View MAX5222_30102.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-1720; Rev 0; 4/00
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23
General Description
The MAX5222 contains two 8-bit, buffered, voltage-output digital-to-analog converters (DAC A and DAC B) in a small 8-pin SOT23 package. Both DAC outputs can source and sink 1mA to within 100mV of ground and VDD. The MAX5222 operates with a single +2.7V to +5.5V supply. The device uses a 3-wire serial interface, which operates at clock rates up to 25MHz and is compatible with SPITM, QSPITM, and MICROWIRETM interface standards. The serial input shift register is 16 bits long and consists of 8 bits of DAC input data and 8 bits for DAC selection and shutdown control. DAC registers can be loaded independently or in parallel at the positive edge of CS. The MAX5222's ultra-low power consumption and tiny 8-pin SOT23 package make it ideal for portable and battery-powered applications. Supply current is less than 1mA and drops below 1A in shutdown mode. In addition, the reference input is disconnected from the REF pin during shutdown, further reducing the system's total power consumption.
Features
o Operates from a Single +2.7V to +5.5V Supply o Tiny 8-Pin SOT23 Package (3mm 3mm) o Dual Buffered Voltage Output o Low Power Consumption 0.4mA Operating Current <1A Shutdown Current o Programmable Shutdown Mode o 25MHz, 3-Wire Serial Interface o SPI, QSPI, and MICROWIRE Compatible
MAX5222
Ordering Information
PART MAX5222EKA-T TEMP. RANGE -40C to +85C PIN-PACKAGE 8 SOT23-8
________________________Applications
Digital Gain and Offset Adjustment Programmable Current Source Programmable Voltage Source Power-Amp Bias Control VCO Tuning
SCLK 4 8 DIN 0.22F
Functional Diagram
0.1F (OPTIONAL) 3 VDD 7 REF
Pin Configuration
TOP VIEW
16-BIT SHIFT REGISTER CONTROL (8) DATA (8)
OUTA VOUTA DAC LATCH A DAC A 5
DAC LATCH B
DAC B
OUTB VOUTB 6
CS 1 GND 2 VDD 3 SCLK 4
8
DIN REF OUTB OUTA
MAX5222
7 6 5
CS 1
MAX5222
2 GND
SOT23-8
SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp. ________________________________________________________________ Maxim Integrated Products 1
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769.
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23 MAX5222
ABSOLUTE MAXIMUM RATINGS
VDD to GND ............................................................. -0.3V to +6V All Other Pins to GND (Note 1).................. -0.3V to (VDD + 0.3V) Continuous Power Dissipation (TA = +70C) 8-Pin SOT23 (derate 8.7mW/C above +70C)............696mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
Note 1: The outputs may be shorted to VDD or GND if the package power dissipation is not exceeded. Typical short-circuit current to GND is 70mA.
