Maxim MAX5139 Low-power, single, 16-/12-bit, buffered voltage-output dac Datasheet

19-4428; Rev 1; 4/09
KIT
ATION
EVALU
E
L
B
A
AVAIL
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
The MAX5138/MAX5139 are a family of single-channel
pin-compatible and software-compatible 16-bit and 12bit DACs. The MAX5138/MAX5139 are low-power, 16bit/12-bit, buffered voltage-output, high-linearity DACs.
They use a precision internal reference or a precision
external reference for rail-to-rail operation. The
MAX5138/MAX5139 accept a wide +2.7V to +5.25V supply-voltage range to accommodate most low-power and
low-voltage applications. These devices accept a 3-wire
SPITM-/QSPITM-/MICROWIRETM-/DSP-compatible serial
interface to save board space and reduce the complexity of optically isolated and transformer-isolated applications. The digital interface’s double-buffered hardware
and software LDAC provide simultaneous output update.
The serial interface features a READY output for easy
daisy-chaining of several MAX5138/MAX5139 devices
and/or other compatible devices. The MAX5138/MAX5139
include a hardware input to reset the DAC outputs to
zero or midscale upon power-up or reset, providing
additional safety for applications that drive valves or
other transducers that need to be off during power-up.
The high linearity of the DACs makes these devices ideal
for precision control and instrumentation applications.
The MAX5138/MAX5139 are available in an ultra-small
(3mm x 3mm), 16-pin TQFN package and are specified
over the -40°C to +105°C extended industrial temperature range.
Applications
Automatic Test Equipment
Features
o 16-/12-Bit Resolution in a 3mm x 3mm, 16-Pin
TQFN Package
o Hardware-Selectable on Power-Up or Reset-toZero/Midscale DAC Output
o Double-Buffered Input Registers
o LDAC Asynchronously Updates DAC Output
o READY Facilitates Daisy Chaining
o High-Performance 10ppm/°C Internal Reference
o Guaranteed Monotonic Over All Operating
Conditions
o Wide +2.7V to +5.25V Supply Range
o Rail-to-Rail Buffered Output Operation
o Low Gain Error (Less Than ±0.5% FS) and Offset
(Less Than ±10mV)
o 30MHz 3-Wire SPI-/QSPI-/MICROWIRE-/
DSP-Compatible Serial Interface
o CMOS-Compatible Inputs with Hysteresis
o Low Power Consumption (ISHDN = 2µA max)
Ordering Information
PART
RESOLUTION
(BITS)
PIN-PACKAGE
MAX5138BGTE+
16 TQFN-EP*
16
MAX5139GTE+
16 TQFN-EP*
12
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Note: All devices are specified over the -40°C to +105°C operating
temperature range.
Automatic Tuning
Pin Configuration
Portable Instrumentation
Power-Amplifier Control
N.C.
TOP VIEW
READY
Gain and Offset Adjustment
DVDD
Data Acquisition
OUT
Communication Systems
12
11
10
9
AVDD 13
8
AGND
REFI 14
7
DIN
6
CS
5
SCLK
Process Control and Servo Loops
MAX5138
MAX5139
REFO 15
*EP
+
1
N.C.
SPI and QSPI are trademarks of Motorola Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
*EXPOSED PAD
2
3
4
N.C.
AGND 16
LDAC
Functional Diagram and Typical Operating Circuit appear
at end of data sheet.
M/Z
Programmable Voltage and Current Sources
TQFN
3mm x 3mm
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX5138/MAX5139
General Description
MAX5138/MAX5139
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
ABSOLUTE MAXIMUM RATINGS
AVDD to AGND ........................................................-0.3V to +6V
DVDD to AGND ........................................................-0.3V to +6V
OUT to AGND...............................................-0.3V to the lower of
(AVDD + 0.3V) and +6V
REFI, REFO, M/Z to AGND ...........................-0.3V to the lower of
(AVDD + 0.3V) and +6V
SCLK, DIN, CS to AGND ..............................-0.3V to the lower of
(DVDD + 0.3V) and +6V
LDAC, READY to AGND...............................-0.3V to the lower of
(DVDD + 0.3V) and +6V
Continuous Power Dissipation (TA = +70°C)
16-Pin TQFN (derate at 14.7mW/°C above +70°C) ..1176.5mW
Maximum Current into Any Input or Output
with the Exception of M/Z Pin .......................................±50mA
Maximum Current into M/Z Pin ...........................................±5mA
Operating Temperature Range .........................-40°C to +105°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°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.
