SGMICRO launches DAC SGM5349A -16 for industrial sites
SGMICRO has just launched an 8 -channel, 16-bit DAC, which has begun bulk shipments to industrial customers.
Parameters
- 8-Channel, 16-Bit Buffered Voltage Output DAC
- Power supply range supports 2.7V to 5.5V, and the design guarantees monotonicity
- Normal working power consumption: 0.8mA, shutdown working power consumption: 1μA
- External benchmark
- Power-on reset to zero scale until a valid write is performed
- Rail-to-Rail Output Swing
- Support multi-function three-wire serial interface, support up to 50MHz clock frequency operation
- /LDAC function, which can update all DAC outputs at the same time, and can also select the update channel
- /CLR function, clear to programmable code (zero-scale, mid-scale or full-scale )
- Green TSSOP-16 and TQFN-4×4-16L packages
- The working temperature range supports -40℃~+125℃
Typical application of SGM5349A-16 in PLC analog output plus or minus 10V
Coordinate with SGMICRO OPA and voltage reference
The above circuit uses SGMICRO SGM5349A-16 to output 0V to 2.5V voltage, and the external reference uses SGMICRO's high-precision 20ppm voltage reference source SGM4030-2.5, using SGMICRO 36V process, 10μV high-precision OPA SGM8255A-2 with input offset voltage to condition the signal plus or minus 10V output. The power supply of the OPA is plus or minus 15V, and the differential amplification factor of the OPA circuit is 8 times. When the output of the SGM5349A-16 is zero, the output of the differential OPA is (0V - 1.25V) × 8 = -10V, when the SGM5349A-16 full amplitude output is 2.5V, the differential OPA output is (2.5V - 1.25V) × 8 = 10V.
Test evaluation board software setting interface:
In addition to the SGM5349A-16 DAC and solutions introduced above, SGMICRO will soon launch single-channel and four-channel 16-bit DACs and analog outputs 0mA to 20mA and 4mA to 20mA current source solutions such as PLC/DCS, which effectively simplifies industrial design.
SGMICRO launches the automotive-grade voltage reference analog IC LM431BQ
The voltage reference analog IC of SGMICRO has an extremely wide range of applications in the industrial market. In recent years, the development of new energy vehicles has been in full swing. The electronic system of new energy vehicles is inseparable from the vehicle-grade voltage reference analog IC. SGMICRO officially launched in 2021. The AEC-Q100 automotive standard upgrade of the voltage reference analog IC, the first to support AEC - Q100 standard voltage reference analog IC LM431BQ has been officially delivered to users.
Basic parameters of LM431BQ:
- Support AEC-Q 100 Grade 1 temperature level requirements (TA = -40 ℃ to +125 ℃ );
- Adjustable output voltage VREF to 36V;
- Sink current capability 1mA to 100mA;
- Reference voltage accuracy 0.5% at room temperature;
- Temperature drift 5mV (TYP);
- Output impedance 0.1Ω (TYP);
- Support high stability under capacitive load;
- Low noise output;
- SOT-23 environmental friendly package.
LM431BQ application circuit diagram and internal block diagram
With the unique design of internal circuit, the LM431BQ does not have any restrictions on the size of the output capacitor, can use large capacitors, and has strong anti-interference ability. For the traditional XX431 analog IC, since the stability of the reference output is affected by the output capacitor, the size of the output capacitor is often limite, which brings great inconvenience to the end-customer's compatible alternative design.
The LM431BQ does not require any output capacitor
SGMICRO synchronous buck converter SGM61230, designed for combatting extreme overload
SGM61230 is a synchronous buck converter with an input voltage of 4.5V to 28V and has continuous output current of 3A. It includes two integrated switching field effect transistors, internal loop compensation and internal 5ms soft start, effectively reduce components usage amount. Frequency hopping mode is used to maximize light-load efficiency and reduce power loss; the cycle-by-cycle current limit of the 66mΩ high-side N-channel MOSFET protects the converter under overload conditions, and the freewheeling current limit function of the 36mΩ low-side MOSFET Prevent current runaway.
Figure 1 5V/3A reference design
Typical features
- 4.5V to 28V Wide input voltage range
- Integrated 66mΩ and 36mΩ MOSFETs for 3A continuous output current
- 2µA Shutdown current, 25µA Quiescent current
- Internal 5ms soft start
- Fixed 410kHz switching frequency
- Internal PWM and frequency hopping mode
- Peak current mode control
- Internal loop compensation
- Overcurrent protection of two MOSFETs
- Over voltage protection
- Thermal shutdown
- -40°C to +125°C operating temperature range
- Green TSOT-23-6 package
Features
Anti-overload characteristic is one of the most prominent features of SGM61230 . Compared with products of the same specification in the market, SGM61230 will not trigger hiccup or current foldback protection immediately when encountering overload conditions, and can maintain continuous output under the default state of maximum peak current control, ensuring that the system can continue to provide load output under extreme conditions. Until the thermal protection of the product, this greatly supports the maximum operating state of the system, and prevents the system from being shut down due to insufficient load output suddenly.
This means that in the case of slight overload, the SGM61230 can continue to output the maximum load until the system returns to normal load. Even if the system is continuously overloaded, the SGM61230 will continue to output the maximum capacity until the chip thermal protection or the load is released.
The synchronous architecture integrates high-side ( 66mΩ ) and low-side ( 36mΩ ) MOSFETs internally , and a lower R ON can optimize the output efficiency of the product. The chip implements current-mode control by using an internal compensation voltage to control the turn- off of the high-side MOSFET and the turn-on of the low-side MOSFET. During each cycle, the switch current is compared to a reference current generated by an internal compensation voltage. When the peak switch current intersects the reference current (Intersect), the high-side switch is turned off. At the same time, the conduction current is monitored by internal circuitry when the low-side MOSFET is turned on. During normal operation, the low-side MOSFET provides Source Current to the load. At the end of each clock cycle, the low-side MOSFET source current is compared to the internally programmed low-side source current limit. When the inductor valley current exceeds the low-side source current limit, the high-side MOSFET does not conduct during the next cycle, while the low-side MOSFET continues to conduct. As shown in the figure below, when the inductor valley current falls below the low-side source current limit, the high-side MOSFET turns on again.
Figure 2 Overcurrent protection via MOSFET
SGM61230 adopts 410kHz fixed frequency PWM control method, but thanks to frequency hopping mode, it can also achieve high efficiency in light load mode. Specifically, when the peak inductor current is lower than 500mA , the chip will consider the load to be a light load and can gradually reduce the switching frequency according to the load current, so as to achieve high efficiency at light load. The data in Table 1 and Figures 3 and 4 demonstrate this feature.
Table 1 Efficiency of SGM61230 at different output currents
Figure 3 Efficiency curve of SGM61230 at different output currents
Figure 4 Efficiency curve of SGM61230 at light load
White goods, set-top boxes, digital TVs, printers, and 12V distributed power bus power supply in industry are the main application fields of SGM61230. With its excellent anti-overload performance, high efficiency, small size packaging and many other advantages, it is becoming a domestic cost-effective analog The preferred material for chips.
