LTC1663 10-Bit Rail-to-Rail Micropower DAC with 2-Wire Interface DESCRIPTION FEATURES n n n n n n n n n n n n Micropower 10-Bit DAC in SOT-23 Low Operating Current: 60μA Ultralow Power Shutdown Mode: 10μA 2-Wire Serial Interface Compatible with SMBus Selectable Internal Reference or Ratiometric to VCC Maximum DNL Error: 0.75LSB 8 User Selectable Addresses (MSOP Package) Single 2.7V to 5.5V Operation Buffered True Rail-to-Rail Voltage Output Power-On Reset 0.6V VIL and 1.4V VIH for SDA and SCL Small 5-Lead SOT-23 and 8-Lead MSOP Packages APPLICATIONS n n n n n n The LTC®1663 is a 10-bit voltage output DAC with true buffered rail-to-rail output voltage capability. It operates from a single supply with a range of 2.7V to 5.5V. The reference for the DAC is selectable between the supply voltage or an internal bandgap reference. Selecting the internal bandgap reference will set the full-scale output voltage range to 2.5V. Selecting the supply as the reference sets the output voltage range to the supply voltage. The part features a simple 2-wire serial interface compatible with SMBus that allows communication between many devices. The internal data registers are double buffered to allow for simultaneous update of several devices at once. The DAC can be put in low current power-down mode for use in power conscious systems. Power-on reset ensures the DAC output is at 0V when power is initially applied, and all internal registers are cleared. Digital Calibration Offset/Gain Adjustment Industrial Process Control Automatic Test Equipment Arbitrary Function Generators Battery-Powered Data Conversion Products For I2C designs, please refer to the LTC1669. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. BLOCK DIAGRAM 4 (5) Differential Nonlinearity (DNL) VCC 1.25V BANDGAP REFERENCE 1.0 VREF = VCC = 5V TA = 25°C 0.8 0.6 REFERENCE SELECT 10-BIT DAC LATCH + VOUT 3 (8) COMMAND LATCH –1.0 0 R (6) AD0 (2) AD1 (3) AD2 –0.4 –0.8 R INPUT LATCH 0 –0.2 –0.6 – MSOP PACKAGE ONLY ERROR (LSB) 0.4 0.2 28 156 384 512 640 768 896 1024 CODE 1663 TA01 2-WIRE INTERFACE SDA SCL GND 1 (1) 5 (4) 2 (7) 1663 BD NOTE: PIN NUMBERS IN PARENTHESES REFER TO THE MSOP PACKAGE 1663fd 1 LTC1663 ABSOLUTE MAXIMUM RATINGS (Note 1) VCC to GND .............................................. – 0.3V to 7.5V SDA, SCL ................................................. –0.3V to 7.5V AD0, AD1, AD2 (MSOP Only) ........–0.3V to (VCC + 0.3V) VOUT .............................................–0.3V to (VCC + 0.3V) Storage Temperature Range.................. –65°C to 150°C Operating Temperature Range LTC1663C ............................................... 0°C to 70°C LTC1663I............................................. –40°C to 85°C LTC1663E (Note 8).............................. –40°C to 85°C Lead Temperature (Soldering, 10 sec) ................. 