Datasheet AD780 (Analog Devices)

2.5 V/3.0 V High Precision Reference Data Sheet AD780 FEATURES FUNCTIONAL BLOCK DIAGRAM Pin programmable 2.5 V or 3.0 V output +VIN DNC 2 7 Ultralow drift: 3 ppm/°C max AD780 High accuracy: 2.5 V or 3.0 V ±1 mV max Low noise: 100 nV/√Hz R10 R11 Noise reduction capability DNC 1 Low quiescent current: 1 mA max 6 VOUT R13 Output trim capability Q6 Plug-in upgrade for present references Q7 R16 5 TRIM Temperature output pin R5 R14 Series or shunt mode operation (±2.5 V, ±3.0 V) TEMP 3 R15 R4 4 8 GND O/P SELECT
01 0
2.5V – DNC
41-
DNC = DO NOT CONNECT TO THIS PIN 3.0V – GND
08 0 Figure 1.
GENERAL DESCRIPTION
The AD780 is an ultrahigh precision band gap reference voltage The AD780 is a pin compatible performance upgrade for the that provides a 2.5 V or 3.0 V output from inputs between 4.0 V LT1019(A)–2.5 and the AD680. The latter is targeted toward and 36 V. Low initial error and temperature drift combined with low power applications. low output noise and the ability to drive any value of capacitance The AD780 is available in three grades in PDIP and SOIC make the AD780 the ideal choice for enhancing the performance packages. The AD780AN, AD780AR, AD780BN, AD780BR, of high resolution analog-to-digital converters (ADCs) and and AD780CR are specified for operation from −40°C to +85°C. digital-to-analog converters (DACs), and for any general-purpose precision reference application. A unique low headroom design
PRODUCT HIGHLIGHTS
facilitates a 3.0 V output from a 5.0 V 10% input, providing a 1. The AD780 provides a pin programmable 2.5 V or 3.0 V 20% boost to the dynamic range of an ADC over performance output from a 4 V to 36 V input. with existing 2.5 V references. 2. Laser trimming of both initial accuracy and temperature The AD780 can be used to source or sink up to 10 mA, and can coefficients results in low errors over temperature without be used in series or shunt mode, thus allowing positive or negative the use of external components. The AD780BN has a output voltages without external components. This makes it maximum variation of 0.9 mV from −40°C to +85°C. suitable for virtually any high performance reference application. 3. For applications that require even higher accuracy, an Unlike some competing references, the AD780 has no region of optional fine-trim connection is provided. possible instability. The part is stable under all load conditions 4. The AD780 noise is extremely low, typically 4 mV p-p when a 1 μF bypass capacitor is used on the supply. from 0.1 Hz to 10 Hz and a wideband spectral noise density of typically 100 nV/√Hz. This can be further A temperature output pin on the AD780 provides an output reduced, if desired, by using two external capacitors. voltage that varies linearly with temperature, allowing the part 5. The temperature output pin enables the AD780 to be to be configured as a temperature transducer while providing a configured as a temperature transducer while providing a stable 2.5 V or 3.0 V output. stable output reference.
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Document Outline Features Functional Block Diagram General Description Product Highlights Table of Contents Revision History Specifications Absolute Maximum Ratings Thermal Resistance Notes ESD Caution Theory of Operation Applying the AD780 Noise Performance Noise Comparison Temperature Performance Temperature Output Pin Temperature Transducer Circuit Supply Current Over Temperature Turn-On Time Dynamic Performance Line Regulation Precision Reference for High Resolution 5 V Data Converters 4.5 V Reference from 5 V Supply Negative (–2.5 V) Reference Outline Dimensions Ordering Guide