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VDD = +2.7V to +5.5V, REF = VDD, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER STATIC PERFORMANCE Resolution Differential Nonlinearity Integral Nonlinearity Total Unadjusted Error Zero-Code Offset Zero-Code Temperature Coefficient Power-Supply Rejection Ratio REFERENCE INPUT Reference Input Voltage Range Reference Input Capacitance Reference Input Resistance Reference Input Resistance (Shutdown Mode) DAC OUTPUTS Output Voltage Range Capacitive Load at OUT_ Output Resistance DIGITAL INPUTS Input High Voltage Input Low Voltage Input Current Input Capacitance VIH VIL IIN CIN VIN = 0 or VDD (Note 4) 0.1 0.7 x VDD 0.3 x VDD 10 10 V V A pF 50 0 REF 100 V pF RREF (Note 3) 8 GND 25 16 2 VDD V pF k M N DNL INL TUE VZS TCVZS PSRR 4.5V VDD 5.5V, VREF = 4.096V 2.7V VDD 3.6V, VREF = 2.4V Guaranteed monotonic (Note 2) (Note 2) 8 0.3 0.3 1 10 100 0.15 0.5 1 1 Bits LSB LSB LSB mV V/C mV/V SYMBOL CONDITIONS MIN TYP MAX UNITS
2
_______________________________________________________________________________________
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23 MAX5222
ELECTRICAL CHARACTERISTICS (continued)
(VDD = +2.7V to +5.5V, REF = VDD, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER DYNAMIC PERFORMANCE Voltage-Output Slew Rate Voltage-Output Settling Time Digital Feedthrough and Crosstalk POWER SUPPLY Supply Voltage Range Supply Current Shutdown Supply Current VDD IDD All inputs = 0 VDD = 5.5V VDD = 5.5V VDD = 3.6V 2.7 0.55 0.38 0.1 5.5 1 0.8 V mA A SR CL = 100pF To 12LSB, CL = 100pF All 0s to all 1s 1 10 0.25 V/s s nV-s SYMBOL CONDITIONS MIN TYP MAX UNITS
TIMING CHARACTERISTICS
(Figure 3, VDD = +2.7V to +5.5V, TA = TMIN to TMAX, unless otherwise noted.) (Note 4) PARAMETER SERIAL INTERFACE TIMING -- -- CS Fall to SCLK Rise Setup Time -- -- SCLK Rise to CS Rise Setup Time DIN to SCLK Rise Setup Time DIN to SCLK Rise Hold Time SCLK Pulse Width High SCLK Pulse Width Low -- -- CS Pulse Width High SYMBOL tCSS tCSH tDS tDH tCH tCL tCSPWH CONDITIONS MIN 50 50 20 20 20 20 50 TYP MAX UNITS ns ns ns ns ns ns ns
Note 2: Reduced digital code range (code 24 through code 232) is due to swing limitations of the output amplifiers. See Typical Operating Characteristics. Note 3: Reference input resistance is code dependent. The lowest input resistance occurs at code 55hex. See the Reference Input section. Note 4: Guaranteed by design. Not production tested.
_______________________________________________________________________________________
3
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23 MAX5222
__________________________________________Typical Operating Characteristics
(VDD = +3V, TA = +25C, unless otherwise noted.)
OUTPUT VOLTAGE vs. OUTPUT SOURCE CURRENT (VDD = 3V)
MAX5222-01
OUTPUT VOLTAGE vs. OUTPUT SOURCE CURRENT (VDD = 5V)
MAX5222-02
OUTPUT VOLTAGE vs. OUTPUT SINK CURRENT
700 600 OUTPUT VOLTAGE (mV)
MAX5222-03
3.5 3.0 OUTPUT VOLTAGE (V) 2.5 2.0 1.5 1.0 0.5 0 0.001
6 5 OUTPUT VOLTAGE (V) 4 3 2 1
800
500 400 300 200 100 0
0.01
0.1
1
10
100
0 0.0001
0.01
1
100
-100 0.0001
0.001
0.01
0.1
1
10
OUTPUT SOURCE CURRENT (mA)
OUTPUT SOURCE CURRENT (mA)
OUTPUT SINK CURRENT (mA)
INTEGRAL NONLINEARITY vs. DIGITAL CODE
MAX5222-04
DIFFERENTIAL NONLINEARITY vs. DIGITAL CODE
MAX5222-05
POSITIVE SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX5222-06
0.3 0.2 0.1
0.20 0.15 0.10
0.6 0.5 0.4
DNL (LSB)
INL (LSB)
IDD (mA) 0 50 100 150 CODE 200 250 300
0.05 0 -0.05 -0.10
0 -0.1 -0.2 -0.3 0 50 100 150 CODE 200 250 300
0.3 0.2 0.1 0 2 3 4 VDD (V) 5
-0.15 -0.20
POSITIVE SUPPLY CURRENT vs. TEMPERATURE
MAX5222-07
SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX5222-08
REFERENCE SMALL-SIGNAL FREQUENCY RESPONSE
MAX5222-09
0.65
0.6 0.5 0.4
5 0 RELATIVE OUTPUT (dB) -5 -10 -15 -20 -25
0.60
IDD (mA)
IDD (A)
0.55
0.3 0.2
0.50
0.45
0.1 0 -50 0 50 100 2 3 4 SUPPLY VOLTAGE (V) 5 6 TEMPERATURE (C)
0.40
0.1
1
10
100
1000
10,000
FREQUENCY (kHz)
4
_______________________________________________________________________________________
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23
Typical Operating Characteristics (continued)
(VDD = +3V, TA = +25C, unless otherwise noted.)
