Datasheet

ManualsBrandsMICROCHIP TECHNOLOGY ManualsData collecting ICsData acquisition IC - DA converter (DAC) MSOP 8

 2010 Microchip Technology Inc. DS22249A-page 1

MCP4802/4812/4822

Features

• MCP4802: Dual 8-Bit Voltage Output DAC

• MCP4812: Dual 10-Bit Voltage Output DAC

• MCP4822: Dual 12-Bit Voltage Output DAC

• Rail-to-Rail Output

• SPI Interface with 20 MHz Clock Support

• Simultaneous Latching of the Dual DACs

with LDAC pin

• Fast Settling Time of 4.5 µs

• Selectable Unity or 2x Gain Output

• 2.048V Internal Voltage Reference

•50ppm/°C V

REF

Temperature Coefficient

• 2.7V to 5.5V Single-Supply Operation

• Extended Temperature Range: -40°C to +125°C

Applications

• Set Point or Offset Trimming

• Sensor Calibration

• Precision Selectable Voltage Reference

• Portable Instrumentation (Battery-Powered)

• Calibration of Optical Communication Devices

Description

The MCP4802/4812/4822 devices are dual 8-bit, 10-bit

and 12-bit buffered voltage output Digital-to-Analog

Converters (DACs), respectively. The devices operate

from a single 2.7V to 5.5V supply with SPI compatible

Serial Peripheral Interface.

The devices have a high precision internal voltage

reference (V

REF

= 2.048V). The user can configure the

full-scale range of the device to be 2.048V or 4.096V by

setting the Gain Selection Option bit (gain of 1 of 2).

Each DAC channel can be operated in Active or

Shutdown mode individually by setting the Configuration

circuits in the shutdown channel are turned off for power

savings and the output amplifier is configured to present

a known high resistance output load (500 k typical.

The devices include double-buffered registers,

allowing synchronous updates of two DAC outputs

using the LDAC

pin. These devices also incorporate a

Power-on Reset (POR) circuit to ensure reliable power-

up.

The devices utilize a resistive string architecture, with

its inherent advantages of low DNL error, low ratio

metric temperature coefficient and fast settling time.

These devices are specified over the extended

temperature range (+125°C).

The devices provide high accuracy and low noise

performance for consumer and industrial applications

where calibration or compensation of signals (such as

temperature, pressure and humidity) are required.

The MCP4802/4812/4822 devices are available in the

PDIP, SOIC and MSOP packages.

Package Types

Summary of content (46 pages)

