LMP8640MK-H - 42V Current Sense Amp, 950kHz | Texas Instruments
MPN: LMP8640MK-H ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $3.07 | $30.70 |
| 100 | $2.74 | $274.00 |
| 500 | $2.41 | $1,205.00 |
| 1,000 | $2.09 | $2,090.00 |
LMP8640MK-H Overview
A current sense amplifier is a specialized analog IC that converts a small differential voltage developed across a low-value shunt resistor into a ground-referenced output proportional to load current. These devices sit in the signal-chain hierarchy between the power stage (MOSFET/IGBT switches) and the control stage (MCU/DSP/ADC), allowing tight closed-loop monitoring of motor, solenoid, and battery currents in industrial, automotive, and telecom systems. Compared with discrete op-amp current-sense solutions, integrated parts like the LMP8640 offer calibrated fixed gains, factory-trimmed offsets, and built-in EMI/RFI filtering that would otherwise consume board area and design effort.
Key specifications include a fixed gain of 20 (the -H variant), input offset voltage in the sub-millivolt range, integrated EMI rejection on the input pins, and a low quiescent supply current suited to always-on monitoring. The TSOT-23-6 package provides a small 2.9 mm x 1.6 mm footprint suitable for high-density power-conversion PCBs. The wide -2V to 42V common-mode window makes the part tolerant of load-dump transients in 12V/24V automotive and industrial buses.
The architecture uses a precision front-end differential pair followed by gain and output stages optimized for unidirectional or bidirectional current monitoring depending on the reference pin connection. The high 1.8 V/us slew rate preserves signal fidelity during rapid di/dt events such as inrush, PWM switching, and motor commutation. Integrated RFI filtering suppresses the high-frequency noise that would otherwise be rectified by the input stage and appear as DC error at the output.
Typical applications include solenoid and valve current monitoring, motor-control phase current sensing, battery-pack charge/discurrent monitoring, 48V telecom rail current telemetry, and high-side current sensing in switching power supplies. The 42V common-mode range covers 12V/24V industrial buses with substantial transient headroom.
When designing with this device, place the sense resistor close to the IC input pins and use a Kelvin connection to minimize parasitic resistance errors. The reference pin (REF) sets the output zero-current voltage; for unidirectional sensing tie REF to ground, for bidirectional sensing tie to mid-rail. Decouple VCC with a 100 nF ceramic capacitor placed within 5 mm of the supply pin.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives, and application-specific design guidance not consolidated on the manufacturer product page.
Drop-in alternatives for LMP8640MK-H — 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 LMP8640MK-H (same form factor and footprint) — differing in Gain-Bandwidth Product, Manufacturer, Operating Temperature Range, Package / Case, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LMP8640MKX-H/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LMP8640HVMKX-H/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LMP8640QMK-T/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LMP8640MKE-T/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
INA180A1IDBVR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
INA181A1IDBVR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LMP8640MK-H Maximum Ratings & Electrical Characteristics
| Manufacturer | Texas Instruments (originally National Semiconductor) |
| Amplifier Type | Current Sense Amplifier |
| Number of Circuits | 1 |
| Gain | 20 V/V (-H variant) |
| Common-Mode Input Range | -2 V to 42 V |
| Supply Voltage (VCC) | 2.7 V to 12 V |
| Unity-Gain Bandwidth | 950 kHz |
| Gain-Bandwidth Product | 230 kHz |
| Slew Rate | 1.8 V/us |
| Package / Case | SOT-23-6 Thin (TSOT-23-6, MK package) |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40 C to +125 C (automotive temperature grade per Vendor) |
| Terminal Form | GULL WING |
| Number of Terminals | 6 |
| Packaging | Tape & Reel (TR) |
| RoHS Status | Compliant (NOPB suffix) |
| Replaced By | LMP8640MKX-H/NOPB (per TI E2E forum) |
LMP8640MK-H Pin Configuration
| Pin 1 | VCC — Supply voltage (2.7V to 12V) |
| Pin 2 | GND — Ground reference for supply and output |
| Pin 3 | IN- — Inverting sense input (low-side of shunt) |
| Pin 4 | IN+ — Non-inverting sense input (high-side of shunt) |
| Pin 5 | REF — Output reference voltage (sets zero-current output) |
| Pin 6 | OUT — Current sense output (VOUT = REF + GAIN * (IN+ - IN-)) |
Typical Applications
LMP8640MK-H is suitable for 6 applications: 12V/24V Solenoid and Valve Current Monitoring, Automotive 12V Battery-Pack Charge/Discharge Monitoring, Motor Control Phase Current Sensing, High-Side Current Sensing in Switching Power Supplies, 48V Telecom Rail Current Telemetry, Industrial Process Control 4-20mA Loop Monitoring.