MAX5222
LARGE-SIGNAL OUTPUT STEP RESPONSE
MAX5222-10
CLOCK FEEDTHROUGH
MAX5222-11
VREF = VDD = 3V, RL = 10k, CL = 100pF CH1 CH1 CS 2V/div SCLK, 5MHz 0 TO 2.9V 5V/div
CH2 CH2 OUT_ 1V/div CS = HIGH, SCLK = 5MHz 2s/div 50ns/div
OUT_ 10mV/div AC-COUPLED
POWER-UP OUTPUT GLITCH
MAX5222-12
POWER-UP OUTPUT GLITCH
MAX5222-13
CH1 CH2 100s/div VDD = CHANGES BETWEEN 0 AND 5V RAMP TIME IS 10s
VDD 1V/div OUT_ 50mV/div
CH1 CH2 2ms/div VDD = CHANGES BETWEEN 0 AND 5V RAMP TIME IS 1ms
VDD 1V/div OUT_ 50mV/div
_______________________________________________________________________________________
5
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23 MAX5222
Typical Operating Characteristics (continued)
(VDD = +3V, TA = +25C, unless otherwise noted.)
NEGATIVE SETTLING TIME
MAX5222-14
POSITIVE SETTLING TIME
MAX5222-15
VDD = 3V, REF = VDD, RL = 10k, CL = 100pF ALL BITS OFF TO ALL BITS ON CH1 CS 2V/div OUT_ 200mV/div
CH1
OUT_ 200mV/div AC-COUPLED CS 2V/div VDD = 3V, REF = VDD, RL = 10k, CL = 100pF ALL BITS OFF TO ALL BITS ON 1s/div
CH2
CH2
1s/div
OUTPUT VOLTAGE NOISE (DC TO 1MHz)
MAX5222-16
CH1
OUTA 2mV/div AC-COUPLED
VDD = 3V, REF = VDD, NO LOAD, DIGITAL CODE = FF 2ms/div
6
_______________________________________________________________________________________
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23
______________________________________________________________Pin Description
PIN NAME -- -- CS GND VDD SCLK OUTA OUTB REF DIN FUNCTION Chip Select, Active Low. Enables data to be shifted into the 16-bit shift register. Programming commands -- -- are executed at the rising edge of C S. Ground Positive Power Supply (+2.7V to +5.5V). Bypass with 0.22F to GND. Serial Clock Input. Data is clocked in on the rising edge of SCLK. DAC A Output Voltage (Buffered) DAC B Output Voltage (Buffered) Reference Input for DAC A and DAC B Serial Data Input of the 16-bit Shift Register. Data is clocked into the register on the rising edge of SCLK.
