feature

Compact TSOT assembly; low temperature coefficient; B grade: 9ppm/°C; A grade: 25 ppm/°C initial accuracy; B grade: ±3 mV max; A grade: ±6 mV max; ultra-low output noise: 6.8 μV pp ( 0.1hz to 10hz); low dropout: 300 mV; low supply current: 190 μA max, no external capacitor required; output current: +5 mA/-1 mA; wide temperature range: –40°C to +125°C; Suitable for automotive applications.

application

Battery powered instruments; portable medical devices; data acquisition systems; industrial process control vehicles.

General Instructions

The ADR360 /ADR361/ADR363/ADR364/ADR365/ADR366 are 2.048V, 2.5V, 3.0V, 4.096V, 5.0V, and 3.3V accurate bandgap voltage references that provide low power consumption and high accuracy in tiny packages. The ADR36x references utilize a patented temperature drift curvature correction technique from Analog Devices, Inc. to achieve a low temperature drift of 9ppm/°C in a TSOT package.

The ADR36x family of micropower, low voltage drop reference voltage sources provide a regulated output voltage from a minimum value of 300 mV above the output. Their advanced design eliminates the need for external capacitors, which further reduces board space and system cost. The combination of low power operation, small size, and ease of use makes the ADR36x precision voltage references ideal for battery-powered applications.

See the Automotive Grade Ordering Guide.

Absolute Maximum Ratings

T=25°C unless otherwise noted.

Stresses above the Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device under the conditions described in the operating section of this specification or any other conditions above is not implied. Long-term exposure to absolute maximum rating conditions may affect device reliability.

Thermal resistance

θ is specified for the worst case, that is, a device soldered in a circuit board for a surface mount package.

Typical performance characteristics

the term

Temperature Coefficient

Change in output voltage relative to normalized operating temperature change in output voltage at 25°C. This parameter is expressed in ppm/°C and can be obtained by:

Where: VOUT(25°C) = VOUT at 25°C; VOUT(T1) = VOUT at temperature 1; VOUT(T2) = VOUT at temperature 2.

Line conditioning

The change in output voltage due to a specific change in input voltage. This parameter accounts for the effect of self-heating. Line regulation is expressed in percent per volt, parts per million per volt, or microvolts per volt of input voltage change.

load regulation

The change in output voltage due to a specific change in load current. This parameter accounts for the effect of self-heating. Load regulation is expressed in microvolts per milliamp, millionths per milliamp, or DC output resistance in ohms.

long-term stability

Typical shift in output voltage for a sample of parts tested at 25°C for 1000 hours at 25°C.

Where: VOUT(t0) = VOUT at 25°C at time 0; VOUT(t1) = VOUT at 25°C after 1000 hours of operation at 25°C.

thermal hysteresis

Change in output voltage after cycling the device from +25°C to -40°C to +125°C and back to +25°C. This is typical for a sample of parts going through such a cycle.

where: VOUT(25°C) = VOUT at 25°C; VOUT_TC = cycle from -40°C to +125°C at +25°C and back to +25°C.

theory of operation

Bandgap references are high performance solutions for low supply voltage and low power voltage reference applications, and the ADR36x family is no exception. What makes these products unique is their structure. The ideal zero TC bandgap voltage refers to the output, not to ground (see Figure 32). Therefore, if noise is present on the ground wire, it will be greatly attenuated on V. The bandgap unit consists of PNP pairs Q53 and Q52 operating at different current densities. The difference in V produces a voltage at a positive TC, which is passed through:

This PTAT voltage, combined with the voltages of Q53 and Q52, produces a stable bandgap voltage. become

The band gap curvature is reduced by the ratio of resistor R44 and resistor R59, one of which is linear with temperature. Adopt patented circuit technology such as precision laser trimming to further improve drift performance.

Device Power Consumption Considerations

The ADR36x family is capable of delivering up to 5 mA of load current at input voltages from 2.348 V (ADR360 only) to 18 V. When the device is used in applications with large input voltages, care should be taken to avoid exceeding the specified maximum power dissipation or junction temperature, as this may cause the device to fail prematurely. Use the following formula to calculate the maximum junction temperature or dissipation of the device:

Where: TJ and TA are the junction temperature and ambient temperature, respectively; PD is the power dissipation of the device; θJA is the thermal resistance of the device package.

input capacitor

The ADR36x do not require input capacitors. There is no limit to the value of the capacitor used on the input, but using a 1µF to 10µF capacitor on the input can improve transient response in applications with sudden power supply changes. An additional 0.1µF parallel capacitor also helps reduce power supply noise.

output capacitor

The ADR36x does not require an output capacitor for stability under any load conditions. The output capacitor, typically 0.1µF, filters out low-level noise voltages that do not affect the operation of the part. On the other hand, in the case of 0.1μF capacitors in parallel, adding 1~10μF output capacitor can improve the load transient response. The additional capacitor acts as a storage source for a sudden increase in load current, the only parameter that decreases is the turn-on time. The degree of degradation depends on the size of the capacitor chosen.

application information

Reference voltage connection

The circuit in Figure 33 illustrates the basic configuration of the ADR36x family. Circuit stability does not require decoupling capacitors. The ADR36x family is capable of driving capacitive loads from 0µF to 10µF. However, a 0.1µF ceramic output capacitor is recommended to absorb and transfer the charge required by dynamic loads.

Stacked Reference ICs for Arbitrary Outputs

Some applications require two voltage references, which are the combined sum of the standard outputs. Figure 34 shows how this stack output reference is implemented.

Two reference ICs are used and fed from an unregulated input, V. The outputs of a single integrated circuit are connected in series to provide two output voltages, V and V. V is the terminal voltage of U1, and V is the sum of this voltage and the terminal voltage of U2. U1 and U2 are used to provide the two voltages for the desired output (see Table 10). For example, if U1 and U2 are both ADR361s, V is 2.5 V and V is 5.0 V.

Negative precision reference without precision resistors

The negative reference is easily generated by adding op amp A1 (see Figure 35). V and V are at virtual ground, so the negative reference can be taken directly from the output of the op amp. If the negative supply voltage is close to the reference output, the op amp must be dual-supply, low-skew, and rail-to-rail.

Universal Current Source

Often in low power applications, a precision current source capable of operating at low supply voltages is required. The ADR36x can be configured as a precision current source (see Figure 36). The circuit configuration shown is a floating current source with a grounded load. The referenced output voltage is bootstrapped through R, which sets the output current of the load. With this configuration, circuit accuracy can be maintained from a reference supply current (typically 150µA) to a load current of approximately 5mA.

Trim terminal

The ADR36x trim terminals can be used to adjust output voltages above the rated voltage. This feature allows system designers to correct system errors by setting the reference to a voltage other than the standard voltage option. Resistor R1 is used for trimming and can be omitted if desired. Resistor values should be carefully chosen to ensure that the maximum current drive of the part is not exceeded.

Dimensions

automotive products

The ADR365W and ADR366W models offer controlled manufacturing to support quality and reliability demanding automotive applications. Note that specifications for these models may differ from commercial models; therefore, designers should carefully review the Specifications section of this data sheet. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Equipment account representative for specific product ordering information and obtain specific vehicle reliability reports for these models.