PAGE 1
MCP4802/4812/4822 8/10/12-Bit Dual Voltage Output Digital-to-Analog Converter with Internal VREF and SPI Interface Features Description • • • • • • The MCP4802/4812/4822 devices are dual 8-bit, 10-bit and 12-bit buffered voltage output Digital-to-Analog Converters (DACs), respectively. The devices operate from a single 2.7V to 5.5V supply with SPI compatible Serial Peripheral Interface. The devices have a high precision internal voltage reference (VREF = 2.048V).
PAGE 2
MCP4802/4812/4822 Block Diagram CS SDI SCK LDAC Power-on Reset Interface Logic VDD VSS Input Input Register A Register B DACA Register DACB Register String DACA String DACB Gain Logic 2.048V VREF Gain Logic Output Op Amps Output Logic VOUTA DS22249A-page 2 VOUTB  2010 Microchip Technology Inc.
PAGE 3
MCP4802/4812/4822 1.0 ELECTRICAL CHARACTERISTICS † Notice: Stresses above those listed under “Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. Absolute Maximum Ratings † VDD...............................................
PAGE 4
MCP4802/4812/4822 ELECTRICAL CHARACTERISTICS (CONTINUED) Electrical Specifications: Unless otherwise indicated, VDD = 5V, VSS = 0V, VREF = 2.048V, Output Buffer Gain (G) = 2x, RL = 5 k to GND, CL = 100 pF, TA = -40 to +85°C. Typical values are at +25°C. Parameters Sym Min Typ Max Units Conditions VREF 2.008 2.048 2.088 V VREF/°C — 125 325 ppm/°C -40°C to 0°C — 0.25 0.
PAGE 5
MCP4802/4812/4822 ELECTRICAL CHARACTERISTIC WITH EXTENDED TEMPERATURE Electrical Specifications: Unless otherwise indicated, VDD = 5V, VSS = 0V, VREF = 2.048V, Output Buffer Gain (G) = 2x, RL = 5 k to GND, CL = 100 pF. Typical values are at +125°C by characterization or simulation. Parameters Sym Min Typ Max VDD Units 2.7 — 5.5 V IDD — 440 — µA Software Shutdown Current ISHDN_SW — 5 — µA Power-On Reset threshold VPOR — 1.
PAGE 6
MCP4802/4812/4822 ELECTRICAL CHARACTERISTIC WITH EXTENDED TEMPERATURE (CONTINUED) Electrical Specifications: Unless otherwise indicated, VDD = 5V, VSS = 0V, VREF = 2.048V, Output Buffer Gain (G) = 2x, RL = 5 k to GND, CL = 100 pF. Typical values are at +125°C by characterization or simulation. Parameters Sym Min Typ Max Units Conditions Output Swing VOUT — 0.01 to VDD – 0.04 — V Accuracy is better than 1 LSb for VOUT = 10 mV to (VDD – 40 mV) Phase Margin PM — 66 — Slew Rate SR — 0.
PAGE 7
MCP4802/4812/4822 AC CHARACTERISTICS (SPI TIMING SPECIFICATIONS) Electrical Specifications: Unless otherwise indicated, VDD= 2.7V – 5.5V, TA= -40 to +125°C. Typical values are at +25°C. Parameters Sym Min Typ Max Units tCSH 15 — — ns Note 1 LDAC Pulse Width tLD 100 — — ns Note 1 LDAC Setup Time tLS 40 — — ns Note 1 tIDLE 40 — — ns Note 1 CS High Time SCK Idle Time before CS Fall Note 1: Conditions This parameter is ensured by design and not 100% tested.
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MCP4802/4812/4822 NOTES: DS22249A-page 8  2010 Microchip Technology Inc.
PAGE 9
MCP4802/4812/4822 2.0 TYPICAL PERFORMANCE CURVES Note: The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
PAGE 10
MCP4802/4812/4822 Note: Unless otherwise indicated, TA = +25°C, VDD = 5V, VSS = 0V, VREF = 2.048V, Gain = 2x, RL = 5 k, CL = 100 pF. 0.3 0.6 o - 40 C INL (LSB) DNL (LSB) 0.4 0.1 0 -0.1 o 85 C 0.3 0.2 0.1 0 125oC -0.1 -0.2 0 128 256 384 512 Code 640 768 -0.3 0 896 1024 FIGURE 2-7: DNL vs. Code and Temperature (MCP4812). 85oC 0 -0.5 -1 -1.5 25oC -2 o -2.
PAGE 11
