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Analog Devices Inc. LT1999CMS8-50#PBF
- Part No.:
- LT1999CMS8-50#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT1999CMS8-50#PBF.pdf
- Description:
- IC CURRENT SENSE 1 CIRCUIT 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:200
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Product details
Overview
LT1999CMS8-50#PBF from Analog Devices is a high-voltage, bidirectional current sense amplifier with 50V/V fixed gain, –5V to 80V input common mode range, 1.2MHz small-signal bandwidth, and ±0.5% gain accuracy. It senses current via external shunt resistor and outputs a voltage referenced to mid-supply or external REF, enabling precise bidirectional monitoring in H-bridge motor controls and battery charge/discharge systems.
For engineers reviewing the LT1999CMS8-50#PBF datasheet, LT1999CMS8-50#PBF pinout, LT1999CMS8-50#PBF application, or LT1999CMS8-50#PBF equivalent, this device supports high-side/low-side sensing in automotive-grade power systems, PWM control loops, and fuse/MOSFET monitoring where wide common mode, fast recovery (<1.3µs), and AEC-Q100 qualification are critical.
Technical Context
The LT1999CMS8-50#PBF uses matched on-chip resistive networks (R+IN/R–IN = 4kΩ each) and transconductance amplification to convert differential shunt voltage into output current, then applies a fixed 50V/V gain via internal 200kΩ/4kΩ resistor ratio. Its architecture enables smooth, continuous operation across the full –5V to 80V common mode range without gain or offset discontinuity.
It features dual-stage biasing: for VCM > V+, inputs operate with D1 off; for –5V < VCM < V+, integrated diode D1 activates to maintain ≥2.25V headroom above GND at GIN inputs. REF pin sets output common-mode level and accepts external voltage within 1.125V to (V+ – 1.125V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain | 50V/V - fixed ratio ensures predictable scaling of shunt voltage to output; enables ±20mV full-scale input for ±1V output swing. |
| Common Mode Range | –5V to 80V - supports direct sensing in 48V/60V industrial bus, battery packs, and high-side switching nodes without level-shifting circuitry. |
| Bandwidth | 1.2MHz - sufficient for accurate current capture in 500kHz PWM motor drives and fast transient detection in protection circuits. |
| Gain Accuracy | ±0.5% max - guarantees ≤10mV error at ±1V output, critical for closed-loop current regulation and energy metering precision. |
| Input Offset Voltage | ±500µV max - limits zero-current output error to ±25mV, preserving resolution for low-current sensing down to ~500mA with 50mΩ shunt. |
| Supply Current | 1.55mA typical at VCM > 5.5V - enables low-power operation in always-on monitoring paths; shutdown draws <10µA. |
| CMRR | ≥96dB over full VCM range - rejects noise from noisy power rails, essential for clean signal extraction in EMI-heavy motor drive environments. |
Pinout & Package
LT1999CMS8-50#PBF is housed in an 8-lead MSOP package (MS8), 3mm × 3mm, 0.65mm pitch, with original pinout (not FMEA-optimized). Thermal resistance θJA = 300°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| V+ (Pins 1, 4) | Power supply input | Internally tied pins accept 4.5V–5.5V; lower voltages possible but not specified; powers all internal amplifiers and bias networks. |
| +IN (Pin 2) | Positive sense input | Connects to high-side of shunt; matched 4kΩ input impedance ensures balanced differential sensing and CMRR integrity. |
| –IN (Pin 3) | Negative sense input | Connects to low-side of shunt; identical impedance to +IN; differential input handles ±80mV full-scale for 50× gain. |
| GND (Pin 5) | Analog ground reference | Return path for REF divider and output stage; must be low-impedance to avoid ground bounce degrading CMRR. |
| REF (Pin 6) | Output common-mode reference | Sets VOUT midpoint; default = V+/2 via internal 160k/160k divider; externally overdrivable for custom output offset. |
| OUT (Pin 7) | Amplified output | Low-impedance voltage source (0.15Ω); drives ≤200pF directly; requires series resistor for larger capacitive loads. |