300°C PACKAGE/ORDER INFORMATION ORDER PART NUMBER TOP VIEW TOP VIEW SDA AD1 AD2 SCL 1 2 3 4 ORDER PART NUMBER 8 7 6 5 LTC1663CMS8 LTC1663IMS8 LTC1663-8CMS8 LTC1663-8IMS8 VOUT GND AD0 VCC MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 125°C, θJA = 150°C/W SDA 1 GND 2 VOUT 3 MS8 PART MARKING LTEQ LTJJ LTC1663CS5 LTC1663-1CS5 LTC1663-2CS5 LTC1663ES5 5 SCL 4 VCC S5 PACKAGE 5-LEAD PLASTIC SOT-23 TJMAX = 125°C, θJA = 250°C/W S5 PART MARKING* LTA6 LTA7 LTEP LTSA LTSB LTEP Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 2.7V to 5.5V, VCC set as reference, VOUT unloaded, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS DAC Resolution l 10 10 Bits Monotonicity (Note 2) l DNL Differential Nonlinearity Guaranteed Monotonic (Note 2) l ± 0.2 ±0.75 LSB INL Integral Nonlinearity (Note 2) LTC1663E (Note 2) l l ±0.5 ±0.5 ± 2.5 ±3 LSB LSB VOS Offset Error Measured at Code 20 Measured at Code 20 (LTC1663E) l l ±10 ±10 ±30 ±35 mV mV VOSTC Offset Error Temperature Coefficient FSE Full-Scale Error Reference Set to VCC Reference Set to Internal Bandgap Reference Set to VCC (LTC1663E) Reference Set to Internal Bandgap (LTC1663E) VOUT DAC Output Span Reference Set to VCC Reference Set to Internal Bandgap 0 to VCC 0 to 2.5 VFSTC Full-Scale Voltage Temperature Coefficient Reference Set to VCC Reference Set to Internal Bandgap ±30 ±50 μV/°C μV/°C PSRR Power Supply Rejection Ratio Reference Set to Internal Bandgap, Code = 1023 ±0.4 LSB/V Bits ±15 l l l l ±3 ±3 μV/°C ±15 ±15 ±20 ±20 LSB LSB LSB LSB V V 1663fd 2 LTC1663 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 2.7V to 5.5V, VCC set as reference, VOUT unloaded, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN VCC Positive Supply Voltage l ICC Supply Current VCC = 3V (Note 3) VCC = 5V (Note 3) l l ISD Supply Current in Shutdown Mode (Note 3) LTC1663E (Note 3) Short-Circuit Current (Sourcing) TYP MAX 2.7 UNITS 5.5 V 60 75 100 125 μA μA l l 10 12 16 24 μA μA VOUT Shorted to GND, Input Code = 1023 l 25 100 mA Short-Circuit Current (Sinking) VOUT Shorted to VCC, Input Code = 0 l 30 120 mA Output Impedance to GND Input Code = 0, VCC = 5V Input Code = 0, VCC = 3V In Shutdown Mode 65 150 500 Ω Ω kΩ Output Impedance to VCC Input Code = 1023, VCC = 5V Input Code = 1023, VCC = 3V 80 120 Ω Ω Voltage Output Slew Rate Rising (Notes 4, 5) Falling (Notes 4, 5) 0.75 0.25 V/μs V/μs Voltage Output Settling Time To ± 0.5LSB (Notes 4, 5) Op Amp DC Performance AC Performance 30 Digital Feedthrough Digital-to-Analog Glitch Impulse 1LSB Change Around Major Carry μs 0.75 nV•s 70 nV•s Digital Inputs SCL, SDA VIH High Level Input Voltage l VIL Low Level Input Voltage l 1.4 V 0.6 V VLTH Logic Threshold Voltage ILEAK Digital Input Leakage VCC = 5.5V and 0V, VIN = GND to VCC VCC = 5.5V and 0V, VIN = GND to VCC (LTC1663E) l l 1 ±1.0 ±1.2 μA μA V CIN Digital Input Capacitance (Note 7) l 10 pF IPULLUP = 350μA l 0.4 V VIN = 0V l 1.5 μA Digital Output SDA VOL Digital Output Low Voltage Address Inputs AD0, AD1, AD2 (MSOP Only) IUP Address Pin Pull-Up Current VIH High Level Input Voltage l VIL Low Level Input Voltage l 0.5 VCC – 0.3 V 0.8 V TIMING CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 2.7V to 5.5V, VCC set as reference, VOUT unloaded, unless otherwise noted. SYMBOL PARAMETER MIN TYP MAX UNITS 100 kHz SMBus Timing Characteristics (Notes 6, 7) fSMB SMBus Operating Frequency ● 10 tBUF Bus Free Time Between Stop and Start Condition ● 4.7 μs tHD, STA Hold Time After (Repeated) Start Condition ● 4.0 μs tSU, STA Repeated Start Condition Setup Time ● 4.7 μs tSU, STO Stop Condition Setup Time ● 4.0 μs tHD, DAT Data Hold Time ● 300 ns 1663fd 3 LTC1663 TIMING CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 2.7V to 5.5V, VCC set