MCP4802/4812/4822 Note: Unless otherwise indicated, TA = +25°C, VDD = 5V, VSS = 0V, VREF = 2.048V, Gain = 2x, RL = 5 k, CL = 100 pF. 25 Output Noise Voltage Density (µV/Hz) 100 1.E-04 Occurrence 20 1.E-05 10 1 1.E-06 15 10 5 FIGURE 2-16: FIGURE 2-14: Output Noise Voltage (VREF Noise Voltage) vs. Bandwidth. Gain = 1x. 340 440 435 430 425 420 435 430 IDD (µA) FIGURE 2-17: IDD Histogram (VDD = 5.0V). 5.5V 5.0V 4.0V 3.0V 2.
PAGE 12
MCP4802/4812/4822 Note: Unless otherwise indicated, TA = +25°C, VDD = 5V, VSS = 0V, VREF = 2.048V, Gain = 2x, RL = 5 k, CL = 100 pF. 5.5V 4 5.0V 3.5 ISHDN_SW (µA) 3.5 3 4.0V 2.5 3.0V 2.7V 2 V DD 1.5 VIN Hi Threshold (V) 4 VDD 5.5V 5.0V 3 4.0V 2.5 2 3.0V 2.7V 1.5 1 1 -40 -20 0 20 40 60 80 100 -40 120 -20 FIGURE 2-18: Software Shutdown Current vs. Temperature and VDD. 20 40 60 80 100 120 FIGURE 2-21: VIN High Threshold vs. Temperature and VDD. 1.6 0.09 0.07 0.05 5.5V 0.
PAGE 13
MCP4802/4812/4822 Note: Unless otherwise indicated, TA = +25°C, VDD = 5V, VSS = 0V, VREF = 2.048V, Gain = 2x, RL = 5 k, CL = 100 pF. 2.5 5.5V 2 5.0V 1.75 1.5 4.0V 1.25 1 3.0V 2.7V 0.75 0.5 5.5V 5.0V 4.0V 3.0V 2.7V 15 IOUT_HI_SHORTED (mA) VIN_SPI Hysteresis (V) 16 VDD 2.25 14 VDD 13 12 11 0.25 10 0 -40 -20 0 20 40 60 80 -40 100 120 -20 Ambient Temperature (ºC) FIGURE 2-23: Input Hysteresis vs. Temperature and VDD. 0.035 40 60 80 100 120 6.0 0.031 5.0 0.029 4.0 0.
PAGE 14
MCP4802/4812/4822 Note: Unless otherwise indicated, TA = +25°C, VDD = 5V, VSS = 0V, VREF = 2.048V, Gain = 2x, RL = 5 k, CL = 100 pF. VOUT VOUT SCK LDAC LDAC Time (1 µs/div) FIGURE 2-28: VOUT Rise Time. Time (1 µs/div) FIGURE 2-31: VOUT Rise Time. VOUT VOUT SCK SCK LDAC LDAC Time (1 µs/div) VOUT Fall Time. FIGURE 2-32: Shutdown. VOUT SCK LDAC Time (1 µs/div) FIGURE 2-30: DS22249A-page 14 VOUT Rise Time Exit Ripple Rejection (dB) FIGURE 2-29: Time (1 µs/div) VOUT Rise Time.
PAGE 15
MCP4802/4812/4822 3.0 PIN DESCRIPTIONS The descriptions of the pins are listed in Table 3-1. TABLE 3-1: PIN FUNCTION TABLE FOR MCP4802/4812/4822 MCP4802/4812/4822 MSOP, PDIP, SOIC 3.1 Symbol Description 1 VDD Supply Voltage Input (2.7V to 5.5V) 2 CS Chip Select Input 3 SCK Serial Clock Input 4 SDI Serial Data Input 5 LDAC Synchronization Input.
PAGE 16
MCP4802/4812/4822 NOTES: DS22249A-page 16  2010 Microchip Technology Inc.
PAGE 17
MCP4802/4812/4822 4.0 GENERAL OVERVIEW The MCP4802, MCP4812 and MCP4822 are dual voltage output 8-bit, 10-bit and 12-bit DAC devices, respectively. These devices include rail-to-rail output amplifiers, internal voltage reference, shutdown and reset-management circuitry. The devices use an SPI serial communication interface and operate with a single supply voltage from 2.7V to 5.5V. The DAC input coding of these devices is straight binary. Equation 4-1 shows the DAC analog output voltage calculation.
PAGE 18
MCP4802/4812/4822 4.0.2 4.1 DNL ACCURACY A Differential Non-Linearity (DNL) error is the measure of variations in code widths from the ideal code width. A DNL error of zero indicates that every code is exactly 1 LSb wide. 111 110 Actual Transfer Function 101 Digital Input Code 100 Ideal Transfer Function 011 001 Wide Code, >1 LSb 000 Narrow Code, <1 LSb DAC Output 4.0.3 Example for DNL Error.
PAGE 19
MCP4802/4812/4822 4.1.3 POWER-ON RESET CIRCUIT The internal Power-on Reset (POR) circuit monitors the power supply voltage (VDD) during the device operation. The circuit also ensures that the DAC powers up with high output impedance ( = 0, typically 500 k. The devices will continue to have a high-impedance output until a valid write command is received and the LDAC pin meets the input low threshold. If the power supply voltage is less than the POR threshold (VPOR = 2.