| SHDN (Pin 8) | Shutdown control | Active-low logic input; <0.5V pulls device into <10µA shutdown; floating defaults to active via 2µA internal pull-up. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional current sensing | Outputs positive/negative voltage relative to REF to indicate current direction-enables regenerative braking and battery charge/discharge state detection. |
| FMEA-compatible pinout option available | Alternate MSOP variant (LT1999CMS8-50F#PBF) relocates NC to Pin 3 to prevent misconnection during assembly-reduces field failure risk in safety-critical automotive systems. |
| High common mode step recovery | 1.3µs recovery from ±50V common mode transients ensures stable output during MOSFET switching edges in half-bridge topologies. |
| AEC-Q100 qualified | Rated for –40°C to 125°C operation (H-grade variants); validated for automotive powertrain and chassis applications requiring long-term reliability under thermal stress. |
| ESD robustness | 4kV HBM / 1kV CDM tolerance protects against handling and system-level ESD events without external clamping diodes. |
Applications
| H-Bridge Motor Control | Solenoid Current Sense |
|---|---|
Use Scenario: Monitoring phase current in 24V–48V brushed DC or BLDC motor drivers with PWM switching up to 100kHz. IC Role / Device Role / Timing Role: Bidirectional current amplifier providing real-time magnitude/direction feedback to MCU for torque control and stall detection. Use Value: 1.2MHz bandwidth captures PWM ripple; ±0.5% gain accuracy enables precise current limiting at ±5A with 10mΩ shunt; 80V CM range covers back-EMF spikes. | Use Scenario: Measuring energizing/de-energizing current in automotive fuel injectors or ABS solenoids operating from 12V battery rail. IC Role / Device Role / Timing Role: High-speed analog front-end converting solenoid coil current into clean voltage for ADC sampling and fault classification. Use Value: 1.3µs common mode recovery suppresses switching noise from driver ICs; –5V to 80V range accommodates inductive kickback exceeding battery voltage. |
| High Voltage Data Acquisition | PWM Control Loops |
Use Scenario: Isolated current measurement in telecom rectifiers or server PSU secondary-side monitoring with 48V–54V output rails. IC Role / Device Role / Timing Role: Precision analog signal conditioner interfacing shunt to isolated sigma-delta ADC, eliminating need for optocoupler-based isolation. Use Value: 96dB CMRR rejects common-mode noise from high-frequency transformer leakage; ±500µV offset enables sub-ampere resolution with 100mΩ shunt. | Use Scenario: Real-time current feedback in digitally controlled LLC resonant converters with variable frequency modulation. IC Role / Device Role / Timing Role: Fast-settling (2.5µs to 0.5%) analog sensor feeding current-mode PWM controller for cycle-by-cycle current limiting. Use Value: 2.5µs settling time prevents false overcurrent trips during load transients; 50V/V gain provides optimal dynamic range for 0–10A sensing with 20mΩ shunt. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar current sense amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA240A1QDRQ1 | 50V/V gain, –4V to 80V CM range, 4.5MHz bandwidth, 150nV/√Hz noise, no REF pin - output referenced to GND only. | Requires level-shifting for mid-supply referenced output; higher bandwidth suits faster switching but adds noise sensitivity. | Select when GND-referenced output suffices and higher speed is prioritized over REF flexibility. |
| MAX40056ATA+T | 50V/V gain, –5V to 65V CM range, 1.5MHz bandwidth, integrated 2.5V REF, no shutdown pin - fixed internal reference only. | Limited to ≤65V common mode; lacks SHDN control; REF not overdrivable - less flexible for custom biasing. | Select when board space is constrained and internal 2.5V REF aligns with system ADC reference. |
Compared with INA240A1QDRQ1 and MAX40056ATA+T, the LT1999CMS8-50#PBF uniquely combines user-configurable REF pin, true bidirectional output swing, and AEC-Q100 qualification in MSOP - making it optimal for automotive H-bridge and industrial battery management where output referencing and safety compliance are non-negotiable.
Availability
LT1999CMS8-50#PBF is available at Aetrix Electronics and suitable for H-bridge motor control, solenoid current monitoring, and high-voltage data acquisition requiring stable component supply across automotive, industrial, and energy storage applications.