ELECTRICAL CHARACTERISTICS
(VAVDD = 2.7V to 5.25V, VDVDD = 2.7V to 5.25V, VAVDD ≥ VDVDD, VAGND = 0, VREFI = VAVDD - 0.25V, COUT = 200pF, ROUT = 10kΩ,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
STATIC ACCURACY (Notes 1, 2)
Resolution
MAX5138 Integral Nonlinearity
N
INL
MAX5138
16
MAX5139
12
VREFI = 5V,
AVDD = 5.25V
(Note 3)
-9
INL
VREFI = 5V, AVDD = 5.25V
DNL
Guaranteed monotonic
-1.0
-1
(Note 4)
-10
Offset-Error Drift
Gain Error
+11
±6
Differential Nonlinearity
OE
±2
TA = +25°C
MAX5139 Integral Nonlinearity
Offset Error
Bits
±0.25
±1
+1
LSB
+1.0
LSB
+10
±4
GE
(Note 4)
-0.5
Gain Temperature Coefficient
±0.2
LSB
mV
µV/°C
+0.5
% of FS
ppm
FS/°C
±2
REFERENCE INPUT
AVDD = 3V to 5.25V
Reference-Input Voltage Range
VREFI
AVDD = 2.7V to 3V
2
AVDD
2
AVDD 0.2
Reference Input Impedance
113
V
kΩ
INTERNAL REFERENCE
Reference Voltage
VREFO
Reference Temperature Coefficient
(Note 5)
Reference Output Impedance
Line Regulation
Maximum Capacitive Load
2
TA = +25°C
CR
2.437
2.440
2.443
V
10
25
ppm/°C
1
Ω
100
ppm/V
0.1
nF
_______________________________________________________________________________________
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
(VAVDD = 2.7V to 5.25V, VDVDD = 2.7V to 5.25V, VAVDD ≥ VDVDD, VAGND = 0, VREFI = VAVDD - 0.25V, COUT = 200pF, ROUT = 10kΩ,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
AVDD
- 0.02
V
DAC OUTPUT VOLTAGE (Note 2)
Output Voltage Range
No load
0.02
DC Output Impedance
Maximum Capacitive Load
(Note 5)
CL
Resistive Load
RL
Short-Circuit Current
ISC
Power-Up Time
Series resistance = 0Ω
Series resistance = 500Ω
0.1
Ω
0.2
nF
15
µF
2
AVDD = 5.25V
AVDD = 2.7V
kΩ
±35
-40
From power-down mode
±20
+40
25
mA
µs
DIGITAL INPUTS (SCLK, DIN, CS, LDAC) (Note 6)
Input High Voltage
VIH
Input Low Voltage
VIL
Input Leakage Current
IIN
Input Capacitance
CIN
0.7 x
DVDD
VIN = 0 or DVDD
-1
V
±0.1
0.3 x
DVDD
V
+1
µA
10
pF
DIGITAL OUTPUTS (READY)
Output High Voltage
VOH
ISOURCE = 3mA
Output Low Voltage
VOL
ISINK = 2mA
DVDD
- 0.5
V
0.4
V
DYNAMIC PERFORMANCE
Voltage-Output Slew Rate
Voltage-Output Settling Time
Digital Feedthrough
SR
Positive and negative
1.25
V/µs
tS
1/4 scale to 3/4 scale VREFI = AVDD = 5V
settle to ±2 LSB (Note 5)
5
µs
Code 0, all digital inputs from 0 to DVDD
0.5
nV•s
25
nV•s
Major Code Transition Analog
Glitch Impulse
Output Noise
10kHz
120
nV/√Hz
Integrated Output Noise
1Hz to 10kHz
18
µV
_______________________________________________________________________________________
3
MAX5138/MAX5139
ELECTRICAL CHARACTERISTICS (continued)
MAX5138/MAX5139
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
ELECTRICAL CHARACTERISTICS (continued)
(VAVDD = 2.7V to 5.25V, VDVDD = 2.7V to 5.25V, VAVDD ≥ VDVDD, VAGND = 0, VREFI = VAVDD - 0.25V, COUT = 200pF, ROUT = 10kΩ,
TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
POWER REQUIREMENTS (Note 7)
Analog Supply Voltage Range
AVDD
2.7
5.25
Digital Supply Voltage Range
DVDD
2.7
AVDD
V
1
1.6
mA
µA
IAVDD
Supply Current
IDVDD
IAVPD
Power-Down Supply Current
IDVPD
No load, all digital inputs at 0 or DVDD
No load, all digital inputs at 0 or DVDD
1
10
0.2
2
0.1
2
µA
TIMING CHARACTERISTICS (Note 8) (Figure 1)
Serial-Clock Frequency
fSCLK
0
SCLK Pulse-Width High
tCH
13
30
MHz
SCLK Pulse-Width Low
tCL
13
ns
CS Fall-to-SCLK Fall Setup Time
tCSS
8
ns
SCLK Fall-to CS-Rise Hold Time
tCSH
5
ns
DIN-to-SCLK Fall Setup Time
tDS
10
ns
DIN-to-SCLK Fall Hold Time
tDH
2
ns
ns
SCLK Fall to READY Transition
tSRL
CS Pulse-Width High
tCSW
33
ns
tLDACPWL
33
ns
LDAC Pulse Width
(Note 9)
30
ns
Static accuracy tested without load.