PAGE 20
MCP4802/4812/4822 NOTES: DS22249A-page 20  2010 Microchip Technology Inc.
PAGE 21
MCP4802/4812/4822 5.0 SERIAL INTERFACE 5.1 Overview The MCP4802/4812/4822 devices are designed to interface directly with the Serial Peripheral Interface (SPI) port, available on many microcontrollers, and supports Mode 0,0 and Mode 1,1. Commands and data are sent to the device via the SDI pin, with data being clocked-in on the rising edge of SCK. The communications are unidirectional and, thus, data cannot be read out of the MCP4802/4812/4822 devices.
PAGE 22
MCP4802/4812/4822 REGISTER 5-1: WRITE COMMAND REGISTER FOR MCP4822 (12-BIT DAC) W-x W-x W-x W-0 W-x W-x W-x W-x W-x W-x W-x W-x W-x W-x W-x W-x A/B — GA SHDN D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 bit 15 bit 0 REGISTER 5-2: WRITE COMMAND REGISTER FOR MCP4812 (10-BIT DAC) W-x W-x W-x W-0 W-x W-x W-x W-x W-x W-x W-x W-x W-x W-x W-x A/B — GA SHDN D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 x bit 15 W-x x bit 0 REGISTER 5-3: WRITE COMMAND REGISTER FOR MCP4
PAGE 23
MCP4802/4812/4822 CS 0 1 2 3 4 5 6 7 8 9 10 11 12 (Mode 1,1) 13 14 15 SCK (Mode 0,0) config bits A/B SDI 12 data bits — GA SHDN D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 LDAC VOUT FIGURE 5-1: Write Command for MCP4822 (12-bit DAC). CS 0 1 2 3 4 5 6 7 8 9 10 11 12 (Mode 1,1) 13 14 15 SCK (Mode 0,0) config bits A/B SDI 12 data bits — GA SHDN D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X LDAC VOUT Note: X = “don’t care” bits. FIGURE 5-2: Write Command for MCP4812 (10-bit DAC).
PAGE 24
MCP4802/4812/4822 NOTES: DS22249A-page 24  2010 Microchip Technology Inc.
PAGE 25
MCP4802/4812/4822 6.0 TYPICAL APPLICATIONS 6.3 Output Noise Considerations The MCP4802/4812/4822 family of devices are general purpose DACs for various applications where a precision operation with low-power and internal voltage reference is required. The voltage noise density (in µV/Hz) is illustrated in Figure 2-13. This noise appears at VOUTX, and is primarily a result of the internal reference voltage. Its 1/f corner (fCORNER) is approximately 400 Hz.
PAGE 26
MCP4802/4812/4822 6.5 Single-Supply Operation 6.5.1.1 Decreasing Output Step Size The MCP4802/4812/4822 family of devices are rail-torail voltage output DAC devices designed to operate with a VDD range of 2.7V to 5.5V. Its output amplifier is robust enough to drive small-signal loads directly. Therefore, it does not require any external output buffer for most applications. If the application is calibrating the bias voltage of a diode or transistor, a bias voltage range of 0.
PAGE 27
MCP4802/4812/4822 6.5.1.2 Building a “Window” DAC If the threshold is not near VREF, 2VREF or VSS, then creating a “window” around the threshold has several advantages. One simple method to create this “window” is to use a voltage divider network with a pullup and pull-down resistor. Example 6-2 shows this concept. When calibrating a set point or threshold of a sensor, typically only a small portion of the DAC output range is utilized.
PAGE 28
MCP4802/4812/4822 6.6 Bipolar Operation Example 6-3 illustrates a simple bipolar voltage source configuration. R1 and R2 allow the gain to be selected, while R3 and R4 shift the DAC's output to a selected offset. Note that R4 can be tied to VDD, instead of VSS, if a higher offset is desired. Also note that a pull-up to VDD could be used instead of R4, or in addition to R4, if a higher offset is desired.
PAGE 29
