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MAX5156/MAX5157

Low-Power, Dual, 12-Bit Voltage-Output DACs

with Configurable Outputs

________________________________________________________________

Maxim Integrated Products

19-1317; Rev 1; 12/97

_______________General Description

The MAX5156/MAX5157 low-power, serial, voltage-out-

put, dual 12-bit digital-to-analog converters (DACs)

consume only 500µA from a single +5V (MAX5156) or

+3V (MAX5157) supply. These devices feature Rail-to-

Rail

output swing and are available in space-saving

16-pin QSOP and DIP packages. Access to the invert-

ing input allows for specific gain configurations, remote

sensing, and high output current capability, making

these devices ideally suited for industrial process con-

trols. These devices are also well suited for digitally

programmable (4–20mA) current loops.

The 3-wire serial interface is SPI™/QSPI™ and

Microwire™ compatible. Each DAC has a double-

buffered input organized as an input register followed

by a DAC register, which allows the input and DAC reg-

isters to be updated independently or simultaneously.

Additional features include a programmable shutdown

(2µA), hardware-shutdown lockout, a separate voltage

reference for each DAC, power-on reset, and an active-

low clear input (CL) that resets all registers and DACs to

zero. The MAX5156/MAX5157 provide a programmable

logic output pin for added functionality, and a serial-

data output pin for daisy chaining.

________________________Applications

Industrial Process Control Motion Control

Digital Offset and Gain Digitally Programmable

Adjustment 4–20mA Current Loops

Remote Industrial Controls Automatic Test Equipment

____________________________Features

♦ 12-Bit Dual DAC with Configurable Output

Amplifier

♦ Single-Supply Operation: +5V (MAX5156)

+3V (MAX5157)

♦ Rail-to-Rail Output Swing

♦ Low Quiescent Current: 500µA (normal operation)

2µA (shutdown mode)

♦ Power-On Reset Clears DAC Outputs to Zero

♦ SPI/QSPI and Microwire Compatible

♦ Space-Saving 16-Pin QSOP Package

_______________Ordering Information

Rail-to-Rail is a registered trademark of Nippon Motorola Ltd. SPI and QSPI are trademarks of Motorola, Inc.

Microwire is a trademark of National Semiconductor Corp.

Ordering Information continued at end of data sheet.

Pin Configuration appears at end of data sheet.

REFACLDOUT

16-BIT

SHIFT

CONTROL

INPUT

REG A

SCLK

UPO

REFB

DINCS

DAC A

DAC B

FBA

FBB

OUTA

OUTB

DAC

REG A

INPUT

REG B

LOGIC

OUTPUT

DECODE

CONTROL

DAC

REG B

MAX5156

MAX5157

AGND

DGNDPDL

_________________________________________________________Functional Diagram

INL

(LSB)

PIN-PACKAGETEMP. RANGEPART

±116 QSOP0°C to +70°CMAX5156BCEE

±1/2

±1

±1/2

16 QSOP

16 Plastic DIP

16 Plastic DIP0°C to +70°C

0°C to +70°C

0°C to +70°CMAX5156ACEE

MAX5156BCPE

MAX5156ACPE

Summary of content (16 pages)