Linearity is tested within 20mV of AGND and AVDD, allowing for gain and offset error.
Codes above 2047 are guaranteed to be within ±9 LSB.
Gain and offset tested within 100mV of AGND and AVDD.
Guaranteed by design.
Device draws current in excess of the specified supply current when a digital input is driven with a voltage of VI < DVDD - 0.6V
or VI > 0.5V. At VI = 2.2V with DVDD = 5.25V, this current can be as high as 2mA. The SPI inputs are CMOS-input-level compatible. The 30MHz clock frequency cannot be guaranteed for a minimum signal swing.
Note 7: Excess current from AVDD is 10mA when powered without DVDD. Excess current from DVDD is 1mA when powered without
AVDD.
Note 8: All timing specifications are with respect to the digital input and output thresholds.
Note 9: Maximum daisy-chain clock frequency is limited to 25MHz.
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
tCSW
COMMAND EXECUTED ON
24th FALLING EDGE OF SCLK
CS
tCL
tCSS
tCH
tCSH
SCLK
tDS
DIN
X
C7
C6
C5
D3
tDH
D2
D1
D0
X
tSRL
READY
X = DON'T CARE.
Figure 1. Serial-Interface Timing Diagram
4
_______________________________________________________________________________________
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
INTEGRAL NONLINEARITY
vs. ANALOG SUPPLY VOLTAGE
6
7
5
5
-6
3
INL (LSB)
INL (LSB)
1
-1
-3
-5
-5
-7
-7
-9
-9
16,384
32,768
49,152
-9
2.7
65,536
3.7
3.2
4.2
4.7
5.2
-40
20
40
60
80
TEMPERATURE (°C)
DIFFERENTIAL NONLINEARITY
vs. DIGITAL INPUT CODE
DIFFERENTIAL NONLINEARITY
vs. ANALOG SUPPLY VOLTAGE
DIFFERENTIAL NONLINEARITY
vs. TEMPERATURE
0.6
0.8
0.6
1.0
0.8
0.6
0.4
0.2
0.2
0.2
-0.2
DNL (LSB)
0.4
DNL (LSB)
0.4
0
0
-0.2
0
-0.2
-0.4
-0.4
-0.4
-0.6
-0.6
-0.6
-0.8
-0.8
-0.8
-1.0
-1.0
16,384
32,768
49,52
65,536
100
MAX5138 toc06
1.0
MAX5138 toc04
0.8
-1.0
2.7
3.2
3.7
4.2
4.7
5.2
-40
-20
0
20
40
60
80
100
DIGITAL INPUT CODE (LSB)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
OFFSET ERROR
vs. ANALOG SUPPLY VOLTAGE
12-BIT DIFFERENTIAL NONLINEARITY
vs. DIGITAL INPUT CODE
12-BIT INTEGRAL NONLINEARITY
vs. DIGITAL INPUT CODE
6
0.08
0.06
0.04
2
0.02
DNL (LSB)
4
0
-2
0
-0.04
-6
-0.06
-8
-0.08
-10
3.7
4.2
SUPPLY VOLTAGE (V)
4.7
5.2
0.25
0
-0.25
-0.50
-0.75
-1.00
-0.10
3.2
0.75
0.50
-0.02
-4
1.00
INL (LSB)
8
MAX5138 toc09
0.10
MAX5138 toc07
10
2.7
0
SUPPLY VOLTAGE (V)
1.0
0
-20
DIGITAL INPUT CODE (LSB)
MAX5138 toc05
0
1
-1
-3
MAX5138 toc08
INL (LSB)
0
-3
DNL (LSB)
7
3
3
OFFSET ERROR (mV)
9
MAX5138 toc02
9
MAX5138 toc01
9
INTEGRAL NONLINEARITY
vs. TEMPERATURE
MAX5138 toc03
MAX5138 INTEGRAL NONLINEARITY
vs. DIGITAL INPUT CODE
0
1024
2048
3072
DIGITAL INPUT CODE (LSB)
4096
0
1024
2048
3072
4096
DIGITAL INPUT CODE (LSB)
_______________________________________________________________________________________
5
MAX5138/MAX5139
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
-0.2
-0.4
-0.6
0.2
0.1
0
-0.1
-0.2
MAX5138 toc12
0.3
0.032
GAIN ERROR (%FS)
VAVDD = 5.25V
VREF = 5V
0
0.4
GAIN ERROR (%FS)
0.4
0.036
MAX5138 toc11
0.6
VAVDD = 5.25V
VREF = 5V
0.028
0.024
0.020
0.016
-0.3
VAVDD = 2.7V
VREF = 2.5V
-0.8
-0.5
-1.0
0
20
40
60
80
3.2
3.7
4.2
4.7
5.2
-40
0
20
40
60
100
TEMPERATURE (°C)
ANALOG SUPPLY CURRENT
vs. ANALOG SUPPLY VOLTAGE
ANALOG SUPPLY CURRENT
vs. TEMPERATURE
ANALOG SUPPLY CURRENT vs. SUPPLY
VOLTAGE (POWER-DOWN MODE)
0.92
0.90
VOUT = 0
0.88
0.86
0.84
0.8
0.7
IAVDD
0.6
0.5
0.4
0.3
0.2
IDVDD
0.8
0
3.2
3.7
4.2
4.7
5.2
0.7
0.6
TA = -40°C
0.5
0.4
TA = +105°C
0.3
TA = +25°C
0.2
0.1
