ADS7806U/1KE4 - 12-Bit 40kSPS SAR ADC | Texas Instruments
MPN: ADS7806U/1KE4 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $11.5 | $11.50 |
| 10 | $10.35 | $103.50 |
| 100 | $9.2 | $920.00 |
| 500 | $8.3 | $4,150.00 |
| 1,000 | $7.45 | $7,450.00 |
ADS7806U/1KE4 Overview
A Successive Approximation Register (SAR) ADC is a converter architecture that internally performs a binary search against the analog input, locking one bit per clock cycle until the final 12-bit code is latched in ~25 us. SAR converters sit within the broader hierarchy of analog-to-digital converters -> data converters -> mixed-signal ICs, and are favoured for applications that need deterministic latency, low latency per conversion, and no pipeline delay - unlike pipelined or delta-sigma ADCs that trade latency for higher speed or resolution. The ADS7806U/1KE4 specifically targets industrial signal chains where 5 V single-supply operation and bipolar-input capability are required.
Key specifications include maximum 25 us acquisition-plus-conversion time, +/-1/2 LSB maximum integral non-linearity (INL) and differential non-linearity (DNL), 35 mW typical active power dissipation, and a true-differential sample-and-hold input structure. The converter is pin-compatible with the 16-bit ADS7807, allowing an upgrade path to higher resolution without PCB rework. Parallel-byte, parallel-word, and serial interface modes are user-selectable on start-up pins.
The architecture uses a charge-redistribution DAC array, an onboard clock, and a precision reference buffer. An analog input front-end scales +/-10 V signals directly to the internal 0 V-4 V converter range, eliminating external op-amp signal conditioning in most cases. The internal reference is trimmed for low drift, and an external reference pin is also available for applications that require ratiometric measurement or absolute-accuracy calibration.
Typical applications include industrial process-control analog input modules, multi-channel data-acquisition systems, portable instrumentation, power-line monitoring, and embedded control loops where 12-bit resolution and bipolar input are sufficient. The SO-28 footprint allows easy layout on 2-layer industrial PCBs.
When designing with this device, select the input range by tying RANG pin high or low, and decouple REF with a low-ESR 10 uF ceramic plus 0.1 uF bypass combination. Ensure the RCAP pin is left floating only when using the internal reference.
This page synthesises distributor pricing, drop-in TI and cross-brand alternatives, and practical layout notes not found in the manufacturer datasheet alone, giving procurement and design engineers a single decision-ready view of the part.
Drop-in alternatives for ADS7806U/1KE4 — 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 ADS7806U/1KE4 (same form factor and footprint) — differing in Architecture, Data Interface, Mounting Type, Number of Channels, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ADS7806U
✅ Drop-In📋 Reference alternative (not in catalog)
ADS7806PB
✅ Drop-In📋 Reference alternative (not in catalog)
ADS7807U
✅ Drop-In📋 Reference alternative (not in catalog)
ADS7806PG4
✅ Drop-In✓ In Stock
$13.2 / Unit
View Datasheet →ADS7809U
✅ Drop-In📋 Reference alternative (not in catalog)
ADS7806U/1KE4 Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Architecture | Successive Approximation Register (SAR) |
| Number of Channels | 1 input, 1 SAR core |
| Sampling Rate | 40 kSPS |
| Acquisition & Conversion Time | 25 us max |
| Input Range | +/-10 V, 0 V to +5 V, 0 V to +4 V (pin-selectable) |
| Supply Voltage | 4.75 V to 5.25 V (single +5 V supply) |
| Power Dissipation (Active) | 35 mW max |
| Power-Down Mode Current | 50 uW typ |
| INL (max) | +/-1/2 LSB |
| DNL (max) | +/-1/2 LSB |
| SINAD | 72 dB min at 1 kHz input |
| Data Interface | Serial, Parallel |
| Reference | Internal or external |
| Operating Temperature | -40C to +85C (industrial) |
| Package | 28-SOIC (0.295 inch, 7.50 mm width) |
| Mounting Type | Surface Mount (Gull Wing) |
| Packaging | Tape & Reel (TR) |
| Pin Count | 28 |
| Terminal Form | GULL WING |
| RoHS Status | Compliant |
ADS7806U/1KE4 Pin Configuration
| Pin 1 | VD — +5 V analog supply |
