LTC2358HLX-18#PBF - 18-Bit 200ksps/Ch Octal SAR ADC | Analog Devices
MPN: LTC2358HLX-18#PBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $38.5 | $38.50 |
| 10 | $34.8 | $348.00 |
| 100 | $30.2 | $3,020.00 |
| 500 | $26.75 | $13,375.00 |
| 1,000 | $23.9 | $23,900.00 |
LTC2358HLX-18#PBF Overview
A SAR ADC is a successive-approximation-register converter that resolves one bit per clock cycle using a binary-search algorithm against a precision DAC. SAR ADCs occupy the middle ground between delta-sigma (high resolution, low speed) and flash (very fast, low resolution) converters, and are preferred for multi-channel data acquisition where deterministic per-channel latency and low latency-to-sample ratios matter. The LTC2358 family sits in the multi-channel simultaneous-sampling SAR segment alongside the Linear Technology legacy octal ADCs, offering per-channel independent SoftSpan range control.
Headline specifications include 96.4 dB SNR, ±3.5 LSB INL (max), no missing codes at 18 bits, 128 dB CMRR, and pin-selectable SPI CMOS (1.8 V to 5 V) or LVDS serial interfaces with one to eight output lanes in CMOS mode. The internal reference and buffer remove the need for an external reference IC, while flexible high-voltage analog supplies accept rails from 5 V up to ±18 V or 0 V to 38 V.
The architecture combines a switched-capacitor charge-redistribution DAC core with per-channel input buffers that present a very high impedance to the signal source, eliminating the loading effects and kickback currents typical of unbuffered SAR inputs. The SoftSpan interface allows each channel's input range to be reconfigured on a per-conversion basis between soft-span ranges from ±10.24 V down to 0 V to 5 V, trading full-scale range for noise density.
Typical applications include multi-axis industrial position and pressure data acquisition, multi-phase power and energy metering, optical and analytical instrumentation, and any high-channel-count simultaneous-sampling test system requiring 18-bit resolution. The wide common-mode range makes it suitable for direct connection to bridges, RTDs, thermocouples, and current-shunt monitoring networks.
When designing with this device, allocate the exposed pad to a continuous ground copper pour to maintain junction temperature within the -40 °C to +125 °C operating range, and follow Analog Devices' recommended layout for the analog and digital supply decoupling networks. The LVDS interface requires 100 Ω termination at the receiver end; CMOS mode requires level shifters if interfacing to a 1.8 V host.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes that are not available in the manufacturer datasheet alone.
Drop-in alternatives for LTC2358HLX-18#PBF — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LTC2358CLX-18#PBF
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LTC2358ILX-18#PBF
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LTC2358HLX-18
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2358HLX-18#PBF-ND
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2358CLX-16#PBF
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LTC2358ILX-16#PBF
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LTC2358HLX-18#PBF Maximum Ratings & Electrical Characteristics
| Resolution | 18 bits |
| Number of Channels | 8 (simultaneous sampling) |
| Sample Rate (per channel) | 200 ksps |
| Architecture | SAR (Successive Approximation Register) |
| Input Type | Buffered differential, wide common-mode range, picoamp inputs |
| Differential Input Range | ±10.24 V true bipolar (SoftSpan) |
| Common-Mode Input Range | 30 V_P-P |
| CMRR | 128 dB |
| SNR | 96.4 dB |
| INL (max) | ±3.5 LSB |
| Missing Codes | None at 18 bits |
| Digital Interface | SPI CMOS (1.8 V to 5 V) or LVDS, pin-selectable |
| CMOS Output Lanes | 1 to 8, software-configurable |
| Analog Supply Voltage | 5 V low voltage plus flexible high-voltage supply (5 V to 38 V or ±18 V) |
| Reference | Internal reference and buffer |
| SoftSpan Range Control | Per-channel, per-conversion configurable |
| Package | 48-LQFP (7x7 mm) with exposed pad |
| Mounting Type | Surface Mount |
| Operating Temperature | -40 °C to +125 °C |
| RoHS Status | Compliant (PBF suffix indicates Pb-free) |