0.1
0.80
MAX5138 toc15
0.9
ANALOG SUPPLY CURRENT (μA)
VOUT = VREFO
0.94
1.0
0.82
0
-40
-20
0
20
40
60
80
ANALOG SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
EXITING/ENTERING
POWER-DOWN MODE
MAJOR CODE TRANSITION
100
2.7
3.2
3.7
4.2
MAX5138 toc18
500mV/div
500mV/div
4μs/div
1μs/div
5.2
SETTLING TIME UP
20mV/div
VOUT
4.7
SUPPLY VOLTAGE (V)
MAX5138 toc17
MAX5138 toc16
6
80
SUPPLY VOLTAGE (V)
0.96
2.7
-20
TEMPERATURE (°C)
VDVDD = 2.7V
0.98
0.008
2.7
100
ANALOG SUPPLY CURRENT (mA)
1.00
-20
MAX5138 toc13
-40
VAVDD = 2.7V
VREF = 2.5V
0.012
-0.4
MAX5138 toc14
OFFSET ERROR (mV)
0.5
MAX5138 toc10
0.8
0.2
GAIN ERROR
vs. TEMPERATURE
GAIN ERROR
vs. ANALOG SUPPLY VOLTAGE
OFFSET ERROR
vs. TEMPERATURE
ANALOG SUPPLY CURRENT (mA)
MAX5138/MAX5139
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
400ns/div
_______________________________________________________________________________________
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
SETTLING TIME DOWN
DIGITAL FEEDTHROUGH
MAX5138 toc19
MAX5138 toc20
SCLK
5V/div
500mV/div
50mV/div
VOUT
400ns/div
40ns/div
REFERENCE VOLTAGE
vs. SUPPLY VOLTAGE
TA = +25°C
2.4380
2.4380
2.4375
0.30
0.25
0.20
VREFO (V)
2.4375
2.4370
2.4365
TA = +105°C
0.10
2.4355
0.05
2.4350
2.4355
TA = -40°C
2.4350
2.4345
3.2
3.7
4.2
4.7
2.7
5.2
3.2
3.7
4.2
4.7
5.2
2.4345
-40
-20
0
20
40
60
DIGITAL SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
DIGITAL SUPPLY CURRENT
vs. DIGITAL INPUT VOLTAGE
FULL-SCALE OUTPUT
vs. TEMPERATURE
OUTPUT VOLTAGE
vs. SUPPLY CURRENT
UP
2.50
OUTPUT VOLTAGE (V)
2000
1500
DOWN
1000
2.51
2.49
EXTERNAL REF = 2.5V
2.48
2.47
2.46
2.45
INTERNAL REF
500
80
100
2.45
VAVDD = 5V
2.44
OUTPUT VOLTAGE (V)
VAVDD = VDVDD = 5.25V
MAX5138 toc24
2500
MAX5138 toc25
2.7
2.4365
2.4360
2.4360
0.15
2.4370
MAX5138 toc26
0.35
0
DIGITAL SUPPLY CURRENT (μA)
2.4385
VREFO (V)
DIGITAL SUPPLY CURRENT (μA)
0.40
2.4385
MAX5138 toc22
VAVDD = 5.25V
fSCLK = 1MHz
0.45
2.4390
MAX5138 toc21
0.50
REFERENCE VOLTAGE
vs. TEMPERATURE
MAX5138 toc23
DIGITAL SUPPLY CURRENT
vs. DIGITAL SUPPLY VOLTAGE
VAVDD = 3.3V
2.43
2.42
2.41
2.44
2.40
2.43
0
0
1
2
3
4
DIGITAL INPUT VOLTAGE (V)
5
6
-40
-20
0
20
40
60
TEMPERATURE (°C)
80
100
0
10
20
30
OUTPUT CURRENT (mA)
_______________________________________________________________________________________
7
MAX5138/MAX5139
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
FULL-SCALE REFERENCE FEEDTHROUGH
ZERO-SCALE REFERENCE FEEDTHROUGH
MAX5138 toc27
MAX5138 toc28
VOUT
500mV/div
VREF
500mV/div
VREF
500mV/div
0 VOUT
VOUT
20mV/div
0 VREF
20μs/div
20μs/div
REFERENCE INPUT RESPONSE
vs. FREQUENCY
POWER-UP GLITCH, ZERO-SCALE,
INTERNAL REFERENCE
POWER-UP GLITCH, ZERO-SCALE,
EXTERNAL REFERENCE
MAX5138 toc31
MAX5138 toc30
MAX5138 toc29
0
-5
ATTENUATION (dB)
MAX5138/MAX5139
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
2V/div
2V/div
-10
VAVDD
VAVDD
-15
-20
-25
-30
VOUT
1V/div
VOUT
1V/div
-35
1
10
100
10,000
1000
4μs/div
4μs/div
POWER-UP GLITCH, MIDSCALE,
INTERNAL REFERENCE
DC NOISE SPECTRUM, FFT PLOT
BUFFERED OUTPUT
INPUT FREQUENCY (kHz)
POWER-UP GLITCH, MIDSCALE,
EXTERNAL REFERENCE
MAX5138 toc32
MAX5138 toc34
MAX5138 toc33
-40dBm
2V/div
2V/div
RESOLUTION BANDWIDTH = 1Hz
50Ω LOAD
VAVDD
VAVDD
10dB/div
1V/div
VOUT
1V/div
VOUT
25kHz/div
4μs/div
8
4μs/div
2.5kHz/div
_______________________________________________________________________________________
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
PIN
NAME
1, 4, 9
N.C.