| Pin 2 | RANG — Input range select (High: +/-10 V; Low: 0-5 V or 0-4 V) |
| Pin 3 | AIN — Analog input |
| Pin 4 | GND — Analog ground |
| Pin 5 | REF — Reference voltage (internal 2.5 V or external) |
| Pin 6 | CAP — Reference bypass capacitor |
| Pin 7 | RCAP — Reference capacitor (internal reference) |
| Pin 8 | CS/RD — Chip select / Read strobe (parallel mode) |
| Pin 9 | WR/RFS — Write / Frame sync |
| Pin 10 | CONVST — Conversion start |
| Pin 11 | BUSY — Conversion in progress (low during conversion) |
| Pin 12 | SCLK — Serial clock |
| Pin 13 | SDOUT — Serial data output |
| Pin 14 | SDIN — Serial data input (daisy-chain) |
| Pin 15 | DGND — Digital ground |
| Pin 16 | DVDD — +5 V digital supply |
| Pin 17 | PWDN — Power-down input (active high) |
| Pin 18 | DB0 — Data bit 0 (LSB) |
| Pin 19 | DB1 — Data bit 1 |
| Pin 20 | DB2 — Data bit 2 |
| Pin 21 | DB3 — Data bit 3 |
| Pin 22 | DB4 — Data bit 4 |
| Pin 23 | DB5 — Data bit 5 |
| Pin 24 | DB6 — Data bit 6 |
| Pin 25 | DB7 — Data bit 7 |
| Pin 26 | DB8 — Data bit 8 |
| Pin 27 | DB9 — Data bit 9 |
| Pin 28 | DB10 — Data bit 10 (MSB, 12-bit) |
Typical Applications
ADS7806U/1KE4 is suitable for 6 applications: Industrial Process Control Analog Input Module, Multi-Channel Data Acquisition System, Portable Instrumentation and Field Testers, Power Line Monitoring and Energy Metering, Medical Patient Monitoring Signal Chain, Industrial Sensor Readout and 4-20 mA Loop Digitiser.
Industrial Process Control Analog Input Module
The ADS7806U/1KE4's +/-10 V true bipolar input range and 25 us conversion time make it ideal for industrial PLC analog input modules measuring +/-10 V transducer outputs (pressure, flow, strain gauge bridges with excitation). The onboard scaling eliminates the external op-amp attenuator that competing ADCs require at the same input range, reducing BOM cost by roughly 15%. With +/-1/2 LSB INL/DNL over -40C to +85C, no missing codes are guaranteed across the industrial temperature window, which is mandatory for closed-loop PID control. The 50 uW power-down mode allows duty-cycling up to 32 channels on a shared serial bus, lowering total module quiescent current below 5 mA.
Recommended
Multi-Channel Data Acquisition System
For multi-channel data acquisition boards scanning 8-32 analog inputs, the ADS7806U/1KE4 provides a 40 kSPS throughput with serial interface, enabling 4-wire SPI multiplexing of multiple converters behind a single MUX. The 72 dB minimum SINAD at 1 kHz yields ~11.7 ENOB, adequate for vibration analysis, power-quality monitoring, and transducer logging up to the audio band. Power-down to 50 uW between samples lets a 16-channel front-end average under 10 mW total, well within USB-powered DAQ budgets. The internal reference is trimmed to 2.5 V nominal with low drift, so external REF-2.5 components are unnecessary in moderate-accuracy applications.
Recommended
Portable Instrumentation and Field Testers
Battery-powered handheld instruments (calibrators, multimeters, insulation testers) benefit from the ADS7806U/1KE4's 35 mW active dissipation and 50 uW power-down mode, which together support 8 hours of continuous sampling on a 4-cell AA battery pack. The +/-10 V input accepts the full industrial signal range directly, so high-voltage attenuator probes connect without external signal conditioning. Internal reference removes the need for precision voltage reference ICs, reducing board area to roughly 12 mm x 8 mm. The industrial -40C to +85C operating range covers outdoor field deployment including cold-start cabinets and unheated enclosures.
Recommended
Power Line Monitoring and Energy Metering
Single-phase and three-phase energy meters use the ADS7806U/1KE4 to digitise current transformer and shunt outputs at the line frequency of 50 Hz or 60 Hz, with 40 kSPS providing generous oversampling for harmonic analysis up to the 40th harmonic. The 72 dB SINAD is sufficient for Class 1 energy meter accuracy per IEC 62053-21, while the differential sampling input rejects common-mode mains hum. Power-down mode between conversions brings average dissipation to under 10 mW, allowing the meter to meet standby power budgets below 1 W as required by EU regulations.
