General Description

The MAX6035 is a high-voltage, precision micropower voltage reference. This three-terminal device is available with output voltage options of 2.5V, 3.0V, and 5.0V. It is an excellent upgrade for industry-standard devices such as the REF02 and REF43. The MAX6035 offers 14x lower power than the REF02 and 5x lower power than the REF43, as well as a reduced package size from an 8-pin SO to a 3-pin SOT23. The MAX6035 features a proprietary temperature coefficient curvature-correction circuit and laser-trimmed, thin-film resistors that result in a very low temperature coefficient of 25ppm/°C (max) and an initial accuracy of ±0.2% (max).
The MAX6035 typically draws only 73µA of supply current and can source 10mA or sink 2mA of load current.Unlike conventional shunt-mode (two-terminal) references that waste supply current and require an external resistor, this device offers a supply current that is virtually independent of the supply voltage and does not require an external resistor. Additionally, this internally compensated device does not require an external compensation capacitor, but is also stable with capacitive loads up to 5µF. Eliminating the external compensation capacitor saves valuable board area in space-critical applications. The supply independent, ultra-low supply current makes this device ideal for battery-operated, high-performance systems.
The MAX6035 is available in a 3-pin SOT23 package and is specified for operation from -40°C to +125°C.

 

Applications

4mA to 20mA Industrial
Control Loops
Li+ Battery Chargers
12-Bit A/D and D/A
Converters
Digital Multimeters
Portable Data-Acquisition
Systems
Low-Power Test
Equipment

 

Features

♦ Wide Supply Voltage Range: Up to 33V
♦ 25ppm/°C (max) Temperature Coefficient (-40°C to +85°C)
♦ ±0.2% (max) Initial Accuracy
♦ 95µA (max) Quiescent Supply Current
♦ 10mA Source Current, 2mA Sink Current
♦ No Output Capacitor Required
♦ Stable with Capacitive Loads up to 5µF

 

Applications Information

Input Bypassing

For the best line-transient performance, decouple the input with a 0.1µF ceramic capacitor as shown in the Typical Operating Circuit. Locate the capacitor as close to the device as possible. Where transient performance is less important, no capacitor is necessary.

Output/Load Capacitance

Devices in the MAX6035 family do not require any output capacitance for frequency stability. In applications where the load or the supply can experience step changes, an output capacitor of at least 0.1µF reduces the amount of overshoot (undershoot) and improves the circuit’s transient response. Many applications do not require an external capacitor, and the MAX6035 family can offer a significant advantage in these applications when board space is critical.

Supply Current

The quiescent supply current of the MAX6035 seriesmode family is typically 73µA and is virtually independent of the supply voltage, with only a 0.7µA/V (max) variation with supply voltage. In contrast, the quiescent current of a shunt-mode reference is a function of the input voltage due to a series resistor connected to the power supply. Additionally, shunt-mode references have to be biased at the maximum expected load current, even if the load current is not present at the time.
In the MAX6035 family, the load current is drawn from the input voltage only when required, so supply current is not wasted and efficiency is maximized at all input voltages. This improved efficiency reduces power dissipation and extends battery life.

Thermal Hysteresis

Thermal hysteresis is the change of output voltage at TA = +25°C before and after the device is cycled over its entire operating temperature range. The typical temperature hysteresis value is 135ppm.

Turn-On Time

These devices typically turn on and settle to within 0.1% of their final value in 240µs. Increased output capacitance also increases turn-on time.
In reality, the absolute static accuracy of a data converter is dependent on the combination of many parameters such as integral nonlinearity, differential nonlinearity, offset error, gain error, as well as voltage reference changes.