No Connection. Not internally connected.
FUNCTION
2
M/Z
Power-Up Reset Select. Connect M/Z low to AGND to power up the DAC output. Connect M/Z
high to power up the DAC output to midscale.
3
LDAC
Load DAC. Active-low hardware load DAC input.
5
SCLK
Serial-Clock Input
6
CS
Active-Low Chip-Select Input
7
DIN
Data In
8
AGND
Analog Ground. Internally connected to AGND. Connect AGND to AGND externally.
10
READY
Data Output
11
DVDD
12
OUT
13
AVDD
14
REFI
Reference Voltage Input. Bypass REFI with a 0.1µF capacitor to AGND.
15
REFO
Reference Voltage Output
16
AGND
—
EP
Digital Power Supply. Bypass DVDD with a 0.1µF capacitor to AGND.
Buffered DAC Output
Analog Power Supply. Bypass AVDD with a 0.1µF capacitor to AGND.
DAC Ground. Internally connected to AGND. Connect AGND to AGND externally.
Exposed Pad. Not internally connected. Connect to a ground or leave unconnected. Not intended
as an electrical connection point.
Detailed Description
The MAX5138/MAX5139 are a family of single-channel,
pin-compatible and software-compatible, 16-bit and 12bit DACs. The parts are low-power, buffered voltageoutput, high-linearity DACs. The MAX5138/MAX5139
minimize the digital noise feedthrough from input to output by powering down the SCLK and DIN input buffers
after completion of each 24-bit serial input. On powerup, the MAX5138/MAX5139 reset the DAC output to zero
or midscale, depending on the state of the M/Z input,
providing additional safety for applications that drive
valves or other transducers that need to be off on powerup. The MAX5138/MAX5139 contain a segmented resistor string-type DAC, a serial-in parallel-out shift register,
a DAC register, power-on reset (POR) circuit, and control logic. On the falling edge of the clock (SCLK) pulse,
the serial input (DIN) data is shifted into the device, MSB
first. During power-down, an internal 80kΩ resistor pulls
DAC outputs to AGND.
Output Amplifier (OUT)
The MAX5138/MAX5139 include an internal buffer for the
DAC output. The internal buffer provides improved load
regulation and transition glitch suppression for the DAC
output. The output buffer slews at 1.25V/µs and drives up
to 2kΩ in parallel with 200pF. The analog supply voltage
(AVDD) determines the maximum output voltage range
of the device as AVDD powers the output buffer.
DAC Reference
Internal Reference
The MAX5138/MAX5139 feature an internal reference
with a nominal +2.44V output. Connect REFO to REFI
when using the internal reference. Bypass REFO to
AGND with a 47pF (maximum 100pF) capacitor.
Alternatively, if heavier decoupling is required, add a
1kΩ resistor in series with a 1µF capacitor in parallel
with the existing 100pF capacitor. REFO can deliver up
to 100µA of current with no degradation in performance. Configure other reference voltages by applying
a resistive potential divider with a total resistance
greater than 33kΩ from REFO to AGND.
_______________________________________________________________________________________
9
MAX5138/MAX5139
Pin Description
MAX5138/MAX5139
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
External Reference
The external reference input features a typical input
impedance of 113kΩ and accepts an input voltage
from +2V to AVDD. Connect an external voltage
supply between REFI and AGND to apply an external reference. Leave REFO unconnected. Visit
www.maxim-ic.com/products/references for a list of
available external voltage-reference devices.
high-to-low transition, the data is shifted synchronously
and latched into the input register on each falling edge
of the serial-clock input (SCLK). Each serial word is 24
bits. The first 8 bits are the control word followed by 16
data bits (MSB first), as shown in Table 1. The serial
input register transfers its contents to the input registers
after loading 24 bits of data. To initiate a new data
transfer, drive CS high and keep CS high for a minimum
of 33ns before the next write sequence. The SCLK can
be either high or low between CS write pulses. Figure 1
shows the timing diagram for the complete 3-wire serialinterface transmission.
