MAX9919NASA+T - ±75V Bidirectional Current-Sense Amp | Analog Devices
MPN: MAX9919NASA+T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.95 | $2.95 |
| 10 | $2.66 | $26.60 |
| 100 | $2.18 | $218.00 |
| 500 | $1.86 | $930.00 |
| 1,000 | $1.65 | $1,650.00 |
| 2,500 | $1.45 | $3,625.00 |
MAX9919NASA+T Overview
A current-sense amplifier is a specialized analog building block that measures the small differential voltage across a shunt resistor in the presence of a large common-mode voltage, converting that differential signal to a ground-referenced output proportional to load current. Within the broader taxonomy, the MAX9919 belongs to the instrumentation amplifier family, sits under the special-purpose amplifier category, and connects upward to the power-management and signal-conditioning IC hierarchy used in motor-drive, solenoid-drive, and battery-monitoring systems.
Key differentiating features of the MAX9919 include the very wide -20 V to +75 V input common-mode range, support for unidirectional or bidirectional current measurement, 400 uV maximum input offset voltage for high DC accuracy, 0.6 % maximum gain error, and operation from a single 4.5 V to 5.5 V supply. The architecture uses a precision input pair and integrated gain resistor network, eliminating the requirement for external precision resistors in most applications.
The device covers three variants in the same SOIC-EP footprint: the MAX9918 (low-bandwidth, unidirectional), the MAX9919 (bidirectional 90 V/V), and the MAX9920 (high-bandwidth, unidirectional). Selection between them is by application topology - bidirectional H-bridge current sensing on the MAX9919, simple high-side monitoring on the MAX9918/MAX9920.
Typical applications include H-bridge motor current sensing, electronic throttle control, transmission control current monitoring, high- and low-side current sensing in 48 V automotive rails, and precision high-voltage current monitoring for industrial PLCs.
Design consideration: the input common-mode range of -20 V to +75 V allows the device to survive load-dump transients and inductive kickback without protection diodes in many 12 V and 24 V automotive systems. The exposed pad must be soldered to the PCB ground plane for thermal dissipation; without a soldered EP the part exceeds the absolute maximum ratings at high load current.
This page synthesizes distributor pricing, drop-in same-family and cross-brand alternatives, and design notes not found in the standalone manufacturer datasheet.
Drop-in alternatives for MAX9919NASA+T — 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:
MAX9918NASA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX9920ASA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX9919FASA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX9919NASA/V+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX9919NASA+T Maximum Ratings & Electrical Characteristics
| Manufacturer | Analog Devices (formerly Maxim Integrated) |
| Part Number | MAX9919NASA+T |
| Amplifier Type | Current Sense Amplifier |
| Number of Channels | 1 |
| Output Type | Rail-to-Rail |
| Input Common-Mode Range | -20 V to +75 V |
| Fixed Gain | 90 V/V |
| Input Offset Voltage (max) | 400 uV |
| Gain Error (max) | 0.6 % |
| Supply Voltage | 4.5 V to 5.5 V (single supply) |
| Direction | Bidirectional (unipolar and bipolar output) |
| Operating Temperature Range | -40 C to +85 C (N suffix) |
| Package | 8-pin SOIC-EP (SA package code, 3.90 mm body, exposed pad) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead Finish | Lead-free (per REACH and RoHS) |
| Product Family | MAX9918 / MAX9919 / MAX9920 (same datasheet) |
MAX9919NASA+T Pin Configuration
| Pin 1 | VCC — 5 V single-supply input (4.5 V to 5.5 V) |
| Pin 2 | GND — Supply ground |
| Pin 3 | REF — Output reference voltage - sets zero-current output level for bidirectional operation |
| Pin 4 | OUT — Amplified output (VREF plus 90 x VRS+ - VRS-) |
| Pin 5 | RS- — Sense amplifier negative input (connect to shunt low side) |
| Pin 6 | RS+ — Sense amplifier positive input (connect to shunt high side) |
| Pin 7 | GND — Supply ground (alternate bond pin) |
| Pin 8 | NC — Not connected internally on this part per datasheet; check manufacturer pinout doc for variant |
Typical Applications
MAX9919NASA+T is suitable for 6 applications: H-Bridge Motor Current Sensing, Electronic Throttle Control, Transmission Control Current Monitoring, 48 V Automotive Rail Monitoring, High-Side and Low-Side Precision Current Sensing, Solenoid and Valve Current Monitoring.
H-Bridge Motor Current Sensing
The MAX9919NASA+T is well-suited to H-bridge motor current sensing because its -20 V to +75 V input common-mode range survives the negative-voltage transients produced by inductive kickback when the bridge switches. The bidirectional output at 90 V/V fixed gain lets a single IC measure both positive (motoring) and negative (regenerative-braking) currents, eliminating two unidirectional current-sense amplifiers per phase. With 400 uV max input offset and 0.6 % max gain error, the device supports accurate torque control in BLDC and brushed DC drives from fractional-horsepower up to multi-kW industrial servos. Compared to discrete op-amp shunts, the integrated gain network removes calibration drift and shrinks the BOM to two decoupling caps plus the shunt.
Recommended
Electronic Throttle Control
Electronic throttle control (ETC) systems demand precise, low-noise current feedback to a motor that drives the throttle plate. The MAX9919NASA+T's 400 uV max VOS and 0.6 % gain error let it resolve sub-mA errors from a 10 mOhm shunt, providing the closed-loop accuracy an ETC servo motor requires. The wide -20 V to +75 V common-mode range tolerates the 12 V cranking pulses, load-dump transients, and reverse-battery events common in automotive electrical environments, removing the need for a discrete protection network. The 8-pin SOIC-EP footprint supports a small PCB area suitable for the throttle body's integrated electronics, and the exposed pad gives enough thermal margin for the continuous 100-200 mA ETC motor currents.