PAGE 1
9-1317; Rev 1; 12/97 Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs ________________________Applications Industrial Process Control Motion Control Digital Offset and Gain Adjustment Digitally Programmable 4–20mA Current Loops Remote Industrial Controls Automatic Test Equipment ____________________________Features ♦ 12-Bit Dual DAC with Configurable Output Amplifier ♦ Single-Supply Operation: +5V (MAX5156) +3V (MAX5157) ♦ Rail-to-Rail Output Swing ♦ Low Quiescent Current: 500µ
PAGE 2
MAX5156/MAX5157 Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs ABSOLUTE MAXIMUM RATINGS VDD to AGND............................................................-0.3V to +6V VDD to DGND ...........................................................-0.3V to +6V AGND to DGND ..................................................................±0.3V FBA, FBB to AGND.....................................-0.3V to (VDD + 0.3V) REF_, OUT_ to AGND.................................-0.3V to (VDD + 0.
PAGE 3
Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs (VDD = +5V ±10%, VREFA = VREFB = 2.5V, RL = 10kΩ, 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 OUTPUTS (DOUT, UPO) Output High Voltage VOH ISOURCE = 2mA Output Low Voltage VOL ISINK = 2mA VDD - 0.5 V 0.13 0.
PAGE 4
MAX5156/MAX5157 Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs ELECTRICAL CHARACTERISTICS—MAX5157 (VDD = +2.7V to +3.6V, VREFA = VREFB = 1.25V, RL = 10kΩ, 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, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs (VDD = +2.7V to +3.6V, VREFA = VREFB = 1.25V, RL = 10kΩ, 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 POWER SUPPLIES Positive Supply Voltage VDD Power-Supply Current IDD Power-Supply Current in Shutdown 2.7 (Note 7) IDD(SHDN) (Note 7) Reference Current in Shutdown 3.
PAGE 6
__________________________________________Typical Operating Characteristics (VDD = +5V, RL = 10kΩ, CL = 100pF, FB_ connected to OUT_, TA = +25°C, unless otherwise noted.) MAX5156 SUPPLY CURRENT vs. TEMPERATURE -8 -10 -12 -14 CODE = 1FFE (HEX) VREF = 1Vp-p @ 2.5VDC CODE = 1FFE (HEX) -40 0.55 0.50 CODE = 0000 (HEX) -50 -60 -70 0.45 -16 VREF = 0.67Vp-p @ 2.5VDC CODE = 1FFE (HEX) -18 -80 0.
PAGE 7
Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs MAX5157 SUPPLY CURRENT vs. TEMPERATURE -8 -10 -12 -14 500 1000 1500 2000 2500 -60 -70 CODE = 0000 (HEX) -90 -60 -20 20 60 100 140 0 10 100 FREQUENCY (kHz) FULL-SCALE ERROR vs. RESISTIVE LOAD REFERENCE FEEDTHROUGH AT 1kHz POWER-DOWN CURRENT vs. TEMPERATURE -70 RELATIVE OUTPUT (dB) -0.2 -0.3 -0.4 VREF = 1.6Vp-p @ 0.88VDC CODE = 0000 (HEX) -80 -90 -100 -110 -120 -130 -0.5 3.0 2.0 1.5 1.0 0.5 0 -150 -0.6 1 2.
PAGE 8
____________________________Typical Operating Characteristics (continued) (VDD = +5V (MAX5156), VDD = +3V (MAX5157), RL = 10kΩ, CL = 100pF, FB_ connected to OUT_, TA = TMIN to TMAX, unless otherwise noted.) MAX5156/MAX5157 MAX5157 SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX5156 SUPPLY CURRENT vs. SUPPLY VOLTAGE CODE = 1FFE (HEX) 0.50 SUPPLY CURRENT (mA) CODE = 1FFE (HEX) MAX5156 TOC19a 0.55 0.55 MAX5156 TOC19 0.
PAGE 9
Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs PIN NAME 1 AGND Analog Ground 2 OUTA DAC A Output Voltage 3 FBA 4 REFA FUNCTION DAC A Output Amplifier Feedback Input. Inverting input of the output amplifier. Reference for DAC A 5 CL Active-Low Clear Input. Resets all registers to zero. DAC outputs go to 0V.
PAGE 10
MAX5156/MAX5157 Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs Table 1. Serial-Interface Programming Commands 16-BIT SERIAL WORD FUNCTION A0 C1 C0 D11................D0 MSB LSB S0 0 0 1 12 bits of DAC data 0 Load input register A; DAC register is unchanged. 1 0 1 12 bits of DAC data 0 Load input register B; DAC register is unchanged. 0 1 0 12 bits of DAC data 0 Load input register A; all DAC registers are updated.
PAGE 11
Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs SK DIN SO CS I/O MICROWIRE PORT Figure 2. Connections for Microwire The general timing diagram in Figure 5 illustrates how data is acquired. Driving CS low enables the device to receive data. Otherwise, the interface control circuitry is disabled. With CS low, data at DIN is clocked into the register on the rising edge of SCLK.
PAGE 12
MAX5156/MAX5157 Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs CS COMMAND EXECUTED SCLK 1 DIN 8 C1 A0 C0 D11 D10 D9 D8 9 D7 D6 16 D5 D4 D3 D2 D1 D0 S0 Figure 5. Serial-Interface Timing Diagram tCSW CS tCSS tCSO tCL tCP tCH tCSH tCS1 SCLK tDS tDH DIN Figure 6. Detailed Serial-Interface Timing Diagram SCLK SCLK MAX5156 MAX5157 DIN DOUT CS SCLK MAX5156 MAX5157 DIN DOUT CS MAX5156 MAX5157 DIN CS DOUT TO OTHER SERIAL DEVICES Figure 7.
PAGE 13
Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs MAX5156/MAX5157 DIN SCLK CS1 CS2 TO OTHER SERIAL DEVICES CS3 CS CS MAX5156 MAX5157 CS MAX5156 MAX5157 MAX5156 MAX5157 SCLK SCLK SCLK DIN DIN DIN Figure 8. Multiple MAX5156/MAX5157s Sharing a Common DIN Line Table 2.
PAGE 14
MAX5156/MAX5157 Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs +5V/+3V REF_ +5V/+3V REF_ 10k 10k VDD R2 MAX5156 MAX5157 VDD FB_ V+ FB_ MAX5156 MAX5157 R1 VOUT DAC VOUT OUT_ DAC _ DGND OUT_ V- AGND DGND AGND ( ) ( )( ) VOUT = 1 + R1 R2 N VREF_ 4096 Figure 10. Configurable Output Gain Figure 11. Bipolar Output Circuit Table 3.
PAGE 15
Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs Figure 13 shows the MAX5156/MAX5157 in a digital calibration application. With a bright value applied to the photodiode (on), the DAC is digitally ramped up until it trips the comparator. The microprocessor stores this high calibration value. Repeat the process with a dim light (off) to obtain the dark current calibration. The microprocessor then programs the DAC to set an output voltage that is the midpoint of the two calibration values.
PAGE 16
MAX5156/MAX5157 Low-Power, Dual, 12-Bit Voltage-Output DACs with Configurable Outputs Digitally Programmable Current Source Figure 15 depicts a digitally programmable, unidirectional current source that can be used in industrial control applications. The output current is: IOUT = (VREF / R) (NB / 4096) where NB is the DAC code and R is the sense resistor. Power-Supply Considerations +5V/+3V REF_ VL VDD On power-up, the input and DAC registers clear (resets to zero code).