Datasheet

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

__________________General Description

The MAX525 combines four low-power, voltage-output,

12-bit digital-to-analog converters (DACs) and four pre-

cision output amplifiers in a space-saving, 20-pin pack-

age. 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

MAX525 ideal for industrial-process-control applica-

tions. Other features include software shutdown, hard-

ware shutdown lockout, an active-low reset which 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 serial

interface is compatible with SPI™/QSPI™ and

MICROWIRE™. It allows the input and DAC registers to

be updated independently or simultaneously with a sin-

gle software command. The DAC registers can be

simultaneously updated through the 3-wire serial inter-

face. All logic inputs are TTL/CMOS-logic compatible.

________________________Applications

Industrial Process Controls

Automatic Test Equipment

Digital Offset and Gain Adjustment

Motion Control

Remote Industrial Controls

Microprocessor-Controlled Systems

______________________________Features

♦ Four 12-Bit DACs with Configurable

Output Amplifiers

♦ +5V Single-Supply Operation

♦ Low Supply Current: 0.85mA Normal Operation

10µA Shutdown Mode

♦ Available in 20-Pin SSOP

♦ Power-On Reset Clears all Registers and

DACs to Zero

♦ Capable of Recalling Last State Prior to Shutdown

♦ SPI/QSPI and MICROWIRE Compatible

♦ Simultaneous or Independent Control of DACs

through 3-Wire Serial Interface

♦ User-Programmable Digital Output

MAX525

Low-Power, Quad, 12-Bit Voltage-Output DAC

with Serial Interface

________________________________________________________________ Maxim Integrated Products 1

MAX525

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

19-1098; Rev 2; 10/02

PART

MAX525ACPP

MAX525BCPP 0°C to +70°C

0°C to +70°C

TEMP RANGE PIN-PACKAGE

20 Plastic DIP

_________________Ordering Information

Ordering Information continued at end of data sheet.

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.

MAX525ACAP

MAX525BCAP 0°C to +70°C

0°C to +70°C 20 SSOP

20 SSOP

±1/2

±1

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Summary of content (16 pages)

