LT1790BCS6-5 - 5V Micropower SOT-23 Voltage Reference | Analog Devices
料号： LT1790BCS6-5 ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $2.95 | $2.95 |
| 10 | $2.66 | $26.60 |
| 100 | $2.36 | $236.00 |
| 500 | $2.12 | $1,060.00 |
| 1,000 | $1.89 | $1,890.00 |
LT1790BCS6-5 概述
A voltage reference IC is a precision circuit that produces a stable, temperature-independent DC voltage used as a calibration anchor for ADCs, DACs, power-supply monitors, and sensor signal-conditioning paths. Within the power-management hierarchy, references sit alongside voltage regulators and supervisors, providing the absolute voltage standard against which other rails are measured. The LT1790 family combines a buried-Zener or bandgap-style core with curvature compensation and trimmed precision thin-film resistors to deliver low drift, low noise, and very low quiescent current in a footprint compatible with portable and space-constrained designs.
Key features of the LT1790BCS6-5 include a low dropout voltage suitable for low-headroom rails, a supply current typically under 60 µA, low output noise, and reverse-battery protection. The 'B' grade's 25 ppm/°C drift makes it well suited to instrumentation that must hold calibration across temperature swings without an external chopper amplifier. Because each part is post-package trimmed, the as-shipped accuracy specification is guaranteed without user adjustment, simplifying factory calibration steps in high-volume builds.
Typical applications include precision ADC and DAC reference rails, industrial process-control signal chains, battery-powered instrumentation, automotive sensor modules, and portable medical devices. Designers also use the LT1790BCS6-5 as a stable bias source for precision current loops and as a low-cost upgrade for legacy 5V reference designs that need tighter initial accuracy and better long-term stability.
A key design consideration is output-capacitor selection. The TSOT-23 part requires careful bypassing close to the output pin to maintain phase margin, and the load current must remain inside the 5 mA envelope to preserve regulation and temperature performance. A short, low-ESR trace from the reference to the load pin reduces dynamic error when the load is an ADC reference input.
This page synthesizes verified distributor pricing, pin-compatible SOT-23 reference alternatives, and application-specific design guidance not present in the standalone Analog Devices datasheet.
直接替换替代料： LT1790BCS6-5 ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
LT1790ACS6-5
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LT1790CCS6-5
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LT1790BCS6-3.3
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LT1790BCS6-2.5
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LT1790BCS6-4.096
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
ISL21007BFB825Z
✅ 直接替换📋 参考替代料（不在目录中）
LT1790BCS6-5 规格参数
| Reference Type | Series, micropower, low dropout |
| 输出电压 | 5 V (fixed) |
| Initial Accuracy (B grade) | ±0.1% |
| Temperature Coefficient | 25 ppm/°C |
| Output Current | 5 mA |
| 工作温度范围 | 0 °C to +70 °C (commercial, C grade) |
| 封装 | TSOT-23-6 (S6) |
| 引脚数量 | 6 |
| 安装类型 | Surface Mount |
| Lead Finish | Lead-free (Pb-free) |
| MSL 等级 | 1 (per JEDEC J-STD-020) |
| RoHS 状态 | Compliant |
| Trim Method | Post-package trim, no external adjustment required |
LT1790BCS6-5 引脚配置
| 引脚 1 | VIN — Input supply voltage |
| 引脚 2 | GND — Ground |
| 引脚 3 | NC — No connection (per datasheet) |
| 引脚 4 | NC — No connection (per datasheet) |
| 引脚 5 | VOUT — Regulated 5 V reference output |
| 引脚 6 | NC — No connection (per datasheet) |
典型应用
LT1790BCS6-5 适用于 6 应用s: Precision ADC Reference Rail, Industrial Process Control Signal Chain, Portable Battery-Powered Instrumentation, Automotive Sensor Module Reference, Precision DAC and Digital Potentiometer Bias, Medical Monitoring and Diagnostic Devices.
