Datasheet MAX5304CUA, MAX5304EUA Datasheet (Maxim)

General Description

The MAX5304 combines a low-power, voltage-output,
10-bit digital-to-analog converter (DAC) and a precision
output amplifier in an 8-pin µMAX package. It operates
from a single +5V supply, drawing less than 280µA of
supply current.

The output amplifier’s inverting input is available to the
user, allowing specific gain configurations, remote
sensing, and high output-current capability. This makes
the MAX5304 ideal for a wide range of applications,
including industrial process control. Other features
include a software shutdown and power-on reset.

The serial interface is SPI™/QSPI™/MICROWIRE™
compatible. The DAC has a double-buffered input,
organized as an input register followed by a DAC regis­ter. A 16-bit serial word loads data into the input regis­ter. The DAC register can be updated independently or
simultaneously with the input register. All logic inputs
are TTL/CMOS-logic compatible and buffered with
Schmitt triggers to allow direct interfacing to optocou­plers.

Applications

Digital Offset and Gain Adjustment

Industrial Process Control

Microprocessor-Controlled Systems

Portable Test Instruments

Remote Industrial Control

Features

♦ 10-Bit DAC with Configurable Output Amplifier

♦ +5V Single-Supply Operation

♦ Low Supply Current

0.28mA Normal Operation
2µA Shutdown Mode

♦ Available in 8-Pin µMAX

♦ Power-On Reset Clears DAC Output to Zero

♦ SPI/QSPI/MICROWIRE Compatible

♦ Schmitt-Trigger Digital Inputs for Direct

Optocoupler Interface

MAX5304

10-Bit Voltage-Output DAC

in 8-Pin µMAX

________________________________________________________________ Maxim Integrated Products 1

Functional Diagram

REF

DIN

FB

SCLK

1

2

8

7

V

DD

GND

CS

OUT

MAX5304

µMAX

TOP VIEW

3

4

6

5

Pin Configuration

19-1562; Rev 0; 10/99

PART

MAX5304CUA

MAX5304EUA -40°C to +85°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

8 µMAX

8 µMAX

_________________Ordering Information

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

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone].

V

GND

CONTROL

CS

DIN

SCLK

REGISTER

DD

DAC

REGISTER

INPUT

REGISTER

16-BIT

SHIFT

REF

FB

OUT

DAC

MAX5304

MAX5304

10-Bit Voltage-Output DAC
in 8-Pin µMAX

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 8, VDD= +5V ±10%, V

REF

= +2.5V, RL= 5kΩ, CL= 100pF, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values

are at T

A

= +25°C. Output buffer connected in unity-gain configuration.)

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.

V

DD

to GND...............................................................-0.3V to +6V

REF, OUT, FB to GND.................................-0.3V to (V

DD

+ 0.3V)

Digital Inputs to GND................................................-0.3V to +6V

Continuous Current into Any Pin.......................................±20mA

Continuous Power Dissipation (T

A

= +70°C)

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

Operating Temperature Ranges

MAX5304CUA...................................................0°C to +70°C

MAX5304EUA ................................................-40°C to +85°C

Junction Temperature......................................................+150°C

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

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

Code dependent, minimum at code 1550 hex

4.5V ≤ VDD≤ 5.5V

Guaranteed monotonic

CONDITIONS

kΩ18 30R

REF

Reference Input Resistance

V0V

DD

- 1.4V

REF

Reference Input Range

µV/VPSRRPower-Supply Rejection Ratio 800

Bits10NResolution

ppm/°C1Gain-Error Tempco

LSBGEGain Error (Note 1) -0.3 ±2

ppm/°C6TCV

OS

Offset-Error Tempco

LSBDNLDifferential Nonlinearity ±1.0

±0.3 ±8 mVV

OS

Offset Error

UNITSMIN TYP MAXSYMBOLPARAMETER

LSB±4INL

Integral Nonlinearity
(Note 1)

V

REF

= 0.67Vp-p kHz650Reference -3dB Bandwidth

Input code = all 0s, V

REF

= 3.6Vp-p at 1kHz

V

REF

= 1Vp-p at 25kHz, code = full scale dB77SINAD

Signal-to-Noise Plus
Distortion Ratio

dB-84Reference Feedthrough

V2.4V

IH

Input High Voltage

VIN= 0 or V

DD

pF8C

IN

Input Capacitance

µA0.001 ±0.5I

IN

Input Leakage Current

V0.8V

IL

Input Low Voltage

STATIC PERFORMANCE—ANALOG SECTION

DIGITAL INPUTS

REFERENCE INPUT

MULTIPLYING-MODE PERFORMANCE

MAX5304

10-Bit Voltage-Output DAC

in 8-Pin µMAX

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 8, VDD= +5V ±10%, V

REF

= +2.5V, RL= 5kΩ, CL= 100pF, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values

are at T

A

= +25°C. Output buffer connected in unity-gain configuration.)