PAGE 1
9-1098; Rev 2; 10/02 Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface ______________________________Features ♦ Four 12-Bit DACs with Configurable Output Amplifiers 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 serial interface is compatible with SPI™/QSPI™ and MICROWIRE™.
PAGE 2
MAX525 Low-Power, Quad, 12-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
Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface (VDD = +5V ±10%, AGND = DGND = 0V, REFAB = REFCD = 2.5V, 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 = 3.
PAGE 4
ELECTRICAL CHARACTERISTICS (continued) (VDD = +5V ±10%, AGND = DGND = 0V, REFAB = REFCD = 2.5V, 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
Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY DAC CODE = ALL 1s REFAB = 1VP-P RL = 5kΩ CL = 100pF 0.45 THD + NOISE (%) 900 850 800 750 0.35 0.30 0.25 0.20 0.15 700 0.10 4.4 -40 -60 -80 0 600 4.6 4.8 5.0 5.2 5.4 1 5.6 1.6 FREQUENCY (kHz) SUPPLY VOLTAGE (V) 0 0 REFAB INPUT SIGNAL SIGNAL AMPLITUDE (dB) -2 -3 -20 -5 LOAD (kΩ) 10 4.9 6.0 VREF = 3.
PAGE 6
MAX525 Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface ____________________________Typical Operating Characteristics (continued) (VDD = +5V, TA = +25°C, unless otherwise noted.) MAJOR-CARRY TRANSITION DIGITAL FEEDTHROUGH (SCLK = 100kHz) MAX525-07 MAX525-08 CS 5V/div SCLK, 2V/div OUTB, AC-COUPLED 100mV/div OUTA, AC-COUPLED 10mV/div 10µs/div 2µs/div VREF = 2.5V, RL = 5kΩ, CL = 100pF VREF = 2.
PAGE 7
Low-Power, Quad, 12-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 Clear 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
MAX525 Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface FB_ R 2R 2R D0 R 2R D9 OUT_ R 2R 2R D10 D11 REF_ AGND SHOWN FOR ALL 1s ON DAC Figure 1. Simplified DAC Circuit Diagram _______________Detailed Description The MAX525 contains four 12-bit, voltage-output digital-to-analog converters (DACs) that are easily addressed using a simple 3-wire serial interface.
PAGE 9
Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface MAX525 SCLK SK DIN SO DOUT* SI* CS I/O Serial-Interface Configurations The MAX525’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 12 data bits (MSB first), as shown in Figure 4. The 4-bit address/ control code determines the MAX525’s response outlined in Table 1.
PAGE 10
MAX525 Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface Table 1. Serial-Interface Programming Commands C1 A1 16-BIT C0SERIAL WORD A0 C1 C0 D11.................D0 MSB LSB FUNCTION 0 0 1 1 0 1 0 1 0 0 0 0 1 1 1 1 12-bit DAC data 12-bit DAC data 12-bit DAC data 12-bit DAC data Load input register A; DAC registers unchanged. Load input register B; DAC registers unchanged. Load input register C; DAC registers unchanged. Load input register D; DAC registers unchanged.
PAGE 11
Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface MAX525 CS COMMAND EXECUTED SCLK 1 DIN 8 A0 A1 C1 D8 D9 D11 D10 C0 9 D7 16 D6 D5 D4 D3 D2 D1 D0 D6 D5 D4 D3 D2 D1 D0 DATA PACKET (N) DOUT (MODE 0) A0 A1 C1 C0 D11 D10 D8 D9 D7 A1 MSB FROM PREVIOUS WRITE DATA PACKET (N) DATA PACKET (N-1) DOUT (MODE 1) A1 A0 C1 C0 D11 D10 D8 D9 D7 D6 D5 D4 D3 D2 D1 D0 A1 MSB FROM PREVIOUS WRITE DATA PACKET (N) DATA PACKET (N-1) Figure 5.
PAGE 12
MAX525 Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface MAX525 SCLK DIN DIN CS CS MAX525 MAX525 SCLK SCLK DOUT SCLK DOUT DIN CS DIN DOUT CS TO OTHER SERIAL DEVICES Figure 7. Daisy-Chaining MAX525s DIN SCLK CS1 CS2 TO OTHER SERIAL DEVICES CS3 CS CS MAX525 CS MAX525 MAX525 SCLK SCLK SCLK DIN DIN DIN Figure 8.
PAGE 13
Low-Power, Quad, 12-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 MAX525 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 MAX525 with the output amplifiers configured with a closed-loop gain of +2 to provide 0V to 5V full-scale range when a 2.
PAGE 14
Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface MAX525 Using an AC Reference In applications where the reference has AC signal components, the MAX525 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
Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface VL TOP VIEW MAX525 IOUT DAC_ OUT_ 2N3904 AGND 1 20 VDD FBA 2 19 FBD OUTA 3 FB_ 18 OUTD OUTB 4 R FBB 5 17 OUTC MAX525 Figure 13.
PAGE 16
MAX525 Low-Power, Quad, 12-Bit Voltage-Output DAC with Serial Interface _Ordering Information (continued) TRANSISTOR COUNT: 4337 INL (LSBs) PART TEMP RANGE PIN-PACKAGE MAX525BC/D MAX525AEPP MAX525BEPP 0°C to +70°C -40°C to +85°C -40°C to +85°C Dice* 20 Plastic DIP 20 Plastic DIP ±1 ±1/2 ±1 20 SSOP 20 SSOP 20 CERDIP** 20 CERDIP** ±1/2 ±1 ±1/2 ±1 MAX525AEAP -40°C to +85°C MAX525BEAP -40°C to +85°C MAX525AMJP -55°C to +125°C MAX525BMJP -55°C to +125°C ___________________Chip Information * Dice a