Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsData collecting ICsData acquisition IC - DA converter (DAC) PDIP 8

_______________General Description

The MAX548A/MAX549A/MAX550A serial, 8-bit voltage-

output digital-to-analog converters (DACs) operate from

a single +2.5V to +5.5V supply. Their ±1LSB TUE spec-

ification is guaranteed over temperature. Operating cur-

rent (supply current plus reference current) is typically

75µA per DAC with V

= 2.5V. In shutdown, the DAC

is disconnected from the reference, reducing current

drain to less than 1µA. The MAX548A/MAX549A allow

each DAC to be shut down independently.

The 10MHz, 3-wire serial interface is compatible with

SPI™/QSPI™ and Microwire™ interface standards.

Double-buffered inputs provide flexibility when updat-

ing the DACs; the input and DAC registers can be

updated individually or simultaneously.

The MAX548A is a dual DAC with an asynchronous

load input; it uses V

as the reference input. The

MAX549A is a dual DAC with an external reference

input. The MAX550A is a single DAC with an external

reference input and an asynchronous load input.

The MAX548A/MAX549A/MAX550A’s low power con-

sumption and small µMAX and DIP packages make

these devices ideal for portable and battery-powered

applications.

________________________Applications

Battery-Powered Systems

VCXO Control

Comparator-Level Settings

GaAs Amp Bias Control

Digital Gain and Offset Control

____________________________Features

♦ +2.5V to +5.5V Single-Supply Operation

♦ ±1LSB (max) TUE

♦ Power-On Reset Clears All Registers to Zero

♦ Low Operating Current:

150µA (MAX548A/MAX549A, V

REF

= +2.5V)

75µA (MAX550A, V

REF

= +2.5V)

♦ 1µA Shutdown Mode

♦ 10MHz, 3-Wire Serial Interface Compatible with

SPI/QSPI and Microwire

♦ µMAX Package—50% Smaller than 8-Pin SO

♦ Independent Shutdown of DACs

(MAX548A/MAX549A)

MAX548A/MAX549A/MAX550A

+2.5V to +5.5V, Low-Power, Single/Dual,

8-Bit Voltage-Output DACs in µMAX Package

________________________________________________________________

Maxim Integrated Products

LDAC

SCLK

DIN

OUTB

OUTA

GND

DIP/µMAX

TOP VIEW

MAX548A

_________________Pin Configurations

_____________________Selector Guide

19-1206; Rev 0; 3/97

PART

MAX548ACPA

MAX548ACUA

MAX548AC/D 0°C to +70°C

0°C to +70°C

TEMP. RANGE

PIN-PACKAGE

†

8 Plastic DIP

8 µMAX

Dice*

______________Ordering Information

Ordering Information continued at end of data sheet.

Dice are specified at T

= +25°C, DC parameters only.

†

Contact factory for availability of 8-pin SO package.

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

MAX548A MAX549A

Number of DACs 2 2

DAC Reference V

External

FEATURE

External

Asynchronous

Load DAC Input

√

MAX550A

—

µMAX Package √ √ √

√

SPI and QSPI are trademarks of Motorola Inc.

Microwire is a trademark of National Semiconductor Corp.

MAX548AEPA

MAX548AEUA -40°C to +85°C

-40°C to +85°C 8 Plastic DIP

8 µMAX

Pin Configurations continued at end of data sheet.

Summary of content (16 pages)