(Note 3)

CS = VDD, DIN = 100kHz

Rail-to-rail (Note 2)

To ±1/2LSB, V

STEP

= 2.5V

CONDITIONS

mA0.28 0.4I

DD

Supply Current

V4.5 5.5V

DD

Supply Voltage

nVs5Digital Feedthrough

µs20Start-Up Time

µA0.001 ±0.1Current into FB

V0 to V

DD

Output Voltage Swing

µs10Output Settling Time

V/µs0.6SRVoltage Output Slew Rate

UNITSMIN TYP MAXSYMBOLPARAMETER

(Note 3) µA420Supply Current in Shutdown

µA0.001 ±0.5Reference Current in Shutdown

ns40t

CH

SCLK Pulse Width High

ns100t

CP

SCLK Clock Period

ns40t

CSS

CS Fall to SCLK Rise Setup Time

ns40t

DS

DIN Setup Time

ns0t

CSH

SCLK Rise to CS Rise Hold Time

ns40t

CL

SCLK Pulse Width Low

ns40t

CS1

CS Rise to SCLK Rise Hold Time

ns100t

CSW

CS Pulse Width High

ns40t

CS0

SCLK Rise to CS Fall Delay

ns0t

DH

DIN Hold Time

Note 1: Guaranteed from code 3 to code 1023 in unity-gain configuration.
Note 2: Accuracy is better than 1LSB for V

OUT

= 8mV to (VDD- 100mV), guaranteed by a power-supply rejection test at the end

points.

Note 3: R

L

= ∞, digital inputs at GND or VDD.

DIGITAL INPUTSDYNAMIC PERFORMANCE

POWER SUPPLIES

TIMING CHARACTERISTICS (Figure 6)

MAX5304

10-Bit Voltage-Output DAC
in 8-Pin µMAX

4 _______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(VDD= +5V, RL= 5kΩ, CL= 100pF, TA = +25°C, unless otherwise noted.)

INL (LSB)

-0.050

0.4 1.2 2.0 2.8 3.6

REFERENCE VOLTAGE (V)

MAX5304-01

4.4

0.050

0.025

0

-0.025

INTEGRAL NONLINEARITY
vs. REFERENCE VOLTAGE

0

-4

-8

-12

-16

-20
500k0

1M 1.5M

2M 2.5M 3M

MAX5304-02

RELATIVE OUTPUT (dB)

REFERENCE VOLTAGE INPUT

FREQUENCY RESPONSE

FREQUENCY (Hz)

400

380

360

340

320

300

280

260

240

220

200

-60 -20 20 60 100 140

MAX5304-03

SUPPLY CURRENT (µA)

SUPPLY CURRENT

vs. TEMPERATURE

TEMPERATURE (°C)

RL = ∞

10

9

8

7

6

5

4

3

2

1

0

-60 -20 20 60 100 140

MAX5304-04

POWER-DOWN SUPPLY CURRENT (µA)

POWER-DOWN SUPPLY CURRENT

vs. TEMPERATURE

TEMPERATURE (°C)

-100

0.5 1.6 3.8

OUTPUT FFT PLOT

-60

0

MAX5304-07

FREQUENCY (kHz)

SIGNAL AMPLITUDE (dB)

2.7 4.9 6.0

-20

-40

-80

V

REF

= +3.6Vp-p

CODE = FULL SCALE

f

IN

= 1kHz

4.0 4.4 4.8 6.05.2 5.6

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX5304-05

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (µA)

400

350

500

450

300

250

150

100

200

50

0

-50

-90

1

100

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

-85

MAX5304-06

FREQUENCY (kHz)

THD + NOISE (dB)

-70

-60

10

-55

-80

-75

-65

V

REF

= +2.5VDC + 1Vp-p SINE

CODE = FULL SCALE

2.49956

2.49960

2.49964

2.49968

2.49972

2.49976

2.49980

0.1k 1k 10k 1M100k

OUTPUT VOLTAGE

vs. LOAD

MAX5304-08

LOAD (Ω)

OUTPUT VOLTAGE (V)

-100

0.5 1.6 3.8

REFERENCE FEEDTHROUGH

AT 1kHz

-60

0

MAX5304-09a/09b

FREQUENCY (kHz)

SIGNAL AMPLITUDE (dB)

2.7 4.9 6.0

-20

-40

-80

OUTPUT FEEDTHROUGH

REFERENCE INPUT SIGNAL

MAX5304

10-Bit Voltage-Output DAC

in 8-Pin µMAX

_______________________________________________________________________________________ 5

____________________________Typical Operating Characteristics (continued)

(VDD= +5V, RL= 5kΩ, CL= 100pF, TA = +25°C, unless otherwise noted.)

10µs/div

MAJOR-CARRY TRANSITION

MAX5304-10a

OUT

AC-COUPLED

100mV/div

CS

5V/div

10µs/div

DYNAMIC RESPONSE

MAX5304-12a

OUT

1V/div

GND

GAIN = +2V/V, SWITCHING FROM CODE 0 TO 1005

DIGITAL FEEDTHROUGH (f

SCLK

2V/div

OUT

AC-COUPLED

10mV/div

CODE = 512

2µs/div

CS = 5V

SCLK

= 100kHz)

MAX5304-11a

MAX5304

10-Bit Voltage-Output DAC
in 8-Pin µMAX

6 _______________________________________________________________________________________

_______________Detailed Description

The MAX5304 contains a voltage-output digital-to-ana­log converter (DAC) that is easily addressed using a
simple 3-wire serial interface. Each IC includes a 16-bit
shift register, and has a double-buffered input com­posed of an input register and a DAC register (see the
Functional Diagram). In addition to the voltage output,
the amplifier’s negative input is available to the user.

The DAC is an inverted R-2R ladder network that con­verts a digital input (10 data bits plus 3 sub-bits) into an
equivalent analog output voltage in proportion to the
applied reference voltage. Figure 1 shows a simplified
circuit diagram of the DAC.

Reference Inputs

The reference input accepts positive DC and AC sig­nals. The voltage at the reference input sets the full­scale output voltage for the DAC. The reference input
voltage range is 0V to (VDD- 1.4V). The output voltage
(V

OUT

) is represented by a digitally programmable volt-

age source, as expressed in the following equation:

V

OUT

= (V

REF

· NB / 1024) Gain

where NB is the numeric value of the DAC’s binary
input code (0 to 1023), V

REF

is the reference voltage,

and Gain is the externally set voltage gain.

The impedance at the reference input is code depen­dent, ranging from a low value of 18kΩ when the DAC
has an input code of 1550 hex, to a high value exceed­ing several gigohms (leakage currents) with an input
code of 0000 hex. Because the input impedance at the
reference pin is code dependent, load regulation of the
reference source is important.

In shutdown mode, the MAX5304’s REF input enters a
high-impedance state with a typical input leakage cur­rent of 0.001µA.

The reference input capacitance is also code depen­dent and typically ranges from 15pF (with an input
code of all 0s) to 50pF (at full scale).

The MAX873 +2.5V reference is recommended for use
with the MAX5304.

Output Amplifier

The MAX5304’s DAC output is internally buffered by a
precision amplifier with a typical slew rate of 0.6V/µs.
Access to the output amplifier’s inverting input provides
the user greater flexibility in output gain setting/signal
conditioning (see the Applications Information section).

With a full-scale transition at the MAX5304 output, the
typical settling time to ±1/2LSB is 10µs when loaded
with 5kΩ in parallel with 100pF (loads less than 2kΩ
degrade performance).

The amplifier’s output dynamic responses and settling
performances are shown in the Typical Operating
Characteristics.

Shutdown Mode

The MAX5304 features a software-programmable shut­down that reduces supply current to a typical value of
4µA. Writing 111X XXXX XXXX XXXX as the input-con­trol word puts the device in shutdown mode (Table 1).

Figure 1. Simplified DAC Circuit Diagram

_____________________Pin Description

DAC Output Amplifier FeedbackFB5

Reference Voltage InputREF6

GroundGND7

Positive Power SupplyV

DD

8

Serial-Clock InputSCLK4

Serial-Data InputDIN3

PIN

Chip-Select Input. Active low.

CS

2

DAC Output VoltageOUT1

FUNCTIONNAME

RRR

2R 2R 2R 2R

2R

FB

OUT

MSB

REF

AGND

SHOWN FOR ALL 1s ON DAC

MAX5304

10-Bit Voltage-Output DAC

in 8-Pin µMAX

_______________________________________________________________________________________ 7

In shutdown mode, the amplifier’s output and the refer­ence input enter a high-impedance state. The serial
interface remains active. Data in the input register is
retained in shutdown, allowing the MAX5304 to recall
the output state prior to entering shutdown. Exit shut­down mode by either recalling the previous configura­tion or updating the DAC with new data. When
powering up the device or bringing it out of shutdown,
allow 20µs for the outputs to stabilize.

Serial-Interface Configurations

The MAX5304’s 3-wire serial interface is compatible
with MICROWIRE (Figure 2) and SPI/QSPI (Figure 3).
The serial-input word consists of three control bits fol­lowed by 10+3 data bits (MSB first), as shown in Figure

4. The 3-bit control code determines the MAX5304’s
response outlined in Table 1.

The MAX5304’s digital inputs are double buffered.
Depending on the command issued through the serial
interface, the input register can be loaded without
affecting the DAC register, the DAC register can be
loaded directly, or the DAC register can be updated
from the input register (Table 1).

Serial-Interface Description

The MAX5304 requires 16 bits of serial data. Table 1
lists the serial-interface programming commands. For
certain commands, the 10+3 data bits are “don’t
cares.” Data is sent MSB first and can be sent in two 8­bit packets or one 16-bit word (CS must remain low
until 16 bits are transferred). The serial data is com­posed of three control bits (C2, C1, C0), followed by
the 10+3 data bits D9...D0, S2, S1, S0 (Figure 4). Set
the sub-bits (S2, S1, S0) to zero. The 3-bit control code
determines the register to be updated and the configu­ration when exiting shutdown.

Figure 5 shows the serial-interface timing requirements.
The chip-select pin (CS) must be low to enable the
DAC’s serial interface. When CS is high, the interface
control circuitry is disabled. CS must go low at least
t

CSS

before the rising serial-clock (SCLK) edge to prop-

erly clock in the first bit. When CS is low, data is
clocked into the internal shift register through the serial­data input pin (DIN) on SCLK’s rising edge. The maxi­mum guaranteed clock frequency is 10MHz. Data is
latched into the MAX5304 input/DAC register on CS’s
rising edge.

Figure 2. Connections for MICROWIRE

Figure 3. Connections for SPI/QSPI

Figure 4. Serial-Data Format

3 Control

Bits

10+3 Data Bits

D9 ...............................D0, S2, S1, S0C2 C1 C0

Data Bits

MSB............................LSB Sub-Bits

Control

Bits

16 Bits of Serial Data

MSB ..................................................................................LSB

SCLK

MAX5304

MAX5304

DIN

CS

DIN

SCLK

CS

SK

MICROWIRE

SO

I/O

MOSI

SPI/QSPI

SCK

I/O

CPOL = 0, CPHA = 0

PORT

+5V

SS

PORT

MAX5304

10-Bit Voltage-Output DAC
in 8-Pin µMAX

8 _______________________________________________________________________________________

16-BIT SERIAL WORD

Figure 5. Serial-Interface Timing Diagram

Figure 6. Detailed Serial-Interface Timing Diagram

Table 1. Serial-Interface Programming Commands

X = Don’t care

XXXXXXXXXX

XXXXXXXXXX

10 bits of data

10 bits of data

XXXXXXXXXX

XXX

XXX

C2 C1 C0

000

S2...S0

D9.......................D0

MSB LSB

000

XXX

11 1

X1 0

X0 1

X0 0

01 1

Shutdown

Update DAC register from input register (also exit shutdown; recall
previous state).

Load input register; DAC register unchanged.

FUNCTION

Load input register; DAC register immediately updated (also exit
shutdown).

No operation (NOP)

16-BIT SERIAL WORD

CS

SCLK

DIN

1

C1

C2 S0

C0

D8

D9

8

D7

D6 D3 D2 D1 D0 S2 S1D5 D4

COMMAND

EXECUTED

9

16

CS

SCLK

DIN

t

CSO

t

CSS

t

DS

t

DH

t

CL

t

CH

t

CP

t

CSH

t

CS1

t

CSW

MAX5304

10-Bit Voltage-Output DAC

in 8-Pin µMAX

_______________________________________________________________________________________ 9

Figure 7 shows a method of connecting several
MAX5304s. In this configuration, the clock and the data
bus are common to all devices, and separate chip­select lines are used for each IC.

Applications Information

Unipolar Output

For a unipolar output, the output voltage and the refer­ence input have the same polarity. Figure 8 shows the
MAX5304 unipolar output circuit, which is also the typi­cal operating circuit. Table 2 lists the unipolar output
codes.

Figure 9 illustrates a Rail-to-Rail®output configuration.
This circuit shows the MAX5304 with the output amplifi­er configured for a closed-loop gain of +2V/V to provide
a 0 to 5V full-scale range when a 2.5V reference is used.

Bipolar Output

The MAX5304 output can be configured for bipolar
operation using Figure 10’s circuit according to the fol­lowing equation:

V

OUT

= V

REF

[(2NB / 1024) - 1]

where NB is the numeric value of the DAC’s binary
input code. Table 3 shows digital codes (offset binary)
and corresponding output voltages for Figure 10’s cir­cuit.

Using an AC Reference

In applications where the reference has AC signal com­ponents, the MAX5304 has multiplying capability within
the reference input range specifications. Figure 11
shows a technique for applying a sine-wave signal to
the reference input where the AC signal is offset before
being applied to REF. The reference voltage must
never be more negative than GND.

Figure 7. Multiple MAX5304s Sharing Common DIN and SCLK Lines

Table 2. Unipolar Output Codes

Note: ( ) are for sub-bits.

ANALOG OUTPUT

11 1111 1111 (000)

10 0000 0001 (000)

DAC CONTENTS

MSB LSB

10 0000 0000 (000)

01 1111 1111 (000)

00 0000 0000 (000) 0V

00 0000 0001 (000)

Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.

DIN

SCLK

CS1

CS2

CS3

CS

MAX5304

SCLK

DIN

CS

MAX5304

SCLK

DIN

TO OTHER
SERIAL DEVICES

CS

MAX5304

SCLK

DIN

+V

REF

+V

REF

+V

REF



512



1024



+V

REF

+V

REF



















1024






1024



1023

1024

513

1024

511

1

=+











V

REF

2











MAX5304

10-Bit Voltage-Output DAC
in 8-Pin µMAX

10 ______________________________________________________________________________________

The MAX5304’s total harmonic distortion plus noise
(THD+N) is typically less than -77dB (full-scale code),
given a 1Vp-p signal swing and input frequencies up to
25kHz. The typical -3dB frequency is 650kHz, as
shown in the Typical Operating Characteristics graphs.

Digitally Programmable Current Source

Figure 12’s circuit places an NPN transistor (2N3904 or
similar) within the op amp feedback loop to implement
a digitally programmable, unidirectional current source.
The output current is calculated with the following
equation:

I

OUT

= (V

REF

/ R)(NB / 1024)

where NB is the numeric value of the DAC’s binary
input code, and R is the sense resistor shown in Figure

12.

Note: ( ) are for sub-bits.

Figure 8. Unipolar Output Circuit

Table 3. Bipolar Output Codes

Figure 9. Unipolar Rail-to-Rail Output Circuit

ANALOG OUTPUT

11 1111 1111 (000)

10 0000 0001 (000)

DAC CONTENTS

MSB LSB

10 0000 0000 (000) 0V

01 1111 1111 (000)

00 0000 0000 (000)

00 0000 0001 (000)

+5V

REF

V

MAX5304

DAC

-V

DD



511

+V



REF

512





REF

REF

REF






512
512













512



512

511
512

1






FB

OUT

1











=

+V

-V

-V

REF REF











-V

+5V

REF

V

DD

MAX5304

DAC

FB

OUT

10k

10k

GND

GND

MAX5304

10-Bit Voltage-Output DAC

in 8-Pin µMAX

______________________________________________________________________________________ 11

Power-Supply Considerations

On power-up, the input and DAC registers are cleared
(set to zero code). For rated MAX5304 performance,
REF must be at least 1.4V below VDD. Bypass VDDwith
a 4.7µF capacitor in parallel with a 0.1µF capacitor to
GND. Use short lead lengths, and place the bypass
capacitors as close to the supply pins as possible.

Grounding and Layout Considerations

Digital or AC transient signals on GND can create noise
at the analog output. Connect GND to the highest-qual­ity ground available. Good PC board ground layout
minimizes crosstalk between the DAC output, reference
input, and digital input. Reduce crosstalk by keeping
analog lines away from digital lines. Wire-wrapped
boards are not recommended.

Figure 10. Bipolar Output Circuit

Figure 11. AC Reference Input Circuit

Figure 12. Digitally Programmable Current Source

___________________Chip Information

TRANSISTOR COUNT: 3053

SUBSTRATE CONNECTED TO AGND

REF

DAC

R1

+5V

V

DD

FB

OUT

MAX5304

GND

+5V

REF

V

DD

MAX5304

DAC

R2

V+

V-

R1 = R2 = 10kΩ ±0.1%

V

L

OUT

2N3904

I

OUT

+5V

10k

+5V

DAC

MAX495

REF

V

DD

OUT

26k

AC

REFERENCE

INPUT

500mVp-p

V

OUT

MAX5304

GND

FB

GND

R

MAX5304

10-Bit Voltage-Output DAC
in 8-Pin µMAX

Package Information

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.

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© 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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