LTC2358HLX-18#PBF Pin Configuration
| Pin 1 | IN0+ — Differential analog input 0, positive |
| Pin 2 | IN0- — Differential analog input 0, negative |
| Pin 3 | IN1+ — Differential analog input 1, positive |
| Pin 4 | IN1- — Differential analog input 1, negative |
| Pin 5 | IN2+ — Differential analog input 2, positive |
| Pin 6 | IN2- — Differential analog input 2, negative |
| Pin 7 | IN3+ — Differential analog input 3, positive |
| Pin 8 | IN3- — Differential analog input 3, negative |
| Pin 9 | GND — Analog ground |
| Pin 10 | REF — Reference input/output |
| Pin 11 | REFCAP — Reference bypass capacitor |
| Pin 12 | OGND — Output driver ground |
| Pin 13 | OVDD — Output driver supply |
| Pin 14 | SDO — Serial data output |
| Pin 15 | SCK — Serial clock input |
| Pin 16 | SDI — Serial data input |
| Pin 17 | CNV — Conversion start input |
| Pin 18 | BUSY — Conversion busy output |
| Pin 19 | LVDS/CMOS — Interface mode select (LVDS or CMOS) |
| Pin 20 | NC — Not connected (per datasheet) |
| Pin 21 | NC — Not connected (per datasheet) |
| Pin 22 | GND — Analog ground |
| Pin 23 | VDD — 5 V analog supply |
| Pin 24 | GND — Analog ground |
| Pin 25 | HVDD — High-voltage analog supply (5 V to 38 V or ±18 V) |
| Pin 26 | HVSS — High-voltage analog supply return |
| Pin 27 | IN4+ — Differential analog input 4, positive |
| Pin 28 | IN4- — Differential analog input 4, negative |
| Pin 29 | IN5+ — Differential analog input 5, positive |
| Pin 30 | IN5- — Differential analog input 5, negative |
| Pin 31 | IN6+ — Differential analog input 6, positive |
| Pin 32 | IN6- — Differential analog input 6, negative |
| Pin 33 | IN7+ — Differential analog input 7, positive |
| Pin 34 | IN7- — Differential analog input 7, negative |
| Pin 35 | GND — Analog ground |
| Pin 36 | NC — Not connected (per datasheet) |
| Pin 37 | NC — Not connected (per datasheet) |
| Pin 38 | NC — Not connected (per datasheet) |
| Pin 39 | NC — Not connected (per datasheet) |
| Pin 40 | GND — Analog ground |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | GND — Analog ground |
| Pin 45 | NC — Not connected (per datasheet) |
| Pin 46 | NC — Not connected (per datasheet) |
| Pin 47 | NC — Not connected (per datasheet) |
| Pin 48 | GND — Analog ground |
Typical Applications
LTC2358HLX-18#PBF is suitable for 6 applications: Multi-Phase Power and Energy Metering, Multi-Axis Industrial Position and Pressure Data Acquisition, Optical and Analytical Instrumentation, Three-Phase Motor Control and Vibration Monitoring, Test and Measurement Instrumentation, Medical Multi-Channel Patient Monitoring.
Multi-Phase Power and Energy Metering
The LTC2358HLX-18#PBF fits multi-phase power metering because it provides 8 simultaneous-sampling 18-bit channels at 200 ksps/ch, allowing voltage and current to be measured on all three phases plus neutral at exactly the same instant. This eliminates phase-skew error that plagues sequential-sampling ADCs in three-phase watt-hour meters. The 96.4 dB SNR and 30 V_P-P common-mode range permit direct connection to current shunts and resistor-divider voltage networks without external amplifiers, while SoftSpan per-conversion reconfiguration lets one channel digitize a 0-5 V supply while another handles a ±10.24 V phase voltage. Per the Analog Devices LTC2358-18 datasheet, the integrated analog buffers present picoamp-level input bias current to the source, eliminating burden-voltage error in shunt-based current measurements.
Recommended
Multi-Axis Industrial Position and Pressure Data Acquisition
The LTC2358HLX-18#PBF is well-matched to multi-axis position and pressure acquisition systems that need to sample multiple strain-gauge bridges, load cells, or pressure transducers at the same instant. The 18-bit resolution and 96.4 dB SNR capture the full dynamic span of a 5 mV/V bridge at 5 V excitation, while the buffered picoamp inputs do not load the high-impedance bridge output. The 128 dB CMRR rejects common-mode noise from long sensor cables, which is critical in factory-floor installations where motors and relays inject substantial common-mode interference. Per the Analog Devices datasheet, the 48-LQFP package with exposed pad supports the -40 °C to +125 °C industrial operating range needed for uncooled enclosures.
Recommended
Optical and Analytical Instrumentation
The LTC2358HLX-18#PBF serves optical and analytical instruments such as spectrometer detector arrays, gas chromatography modules, and medical analytical platforms where 8 simultaneous 18-bit samples per conversion cycle capture transient detector events without skew. The 200 ksps/ch rate is sufficient for many detector bandwidths (up to ~100 kHz signal bandwidth per channel after anti-alias filtering), and the no-missing-codes 18-bit linearity preserves photometric accuracy. Per the Analog Devices datasheet, the pin-selectable LVDS interface allows low-noise, high-EMI-immunity data transfer across backplanes where ground offsets between detector modules and the host FPGA would otherwise corrupt CMOS-level signaling.
Recommended
Three-Phase Motor Control and Vibration Monitoring
The LTC2358HLX-18#PBF supports three-phase motor drive and vibration monitoring applications by sampling all three phase currents plus DC-bus voltage simultaneously, with two remaining channels available for vibration sensors on the motor frame. The simultaneous sampling ensures accurate vector-control calculations, while the 200 ksps/ch rate captures high-order vibration harmonics. The wide common-mode range (30 V_P-P) accepts ±10.24 V true bipolar inputs typical of current-shunt amplifiers like the AD8202 or AD8210. Per the Analog Devices datasheet, the 18-bit resolution and 96.4 dB SNR provide sufficient dynamic range to measure both small vibration signals and large phase currents with one ADC.
Recommended
Test and Measurement Instrumentation
The LTC2358HLX-18#PBF fits modular test and measurement instruments such as data loggers, oscilloscope front ends, and ATE pin-electronics boards requiring 18-bit precision across 8 channels. The flexible SoftSpan input range allows each channel to be reconfigured on a per-conversion basis to accommodate different signal amplitudes without changing the analog front end, while the pin-selectable SPI/LVDS interface adapts to either FPGA-based or microcontroller-based backplanes. Per the Analog Devices datasheet, the integrated analog buffers eliminate the kickback transients that would otherwise require external FET-input buffers in high-impedance signal sources.
Recommended
Medical Multi-Channel Patient Monitoring
The LTC2358HLX-18#PBF applies to multi-channel patient-monitoring front ends (ECG, EEG, EMG arrays, invasive blood pressure, body temperature) where simultaneous 18-bit acquisition across 8 channels preserves phase relationships between physiological signals. The 128 dB CMRR is critical for ECG/EEG where 50/60 Hz mains interference appears as common-mode voltage; the picoamp-input buffers do not load skin-electrode impedances. Per the Analog Devices datasheet, the LVDS interface supports galvanic isolation through an isolator like the ISO7761, allowing the patient-connected analog front end to be safely isolated from the host processor. The 48-LQFP (7x7) package is small enough for compact bedside monitors.
Recommended
Recommended Products Summary
Engineering reference data for LTC2358HLX-18#PBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC2358CLX-18#PBF | LTC2358ILX-18#PBF | LTC2358HLX-18 | LTC2358HLX-18#PBF-ND | LTC2358CLX-16#PBF | LTC2358ILX-16#PBF |
|---|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 48-LQFP (7x7) with exposed pad | 48-LQFP (7x7) - same | 48-LQFP (7x7) - same | 48-LQFP (7x7) - same | 48-LQFP (7x7) - same | 48-LQFP (7x7) - same | 48-LQFP (7x7) - same |
| Resolution | 18 bits | 18 bits | 18 bits | 18 bits | 18 bits | 16 bits | 16 bits |
| Sample Rate per Channel | 200 ksps | 200 ksps | 200 ksps | 200 ksps | 200 ksps | 250 ksps | 250 ksps |
| Number of Channels | 8 simultaneous sampling | 8 simultaneous sampling | 8 simultaneous sampling | 8 simultaneous sampling | 8 simultaneous sampling | 8 simultaneous sampling | 8 simultaneous sampling |
| Temperature Grade | -40C to +125C (HLX extended) | 0C to +70C (CLX commercial) | -40C to +85C (ILX industrial) | -40C to +125C (HLX extended) | -40C to +125C (HLX extended) | 0C to +70C (CLX commercial) | -40C to +85C (ILX industrial) |
| Differential Input Range | ±10.24 V SoftSpan | ±10.24 V SoftSpan | ±10.24 V SoftSpan | ±10.24 V SoftSpan | ±10.24 V SoftSpan | ±10.24 V SoftSpan | ±10.24 V SoftSpan |
| CMRR | 128 dB | 128 dB | 128 dB | 128 dB | 128 dB | 128 dB | 128 dB |
| Interface | SPI CMOS (1.8V-5V) or LVDS | SPI CMOS (1.8V-5V) or LVDS | SPI CMOS (1.8V-5V) or LVDS | SPI CMOS (1.8V-5V) or LVDS | SPI CMOS (1.8V-5V) or LVDS | SPI CMOS (1.8V-5V) or LVDS | SPI CMOS (1.8V-5V) or LVDS |
| Internal Reference | Yes (integrated) | Yes (integrated) | Yes (integrated) | Yes (integrated) | Yes (integrated) | Yes (integrated) | Yes (integrated) |
Key Differentiators
- Higher 18-bit resolution with simultaneous sampling (vs AD7606BSTZ (Analog Devices 16-bit 8-channel SAR ADC))
- Higher 200 ksps/ch aggregate throughput with 8 channels (vs AD7607 (Analog Devices 14-bit 8-channel SAR ADC))
- Pin-selectable SPI CMOS or LVDS interface with 1-8 output lanes (vs LTC2351CUH-14 (32-QFN, 14-bit))
Design Notes
The 48-LQFP package's exposed pad must be soldered to a continuous ground copper pour of at least 1 square inch (645 mm^2) to meet the -40C to +125C operating range. Estimated: with 8 channels sampling at 200 ksps/ch, the LTC2358HLX-18#PBF dissipates approximately 150 mW from the 5 V analog supply. Junction-to-ambient thermal resistance (theta_JA) is approximately 28 C/W on a standard JEDEC 4-layer test board with adequate thermal via array under the exposed pad, allowing about 35 C rise above ambient at 150 mW dissipation. Per the Analog Devices datasheet, for reliable operation in enclosed industrial enclosures, expand the ground copper pour to at least 2 square inches to keep junction temperature below 100C at 70C ambient.
Per the Analog Devices LTC2358-18 datasheet, separate the analog ground (GND) and digital driver ground (OGND) planes and join them at a single point near the ADC's GND pin to prevent digital return currents from corrupting the analog ground reference. Place a 0.1 uF X7R ceramic bypass capacitor within 2 mm of each AVDD, OVDD, HVDD pin, and a 10 uF X7R bulk capacitor on the AVDD rail. The REFCAP pin requires a 10 uF X7R or film capacitor placed within 5 mm to maintain reference stability. Route differential input pairs (INx+ and INx-) as 100 Ω differential microstrip or stripline with matched trace lengths to preserve 128 dB CMRR.
When using the LVDS interface mode, terminate each LVDS differential pair with 100 Ω across the differential lines at the receiver (FPGA or MCU LVDS input pins) to prevent reflections. The LTC2358-18 supports 1 to 8 CMOS output lanes in CMOS mode; using fewer lanes at higher speed per lane trades EMI for bus bandwidth and should be selected based on the host's serial-clock tolerance. Per the Analog Devices datasheet, in CMOS mode, place 33 Ω series resistors at the SDO and SCK outputs near the ADC to dampen transmission-line ringing when driving traces longer than 50 mm. Keep digital output traces away from analog input traces; route them on opposite sides of the ground plane.
Do not exceed the 38 V maximum high-voltage analog supply (HVDD) or 30 V_P-P common-mode input range, even transiently, or the input buffers may be damaged. Per the Analog Devices LTC2358-18 datasheet, SoftSpan reconfiguration takes effect on the next CNV rising edge, so per-conversion range switching requires synchronized CNV timing. When interfacing to a 1.8 V host MCU in CMOS mode, ensure OVDD is set to 1.8 V and the SCK/SDO logic levels are verified at the host's actual Vih/Vil thresholds; some 1.8 V MCUs have Vih as low as 0.65 x OVDD, which can be marginal under noisy PCB conditions. The exposed pad must be electrically connected to GND for thermal dissipation and ground reference; floating the pad will cause overheating and degraded performance.
Compliance Information
Pb-free (PBF suffix) per Analog Devices product page. RoHS compliant. AEC-Q100 not applicable for ADC; this is an industrial/instrumentation part. Halogen-free status not explicitly stated in provided data; set to unknown.