Supply support for LT1999CMS8-50#PBF 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
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT1999 family was designed specifically for high-accuracy, high-common-mode bidirectional current sensing in demanding power conversion and motor control systems - emphasizing robustness, precision, and automotive qualification.
FAQ
What is the maximum common mode voltage the LT1999CMS8-50#PBF can handle?
The LT1999CMS8-50#PBF supports an input common mode voltage range of –5V to 80V, verified across its full operating temperature range. This allows direct connection to high-side switching nodes in 48V battery systems and industrial 60V bus architectures without external level-shifting circuitry. Absolute maximum ratings extend to –5.25V and 88V for short-duration transients.
Does the LT1999CMS8-50#PBF require external components for basic operation?
Yes - the LT1999CMS8-50#PBF requires two 0.1µF bypass capacitors on V+ (Pins 1 and 4) to GND (Pin 5), and the REF pin (Pin 6) defaults to mid-supply via internal 160k/160k resistors. No external gain-setting components are needed since gain is fixed at 50V/V. An external shunt resistor is required for current sensing, and optional RC filtering may be added at OUT for noise-sensitive applications.
How does the REF pin function in the LT1999CMS8-50#PBF?
The REF pin (Pin 6) in the LT1999CMS8-50#PBF sets the output common-mode voltage level. By default, it sits at V+/2 due to internal 160k/160k resistors. It can be overdriven by an external voltage source within 1.125V to (V+ – 1.125V) to shift the output baseline - enabling custom zero-current output levels or alignment with downstream ADC references. Input impedance is 60–100kΩ depending on voltage.
Is the LT1999CMS8-50#PBF suitable for automotive applications?
Yes - the LT1999CMS8-50#PBF is offered in automotive-grade versions (e.g., LT1999HMS8-50#PBF) qualified to AEC-Q100 Grade H (–40°C to +125°C). While the C-grade LT1999CMS8-50#PBF is rated for 0°C to 70°C, its core architecture, ESD robustness (4kV HBM), and FMEA-optimized pinout options make it suitable for non-safety-critical automotive subsystems such as body control modules and auxiliary power monitoring.
What is the small-signal bandwidth and slew rate of the LT1999CMS8-50#PBF?
The LT1999CMS8-50#PBF has a small-signal –3dB bandwidth of 1.2MHz and a slew rate of 3V/µs. These specifications ensure faithful reproduction of current waveforms in PWM-driven systems up to ~500kHz switching frequency while maintaining phase margin for stable closed-loop control. Bandwidth is gain-dependent: LT1999-10 and LT1999-20 variants offer 2MHz, while LT1999-50 is optimized for higher precision at reduced speed.
LT1999CMS8-50#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- Current Sense
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 3V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 1.2 MHz
- Current - Input Bias:
- 137.5 µA
- Voltage - Input Offset:
- 500 µV
- Current - Supply:
- 5.8mA
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 4.5 V
- Voltage - Supply Span (Max):
- 5.5 V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MSOP
LT1999CMS8-50#PBF FAQ
1.How can I place an order for LT1999CMS8-50#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1999CMS8-50#PBF 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 LT1999CMS8-50#PBF reliable?
The price and inventory of LT1999CMS8-50#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1999CMS8-50#PBF is usually 5 days.
3.What payment methods are accepted for LT1999CMS8-50#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1999CMS8-50#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1999CMS8-50#PBF?
LT1999CMS8-50#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1999CMS8-50#PBF 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 LT1999CMS8-50#PBF?
For technical support, including LT1999CMS8-50#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1999CMS8-50#PBF requirements.
6.How does Aetrix verify that LT1999CMS8-50#PBF is sourced from the original manufacturer or authorized distributors?
All LT1999CMS8-50#PBF 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 LT1999CMS8-50#PBF meets industry standards.
7.What is the process for return or replacement of LT1999CMS8-50#PBF?
All LT1999CMS8-50#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1999CMS8-50#PBF, 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 LT1999CMS8-50#PBF part is unused and in its original packaging.
Return procedure for LT1999CMS8-50#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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