as reference, VOUT unloaded, unless otherwise noted. SYMBOL PARAMETER MIN tSU, DAT Data Setup Time ● 250 tLOW Clock Low Period ● 4.7 tHIGH Clock High Period ● 4.0 tf Clock, Data Fall Time tr Clock, Data Rise Time TYP MAX UNITS ns μs 50 μs ● 300 ns ● 1000 ns Note 5: VCC = VREF = 5V. DAC switched between 0.1VFS and 0.9VFS, i.e., codes k = 102 and k = 922. Note 6: All values are referenced to VIH and VIL levels. Note 7: Guaranteed by design and not subject to test. Note 8: The LTC1663E is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Nonlinearity and monotonicity are defined from code 20 to code 1003 (full scale). See Applications Information. Note 3: Digital inputs at 0V or VCC. Note 4: Load is 10kΩ in parallel with 100pF. TYPICAL PERFORMANCE CHARACTERISTICS Integral Nonlinearity (INL) 1.0 1.0 VREF = VCC = 5V TA = 25°C 0.8 5.0 VREF = VCC = 5V TA = 25°C 0.8 0.6 OUTPUT VOLTAGE (V) ERROR (LSB) 0 –0.2 0.2 0 –0.2 3.5 3.0 2.5 2.0 –0.4 –0.4 –0.6 –0.6 1.0 –0.8 –0.8 0.5 –1.0 0 28 156 384 512 640 768 896 1024 CODE DAC CODE = 1023 4.0 0.4 0.2 TA = 25°C 4.5 0.6 0.4 ERROR (LSB) Source and Sink Current Capability with VCC = 5V Differential Nonlinearity (DNL) –1.0 0 28 1.5 0 156 384 512 640 768 896 1024 CODE 1663 G01 DAC CODE = 0 1 2 3 4 5 6 7 8 9 10 OUTPUT CURRENT SOURCE/SINK (mA) 0 1663 G02 Large-Signal Step Response 1663 G03 Midscale Glitch Load Regulation vs Output Current 1.0 5 SDA (VOLTS) 0 5 3 VOUT (VOLTS) 2 0.6 VCC = 5V RL = 4.7k CL = 100pF TA = 25°C VOUT 10mV/DIV VCC = 5V RL = 4.7k CL = 100pF TA = 25°C 1 CODE = 32 0 5μs/DIV 1663 G04 2μs/DIV VCC = VREF = 5V VOUT = 2.5V CODE = 512 TA = 25°C 0.4 CODE = 512 TO 511 CODE = 990 ΔVOUT (LSB) 4 0.8 5V SDA 0V 1663 G05 0.2 0 –0.2 SOURCE –0.4 SINK –0.6 –0.8 –1.0 –4 –3 –2 –1 0 1 IOUT (mA) 2 3 4 1663fd 1663 G06 4 LTC1663 TYPICAL PERFORMANCE CHARACTERISTICS Offset Error Voltage vs Temperature Load Regulation vs Output Current OFFSET ERROR VOLTAGE (mV) 0.6 VCC = VREF = 3V VOUT = 1.5V CODE = 512 TA = 25°C ΔVOUT (LSB) 0.4 0.2 0 –0.2 –0.4 SOURCE SINK 5 2.510 4 2.508 3 2.506 OUTPUT VOLTAGE (V) 1.0 0.8 Full-Scale Output Voltage vs Temperature 2 1 0 –1 –2 2.504 2.502 2.500 2.498 2.496 –3 2.494 –0.8 –4 2.492 –1.0 –1.0 –0.8 –0.6 –0.4 –0.2 0 0.2 0.4 0.6 0.8 1.0 IOUT (mA) –5 –60 –40 –20 0 20 40 60 TEMPERATURE (°C) –0.6 1663 G07 80 100 REFERENCE SET TO INTERNAL BANDGAP 2.490 –60 –40 –20 0 20 40 60 TEMPERATURE (°C) 1663 G08 80 100 1663 G09 PIN FUNCTIONS SDA (Pin 1, Pin 1 on SOT-23): Serial Data Bidirectional Pin. Data is shifted into the SDA pin and acknowledged by the SDA pin. High impedance pin while data is shifted in. Open-drain N-channel output during acknowledgment. Requires a pull-up resistor or current source to VCC. AD1 (Pin 2): Slave Address Select Bit 1. Tie this pin to either VCC or GND to modify the corresponding bit of the LTC1663’s slave address. AD2 (Pin 3): Slave Address Select Bit 2. Tie this pin to either VCC or GND to modify the corresponding bit of the LTC1663’s slave address. SCL (Pin 4, Pin 5 on SOT-23): Serial Clock Input Pin. Data is shifted into the SDA pin at the rising edges of the clock. This high impedance pin requires a pull-up resistor or current source to VCC. VCC (Pin 5, Pin 4 on SOT-23): Power Supply. 