MAX5222
1
2 3 4 5 6 7 8
Detailed Description
Analog Section
The MAX5222 contains two 8-bit, voltage-output DACs. The DACs are "inverted" R-2R ladder networks using complementary switches that convert 8-bit digital inputs into equivalent analog output voltages in proportion to the applied reference voltage. The MAX5222 has one reference input that is shared by DAC A and DAC B. The device includes output buffer amplifiers for both DACs and input logic for simple microprocessor (P) and CMOS interfaces. The power-supply range is from +5.5V down to +2.7V. Reference Input and DAC Output Range The voltage at REF sets the full-scale output of the DACs. The input impedance of the REF input is code dependent. The lowest value, approximately 8k, occurs when the input code is 01010101 (55hex). The maximum value of infinity occurs when the input code is zero. In shutdown mode, the selected DAC output is set to zero, while the value stored in the DAC register remains unchanged. This removes the load from the reference input to save power. Bringing the MAX5222 out of shutdown mode restores the DAC output voltage. Because the input resistance at REF is code dependent, the DAC's reference source should have an output impedance of no more than 5. The input capacitance at the
REF pin is also code dependent and typically does not exceed 25pF. The reference voltage on REF can range anywhere from GND to VDD. See the Output Buffer Amplifier section for more information. Figure 1 is the DAC simplified circuit diagram. Output Buffer Amplifiers DAC A and DAC B voltage outputs are internally buffered. The buffer amplifiers have a Rail-to-Rail (R) (GND to VDD) output voltage range. Both DAC output amplifiers can source and sink up to 1mA of current. See the INL vs. Digital Code graph in the Typical Operating Characteristics. The amplifiers are unity-gain stable with a capacitive load of 100pF or smaller. The slew rate is typically 1V/s. Shutdown Mode When programmed to shutdown mode, the outputs of DAC A and DAC B are passively pulled to GND with a series 5k resistor. In shutdown mode, the REF input is high impedance (2M typical) to conserve current drain from the system reference; therefore, the system reference does not have to be powered down. Coming out of shutdown, the DAC outputs return to the values kept in the registers. The recovery time is equivalent to the DAC settling time.
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd. _______________________________________________________________________________________ 7
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23 MAX5222
Table 1. Input Shift Register
B0* B1 DATA BITS
R R R OUT
DAC Data Bit 0 (LSB) DAC Data Bit 1 DAC Data Bit 2 DAC Data Bit 3 DAC Data Bit 4 DAC Data Bit 5 DAC Data Bit 6 DAC Data Bit 7 (MSB) Load Reg DAC A, Active High Load Reg DAC B, Active High Uncommitted Bit 4 Shut Down, Active High Shut Down, Active High Uncommitted Bit 3 Uncommitted Bit 2 Uncommitted Bit 1
B2 B3 B4 B5 B6 B7 LA LB UB4 SA SB UB3 UB2 UB1**
2R
2R
2R
2R
2R
REF GND SHOWN FOR ALL 1s ON DAC
Figure 1. DAC Simplified Circuit Diagram
Serial Interface -- -- An active-low chip select (CS) enables the shift register to receive data from the serial data input. Data is clocked into the shift register on every rising edge of the serial clock signal (SCLK). The clock frequency can be as high as 25MHz.
Data is sent most significant bit (MSB) first and can be transmitted in one 16-bit word. The write cycle can be -- -- segmented when CS is kept active (low) to allow, for example, two 8-bit-wide transfers. After clocking all - - 16 -- bits into the input shift register, the rising edge of CS updates the DAC outputs and the shutdown status. Because of their single buffered structure, DACs cannot be simultaneously updated to different digital values.
*Clocked in last. **Clocked in first.
Serial-Input Data Format and Control Codes Table 2 lists the serial-input data format. The 16-bit input word consists of an 8-bit control byte and an 8-bit data byte. The 8-bit control byte is not decoded internally. Every control bit performs one function. Data is clocked in starting with UB1 (uncommitted bit), followed by the remaining control bits and the data byte. The least significant bit (LSB) of the data byte (B0) is the last bit clocked into the shift register (Figure 2). Table 3 is an example of a 16-bit input word. It performs the following functions: * 80 hex (128 decimal) loaded into DAC registers A and B. * DAC A and DAC B are active.