Recommended
Transmission Control Current Monitoring
Transmission solenoids draw 0.5-2 A continuously while switching at 60-120 Hz, demanding a current-sense amplifier that survives the high dV/dt common-mode swings from 12 V/24 V busses. The MAX9919NASA+T's common-mode range of -20 V to +75 V preserves measurement integrity through these transients, and its fixed 90 V/V gain simplifies A/D scaling on the transmission MCU. Bidirectional sensing handles both apply-side and release-side solenoids using a single IC. Compared to lower-VCM alternatives, this part eliminates the need for external level shifting and protection, reducing PCB area and improving reliability for under-hood automotive temperature ranges.
Recommended
48 V Automotive Rail Monitoring
Mild-hybrid 48 V powertrains require current-sense amplifiers that survive common-mode voltages of 60-70 V during load-dump, while operating from a low-voltage logic supply. The MAX9919's 75 V upper limit gives more than 5 V margin over the worst-case 48 V rail condition, supporting direct connection across the shunt without resistive divider attenuation. The bidirectional output suits both starter-generator motoring and generator modes. With a 0.6 % gain error the part delivers better than 1 LSB accuracy across the 12-bit ADC dynamic range typically used in 48 V DC-DC converters for mild-hybrid vehicles.
Recommended
High-Side and Low-Side Precision Current Sensing
Beyond motor control, the MAX9919NASA+T enables precision high-side or low-side current monitoring in industrial PLCs, battery management, and solar MPPT charge controllers. High-side placement benefits from the part's wide common-mode range up to +75 V, while low-side placement is supported by the -20 V capability, allowing the IC to ride through transients during inrush without saturating. The 400 uV VOS supports detection of 10 mA through a 10 mOhm shunt - useful for sub-1 A sensing required in battery cell-balancing and telemetry circuits. The rail-to-rail output lets it drive an ADC reference input directly without a buffer.
Recommended
Solenoid and Valve Current Monitoring
Hydraulic and pneumatic solenoid drivers often include a closed-loop current controller to set force precisely. The MAX9919NASA+T's 400 uV input offset and 0.6 % gain accuracy support precise solenoid current regulation across the full 0-2 A operating range. Its bidirectional capability is valuable when the solenoid is part of an H-bridge driver (e.g., proportional valves). With a -20 V to +75 V common-mode range the device tolerates the inductive kickback that hydraulic valves produce when de-energized, without needing freewheeling-diode clamps on the sense path.
Recommended
Recommended Products Summary
Engineering reference data for MAX9919NASA+T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX9918NASA+T | MAX9920ASA+T | MAX9919FASA+T | MAX9919NASA/V+T |
|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 8-pin SOIC-EP | 8-pin SOIC-EP - same | 8-pin SOIC-EP - same | 8-pin SOIC-EP - same | 8-pin SOIC-EP - same |
| Direction | Bidirectional | Unidirectional | Unidirectional | Unidirectional (factory option) | Bidirectional |
| Input Common-Mode Range | -20 V to +75 V | -20 V to +75 V | -20 V to +75 V | -20 V to +75 V | -20 V to +75 V |
| Fixed Gain (V/V) | 90 | 60 (per datasheet family table) | 60 (per datasheet family table) | 90 | 90 |
| Input Offset Voltage (max) | 400 uV | 400 uV | 400 uV | 400 uV | 400 uV |
| Gain Error (max) | 0.6 % | 0.6 % | 0.6 % | 0.6 % | 0.6 % |
| Automotive Grade | No (industrial N grade) | No | No | No | Yes (V suffix) |
| Operating Temperature Range | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +125 C (automotive grade) |
Key Differentiators
- Bidirectional sensing in the same 8-pin SOIC-EP footprint (vs MAX9918NASA+T)
- Wide common-mode range -20 V to +75 V survives load-dump and reverse-battery (vs MAX9920ASA+T)
- Pin-compatible unidirectional factory variant available (vs MAX9919FASA+T)
Design Notes
Always solder the exposed pad (EP) of the SOIC-EP package to the PCB ground plane. Without a soldered EP, the part exceeds its absolute maximum junction temperature and may fail or report offset drift at high load currents. Per the Maxim datasheet, the EP provides the primary thermal path for a thermal resistance of approximately 80 C/W. For sustained currents above 0.5 A a thermal via array under the EP is recommended.
Route the RS+ and RS- traces as a differential pair from the shunt resistor to pins 5 and 6, keeping the loop area small and the traces on the top layer with a continuous ground pour beneath. Place a 100 nF decoupling cap within 2 mm of pin 1 (VCC) and a 10 uF bulk cap nearby. Avoid running noisy switching traces between the shunt and the sense inputs, as common-mode rejection falls above a few kHz.
The MAX9919 operates from a single 4.5 V to 5.5 V supply. For reverse-battery protection place an SMBJ24CA TVS or a simple Schottky + fuse between the supply and pin 1. The input RS+/RS- pins withstand -20 V continuously; below -20 V the part enters reverse-input protection mode and accuracy degrades, so add a series resistor (10-100 ohm) if sustained negative transients beyond -20 V are expected.
Compliance Information
RoHS and REACH compliant per Analog Devices product page. The /V+T suffix is the AEC-Q100 automotive qualified variant; the standard MAX9919NASA+T is industrial grade (-40 C to +85 C) and not AEC-Q100 qualified. Halogen-free status not explicitly listed in the provided data - confirm with manufacturer before specifying for halogen-free designs.