2.7V ≤ VCC ≤ 5.5V. Also used as the reference voltage input when the part is programmed to use VCC as the reference. AD0 (Pin 6): Slave Address Select Bit 0. Tie this pin to either VCC or GND to modify the corresponding bit of the LTC1663’s slave address. GND (Pin 7, Pin 2 on SOT-23): System Ground. VOUT (Pin 8, Pin 3 on SOT-23): Voltage Output. Buffered rail-to-rail DAC output. DEFINITIONS Differential Nonlinearity (DNL): The difference between the measured change and the ideal 1LSB change for any two adjacent codes. The DNL error between any two codes is calculated as follows: DNL = (ΔVOUT – LSB)/LSB Where ΔVOUT is the measured voltage difference between two adjacent codes. Digital Feedthrough: The glitch that appears at the analog output caused by AC coupling from the digital inputs when they change state. The area of the glitch is specified in (nV)(sec). Full-Scale Error (FSE): The deviation of the actual full-scale voltage from ideal. FSE includes the effects of offset and gain errors (see Applications Information). 1663fd 5 6 NOTE: X = DON’T CARE 2 1 SCL 3 0 0 4 0 0 5 1 AD2 ADDRESS 6 1 AD1 tr tHIGH tf tSU, DAT tHD, DAT REPEATED START CONDITION tSU, STA tHD, STA STOP CONDITION tBUF tSU, STO START CONDITION 1663 TD 7 1 AD0 8 0 WR 9 ACK 1 X X 2 X X 3 X X 4 X X 5 X X COMMAND 6 0 BG 7 0 SD 8 0 SY 9 ACK 1 1 D7 2 1 D6 3 1 D5 4 1 5 1 D3 LS DATA D4 6 1 D2 7 1 D1 8 1 D0 9 ACK 1 X X 2 X X 3 X X 4 X X 5 X X MS DATA 6 X X 7 1 D9 8 1 D8 9 ACK STOP 1663 TA02 ZERO-SCALE VOLTAGE FULL-SCALE VOLTAGE TIMING DIAGRAM VOUT 1 0 START 1 SDA 0 tLOW Typical LTC1663 Input Waveform—Programming DAC Output for Full Scale (AD2 to AD0 Set High) START CONDITION tHD, STA SCL SDA LTC1663 1663fd LTC1663 DEFINITIONS Integral Nonlinearity (INL): The deviation from a straight line passing through the endpoints of the DAC transfer curve (Endpoint INL). Because the output cannot go below zero, the linearity is measured between full scale and the lowest code that guarantees the output will be greater than zero. The INL error at a given input code is calculated as follows: Resolution (n): Defines the number of DAC output states (2n) that divide the full-scale range. Resolution does not imply linearity. Voltage Offset Error (VOS): Nominally, the voltage at the output when the DAC is loaded with all zeros. A single supply DAC can have a true negative offset, but the output cannot go below zero (see Applications Information). INL = [VOUT – VOS – (VFS – VOS)(code/1023)]/LSB For this reason, single supply DAC offset is measured at the lowest code that guarantees the output will be greater than zero. Where VOUT is the output voltage of the DAC measured at the given input code. Least Significant Bit (LSB): The ideal voltage difference between two successive codes. LSB = VREF/1024 APPLICATIONS INFORMATION Write Word Protocol Used by the LTC1663 1 7 1 1 8 1 8 1 8 1 1 S Slave Address Wr A Command Byte A LSData Byte A MSData Byte A P S = Start Condition, Wr = Write Bit = 0, A = Acknowledge, P = Stop Condition Serial Digital Interface The LTC1663 communicates with a host (master) using the standard 2-wire interface. The Timing Diagram shows the timing relationship of the signals on the bus. The two bus lines, SDA and SCL, must be high when the bus is not in use. External pull-up resistors or current sources, such as the LTC1694 SMBus