Current feedback is critical for drive performance, determining a motor's overall control bandwidth and response time. With rapid growth in automotive electronics, industrial automation, and communication systems, high-quality current-sensing solutions are essential. Silergy's new generation of high-bandwidth, high-precision current-sense amplifiers offer a wide common-mode range and enhanced PWM suppression suitable for motor control, high-performance switch-mode power supplies, and battery management systems.
Overview
The SA59131 series are voltage-output, high-precision current-sense amplifiers supporting high-side or low-side bidirectional current sensing. They support a wide common-mode voltage range from -4V to 80V, and can capture input signals below ground. The devices feature a 500 kHz bandwidth, zero-drift architecture, very high common-mode rejection ratio (CMRR), and enhanced PWM suppression to quickly and effectively respond to system changes caused by large common-mode transients, producing accurate measurements.
Product Versions and Packaging
The SA59131 series is available in automotive-grade and industrial-grade versions, offered in SOP8 and TSSOP8 packages. Automotive versions comply with AEC-Q100 Grade 1. Industrial versions operate over an ambient temperature range of -40 to 125°C. Additional gain options will be released in production.
Key Specifications
- Enhanced PWM suppression
- Common-mode range: -4V to 80V
- High CMRR:
- 132 dB DC CMRR
- 93 dB AC CMRR (50 kHz)
- Gain error: 0.15% (max)
- Gain drift: 2.5 ppm/°C (max)
- Offset voltage: ±25 μV (max)
- Offset drift: 250 nV/°C (max)
- Fixed gain: 50 V/V
- Bandwidth: 500 kHz
- Quiescent current: 2.4 mA (max)
- Automotive: AEC-Q100 Grade 1
- Packages: TSSOP8 / SOP8
Performance Advantages
1. PWM Suppression
In systems with high-speed PWM transitions, such as motor control or switch-mode power supplies, fast common-mode transient response is important. The SA59131's enhanced PWM suppression effectively and rapidly suppresses spikes caused by large common-mode transients, yielding accurate measurement outputs.
2. Excellent DC Performance
The SA59131 uses a zero-drift architecture, delivering excellent DC performance. Maximum offset voltage is ±25 μV with offset drift below 250 nV/°C. Maximum gain error is ±0.15% with gain drift up to 2.5 ppm/°C. These parameters support more accurate current measurement across a range of ambient temperatures.
3. High Bandwidth
The SA59131 features a 500 kHz bandwidth and maintains 93 dB CMRR at 50 kHz, making it suitable for mid-to-high-speed applications.
Applications
The SA59131's enhanced PWM suppression makes it suitable for switching systems with large common-mode transients at the input, such as motor control, HEV/EV DC/DC converters, and battery management systems. It can be used for current sensing and overcurrent protection in these environments.
1. Motor Control
Precise phase-mounted current sensing and real-time detection of motor operating conditions are often required to reduce torque ripple and other disturbances. The sensed current's common-mode bridge voltage typically switches rapidly in PWM form, and inductive motor loads can generate negative voltages below ground during switch turn-off. Conventional amplifiers may not handle these conditions. The SA59131's -4V to 80V common-mode range, up to 132 dB CMRR, and enhanced PWM suppression address common-mode transient effects for accurate measurement.
2. High-Performance Switch-Mode Power Supplies
As in motor control, current-sensing in switch-mode power supplies often faces instantaneous common-mode voltage jumps and negative common-mode voltages from inductor current recirculation. With increasing power density and higher switching frequencies, the SA59131's 500 kHz bandwidth enables rapid response to overcurrent events in many applications.