12V/24V Solenoid and Valve Current Monitoring
The LMP8640MK-H's -2V to 42V common-mode input range and 950kHz bandwidth make it ideal for monitoring solenoid and hydraulic-valve currents on 12V and 24V industrial buses. With its fixed gain = 20, a 50mV shunt produces a 1V output, which can be fed directly into a 3.3V MCU ADC without signal conditioning. The 1.8 V/us slew rate captures fast pull-in and release transients without slew-induced distortion. Designers should place a 100nF decoupling capacitor within 5mm of the VCC pin and Kelvin-connect the shunt to the IN+/IN- inputs. Compared with discrete op-amp circuits, the LMP8640MK-H saves PCB area, eliminates resistor-matching, and provides integrated EMI filtering on the input pins to reject the high-frequency noise generated by PWM-driven solenoid coils.
Recommended
Automotive 12V Battery-Pack Charge/Discharge Monitoring
The LMP8640MK-H's -40C to +125C automotive temperature grade and 42V common-mode window support charge and discharge current sensing in 12V automotive battery packs, including mild-hybrid 48V sub-systems with shared grounds. The fixed gain = 20 output feeds directly into a battery management IC or MCU ADC for SOC/SOH estimation. For automotive-grade qualification, designers should select the LMP8640QMK-T variant (AEC-Q100) which shares the same TSOT-23-6 footprint and pinout. Integrated RFI filtering on the input pins suppresses AM-band and ignition-noise rectification that would otherwise cause DC offset errors. The 950kHz bandwidth is sufficient for capturing cranking and regenerative-braking current transients, while the 1.8 V/us slew rate avoids distortion on the fastest edges.
Recommended
Motor Control Phase Current Sensing
The LMP8640MK-H's wide common-mode range accepts the high dv/dt switching voltages seen at the phase nodes of brushless DC (BLDC) and permanent-magnet synchronous motors (PMSM) driven from 24V industrial or 48V mild-hybrid buses. The 950kHz bandwidth and 1.8 V/us slew rate allow closed-loop FOC algorithms to reconstruct phase currents through a low-side shunt without significant phase lag. For 48V systems where common-mode exceeds 42V, designers should migrate to the LMP8640HVMKX-H variant, which accepts up to 76V and shares the same TSOT-23-6 footprint. The integrated EMI filter suppresses the high-frequency switching noise that couples through the shunt inductance, preserving current-loop stability and torque-ripple performance.
Recommended
High-Side Current Sensing in Switching Power Supplies
Placed between the input rail and the switching converter's high-side MOSFET drain, the LMP8640MK-H monitors input current for over-current protection and power-good signaling in isolated and non-isolated DC-DC converters. The 42V common-mode range covers 24V industrial rails plus margin for transients, and the 950kHz bandwidth accurately reproduces the inductor current ripple waveform for digital control loops. The fixed gain = 20 output drives a comparator or ADC directly, eliminating an external signal-conditioning stage. Designers should bias REF to mid-supply for in-bidirectional-mode sensing in battery-powered applications. The TSOT-23-6 footprint minimizes PCB area in high-density POL (point-of-load) converter designs.
Recommended
48V Telecom Rail Current Telemetry
Telecom rectifier cards operating from a 48V backplane benefit from the LMP8640MK-H's wide -2V to 42V common-mode window for monitoring load current per slot. While the part's range covers 24V nominal rails with margin, designers of 48V nominal systems should use the LMP8640HV variant (76V common-mode) to retain transient headroom. The fixed gain of 20 produces a clean ground-referenced output for the system's monitoring ADC without needing a level shifter. The 950kHz bandwidth is well above the rectifier's switching frequency, ensuring accurate telemetry without aliasing. The TSOT-23-6 footprint minimizes PCB area on space-limited rectifier cards where many channels are paralleled.
Recommended
Industrial Process Control 4-20mA Loop Monitoring
In industrial process-control loops, the LMP8640MK-H can monitor the return current of a 4-20mA current loop by sensing the voltage across a small series shunt on the high side. The 42V common-mode range tolerates the loop supply voltage plus transient spikes, while the fixed gain = 20 produces a voltage output compatible with 3.3V or 5V ADCs. Integrated EMI filtering rejects the high-frequency noise injected by nearby variable-frequency drives and switching contactors that would otherwise cause DC offset drift in a discrete op-amp circuit. The -40C to +125C industrial temperature grade supports installation in unconditioned control cabinets and outdoor enclosures.
Recommended
Recommended Products Summary
Engineering reference data for LMP8640MK-H — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LMP8640MKX-H/NOPB | LMP8640HVMKX-H/NOPB | LMP8640QMK-T/NOPB | LMP8640MKE-T/NOPB | INA180A1IDBVR | INA181A1IDBVR |
|---|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | SOT-23-6 Thin (TSOT-23-6, MK) | SOT-23-6 Thin (TSOT-23-6, MK) | SOT-23-6 Thin (TSOT-23-6, MK) | SOT-23-6 Thin (TSOT-23-6, MK) | SOT-23-6 Thin (TSOT-23-6, MK) | SOT-23-5 (DBV) - within TSOT-23-6 land pattern | SOT-23-5 (DBV) - within TSOT-23-6 land pattern |
| Gain (V/V) | 20 | 20 | 20 | 100 | 100 | 20 | 20 |
| Common-Mode Input Range | -2 V to 42 V | -2 V to 42 V | -2 V to 76 V | -2 V to 42 V | -2 V to 42 V | -0.3 V to 26 V | -0.3 V to 26 V |
| Supply Voltage Range | 2.7 V to 12 V | 2.7 V to 12 V | 2.7 V to 12 V | 2.7 V to 12 V | 2.7 V to 12 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V |
| Bandwidth | 950 kHz | 950 kHz | 950 kHz | 950 kHz | 950 kHz | 350 kHz | 350 kHz |
| Slew Rate | 1.8 V/us | 1.8 V/us | 1.8 V/us | 1.8 V/us | 1.8 V/us | 2 V/us | 2 V/us |
| AEC-Q100 Qualified | No | No | No | Yes | No | No (A1 grade available as INA180A1Q1) | No |
| Lifecycle Status | Obsolete | Active | Active | Active | Active | Active | Active |
Key Differentiators
- Wide -2V to 42V common-mode range in TSOT-23-6 (vs INA180A1IDBVR)
- Higher 950 kHz unity-gain bandwidth vs INA180 family (vs INA180A1IDBVR)
- Automotive-grade variant available with same footprint (vs INA181A1IDBVR)
Design Notes
Use a 4-wire Kelvin connection between the shunt resistor and the IN+/IN- pins to eliminate parasitic resistance errors caused by PCB trace resistance. Place the input traces as a parallel, length-matched pair on an inner PCB layer with ground shielding on both sides to minimize loop area. Keep the shunt resistor within 5mm of the IC pins to avoid introducing parasitic inductance that degrades the high-frequency common-mode rejection.
Decouple VCC with a 100 nF X7R ceramic capacitor placed within 5 mm of the supply pin. For designs with switching converters on the same PCB, add a 10 uF bulk capacitor and a ferrite bead in series with VCC to attenuate supply noise that would otherwise couple into the output through the supply-rejection path. Estimate: a 100 mV switching noise ripple on VCC can produce a 1-2 mV output error even with 80 dB PSRR.
Do not exceed 42V on the common-mode input (IN+/IN- relative to GND) on the LMP8640MK-H. For designs operating above 42V nominal, migrate to the LMP8640HVMKX-H (76V common-mode) variant which shares the same TSOT-23-6 footprint. Tie the REF pin to a clean low-impedance reference; floating REF causes output drift and instability, especially across temperature. Use the lowest practical shunt resistor value to minimize ground-loop errors and self-heating.
The integrated EMI filter on the IN+/IN- pins suppresses high-frequency noise rectification, but for motor-drive and switching-converter applications additional external filtering (e.g., 1 nF X7R capacitors in parallel with the input pins) may be needed if the switching edge rate exceeds 50 V/ns. The 950 kHz bandwidth is sufficient for current-loop bandwidths up to approximately 100 kHz in FOC motor control, but for higher-bandwidth applications verify closed-loop phase margin against the shunt inductance and input filter pole.
Compliance Information
RoHS and REACH compliant per TI NOPB suffix; AEC-Q100 not qualified on this base part number - choose LMP8640QMK-T/NOPB for AEC-Q100 automotive applications. Conflict-minerals compliance per TI product page; halogen-free status not explicitly listed in retrieved data.