Accelerator, are required on these lines. The LTC1663 is a receive-only (slave) device. The master can communicate with the LTC1663 using the Quick Command, Send Byte or Write Word protocols as explained later. The START and STOP Conditions When the bus is not in use, both SCL and SDA must be high. A bus master signals the beginning of a communication to a slave device by transmitting a START condition. A START condition is generated by transitioning SDA from high to low while SCL is high. 1663 TA03 When the master has finished communicating with the slave, it issues a STOP condition. A STOP condition is generated by transitioning SDA from low to high while SCL is high. The bus is then free for communication with another SMBus device. Acknowledge The Acknowledge signal is used for handshaking between the master and the slave. An Acknowledge (active LOW) generated by the slave lets the master know that the latest byte of information was received. The Acknowledge related clock pulse is generated by the master. The master releases the SDA line (HIGH) during the Acknowledge clock pulse. The slave-receiver must pull down the SDA line during the Acknowledge clock pulse so that it remains a stable LOW during the HIGH period of this clock pulse. Write Word Protocol The master initiates communication with the LTC1663 with a START condition and a 7-bit address followed by the Write 1663fd 7 LTC1663 APPLICATIONS INFORMATION Bit (Wr) = 0. The LTC1663 acknowledges and the master delivers the command byte. The LTC1663 acknowledges and latches the command byte into the command byte input register. The master then delivers the least significant data byte. Again the LTC1663 acknowledges and the data is latched into the least significant data byte input register. The master then delivers the most significant data byte. The LTC1663 acknowledges once more and latches the data into the most significant data byte input register. Lastly, the master terminates the communication with a STOP condition. On the reception of the STOP condition, the LTC1663 transfers the input register information to output registers and the DAC output is updated. Slave Address (MSOP Package Only) The LTC1663 can respond to one of eight 7-bit addresses. The first 4 bits (MSBs) have been factory programmed to 0100. The first 4 bits of the LTC1663-8 have been factory programmed to 0011. The three address bits, AD2, AD1 and AD0 are programmed by the user and determine the LSBs of the slave address, as shown in the table below: LTC1663 LTC1663-8 AD2 AD1 AD0 0100 xxx 0011 xxx L L L 0100 000 0011 000 L L H 0100 001 0011 001 L H L 0100 010 0011 010 L H H 0100 011 0011 011 H L L 0100 100 0011 100 H L H 0100 101 0011 101 H H L 0100 110 0011 110 H H H 0100 111 0011 111 Slave Address (SOT-23 Package) The slave address for the SOT-23 package has been factory programmed to be “0100 000” (LTC1663), “0100 001” (LTC1663-1) and “0100 010” (LTC1663-2) If another address is required, please consult the factory. Command Byte 7 6 5 4 3 2 1 0 X X X X X BG SD SY SY 1 0 Allows update on Acknowledge of SYNC Address only Update on Stop condition only (Power-On Default) SD 1 0 Puts the device in power-down mode Puts the device in standard operating mode (Power-On Default) BG 1 0 Selects the