8
_______________________________________________________________________________________
CONTROL BITS
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23 MAX5222
CS INSTRUCTION EXECUTED OPTIONAL DIN UB1 UB2 UB3 SB SA UB4 LB LA D7 D6 D5 D4 D3 D2 D1 D0
SCLK
(CONTROL BYTE)
(DATA BYTE)
Figure 2. 3-Wire Serial-Interface Timing Diagram
Table 2. Serial-Interface Programming Commands
CONTROL UB1 UB2 UB3 SB X X X X X X X X X X X X X X X X X X X X 1 1 1 1 1 1 1 1 1 1 SA UB4 LB LA 0 0 0 1 1 X X X X X X X X X X X X X X X 8-Bit DAC Data 8-Bit DAC Data 8-Bit DAC Data X X X X X X X X X X X X X X X X X X X X X X X X X B7 B6 MSB X X B5 X DATA B4 X B3 X B2 X B1 X B0 LSB X FUNCTION
* * * * *
0 0 1 0 1
* * * * *
0 0 0 1 1
0 0 0 0 0 0 0 0 0 0
0 0 1 0 1
No Operation to DAC Registers Unassigned Command Load Register to DAC B Load Register to DAC A Load Both DAC Registers All DACs Active Unassigned Command Shut Down Shut Down Shut Down
* * * * *
* * * * *
X = Don't care.
* = Not shown, for the sake of clarity. The functions of loading and shutting down the DACs and programming the logic can be combined in a single command.
Table 3. Example of a 16-Bit Input Word
LOADED IN FIRST UB1 X UB2 X UB3 1 SB 0 SA 0 UB4 0 LB 1 LA 1 B7 1 B6 0 B5 0 B4 0 B3 0 B2 0 B1 0 LOADED IN LAST B0 0
_______________________________________________________________________________________
9
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23 MAX5222
CS tCSPWH tCSS tCH SCLK tCSH
tDS tDH
tCL
DIN
Figure 3. Detailed Serial-Interface Timing Diagram
Digital Inputs The digital inputs are compatible with CMOS logic. Supply current increases slightly when toggling the logic inputs through the transition zone between 0.3 VDD and 0.7 VDD. Microprocessor Interfacing The MAX5222 serial interface is compatible with MICROWIRE, SPI, and QSPI. For SPI, clear the CPOL and CPHA bits (CPOL = 0 and CPHA = 0). CPOL = 0 sets the inactive clock state to zero, and CPHA = 0 changes data at the falling edge of SCLK. This setting allows SPI to run at full clock speeds. If a serial port is not available on your P, 3 bits of a parallel port can be used to emulate a serial port by bit manipulation. Minimize digital feedthrough at the voltage outputs by operating the serial clock only when necessary.
Table 4. Code Table
DAC CONTENTS B7 B6 B5 B4 B3 B2 B1 B0 1 1 1 1 1 1 1 1 ANALOG OUTPUT
255 +REF x 256
129 +REF x 256 128 REF +REF x =+ 2 256
1
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
127 +REF x 256 1 +REF x 256
0V
0 0
0 0
0 0
0 0
0 0
0 0
0 0
1 0
1 1LSB = REF x 2-8 = REF x 256 D where D = decimal ANALOG OUTPUT = REF x 256 value of digital input
Note:
10
______________________________________________________________________________________
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23
Applications Information
The MAX5222 is specified for single-supply operation with VDD ranging from 2.7V to 5.5V, covering all commonly used supply voltages in 3V and 5V systems.
MAX5222
Initialization
An internal power-on reset circuit forces the outputs to zero scale and initializes all external registers to zero. This is equivalent to being in the shutdown state. Therefore, at power-up, perform an initial write operation to set the outputs to the desired voltage.
Power-Supply and Ground Management
GND should be connected to the highest quality ground available. Bypass VDD with a 0.1F to 0.22F capacitor to GND. The reference input can be used without bypassing. For optimum line/load-transient response and noise performance, bypass the reference input with 0.1F to 4.7F to GND. Careful PC board layout minimizes crosstalk among DAC outputs, the reference, and digital inputs. Separate analog lines with ground traces between them. Make sure that highfrequency digital lines are not routed in parallel to analog lines.
Chip Information
TRANSISTOR COUNT: 1480 PROCESS TECHNOLOGY: BiCMOS
______________________________________________________________________________________
11
Dual, 8-Bit, Voltage-Output Serial DAC in 8-Pin SOT23 MAX5222
________________________________________________________Package Information
SOT23, 8L.EPS
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

▲Up To Search▲

Price & Availability of MAX5222

	To Download MAX5222 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .