Rainbow Electronics MAX550A User Manual

_______________General Description

The MAX548A/MAX549A/MAX550A serial, 8-bit voltage­output digital-to-analog converters (DACs) operate from
a single +2.5V to +5.5V supply. Their ±1LSB TUE spec­ification is guaranteed over temperature. Operating cur­rent (supply current plus reference current) is typically
75µA per DAC with VDD= 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 updat­ing 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 VDDas 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 con­sumption 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

1

LDAC
SCLK

DIN

1

2

87V

DD

OUTB

OUTA

CS

GND

DIP/µMAX

TOP VIEW

3

4

6

5

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

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 TA= +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 [phone]

MAX548A MAX549A

Number of DACs 2 2
DAC Reference V

DD

External

FEATURE

External

Asynchronous
Load DAC Input

√

MAX550A

1

—

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.

MAX548A/MAX549A/MAX550A

+2.5V to +5.5V, Low-Power, Single/Dual,
8-Bit Voltage-Output DACs in µMAX Package

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= +2.5V to +5.5V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

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.

VDD, SCLK, DIN, CS, LDAC, OUT_ to GND ...............-0.3V to 6V

REF to GND................................................-0.3V to (V

DD

+ 0.3V)

Maximum Current (any pin) .............................................±50mA

Continuous Power Dissipation (T

A

= +70°C)

Plastic DIP (derate 9.09mW/°C above +70°C) .............727mW

µMAX (derate 4.10mW/°C above +70°C) .....................330mW

Operating Temperature Ranges

MAX5_ _AC_ A.....................................................0°C to +70°C

MAX5_ _AE_ A..................................................-40°C to +85°C

Storage Temperature Range.............................-65°C to +150°C

Lead Temperature (soldering, 10sec).............................+300°C

MAX549A

MAX549A/MAX550A for specified
performance

Guaranteed
monotonic

CONDITIONS

16.7

V2.5 V

DD

V

REF

Reference Input
Voltage Range

±0.9

Bits8NResolution

LSB

±0.9

DNLDifferential Nonlinearity

LSB±1ZCEZero-Code Error
LSB±1FSEFull-Scale Error

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX5_ _AEUA (Note 1)
All others

MAX549A/MAX550A

MAX548A

MAX550A

kΩ33.3R

OUT

DAC Output Resistance

V

0 V

REF

DAC Output Voltage Swing

0 V

DD

kΩ

33.3

R

REF

Reference Input Resistance
DAC Code = 55 Hex (Note 2)

MAX548A/MAX549A %±0.2

∆R

OUT

/

R

OUT

DAC Output Resistance
Matching

±1MAX5_ _AEUA (Note 1)

All others

LSB

±1

TUETotal Unadjusted Error

MAX549A

330 550
150 250

MAX550A

165 275

µA

75 125

I

REF

Reference Input Current
DAC Code = 55 Hex (Note 3)

VDD= V

REF

= 5.5V

VDD= V

REF

= 2.5V

VDD= V

REF

= 5.5V

VDD= V

REF

= 2.5V

V0.7V

DD

V

IH

Input High Voltage

V0.3V

DD

V

IL

Input Low Voltage

VIN= 0V or V

DD

µA±1I

IN

Input Current

pF10C

IN

Input Capacitance (Note 4)

STATIC PERFORMANCE

REFERENCE INPUT

DAC OUTPUT

DIGITAL INPUTS

MAX548A/MAX549A/MAX550A

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

8-Bit Voltage-Output DACs in µMAX Package

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +2.5V to +5.5V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C)

TIMING CHARACTERISTICS

(VDD= +2.5V to +5.5V, TA= T

MIN

to T

MAX

, unless otherwise noted. Digital inputs switching from 0V to VDD.) (Figure 3) (Note 4)

Note 1: Cold temperature specifications (to -40°C) guaranteed by design using six sigma design limits.
Note 2: Worst-case input resistance at REF occurs at DAC code 55 hex.
Note 3: Worst-case reference input current occurs at DAC code 55 hex.
Note 4: Guaranteed by design. Not production tested.
Note 5: I

DD

measured with DACs loaded with worst-case DAC code 55 hex.

CS = high, all digital inputs from 0V to V

DD

CL= 20pF

To ±1/2LSB, CL= 20pF

V/µs

3.1

µs

1.4

Voltage-Output Settling Time 4

CONDITIONS

50 nV-sec

Digital Feedthrough and
Crosstalk

UNITSMIN TYP MAXSYMBOLPARAMETER

Voltage-Output Slew Rate

CL= 20pF µsWake-Up Time at Power-Up 4

VDD= 2.5V
VDD= 5.5V

Supply Voltage Range Outputs unloaded, all inputs = GND or V

DD

V

DD

V2.5 5.5

Supply Current
(MAX549A/MAX550A)

Outputs unloaded,
all inputs = GND or
VDD(Note 5)

µA

330 550

I

DD

Supply Current (MAX548A)

Outputs unloaded, all inputs = GND or VDD;
VDD= 5.5V

I

DD

µA0.3 10

VDD= 5.5V
VDD= 2.5V

Shutdown Current Shutdown mode µA0.3

150 250

80

50

SCLK Period t

CP

CS High to LDAC Low

ns

t

CSLD

nsMAX548A/MAX550A only

5

VDDHigh to CS Low

µs

50

LDAC Pulse Width Low

t

LDAC

nsMAX548A/MAX550A only

40

CS Pulse Width High

t

CSW

ns

20

t

CSH1

ns

VDD= 5.5V

10

30

t

DH

CS High to SCLK High Setup

ns

t

CSS1

ns

10

Delay, SCLK High to CS High

VDD= 2.5V

VDD= 5.5V

30

CS Low to SCLK High Setup

t

CSS0

ns

30DIN to SCLK High Setup t

DS

ns

0

DIN to SCLK High Hold

VDD= 2.5V

40SCLK Pulse Width Low t

CL

ns

PARAMETER SYMBOL MIN TYP MAX UNITSCONDITIONS

40SCLK Pulse Width High t

CH

ns

DYNAMIC PERFORMANCE

POWER SUPPLIES

10SCLK High to CS Low Hold t

CSH0

ns

MAX548A/MAX549A/MAX550A

+2.5V to +5.5V, Low-Power, Single/Dual,
8-Bit Voltage-Output DACs in µMAX Package

4 _______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(VDD= V

REF

= 2.5V, RL= 1MΩ, CL= 15pF, TA= +25°C, unless otherwise noted.)

-60 -20 20 100

OPERATING CURRENT PER DAC

vs. TEMPERATURE

75.0

74.6

149.8

150.2

MAX548A-550A TOC-01

TEMPERATURE (°C)

OPERATING CURRENT PER DAC (µA)

60

149.4

75.4

V

DD

= V

REF

= 5.0V

V

DD

= V

REF

= 2.5V

-60 -20 20 100

SHUTDOWN CURRENT

vs. TEMPERATURE

36

32
28

160

200

240

MAX548A-550A TOC-02

TEMPERATURE (°C)

SHUTDOWN CURRENT (nA)

60

120

40

V

DD

= V

REF

= 5.0V

V

DD

= V

REF

= 2.5V

-50
1k 10k 100k 1M 10M

MAX549A/MAX550A

REFERENCE SMALL-SIGNAL

FREQUENCY RESPONSE

-40

10

0

MAX548A-550A TOC-03

FREQUENCY (Hz)

RELATIVE OUTPUT (dB)

-20

-30

-10

DAC CODE = FF hex

V

DD

= 5V

V

REF

= 2Vp-p SINE WAVE

V

DD

= 2.5V

V

REF

= 100mVp-p SINE WAVE

0

-100
10 1M100k10k1k100

MAX549A/MAX550A

REFERENCE AC FEEDTHROUGH

vs. FREQUENCY

-60

-80

MAX548A-550A TOC-04

FREQUENCY (Hz)

RELATIVE OUTPUT (dB)

-40

-20

V

REF

= 1Vp-p SINE WAVE

DAC CODE = 00 hex

DIGITAL FEEDTHROUGH

SCLK, 5V/div

OUT, 50mV/div

200ns/div

MAX548A-550A TOC-05

SETTLING TIME (FALLING)

OUT, 1V/div

2µs/div

MAX548A-550A TOC-06

CS, 5V/div

DAC CODE FF hex to 00 hex

MAX548A/MAX549A/MAX550A

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

8-Bit Voltage-Output DACs in µMAX Package

_______________________________________________________________________________________ 5

OUTPUT GLITCH FILTERING

OUT, 50mV/div, CL = 0pF
OUT, 50mV/div, C

L

= 100pF

OUT, 50mV/div, C

L

= 220pF

5µs/div

OUT, 50mV/div, C

L

= 1000pF

MAX548A-550A TOC-07

CS, 5V/div

CODE = 00 hex

_____________________________Typical Operating Characteristics (continued)

(VDD= V

REF

= 2.5V, RL= 1MΩ, CL= 15pF, TA= +25°C, unless otherwise noted.)

SETTLING TIME (RISING)

OUT, 1V/div

2µs/div

MAX548A-550A TOC-08

CS, 5V/div

DAC CODE 00 hex to FF hex

______________________________________________________________Pin Description

Ground11 1 GND
DAC A Output Voltage22 — OUTA

Chip-Select Input. A logic low on CS enables serial data to be
clocked into the input shift register. Programming commands are
executed at CS’s rising edge.

33 3

CS

DAC Output Voltage—— 2 OUT

Serial-Clock Input. Data is clocked in on SCLK’s rising edge.55 5 SCLK

DAC B Output Voltage67 — OUTB

Load DAC Input. After CS goes high and if programmed by the
control word, a falling edge on LDAC updates the DAC latch(es).
Connect LDAC to V

DD

if unused.

—6 6

LDAC

Serial-Data Input. Data is clocked into the 16-bit input shift register on
SCLK’s rising edge.

44 4 DIN

Positive Power Supply (+2.5V to +5.5V)88 8 V

DD

External Reference Voltage Input for DAC(s)7— 7 REF

MAX548A MAX549A MAX550A

NAME FUNCTION

PIN