internal bandgap reference Selects the supply as the reference (Power-On Default) X X Don’t Care The stop condition normally initiates the update of the DAC’s output latches. Simultaneous update of more than one DAC or other devices on the bus can be achieved by reissuing new start bit, address, command and data bytes before issuing a final stop condition (which will update all the devices). An alternate way to achieve simultaneous LTC1663 updates is to override the stop condition update by setting the “SY” bit of the command byte. Setting this bit sets the device to update the DAC output latches only at the reception of a SYNC address quick command. The actual update occurs on the rising edge of SCL during the Acknowledge. In this way, all devices can update on the reception of the SYNC address quick command instead of the STOP condition. A Shutdown (SD) bit = HIGH will put the device in a low power state but retain all data latch information. Shutdown will occur at the reception of a STOP condition. This way shutdown could be synchronized to other devices. The output impedance of the DAC will go to a high impedance state (≈ 500kΩ to GND). The Bandgap (BG) bit when set to “0” selects the DAC supply voltage as its voltage reference. The full-scale output of the DAC with this setting is equal to the supply voltage. When the BG bit is set to “1,” the internal bandgap reference (≈1.25V) is selected as the DAC’s reference. The full-scale output voltage for this setting is 2.5V. 1663fd 8 LTC1663 APPLICATIONS INFORMATION Data Bytes Least Significant Data Byte 7 6 5 4 3 2 1 0 D7 D6 D5 D4 D3 D2 D1 D0 The SY/CLR bit set high only has meaning when the “SY” bit of the command byte was previously set HIGH. On the otherhand, the SY/CLR bit set LOW will always clear the part, independent of the state of the “SY” bit in the command byte. Most Significant Data Byte 6 5 4 3 2 1 0 Input Threshold X X X = Don’t care X X X X D9 D8 Anticipating the trend toward lower supply voltages, the SMBus is specified with a VIH of 1.4V and a VIL of 0.6V. While some SMBus parts may violate this stringent SMBus specification by allowing a higher VIH value for a correspondingly higher input supply voltage, the LTC1663 meets and maintains the constant SMBus input threshold specification across the entire supply voltage range of 2.7V to 5.5V. The logic input threshold is designed to be 1V with 50mV of hysteresis. 7 Send Byte Protocol The Send Byte protocol used on the LTC1663 is actually a subset of the Write Word protocol described previously. The Send Byte protocol can only be used to send the command byte information to the LTC1663. 1 7 1 1 8 1 1 S Slave Address Wr A Command Byte A P S = Start Condition, Wr = Write Bit, A = Acknowledge, P = Stop Condition 1663 TA04 The Send Byte protocol is also used whenever the Write Word protocol is interrupted for any reason. Reception of a START or STOP condition after the Acknowledge of the command byte, but before the Acknowledge of the last data byte, will cause both data bytes to be ignored and the command byte to be accepted. Reception of a START or STOP condition before the Acknowledge of the command byte will cause the interrupted command byte to be ignored. SYNC Address/Quick Command In addition to the slave