19-4541; Rev 1; 7/09
Quad-Channel, I
2
C-Margining IDACs with
Three Channels of Power-Supply Tracking
General Description
The DS4426 contains four I
2
C-adjustable current DACs
capable of sinking or sourcing current. External resis-
tors set the full-scale range of each output. Each DAC
output has 127 sink and 127 source steps that are pro-
grammed by the I
2
C interface. Power-supply tracking
functionality is provided for three channels using dedi-
cated control inputs. Once power-supply tracking is
accomplished, the current outputs default to zero. Two
address pins allow up to four DS4426 devices to exist
on the same I
2
C bus.
Features
♦
Four Current DACs
50µA to 200µA Adjustable Full-Scale Range
127 Settings Each for Sink and Source
♦
Power-Supply Tracking
Power-Supply Sequencing
Ramp-Up and Ramp-Down Tracking Control
Ratiometric Tracking Support
♦
+2.7V to +5.5V Operation
♦
I
2
C-Compatible Serial Interface
♦
Two Address Input Pins Allow Up to Four Devices
on Same I
2
C Bus
♦
Lead-Free, 28-Pin TQFN Package (4mm x 4mm)
with Exposed Pad
♦
Industrial Temperature Range: -40°C to +85°C
DS4426
Applications
Power-Supply Adjustment
Power-Supply Margining
Power-Supply Tracking
Adjustable Current Sink or Source
Pin Configuration
PART
THR1
THR2
THR3
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 TQFN-EP*
28 TQFN-EP*
DS4426T+
DS4426T+T&R
TOP VIEW
21
FS1 22
FS2 23
FS3 24
GAIN3 25
GAIN2 26
GAIN1 27
N.C. 28
1
SDA
FS0
INN3
16
20
19
18
17
15
14
13
12
INN2
INP2
INN1
INP1
A1
A0
GND
INP3
DNC
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
*EP
= Exposed pad.
DS4426
11
10
+
2
SCL
3
V
CC
4
OUT0
5
OUT1
*EP
9
8
Functional Diagram appears at end of data sheet.
6
OUT2
7
OUT3
THIN QFN
(4mm
×
4mm)
*EXPOSED PAD.
________________________________________________________________
Maxim Integrated Products
1
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.
Quad-Channel, I
2
C-Margining IDACs with
Three Channels of Power-Supply Tracking
DS4426
ABSOLUTE MAXIMUM RATINGS
Voltage Range on SDA, SCL Relative to GND ......-0.5V to +6.0V
Voltage Range on V
CC
Relative to GND ...............-0.5V to +6.0V
Voltage Range on A0, A1, FS[3:0], GAIN[3:1],
INN[3:1], INP[3:1], THR[3:1], and OUT[3:0]
Relative to GND ......................................-0.5V to (V
CC
+ 0.5V)*
*Not
to exceed +6.0V.
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.
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-55°C to +125°C
Soldering Temperature...........................Refer to the IPC/JEDEC
J-STD-020 Specification.
RECOMMENDED OPERATING CONDITIONS
(T
A
= -40°C to +85°C.)
PARAMETER
Supply Voltage
Input Logic 1
(SDA, SCL, A0, A1)
Input Logic 0
(SDA, SCL, A0, A1)
Full-Scale Resistor Values
SYMBOL
V
CC
V
IH
V
IL
R
FS[3:0]
(Note 2)
(Note 1)
CONDITIONS
MIN
2.7
0.7 x
V
CC
-0.3
40
TYP
MAX
5.5
V
CC
+
0.3
0.3 x
V
CC
160
UNITS
V
V
V
k
DC ELECTRICAL CHARACTERISTICS
(V
CC
= +2.7V to +5.5V, T
A
= -40°C to +85°C.)
PARAMETER
Supply Current
Input Leakage Current
(SDA, SCL)
RFS Voltage
Reference Voltage
Temperature Coefficient
Output Leakage Current (SDA)
Output-Current Low (SDA)
I/O Capacitance
I
L
I
OL
C
I/O
V
OL
= +0.4V
V
OL
= +0.6V
-1
3
6
10
SYMBOL
I
CC
I
IL
V
RFS
V
REF
CONDITIONS
V
CC
= +5.5V (Note 3)
V
CC
= +5.5V
T
A
= +25°C
-1
0.940
0.990
1.24
±100
+1
MIN
TYP
MAX
0.9
+1
1.040
UNITS
mA
μA
V
V
ppm/°C
μA
mA
pF
DAC OUTPUT CURRENT CHARACTERISTICS
(V
CC
= +2.7V to +5.5V, T
A
= -40°C to +85°C.)
PARAMETER
Output Current Variation Due to
Power-Supply Change
Output Current Variation Due to
Output-Voltage Change
SYMBOL
CONDITIONS
DC source, V
OUT
measured at +1.2V
DC sink, V
OUT
measured at +1.2V
DC source, V
CC
= +3.6V
DC sink, V
CC
= +3.6V
MIN
TYP
0.33
0.33
0.15
0.30
MAX
UNITS
%/V
%/V
2
_______________________________________________________________________________________
Quad-Channel, I
2
C-Margining IDACs with
Three Channels of Power-Supply Tracking
DAC OUTPUT CURRENT CHARACTERISTICS (continued)
(V
CC
= +2.7V to +5.5V, T
A
= -40°C to +85°C.)