The MAX5138/MAX5139 digital input is double buffered.
Depending on the command issued through the serial
interface, the input register can be loaded without affecting the DAC register using the write command. To update
the DAC register, either pulse the LDAC input low, or use
the software LDAC command. Use the writethrough commands (see Table 1) to update the DAC output immediately after the data is received. Only use the writethrough
command to update the DAC output immediately.
AVDD as Reference
Connect AVDD to REFI to use AVDD as the reference
voltage. Leave REFO unconnected.
Serial Interface
The MAX5138/MAX5139 3-wire serial interface is compatible with MICROWIRE, SPI, QSPI, and DSPs (Figures
2, 3). The interface provides three inputs, SCLK, CS,
and DIN and one output, READY. Use READY to verify
communication or to daisy-chain multiple devices (see
the READY section). READY is capable of driving a
20pF load with a 30ns (max) delay from the falling edge
of SCLK. The chip-select input (CS) frames the serial
data loading at DIN. Following a chip-select input’s
Table 1. Operating Mode Truth Table
24-BIT WORD
CONTROL BITS
DATA BITS
MSB
LSB
C7 C6 C5 C4 C3 C2 C1 C0 D15 D14 D13 D12 D11 D10 D9
D7
D6–D0
X
X
X
NOP
No operation.
X DAC
X
X
LDAC
Set DAC = 1 to move
contents of input to DAC
register.
X
X
X
CLR
0
0
0
0
0
0
0
X
X
X
X
X
X
X
0
0
0
0
0
0
0
1
X
X
X
X
X
X
0
0
0
0
0
0
1
0
X
X
X
X
X
X
0
0
0
0
0
0
1
1
X
X
X
X
X
X
0
0
0
0
0
1
0
1
0
0
0
0
0
0
0
0
0
1
X
X
X DAC D15 D14 D13 D12 D11 D10 D9
LIN
0
1
1
X
X
X DAC D15 D14 D13 D12 D11 D10 D9
0
0
1
0
0
0
0
X
X
X
X
X
X
X DAC READY_EN
0
X
FUNCTION
D8
0
0
DESC
X
Software clear.
X
Set DAC = 1 to power
Power down DAC. Set
Control READY_EN = 1 to
enable READY.
Linearity Optimize DAC linearity.
0
0
0
D8
D7
D6
D8
D7
D6
X
X
X
Write
Write to selected input
registers (DAC output
not affected).
Write to selected input
Write- and DAC register,
through DAC output updated
(writethrough).
NOP
No operation.
*For the MAX5139, D3–D0 are X = don’t-care bits.
10
______________________________________________________________________________________
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
D15–D0 are the data bits that are written to the
internal register.
3) After clocking in the last data bit, drive CS high. CS
must remain high for 33ns before the next transmission is started.
Figure 1 shows a write operation for the transmission of
24 bits. If CS is driven high at any point prior to receiving
24 bits, the transmission is discarded.
Connect the MAX5138/MAX5139 DVDD supply to the
supply of the host DSP or microprocessor. The AVDD
supply may be set to any voltage within the 2.7V to
5.25V operating range, but must be greater than or
equal to the DVDD supply.
READY
Connect READY to a microcontroller (µC) input to monitor the serial interface for valid communications. The
READY pulse appears 24 clock cycles after the negative edge of CS (Figure 4). Since the MAX5138/
MAX5139 look at the first 24 bits of the transmission following the falling edge of CS, it is possible to daisy
chain devices with different command word lengths.
READY goes high 16ns after CS is driven high.
Writing to the MAX5138/MAX5139
Write to the MAX5138/MAX5139 using the following
sequence:
1) Drive CS low, enabling the shift register.
2) Clock 24 bits of data into DIN (C7 first and D0 last),
observing the specified setup and hold times. Bits
+5V
SK
SCLK
MISO*
READY*
MAX5138
MAX5139
SS
SO
DIN
MICROWIRE
PORT
MAX5138
MAX5139
SI*
READY*
MOSI
DIN
SPI/QSPI
PORT
SCK
SCLK
I/O
CS
I/O
CS
*THE READY-TO-SI CONNECTION IS NOT REQUIRED FOR WRITING TO THE
*MAX5138/MAX5139 BUT MAY BE USED FOR TRANSMISSION VERIFICATION.
*THE READY-TO-MISO CONNECTION IS NOT REQUIRED FOR WRITING TO THE
MAX5138/MAX5139 BUT MAY BE USED FOR TRANSMISSION VERIFICATION.
