process compatible. Halogen-free status was not specified in the provided data - confirm with TI's material declaration if required.
