Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsData collecting ICsData acquisition IC - DA converter (DAC) SSOP 20

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__________________General Description

The +3V MAX5251 combines four low-power, voltage-

output, 10-bit digital-to-analog converters (DACs) and

four precision output amplifiers in a space-saving, 20-

pin package. In addition to the four voltage outputs,

each amplifier’s negative input is also available to the

user. This facilitates specific gain configurations, remote

sensing, and high output drive capacity, making the

MAX5251 ideal for industrial-process-control applica-

tions. Other features include software shutdown, hard-

ware shutdown lockout, an active-low reset that clears

all registers and DACs to zero, a user-programmable

logic output, and a serial-data output.

Each DAC has a double-buffered input organized as an

input register followed by a DAC register. A 16-bit serial

word loads data into each input/DAC register. The

3-wire serial interface is compatible with SPI™/QSPI™

and MICROWIRE™. It allows the input and DAC regis-

ters to be updated independently or simultaneously with

a single software command. All logic inputs are

TTL/CMOS-logic compatible.

________________________Applications

Digital Offset and Gain Adjustment

Microprocessor-Controlled Systems

Industrial Process Controls

Automatic Test Equipment

Remote Industrial Controls

Motion Control

______________________________Features

♦ Four 10-Bit DACs with Configurable

Output Amplifiers

♦ +3.0V to +3.6V Single-Supply Operation

♦ Low Supply Current: 0.8mA Normal Operation

3µA Shutdown Mode

♦ Available in 20-Pin SSOP

♦ Power-On Reset Clears all Registers and

DACs to Zero

♦ SPI/QSPI and MICROWIRE Compatible

♦ Simultaneous or Independent Control of DACs

Through 3-Wire Serial Interface

♦ User-Programmable Digital Output

♦ Schmitt-Trigger Digital Inputs for Direct

Optocoupler Interface

♦ 12-Bit Upgrade Available: MAX5253

MAX5251

+3V, Quad, 10-Bit Voltage-Output DAC

with Serial Interface

________________________________________________________________ Maxim Integrated Products 1

MAX5251

OUTA

FBA

FBB

FBC

FBD

DAC A

DAC B

DAC C

DAC D

REFAB

DAC

DECODE

CONTROL

INPUT

DAC

INPUT

DAC

INPUT

DAC

INPUT

16-BIT

SHIFT

CONTROL

LOGIC

OUTPUT

DIN

SCLK

OUTB

OUTC

OUTD

DOUT

PDL

AGND

DGND

UPO REFCD

_________________________________________________________________________Functional Diagram

19-1172; Rev 1; 10/02

PART

MAX5251ACPP

MAX5251BCPP 0°C to +70°C

0°C to +70°C

TEMP RANGE PIN-PACKAGE

20 Plastic DIP

_________________Ordering Information

Ordering Information continued on last page.

Pin Configuration appears at end of data sheet.

INL

(LSB)

±1/2

±1

SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp.

MAX5251ACAP

MAX5251BCAP 0°C to +70°C

0°C to +70°C 20 SSOP

20 SSOP

±1/2

±1

Summary of content (16 pages)