Figure 3. Connections for SPI/QSPI
Figure 2. Connections for MICROWIRE
CS
DIN
SLAVE 1 DATA
SLAVE 2 DATA
SLAVE 3 DATA
SCLK
1
2
3
4
20
21
22
23
24
1
2
3
4
5
21
22
23
24
1
2
3
4
5
21
22
23
24
READY 1
READY 2
READY 3
Figure 4. READY Timing
______________________________________________________________________________________
11
MAX5138/MAX5139
The MAX5138’s DAC code is unipolar binary with VOUT
= (code/65536) x VREF. See Table 1 for the serial interface commands.
The MAX5139’s DAC code is unipolar with V OUT =
(code/4096) x VREF. See Table 1 for the serial interface
commands.
MAX5138/MAX5139
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
Daisy chain multiple MAX5138/MAX5139 devices by
connecting the first device conventionally, then connect
its READY output to the CS of the following device.
Repeat for any other devices in the chain, and drive the
SCLK and DIN lines in parallel (Figure 5). When sending
commands to daisy-chained MAX5138/MAX5139s, the
devices are accessed serially starting with the first
device in the chain. The first 24 data bits are read by the
first device, the second 24 data bits are read by the second device and so on (Figure 4). Figure 6 shows the
configuration when CS is not driven by the µC. These
devices can be daisy chained with other compatible
devices, such as the MAX5510 and the MAX5511.
To perform a daisy-chain write operation, drive CS low
and output the data serially to DIN. The propagation of
the READY signal then controls how the data is read by
each device. As the data propagates through the daisy
chain, each individual command in the chain is executed on the 24th falling clock edge following the falling
edge of the respective CS input. To update just one
device in a daisy chain, send the no-op command to
the other devices in the chain.
If READY is not required, write command 0x03 (power
control) and set READY_EN = 0 (see Table 1) to disable the READY output.
Clear Command
The MAX5138/MAX5139 feature a software clear command (0x02). The software clear command acts as a
software POR, erasing the contents of all registers. The
output returns to the state determined by the M/Z input.
Power-Down Mode
The MAX5138/MAX5139 feature a software-controlled
power-down mode. The internal reference and biasing
circuits power down to conserve power when powered
down. In power-down, the output disconnects from the
buffer and is grounded with an internal 80kΩ resistor.
The DAC register holds the retained code so that the
output is restored when powered up. The serial interface remains active in power-down mode.
Load DAC (LDAC) Input
The MAX5138/MAX5139 feature an active-low LDAC
logic input that updates the output. Keep LDAC high
during normal operation (when the device is controlled
only through the serial interface). Drive LDAC low to
update the DAC output with data from the input register.
Figure 7 shows the LDAC timing with respect to OUT.
Holding LDAC low causes the input register to become
transparent and data written to the DAC register to
immediately update the DAC output. A software command can also activate the LDAC operation. To activate
LDAC by software, set control word 0x01 to load the
DAC, and all other data bits to don’t care. See Table 1
for the data format. This operation updates the DAC output if it is flagged with a 1. If the DAC output is flagged
with a 0 it remains unchanged.
μC
MOSI
SCK
SLAVE 1
DIN
DIN
SCLK
I/O
CS
SLAVE 2
DIN
SCLK
READY
CS
SLAVE 3
SCLK
READY
CS
Figure 5. Daisy-Chain Configuration
12
______________________________________________________________________________________
READY
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
MAX5138/MAX5139
TO OTHER CHIPS/CHAINS
CSm
μC
SLAVE 1
CS1
CS
SCLK
DWRITE
DREAD
INT
CS
SCLK MAX5138
DIN
MAX5139
READY
SLAVE 2
CS
SCLK MAX5138
MAX5139
DIN
READY
SLAVE N
CS
SCLK MAX5138
DIN
MAX5139
DOUT
ERROR
READY
Figure 6. Daisy Chain (CS Not Used)
tLDACPWL
LDAC
tS
±2 LSB
OUT
Figure 7. Output Timing
______________________________________________________________________________________
13
MAX5138/MAX5139
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
Applications Information
Power-On Reset (POR)
On power-up, the input register is set to zero, and the
DAC output powers up to zero or midscale, depending
on the configuration of M/Z. Connect M/Z to AGND to
power the output to AGND. Connect M/Z to AVDD to
power the output to midscale.
To guarantee DAC linearity, wait until the supplies have
settled. Set the LIN bit in the DAC linearity register; wait
10ms, and clear the LIN bit.
Unipolar Output
The MAX5138/MAX5139 unipolar output voltage range is
0 to VREFI. The output buffer drives a 2kΩ load in parallel
with 200pF.
Bipolar Output
Use the MAX5138/MAX5139 in bipolar applications with
additional external components (see the Typical
Operating Circuit).
Power Supplies and
Bypassing Considerations
For best performance, use a separate supply for the
MAX5138/MAX5139. Bypass both DVDD and AVDD
with high-quality ceramic capacitors to a low-impedance ground as close as possible to the device.
Minimize lead lengths to reduce lead inductance.
Connect both MAX5138/MAX5139 AGND inputs to the
analog ground plane.
Table 2. MAX5138 Input Code vs. Output
Voltage
DAC LATCH CONTENTS
MSB
14
ANALOG OUTPUT, VOUT
LSB
1111 1111 1111 1111
VREF x (65,535/65,536)
1000 0000 0000 0000
VREF x (32,768/65,536) = 1/2 VREF
0000 0000 0000 0001
VREF x (1/65,536)
0000 0000 0000 0000
0
Layout Considerations
Digital and AC transient signals on AGND inputs can
create noise at the outputs. Connect both AGND inputs
to form the star ground for the DAC system. Refer
remote DAC loads to this system ground for the best
possible performance. Use proper grounding techniques, such as a multilayer board with a low-inductance ground plane, or star connect all ground return
paths back to the MAX5138/MAX5139 AGND. Do not
use wire-wrapped boards and sockets. Use shielding
to improve noise immunity. Do not run analog and digital signals parallel to one another (especially clock signals) and avoid routing digital lines underneath the
MAX5138/MAX5139 package.
Definitions
Integral Nonlinearity (INL)
INL is the deviation of the measured transfer function
from a best fit straight line drawn between two codes.
This best fit line for the MAX5138 is a line drawn
between codes 3072 and 64,512 of the transfer function and the best fit line for the MAX5139 is a line drawn
between codes 192 and 4032 of the transfer function,
once offset and gain errors have been nullified.
Differential Nonlinearity (DNL)
DNL is the difference between an actual step height
and the ideal value of 1 LSB. If the magnitude of the
DNL is greater than -1 LSB, the DAC guarantees no
missing codes and is monotonic.
Table 3. MAX5139 Input Code vs. Output
Voltage
DAC LATCH CONTENTS
MSB
ANALOG OUTPUT, VOUT
LSB
1111 1111 1111 XXX
1000 0000 0000 XXX
VREF x (4095/4096)
0000 0000 0001 XXX
0000 0000 0000 XXX
VREF x (1/4096)
VREF x (2048/4096)
0
______________________________________________________________________________________
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
Digital-to-Analog Glitch Impulse
A major carry transition occurs at the midscale point
where the MSB changes from low to high and all other
bits change from high to low, or where the MSB
changes from high to low and all other bits change from
low to high. The duration of the magnitude of the
switching glitch during a major carry transition is
referred to as the digital-to-analog glitch impulse.
Gain Error
Gain error is the difference between the ideal and the
actual full-scale output voltage on the transfer curve,
after nullifying the offset error. This error alters the slope
of the transfer function and corresponds to the same
percentage error in each step.
Settling Time
The settling time is the amount of time required from the
start of a transition, until the DAC output settles to the new
output value within the converter’s specified accuracy.
Digital-to-Analog Power-Up Glitch Impulse
The digital-to-analog power-up glitch is the duration of
the magnitude of the switching glitch that occurs as the
device exits power-down mode.
Chip Information
PROCESS: BiCMOS
Digital Feedthrough
Digital feedthrough is the amount of noise that appears
on the DAC output when the DAC digital control lines
are toggled.
Functional Diagram
AVDD
MAX5138
MAX5139
M/Z
DVDD
AGND
REFI
REFO
INTERNAL
BIAS CKT
REFERENCE
POR
CONTROL LOGIC
POWER-DOWN
CONTROL
CS
SCLK
SERIAL-TOPARALLEL
CONVERTER
INPUT
REGISTER
DAC
REGISTER
12-/16-BIT
DAC
DIN
READY
LDAC
OUT
BUFFER
AGND
______________________________________________________________________________________
15
MAX5138/MAX5139
Offset Error
Offset error indicates how well the actual transfer function matches the ideal transfer function at a single point.
Typically, the point at which the offset error is specified is
at or near the zero-scale point of the transfer function.
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
MAX5138/MAX5139
Typical Operating Circuit
DIGITAL POWER
SUPPLY
ANALOG POWER
SUPPLY
100nF
100nF
100nF
DVDD
AVDD
M/Z
LDAC
CS
OUT
DAC
SCLK
DIN
READY
MAX5138
MAX5139
REFO
R1
REFI
47pF
AGND
*SHOWN IN BIPOLAR CONFIGURATION
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
16 TQFN-EP
T1633-5
21-0136
16
______________________________________________________________________________________
R2
Low-Power, Single, 16-/12-Bit,
Buffered Voltage-Output DACs
PAGES
CHANGED
REVISION
NUMBER
REVISION
DATE
0
3/09
Initial release
—
1
4/09
Removed future product reference for MAX5139
1
DESCRIPTION
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 17
© 2009 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX5138/MAX5139
Revision History