Instruction Manual

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__________________General Description

The +5V MAX5250 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

MAX5250 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 registers to

be updated independently or simultaneously with a sin-

gle 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

♦ +5V Single-Supply Operation

♦ Low Supply Current: 0.85mA Normal Operation

10µA Shutdown Mode

♦ Available in 20-Pin SSOP and DIP Packages

♦ Power-On Reset Clears all Registers and

DACs to Zero

♦ SPI/QSPI and Microwire Compatible

♦ Simultaneous or Independent Control of DACs

via 3-Wire Serial Interface

♦ User-Programmable Digital Output

♦ Schmitt-Trigger Inputs for Direct Optocoupler

Interface

♦ 12-Bit Upgrade Available: MAX525

MAX5250

Low-Power, Quad, 10-Bit Voltage-Output DAC

with Serial Interface

________________________________________________________________

Maxim Integrated Products

MAX5250

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

SR

CONTROL

LOGIC

OUTPUT

DIN

SCLK

OUTB

OUTC

OUTD

DOUT

PDL

AGND

DGND

UPO REFCD

_________________________________________________________________________Functional Diagram

19-1171; Rev 0; 12/96

_________________Ordering Information

Ordering Information continued on last page.

Pin Configuration appears at end of data sheet.

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800

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

PART

MAX5250ACPP

MAX5250BCPP

MAX5250ACAP 0°C to +70°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

20 Plastic DIP

20 SSOP

INL

(LSB)

±1/2

±1

±1/2

MAX5250BCAP 0°C to +70°C 20 SSOP ±1

Summary of content (16 pages)

PAGE 1
9-1171; Rev 0; 12/96 Low-Power, Quad, 10-Bit Voltage-Output DAC with Serial Interface ______________________________Features The +5V MAX5250 combines four low-power, voltageoutput, 10-bit digital-to-analog converters (DACs) and four precision output amplifiers in a space-saving, 20pin package. In addition to the four voltage outputs, each amplifier’s negative input is also available to the user.
PAGE 2
MAX5250 Low-Power, 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
Low-Power, Quad, 10-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 DIGITAL INPUTS Input High Voltage VIH Input Low Voltage VIL Input Leakage Current IIN Input Capacitance CIN 2.4 VIN = 0V or VDD V 0.01 0.8 V ±1.
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, 10-Bit Voltage-Output DAC with Serial Interface TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 0.40 THD + NOISE (%) 900 850 800 750 0.35 SIGNAL AMPLITUDE (dB) DAC CODE = FULL SCALE REFAB = 1Vp-p RL = 5kΩ CL = 100pF 0.45 0.30 0.25 0.20 0.15 700 0.10 4.4 4.6 4.8 5.0 5.2 5.4 -60 1.6 FREQUENCY (kHz) 0 REFAB INPUT SIGNAL SIGNAL AMPLITUDE (dB) -0.25 -0.50 -0.75 -20 -1.25 1 LOAD (kΩ) 10 4.9 6.0 VREF = 3.
PAGE 6
MAX5250 Low-Power, Quad, 10-Bit Voltage-Output DAC with Serial Interface ____________________________Typical Operating Characteristics (continued) (VDD = +5V, VREF = 2.5V, RL = 5kΩ, CL = 100pF, TA = +25°C, unless otherwise noted.
PAGE 7
Low-Power, 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 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
MAX5250 Low-Power, 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 _______________Detailed Description The MAX5250 contains four 10-bit, voltage-output digital-to-analog converters (DACs) that are easily addressed using a simple 3-wire serial interface.
PAGE 9
Low-Power, Quad, 10-Bit Voltage-Output DAC with Serial Interface MAX5250 SCLK SK DIN SO DOUT* SI* CS I/O Serial-Interface Configurations The MAX5250’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 MAX5250’s response outlined in Table 1.
PAGE 10
MAX5250 Low-Power, 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
Low-Power, Quad, 10-Bit Voltage-Output DAC with Serial Interface MAX5250 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) C1 A0 A1 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
MAX5250 Low-Power, Quad, 10-Bit Voltage-Output DAC with Serial Interface MAX5250 SCLK SCLK DIN DIN CS CS MAX5250 SCLK DOUT MAX5250 SCLK DOUT DIN CS DOUT DIN CS TO OTHER SERIAL DEVICES Figure 7. Daisy-Chaining MAX5250s DIN SCLK CS1 CS2 TO OTHER SERIAL DEVICES CS3 CS CS MAX5250 CS MAX5250 MAX5250 SCLK SCLK SCLK DIN DIN DIN Figure 8.
PAGE 13
Low-Power, 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 MAX5250 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 MAX5250 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, 10-Bit Voltage-Output DAC with Serial Interface MAX5250 Using an AC Reference REFERENCE INPUTS In applications where the reference has AC signal components, the MAX5250 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, 10-Bit Voltage-Output DAC with Serial Interface VL TOP VIEW MAX5250 IOUT DAC_ OUT_ AGND 1 20 VDD FBA 2 19 FBD 2N3904 OUTA 3 FB_ 18 OUTD OUTB 4 R FBB 5 17 OUTC MAX5250 Figure 13.
PAGE 16
MAX5250 Low-Power, Quad, 10-Bit Voltage-Output DAC with Serial Interface _Ordering Information (continued) PART TEMP. RANGE PIN-PACKAGE INL (LSB) MAX5250AEPP -40°C to +85°C 20 Plastic DIP ±1/2 MAX5250BEPP MAX5250AEAP MAX5250BEAP MAX5250BMJP -40°C to +85°C -40°C to +85°C -40°C to +85°C -55°C to +125°C 20 Plastic DIP 20 SSOP 20 SSOP 20 CERDIP* ±1 ±1/2 ±1 ±1 ___________________Chip Information TRANSISTOR COUNT: 4337 *Contact factory for availability and processing to MIL-STD-883.