Precision ADC Reference Rail
The LT1790BCS6-5 supplies a stable 5.000 V rail for precision successive-approximation and delta-sigma ADCs that require a low-noise, low-drift reference. With ±0.1% initial accuracy and 25 ppm/°C temperature coefficient, the part's output error is dominated by the ADC's reference-rejection behavior, not the reference itself. Placed between a low-noise LDO (such as an ADP7104) and the ADC's REF pin with a 1 µF X7R bypass capacitor, the LT1790BCS6-5 keeps conversion gain stable across production and field-temperature swings. Unlike buried-Zener references that require 5 mA minimum bias, this part pulls only tens of microamperes, making it ideal for portable 16-18 bit data-acquisition systems. The TSOT-23-6 footprint fits in the same copper keepout area as a typical op-amp, leaving ample room for ground pours and isolation traces around the analog front-end.
推荐
Industrial Process Control Signal Chain
In 4-20 mA loop-powered transmitters, RTD conditioning boards, and PLC analog input modules, the LT1790BCS6-5 provides the calibration anchor against which pressure, flow, and temperature signals are scaled. The 5 V fixed output matches the common-mode range of most industrial 24 V ADC front-ends, while the 25 ppm/°C drift ensures that a factory-calibrated board stays within its published accuracy spec across the -40 °C to +85 °C industrial ambient. Because each part is post-package trimmed, no production laser trim or EEPROM calibration is needed - a clear BOM cost reduction versus older bandgap-only references. Combined with a TI INA128 instrumentation amplifier (or a discrete INA) and a low-pass RC filter, the LT1790BCS6-5 anchors a sub-0.1% accurate analog front-end that is stable across multi-year deployment.
推荐
Portable Battery-Powered Instrumentation
Battery-powered multimeters, handheld oscilloscopes, and field data loggers depend on the LT1790BCS6-5's micropower quiescent current and small package to extend runtime and shrink PCB area. Drawing tens of microamperes from a 9 V or 6 V battery, the part keeps working when a switching reference would have already drained the cell. The fixed 5 V output is convenient for biasing op-amps, ADC references, and ratiometric bridge networks where the supply also serves as the excitation source. Reverse-battery protection on the input prevents field-replacement errors from destroying the reference, an important reliability feature in portable test gear that lives in tool bags.
推荐
Automotive Sensor Module Reference
Although the B-grade LT1790BCS6-5 is specified for 0 °C to +70 °C, the underlying LT1790 family is widely used in cabin and body-electronics modules where the 5 V reference must remain stable across automotive temperature profiles. The fixed 5 V output is convenient for ratiometric pressure, position, and current-sensor signal chains where the reference voltage also serves as the excitation rail. Compared with discrete Zener + op-amp references, the LT1790BCS6-5 shrinks the BOM, drops calibration steps, and provides a known thermal-coefficient budget for sensor error analysis. For under-hood applications requiring -40 °C to +125 °C operation, designers migrate to the I-grade version of the family.
推荐
Precision DAC and Digital Potentiometer Bias
The LT1790BCS6-5's low noise and tight initial accuracy make it an excellent bias reference for precision DACs, digital potentiometers, and programmable gain amplifiers that need a fixed absolute-voltage anchor. Connecting VOUT to the DAC's VREF pin (or the digital pot's reference inputs) yields a stable full-scale voltage regardless of supply variation, improving linearity and differential non-linearity (DNL). The 5 mA output current capability comfortably supports multiple DAC reference pins in a small analog subsection, and the 6-pin TSOT-23 footprint fits directly under the DAC's exposed thermal pad on the same copper island.
推荐
Medical Monitoring and Diagnostic Devices
In patient monitors, blood-gas analyzers, and portable diagnostic instruments, the LT1790BCS6-5 provides a stable 5 V reference for the analog front-end that conditions biosensor signals (ECG, SpO2, glucose). The low quiescent current extends battery life in ambulatory monitors, while the ±0.1% initial accuracy preserves the calibrated gain of the front-end over the device's service life. Combined with a low-noise instrumentation amplifier (such as an AD8221) and a 16+ bit sigma-delta ADC, the reference anchors the measurement chain such that small biosignal amplitudes remain resolvable across the device's specified dynamic range. The TSOT-23-6 footprint keeps the analog section compact enough to fit on the smallest wearable form factors.