address, the LTC1663 has an address that can be shared by other devices so that they may be updated synchronously. The address is called to the SYNC address and uses the quick command protocol. The SYNC Address is 1111 110 1 Start 7 1 1 1 1111 110 SY/CLR Ack Stop SYNC Address SY/CLR 1 0 1663 TA05 Update output latches on rising edge of SCL during Acknowledge of SYNC Address Clear all internal latches on rising edge of SCL during Acknowledge of SYNC Address Voltage Output The output amplifier contained in the LTC1663 can source or sink up to 5mA. The output stage swings to within a few millivolts of either supply rail when unloaded and has an equivalent output resistance of 85Ω when driving a load to the rails. The output amplifier is stable driving capacitive loads up to 1000pF. A small resistor placed in series with the output can be used to achieve stability for any load capacitance greater than 1000pF. For example, a 0.1μF load can be driven by the LTC1663 if a 110Ω series resistance is used. The phase margin of the resulting circuit is 45° and increases monotonically from this point if larger values of resistance, capacitance or both are substituted for the values given. Rail-to-Rail Output Considerations As in any rail-to-rail device, the output is limited to voltages within the supply range. If the DAC offset is negative, the output for the lowest codes limits at 0V as shown in Figure 1b. Similarly, limiting can occur near full scale when VCC is used as the reference. If VREF = VCC and the DAC full-scale error (FSE) is positive, the output for the highest codes limits at VCC as shown in Figure 1c. No full-scale limiting can occur if the internal reference is used. 1663fd 9 LTC1663 APPLICATIONS INFORMATION POSITIVE FSE VREF = VCC OUTPUT VOLTAGE INPUT CODE (c) VREF = VCC OUTPUT VOLTAGE 0 512 INPUT CODE (a) 1023 OUTPUT VOLTAGE 0V NEGATIVE OFFSET INPUT CODE (b) 1663 F01 Figure 1. Effects of Rail-to-Rail Operation On a DAC Transfer Curve. (a) Overall Transfer Function (b) Effect of Negative Offset for Codes Near Zero Scale (c) Effect of Positive Full-Scale Error for Input Codes Near Full Scale When VREF = VCC Offset and linearity are defined and tested over the region of the DAC transfer function where no output limiting can occur. Internal Reference In applications where a predictable output is required that is independent of supply voltage, the LTC1663 has a user-selectable internal reference. Selecting the internal reference will set the full-scale output voltage to 2.5V. This can be useful in applications where the supply voltage is poorly regulated. used. The LT1460 is ideal for use as a power supply for the LTC1663 and can provide 3V, 3.3V and 5V full-scale output voltage ranges. The LT1460 provides accuracy, noise immunity and extended supply range to the LTC1663 when the LTC1663 is operated ratiometric to VCC. Since both parts are available in SOT-23 packages, the PC board space for this application is extremely small. See Figure 2. 