MCP4802/4812/4822 6.7 Selectable Gain and Offset Bipolar Voltage Output Using a Dual Output DAC This circuit is typically used for linearizing a sensor whose slope and offset varies. The equation to design a bipolar “window” DAC would be utilized if R3, R4 and R5 are populated. In some applications, precision digital control of the output range is desirable. Example 6-4 illustrates how to use the MCP4802/4812/4822 family of devices to achieve this in a bipolar or single-supply application.
PAGE 30
MCP4802/4812/4822 6.8 Designing a Double-Precision DAC Using a Dual DAC Step 1: Calculate the resolution needed: Example 6-5 illustrates how to design a single-supply voltage output capable of up to 24-bit resolution from a dual 12-bit DAC (MCP4822). This design is simply a voltage divider with a buffered output. As an example, if an application similar to the one developed in Section 6.6.
PAGE 31
MCP4802/4812/4822 6.9 Building Programmable Current Source However, this also reduces the resolution that the current can be controlled with. The voltage divider, or “window”, DAC configuration would allow the range to be reduced, thus increasing resolution around the range of interest. When working with very small sensor voltages, plan on eliminating the amplifier’s offset error by storing the DAC’s setting under known sensor conditions.
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MCP4802/4812/4822 NOTES: DS22249A-page 32  2010 Microchip Technology Inc.
PAGE 33
MCP4802/4812/4822 7.0 DEVELOPMENT SUPPORT 7.1 Evaluation and Demonstration Boards The Mixed Signal PICtail™ Demo Board supports the MCP4802/4812/4822 family of devices. Refer to www.microchip.com for further information on this product’s capabilities and availability.  2010 Microchip Technology Inc.
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MCP4802/4812/4822 NOTES: DS22249A-page 34  2010 Microchip Technology Inc.
PAGE 35
MCP4802/4812/4822 8.0 PACKAGING INFORMATION 8.1 Package Marking Information Example: 8-Lead MSOP XXXXXX YWWNNN 8-Lead PDIP (300 mil) XXXXXXXX XXXXXNNN YYWW Legend: XX...
PAGE 36
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PAGE 37
MCP4802/4812/4822 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging  2010 Microchip Technology Inc.
PAGE 38
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PAGE 39
MCP4802/4812/4822 /HDG 3ODVWLF 6PDOO 2XWOLQH 61 ± 1DUURZ PP %RG\ >62,&@ 1RWH )RU WKH PRVW FXUUHQW SDFNDJH GUDZLQJV SOHDVH VHH WKH 0LFURFKLS 3DFNDJLQJ 6SHFLILFDWLRQ ORFDWHG DW KWWS ZZZ PLFURFKLS FRP SDFNDJLQJ D e N E E1 NOTE 1 1 2 3 α h b h A2 A c φ L A1 β L1 8QLWV 'LPHQVLRQ /LPLWV 1XPEHU RI 3LQV 0,//,0(7(56 0,1 1 120 0$; 3LWFK H 2YHUDOO +HLJKW $ ± %6& ± 0ROGHG 3DFNDJH 7KLFNQHVV $ ± ± 6WDQGRII $ ± 2YHUDOO :LGWK ( 0ROGHG 3DFNDJH
PAGE 40
MCP4802/4812/4822 /HDG 3ODVWLF 6PDOO 2XWOLQH 61 ± 1DUURZ PP %RG\ >62,&@ 1RWH )RU WKH PRVW FXUUHQW SDFNDJH GUDZLQJV SOHDVH VHH WKH 0LFURFKLS 3DFNDJLQJ 6SHFLILFDWLRQ ORFDWHG DW KWWS ZZZ PLFURFKLS FRP SDFNDJLQJ DS22249A-page 40  2010 Microchip Technology Inc.
PAGE 41
MCP4802/4812/4822 APPENDIX A: REVISION HISTORY Revision A (April 2010) • Original Release of this Document.  2010 Microchip Technology Inc.
PAGE 42
MCP4802/4812/4822 NOTES: DS22249A-page 42  2010 Microchip Technology Inc.
PAGE 43
MCP4802/4812/4822 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO.
PAGE 44
MCP4802/4812/4822 NOTES: DS22249A-page 44  2010 Microchip Technology Inc.
PAGE 45
Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature.
PAGE 46
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