PAGE 1
9-1172; Rev 1; 10/02 +3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface ______________________________Features ♦ Four 10-Bit DACs with Configurable Output Amplifiers ♦ +3.0V to +3.6V Single-Supply Operation ♦ Low Supply Current: 0.
PAGE 2
MAX5251 +3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface ABSOLUTE MAXIMUM RATINGS VDD to AGND............................................................-0.3V to +6V VDD to DGND ...........................................................-0.3V to +6V AGND to DGND ..................................................................±0.3V REFAB, REFCD to AGND ...........................-0.3V to (VDD + 0.3V) OUT_, FB_ to AGND...................................-0.3V to (VDD + 0.
PAGE 3
+3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface (VDD = +3.0V to +3.6V, AGND = DGND = 0V, REFAB = REFCD = 1.25V, RL = 5kΩ, CL = 100pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. Output buffer connected in unity-gain configuration (Figure 9).) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS MULTIPLYING-MODE PERFORMANCE Reference -3dB Bandwidth VREF = 0.67VP-P 650 kHz Reference Feedthrough Input code = all 0s, VREF = 1.
PAGE 4
ELECTRICAL CHARACTERISTICS (continued) (VDD = +3.0V to +3.6V, AGND = DGND = 0V, REFAB = REFCD = 1.25V, RL = 5kΩ, CL = 100pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. Output buffer connected in unity-gain configuration (Figure 9).
PAGE 5
+3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 0.40 850 0.35 THD + NOISE (%) 900 800 750 700 650 600 MAX5251-02 0.30 0.25 0.20 0.15 -40 -60 -80 0.10 0.05 CODE = FFC HEX 500 0 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 0.1 1 SUPPLY VOLTAGE (V) 10 100 -1.0 -1.5 -2.5 LOAD (kΩ) 10 100 REFAB INPUT SIGNAL -20 4.9 6.0 VREF = 1.6VP-P AT 1kHz RL = 5kΩ CL = 100pF -40 -60 -80 -2.0 1 3.8 2.
PAGE 6
MAX5251 +3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface ____________________________Typical Operating Characteristics (continued) (VDD = +3.3V, VREF = 1.25V, RL = 5kΩ, CL = 100pF, TA = +25°C, unless otherwise noted.) MAJOR-CARRY TRANSITION DIGITAL FEEDTHROUGH (SCLK = 100kHz) MAX5251-07 MAX5251-08 CS 5V/div SCLK, 2V/div OUTB, AC-COUPLED 50mV/div OUTA, AC-COUPLED 10mV/div 10µs/div 2µs/div CS = PDL = CL = 3.
PAGE 7
+3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface PIN NAME FUNCTION 1 AGND 2 FBA 3 OUTA DAC A Output Voltage 4 OUTB DAC B Output Voltage 5 FBB 6 REFAB 7 CL Clears All DACs and Registers. Resets all outputs (OUT_, UPO, DOUT) to 0, active low. 8 CS Chip-Select Input. Active low. 9 DIN Serial-Data Input 10 SCLK Serial-Clock Input 11 DGND Digital Ground 12 DOUT Serial-Data Output 13 UPO User-Programmable Logic Output 14 PDL Power-Down Lockout. Active low.
PAGE 8
MAX5251 +3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface FB_ R 2R 2R S0 R 2R S1 OUT_ R 2R 2R D0 D9 REF_ AGND SHOWN FOR ALL 1s ON DAC Figure 1. Simplified DAC Circuit Diagram The impedance at each reference input is code dependent, ranging from a low value of 10kΩ when both DACs connected to the reference have an input code of 554 hex, to a high value exceeding several giga ohms (leakage current) with an input code of 000 hex.
PAGE 9
+3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface SCLK SK DIN SO DOUT* SI* CS I/O MAX5251 Serial-Interface Configurations The MAX5251’s 3-wire serial interface is compatible with both MICROWIRE (Figure 2) and SPI/QSPI (Figure 3). The serial input word consists of two address bits and two control bits followed by 10+2 data bits (MSB first), as shown in Figure 4. The 4-bit address/ control code determines the MAX5251’s response outlined in Table 1.
PAGE 10
MAX5251 +3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface Table 1. Serial-Interface Programming Commands 16-BIT SERIAL WORD FUNCTION A1 A0 C1 C0 D9.................D0 MSB.............LSB S1 S0 0 0 1 1 0 1 0 1 0 0 0 0 1 1 1 1 10-bit DAC data 10-bit DAC data 10-bit DAC data 10-bit DAC data 0 0 0 0 0 0 0 0 Load input register A; DAC registers unchanged. Load input register B; DAC registers unchanged. Load input register C; DAC registers unchanged.
PAGE 11
+3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface MAX5251 CS COMMAND EXECUTED SCLK 1 DIN 8 A0 A1 C1 D9 C0 D6 D7 D8 9 D5 16 D4 D3 D2 D1 D0 S1 S0 D4 D3 D2 D1 D0 S1 S0 DATA PACKET (N) DOUT (MODE 0) A0 A1 C1 D9 C0 D6 D7 D8 D5 A1 MSB FROM PREVIOUS WRITE DATA PACKET (N) DATA PACKET (N-1) DOUT (MODE 1) A0 A1 C1 C0 D9 D8 D6 D7 D5 D4 D3 D2 D1 D0 S1 S0 A1 MSB FROM PREVIOUS WRITE DATA PACKET (N) DATA PACKET (N-1) Figure 5.
PAGE 12
MAX5251 +3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface MAX5251 SCLK DIN DIN CS CS MAX5251 SCLK SCLK DOUT MAX5251 SCLK DOUT DIN CS DOUT DIN CS TO OTHER SERIAL DEVICES Figure 7. Daisy-Chaining MAX5251s DIN SCLK CS1 CS2 TO OTHER SERIAL DEVICES CS3 CS CS MAX5251 CS MAX5251 MAX5251 SCLK SCLK SCLK DIN DIN DIN Figure 8.
PAGE 13
+3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface Unipolar Output For a unipolar output, the output voltages and the reference inputs have the same polarity. Figure 9 shows the MAX5251 unipolar output circuit, which is also the typical operating circuit. Table 2 lists the unipolar output codes. For rail-to-rail outputs, see Figure 10. This circuit shows the MAX5251 with the output amplifiers configured with a closed-loop gain of +2.6 to provide 0V to 3.25V fullscale range when a 1.
PAGE 14
+3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface MAX5251 Using an AC Reference REFERENCE INPUTS In applications where the reference has AC signal components, the MAX5251 has multiplying capability within the reference input range specifications. Figure 12 shows a technique for applying a sine-wave signal to the reference input where the AC signal is offset before being applied to REFAB/REFCD. The reference voltage must never be more negative than DGND.
PAGE 15
+3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface TOP VIEW VL MAX5251 IOUT DAC_ OUT_ 2N3904 AGND 1 20 VDD FBA 2 19 FBD OUTA 3 FB_ 18 OUTD OUTB 4 FBB 5 R Figure 13. Digitally Programmable Current Source Power-Supply Considerations On power-up, all input and DAC registers are cleared (set to zero code) and DOUT is in Mode 0 (serial data is shifted out of DOUT on the clock’s falling edge). For rated MAX5251 performance, limit REFAB/REFCD to less than 1.4V below VDD. Bypass VDD with a 4.
PAGE 16
MAX5251 +3V, Quad, 10-Bit Voltage-Output DAC with Serial Interface _Ordering Information (continued) PART TEMP RANGE PIN-PACKAGE MAX5251AEPP MAX5251BEPP MAX5251AEAP MAX5251BEAP MAX5251BMJP -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -55°C to +125°C 20 Plastic DIP 20 Plastic DIP 20 SSOP 20 SSOP 20 CERDIP* ___________________Chip Information TRANSISTOR COUNT: 4337 INL (LSB) ±1/2 ±1 ±1/2 ±1 ±2 *Contact factory for availability and processing to MIL-STD-883.