3.9V TO 20V 0.1μF 1 IN LT1460S3-3 2 OUT + GND In applications where the advantages of using the internal reference are required but the full-scale range needs to be greater than 2.5V, an external series reference can be 0.01μF 3 4 (5) VCC 5 (4) Using the LT®1460 Micropower Series Reference as a Power Supply for the LTC1663 3V TO μP 1 (1) SCL LTC1663 OUT 3 (8) 0V ≤ VOUT ≤ 3V SDA GND LTC1663 PIN NUMBERS IN PARENTHESES REFER TO MSOP PACKAGE 2 (7) 1663 F02 Figure 2. LT1460 As Power Supply for the LTC1663 1663fd 10 LTC1663 PACKAGE DESCRIPTION S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 0.62 MAX 0.95 REF 2.90 BSC (NOTE 4) 1.22 REF 2.80 BSC 1.4 MIN 3.85 MAX 2.62 REF 1.50 – 1.75 (NOTE 4) PIN ONE RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 TYP 5 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 1.90 BSC S5 TSOT-23 0302 MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660) 3.00 ± 0.102 (.118 ± .004) (NOTE 3) 0.889 ± 0.127 (.035 ± .005) 5.23 (.206) MIN 3.20 – 3.45 (.126 – .136) 0.254 (.010) 0.42 ± 0.038 (.0165 ± .0015) TYP 0.65 (.0256) BSC 8 7 6 5 3.00 ± 0.102 (.118 ± .004) (NOTE 4) 4.90 ± 0.152 (.193 ± .006) DETAIL “A” 0.52 (.0205) REF 0° – 6° TYP GAUGE PLANE 1 0.53 ± 0.152 (.021 ± .006) RECOMMENDED SOLDER PAD LAYOUT DETAIL “A” 2 3 1.10 (.043) MAX 4 0.86 (.034) REF 0.18 (.007) SEATING NOTE: PLANE 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 0.22 – 0.38 (.009 – .015) TYP 0.65 (.0256) BSC 0.127 ± 0.076 (.005 ± .003) MSOP (MS8) 0204 1663fd Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 11 LTC1663 TYPICAL APPLICATION Program Up to 8 Control Outputs Per BUS (8 LTC1663 and 8 LTC1663-8 DACs) and Place Them Where They Are Needed VCC = 2.7V TO 5.5V μP SDA SCL 5 4 + 5 4 VCC SCL 1 SDA 8 LTC1663-8CMS8 6 VOUT AD0 2 AD1 3 AD2 GND + 0.1μF SMBus 2 GND 2 + 5 4 VCC SCL 1 SDA 8 LTC1663CMS8 6 VOUT AD0 2 AD1 3 AD2 GND 0.1μF CONTROL OUTPUT 0 0V ≤ VOUT0 < VCC 7 0.1μF CONTROL OUTPUT 8 0V ≤ VOUT8 < VCC 7 + 5 4 VCC SCL 1 SDA 8 LTC1663-8CMS8 6 VOUT AD0 2 AD1 3 AD2 GND + 5 4 VCC SCL 1 SDA 8 LTC1663CMS8 6 VOUT AD0 2 AD1 3 AD2 GND 0.1μF CONTROL OUTPUT 1 0V ≤ VOUT1 < VCC 7 0.1μF CONTROL OUTPUT 9 0V ≤ VOUT9 < VCC 7 + 5 4 VCC SCL 1 SDA 8 LTC1663-8CMS8 6 VOUT AD0 2 AD1 3 AD2 GND TO OTHER SMBus DEVICES 1 VCC SMBus 1 LTC1694 + 5 4 VCC SCL 1 SDA 8 LTC1663CMS8 6 VOUT AD0 2 AD1 3 AD2 GND 0.1μF CONTROL OUTPUT 7 0V ≤ VOUT7 < VCC TO OTHER SMBus DEVICES 7 0.1μF CONTROL OUTPUT 15 0V ≤ VOUT15 < VCC 7 1663 TA06 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1694 SMBus I2C Accelerator Dual SMBus Accelerator with Active AC and DC Pull-Up Current Sources LTC1694-1 SMBus I2C Accelerator Dual SMBus Accelerator with Active AC Pull-Up Current Only Single Rail-to-Rail 12-Bit VOUT DAC in 8-Lead MSOP Package. VCC = 2.7V to 5.5V Low Power Multiplying VOUT DAC. Output Swings from GND to REF. REF Input Can Be Tied to VCC. 3-Wire Interface. DACs LTC1659 LTC1660/LTC1664 Octal/Quad 10-Bit VOUT DACs in 16-Pin Narrow SSOP VCC = 2.7V to 5.5V Micropower Rail-to-Rail Output. 3-Wire Interface LTC1661 Dual 10-Bit VOUT in 8-Lead MSOP Package VCC = 2.7V to 5.5V Micropower Rail-to-Rail Output. 3-Wire Interface. LTC1669 10-Bit VOUT DAC in SOT-23, I2C Interface Pin-Compatible with LTC1663 LTC1285/LTC1288 8-Pin SO, 3V Micropower ADCs 1- or 2-Channel, Autoshutdown LTC1286/LTC1298 8-Pin SO, 5V Micropower ADCs 1- or 2-Channel, Autoshutdown LTC1594/LTC1598 4/8-Channel, 5V Micropower 12-Bit ADCs Low Power, Small Size, Low Cost ADCs 1663fd 12 Linear Technology Corporation LT 1007 REV D • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2007