推荐
推荐产品汇总
工程参考数据： LT1790BCS6-5 ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | LT1790ACS6-5 | LT1790CCS6-5 | LT1790BCS6-3.3 | LT1790BCS6-2.5 | ISL21007BFB825Z |
|---|---|---|---|---|---|---|
| Package | TSOT-23-6 | TSOT-23-6 - same | TSOT-23-6 - same | TSOT-23-6 - same | TSOT-23-6 - same | SOT-23-6 - same footprint |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Renesas (formerly Intersil) |
| Output Voltage | 5.000 V | 5.000 V - same | 5.000 V - same | 3.300 V | 2.500 V | 5.000 V |
| Initial Accuracy | ±0.1% (B grade) | ±0.05% (A grade, tighter) | ±0.2% (C grade, looser) | ±0.1% (B grade, same) | ±0.1% (B grade, same) | ±0.1% |
| Temperature Coefficient | 25 ppm/°C max | 10 ppm/°C max (tighter) | 50 ppm/°C max (looser) | 25 ppm/°C max (same) | 25 ppm/°C max (same) | ~25 ppm/°C max |
| Output Current | 5 mA | 5 mA | 5 mA | 5 mA | 5 mA | 5 mA |
| Operating Temperature Range | 0 °C to +70 °C (commercial) | 0 °C to +70 °C | 0 °C to +70 °C | 0 °C to +70 °C | 0 °C to +70 °C | -40 °C to +125 °C (wider) |
| RoHS / Lead-Free | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes |
关键差异点
- Lower cost than A grade with same package footprint （对比 LT1790ACS6-5)
- Higher accuracy than C grade at modest cost premium （对比 LT1790CCS6-5)
- Industrial-grade alternatives available in same family （对比 ISL21007BFB825Z (Renesas))
设计说明
Estimated: with VIN = 7 V and 5 mA load on a 5 V reference, the LT1790BCS6-5 dissipates roughly (7 V − 5 V) × 5 mA = 10 mW. The TSOT-23-6 has θJA near 250 °C/W (estimated based on JEDEC EIA/JESD51 standard 4-layer test board for SOT-23-6), so the junction temperature rise is ≈ 2.5 °C above ambient - well within the 0 °C to +70 °C commercial range, but keep VIN-VOUT dropout margin in check to avoid saturating the series pass element. For battery-powered designs, the micropower quiescent current (typically <60 µA) is the dominant battery drain, not the load current.
Place a 0.1 µF to 1 µF low-ESR X7R ceramic bypass capacitor within 2-3 mm of the VOUT pin (pin 5) on the LT1790BCS6-5 to maintain phase margin and prevent oscillation. Use a wide ground pour on pin 2 (GND) and route the load trace as a short, low-impedance Kelvin-style connection from VOUT to the load pin. Avoid placing noisy digital or switching traces directly above or beside the TSOT-23-6 footprint, as the reference output noise can couple into adjacent signals on the top layer.
Do not operate the LT1790BCS6-5 with the output pin unloaded - the post-package trim relies on a defined minimum load. Also avoid reverse polarity on VIN (the part has reverse-battery protection but excessive reverse current can still damage the device). When upgrading a board design from the A grade to the B grade or vice versa, verify that the temperature coefficient and drift budget meet the system's calibration-accuracy requirements, not just the initial-accuracy number. Finally, do not bypass VOUT with a tantalum-only capacitor - low-ESR ceramic is required for stability.
The LT1790BCS6-5's output noise is dominated by the reference's own noise density, which can be coupled into downstream ADC conversion results as a small offset variation. To minimize this, place the reference on the same ground plane as the ADC and use a guard trace around the VOUT node where possible. Adding a small RC low-pass filter (10 Ω + 1 µF) between VOUT and the ADC reference pin further reduces wideband noise at the cost of a small settling-time penalty during ADC acquisition.
合规信息
RoHS compliant per Analog Devices product page. Not AEC-Q100 qualified (commercial grade, 0 °C to +70 °C). Halogen-free and conflict-minerals status not explicitly stated in retrieved web data - left as 'unknown'.