PAGE 1
9-1206; Rev 0; 3/97 +2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package ____________________________Features ♦ +2.5V to +5.5V Single-Supply Operation ♦ ±1LSB (max) TUE ♦ Power-On Reset Clears All Registers to Zero ♦ Low Operating Current: 150µA (MAX548A/MAX549A, VREF = +2.5V) 75µA (MAX550A, VREF = +2.
PAGE 2
MAX548A/MAX549A/MAX550A +2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package ABSOLUTE MAXIMUM RATINGS VDD, SCLK, DIN, CS, LDAC, OUT_ to GND ...............-0.3V to 6V REF to GND ................................................-0.3V to (VDD + 0.3V) Maximum Current (any pin) .............................................±50mA Continuous Power Dissipation (TA = +70°C) Plastic DIP (derate 9.09mW/°C above +70°C) .............727mW µMAX (derate 4.10mW/°C above +70°C) .................
PAGE 3
+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package (VDD = +2.5V to +5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DYNAMIC PERFORMANCE Digital Feedthrough and Crosstalk CS = high, all digital inputs from 0V to VDD 50 nV-sec Voltage-Output Settling Time To ±1/2LSB, CL = 20pF 4 µs Voltage-Output Slew Rate CL = 20pF Wake-Up Time at Power-Up CL = 20pF VDD = 2.5V 1.4 VDD = 5.
PAGE 4
__________________________________________Typical Operating Characteristics (VDD = VREF = 2.5V, RL = 1MΩ, CL = 15pF, TA = +25°C, unless otherwise noted.) OPERATING CURRENT PER DAC vs. TEMPERATURE SHUTDOWN CURRENT vs. TEMPERATURE MAX548A-550A TOC-02 200 SHUTDOWN CURRENT (nA) VDD = VREF = 5.0V 149.8 240 MAX548A-550A TOC-01 149.4 75.4 75.0 160 VDD = VREF = 5.0V 120 40 36 32 VDD = VREF = 2.5V 74.6 VDD = VREF = 2.
PAGE 5
+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package (VDD = VREF = 2.5V, RL = 1MΩ, CL = 15pF, TA = +25°C, unless otherwise noted.
PAGE 6
MAX548A/MAX549A/MAX550A +2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package _______________Detailed Description The magnitude of the expected error is the ratio of the DAC output resistance to the DC load resistance at the output. Typically, an energy pulse is coupled into the DAC output on CS’s rising edge.
PAGE 7
+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package Initialization The MAX548A/MAX549A/MAX550A have an internal power-on reset. At power-up, all internal registers are reset to zero; therefore, an initialization write sequence is not necessary. Serial-Input Data Format and Control Codes The control byte determines which input registers/DAC registers are updated (Table 1). The DAC input registers are updated on the rising edge of CS.
PAGE 8
MAX548A/MAX549A/MAX550A +2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package function. Data is clocked in starting with unassigned bit 1 (UB1), followed by the remaining control bits and the DAC data byte. The data byte’s LSB (D0) is the last bit clocked into the input register (Figure 2).
PAGE 9
+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package UB1 UB2 CONTROL BYTE DATA BYTE Loaded First Loaded Last UB3 C2 C1 LDAC C0 A1 A0 D7........D0 Pin 6 MAX548A/MAX549A/MAX550A Table 2.
PAGE 10
MAX548A/MAX549A/MAX550A +2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package Table 2. MAX548A Serial-Interface Programming Commands (continued) COMMANDS FOR POWERING DOWN UB1 UB2 CONTROL BYTE DATA BYTE Loaded First Loaded Last UB3 C2 C1 C0 A1 A0 D7........D0 LDAC Pin 6 COMMAND (Commands executed on CS’s rising edge) COMMANDS POWERING DOWN AND LOADING INPUT REGISTER(S) ONLY X X X 1 0 X 0 1 8-Bit DAC Data X Load DAC A input register and power down DAC A.
PAGE 11
+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package UB1 UB2 CONTROL BYTE DATA BYTE Loaded First Loaded Last UB3 C2 C1 C0 A1 A0 D7........D0 0 X 0 0 XXXXXXXX COMMAND (Commands executed on CS’s rising edge) UNASSIGNED COMMAND X X X X Unassigned command COMMANDS LOADING INPUT REGISTER(S) ONLY X X X 0 0 X 0 1 8-Bit DAC Data Load DAC A input register. DAC registers unchanged. X X X 0 0 X 1 0 8-Bit DAC Data Load DAC B input register.
PAGE 12
MAX548A/MAX549A/MAX550A +2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package Table 4. MAX550A Serial-Interface Programming Commands UB1 UB2 CONTROL BYTE DATA BYTE Loaded First Loaded Last UB3 C2 C1 LDAC C0 A1 A0 D7........D0 Pin 6 COMMAND (Commands executed on CS’s rising edge) UNASSIGNED COMMANDS X X X 0 0 X X 0 XXXXXXXX X Unassigned command X X X 1 X X X 0 XXXXXXXX X Unassigned operation 1 8-Bit DAC Data X Load DAC input register.
PAGE 13
+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package Careful PC board layout minimizes crosstalk in DAC registers, the reference, and the digital inputs. Separate analog traces by running ground traces between them. Make sure that high-frequency digital lines are not routed parallel to analog lines.
PAGE 14
MAX548A/MAX549A/MAX550A +2.5V to +5.
PAGE 15
+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package PDIPN.
PAGE 16
___________________________________________Package Information (continued) 8LUMAXD.EPS MAX548A/MAX549A/MAX550A +2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX Package 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.