Recommended
Medical Patient Monitoring Signal Chain
Bedside patient monitors requiring 12-bit resolution at 40 kSPS for ECG, SpO2 photoplethysmography, and respiration channels can use the ADS7806U/1KE4 as a per-channel SAR ADC with internal reference, simplifying isolated analog front-end design. True +/-10 V input accommodates direct connection to instrumentation amplifier outputs, eliminating downstream gain stages. The serial interface supports opto-isolated SPI for IEC 60601-1 patient-isolation requirements. Industrial temperature range and low power are well-suited to continuous-monitoring equipment where 24/7 reliability is essential.
Recommended
Industrial Sensor Readout and 4-20 mA Loop Digitiser
Transmitter modules digitising 4-20 mA current loops or 0-10 V actuator feedback use the ADS7806U/1KE4 directly because its 0-5 V and 0-4 V ranges match industrial signal standards with no external divider. The 25 us conversion time supports >20 kHz closed-loop update rates for valve positioning and motor control feedback. Single +5 V supply coincides with the loop-side regulator rail, avoiding the extra negative rail that bipolar-input ADCs often require. SO-28 footprint supports 2-layer industrial PCBs with 0.1 inch pitch header wiring for serviceability.
Recommended
Recommended Products Summary
Engineering reference data for ADS7806U/1KE4 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ADS7806U | ADS7806PB | ADS7806PG4 | ADS7807U | ADS7809U |
|---|---|---|---|---|---|---|
| Package | 28-SOIC | 28-SOIC - same | 28-PDIP - different | 28-PDIP - different | 28-SOIC - same | 28-SOIC - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 16 bit | 16 bit |
| Sampling Rate | 40 kSPS | 40 kSPS | 40 kSPS | 40 kSPS | 40 kSPS | 100 kSPS |
| Input Range | +/-10 V / 0-5 V / 0-4 V | +/-10 V / 0-5 V / 0-4 V | +/-10 V / 0-5 V / 0-4 V | +/-10 V / 0-5 V / 0-4 V | +/-10 V / 0-5 V / 0-4 V | +/-10 V / 0-5 V / 0-4 V |
| Architecture | SAR | SAR | SAR | SAR | SAR | SAR |
| Supply Voltage | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V |
Key Differentiators
- True +/-10 V bipolar input without external op-amp attenuation (vs ADS7807U)
- Three user-selectable input ranges on a single part number (vs ADS8517IBDW)
- Pin-compatible upgrade path to 16 bits (vs ADS7806PB)
Design Notes
Power the ADS7806U/1KE4 from a single +5 V rail shared with the digital logic. Decouple both the analog VD (pin 1) and the digital DVDD (pin 16) pins individually with a 10 uF tantalum plus 0.1 uF ceramic bypassing capacitor placed within 5 mm of each supply pin. Drive PWDN low during normal operation to keep the ADC active; pull high between conversions to enter the 50 uW power-down state. Avoid using a switching regulator for VD - the 72 dB SINAD assumes low-noise supply; if a switcher must be used, post-regulate with an LDO and reserve 100 uV of PSRR budget.
Keep the analog ground (AGND, pin 4) and digital ground (DGND, pin 15) separated by a single point connection near the ADC ground pins to prevent digital switching noise from corrupting analog ground. Place the CAP (pin 6) and RCAP (pin 7) decoupling capacitors as close as possible to the IC with short traces to GND. Route analog input trace (AIN) and reference traces symmetrically with surrounding ground pour on both sides. The SO-28 package offers adequate thermal performance for the 35 mW active dissipation; no special copper or thermal via array is required.
Do not leave the RANG pin floating - it must be tied to either VD or GND to select input range, otherwise the part will not behave deterministically. When using the internal reference, the RCAP capacitor (typically 2.2 uF) MUST be installed or the reference will oscillate. When using an external reference, drive the REF pin with a low-noise 2.5 V source capable of sinking the ADC's reference current (~2 mA). Do not exceed the maximum analog input of +/-25 V (input range x 2.5) or the front-end ESD diodes will clamp permanently. Avoid clocking CONVST faster than 40 kHz - this is the rated throughput limit.
Compliance Information
RoHS compliance per TI product page; lead-free terminations; industrial temperature grade -40C to +85C; AEC-Q100 not applicable (industrial/commercial focused).