PARAMETER
Output Voltage for Sinking
Current
Output Voltage for Sourcing
Current
Full-Scale Sink Output Current
Full-Scale Source Output Current
Output-Current Full-Scale
Accuracy
Output-Current Temperature
Coefficient
Output-Current Power-Supply
Rejection Ratio
Output-Leakage Current at Zero
Current Setting
Output-Current Differential
Linearity
Output-Current Integral Linearity
I
ZERO
DNL
INL
(Note 6)
(Note 7)
-1
SYMBOL
V
OUT:SINK
(Note 4)
CONDITIONS
MIN
0.5
0
50
-200
TYP
MAX
3.5
V
CC
-
0.75
200
-50
±5
±130
0.33
+1
0.5
1
UNITS
V
V
μA
μA
%
ppm/°C
%/V
μA
LSB
LSB
DS4426
V
OUT:SOURCE
(Note 4)
I
OUT:SINK
(Note 4)
I
OUT:SOURCE
(Note 4)
I
OUT:FS
I
OUT:TC
T
A
= +25°C
(Note 5)
I
2
C ELECTRICAL CHARACTERISTICS
(V
CC
= +2.7V to +5.5V, T
A
= -40°C to +85°C. Timing referenced to V
IL(MAX)
and V
IH(MIN)
. See Figure 6.)
PARAMETER
SCL Clock Frequency
Bus Free Time Between STOP
and START Conditions
Hold Time (Repeated) START
Condition
Low Period of SCL
High Period of SCL
Data Hold Time
Data Setup Time
START Setup Time
SDA and SCL Rise Time
SDA and SCL Fall Time
STOP Setup Time
SDA and SCL Capacitive
Loading
SYMBOL
f
SCL
t
BUF
t
HD:STA
t
LOW
t
HIGH
t
HD:DAT
t
SU:DAT
t
SU:STA
t
R
t
F
t
SU:STO
C
B
(Note 9)
(Note 9)
(Note 9)
(Note 8)
CONDITIONS
MIN
0
1.3
0.6
1.3
0.6
0
100
0.6
20 +
0.1C
B
20 +
0.1C
B
0.6
400
300
300
0.9
TYP
MAX
400
UNITS
kHz
μs
μs
μs
μs
μs
ns
μs
ns
ns
μs
pF
_______________________________________________________________________________________
3
Quad-Channel, I
2
C-Margining IDACs with
Three Channels of Power-Supply Tracking
DS4426
POWER-SUPPLY TRACKING CHARACTERISTICS
(V
CC
= +2.7V to +5.5V, T
A
= -40°C to +85°C, see Figure 5.)
PARAMETER
Input Divider Ratio
Output Load
Feedback Resistor Ratio
Gain Resistor
Gain Setting Ratio
SYMBOL
R
DIV
R
L
R
F
/R
B
R
G
R
L
/R
G
R
L
/R
G
= 2, R
L
= 5k
,
V
CC
= +3.6V,
T
A
= +25°C
R
L
/R
G
= 5, R
L
= 5k
,
V
CC
= +3.6V,
T
A
= +25°C
3.8
CONDITIONS
R
A
/R
B
and R
C
/R
D
R
L
= (R
F
x R
E
)/(R
F
+R
E
)
MIN
0.5
1
0.5
0.8
1.4
2.4
mA/V
6.2
10
1
INP[3:1] and INN[3:1]
R
L
/R
G
= 1.4; R
L
= 5k
Switch closed, V
CC
= +3.0V, measured at
OUT[3:1], R
L
= 5k
R
L
/R
G
= 1.4, R
G
= 1k , V
CC
= +3.0V,
V
FB
= +0.8V
Switch open
±5
5
12.5
0
0
12
1.5
1
±600
I
BC
I
OFF
V
OS
t
DC
V
HYS
0.5
1
V
CC
-
1.4
μA
V
MHz
V
mA
mV
μA
μA
mV
μs
mV
TYP
MAX
1
20
4.5
10
5
k
k
UNITS
Power-Supply Tracking Gain
G
VI
Power-Supply Tracking Input
Bias Current
Power-Supply Tracking Input
Voltage
Unity Gain Bandwidth
Output Voltage While Tracking
Output Current While Tracking
Tracking Accuracy
Output Leakage
Comparator Input Bias Current
Comparator Input Offset
Switch Delay
Comparator Hysteresis
I
B
V
IN
GBW
V
OUT:TRK
I
OUT:TRK
Note 1:
All voltages are referenced to GND. Current entering the IC is specified positive, and current exiting the IC is negative.
Note 2:
Input resistors (R
FS[3:0]
) must be between the specified values to ensure the device meets its accuracy and linearity specifi-
cations.
Note 3:
Supply current specified with all outputs set to zero current setting and with all inputs at V
CC
or GND. SDA and SCL are
connected to V
CC
. Excludes current through R
FS
resistors (I
RFS
). Total current including I
RFS
is I
CC
+ (2 x I
RFS
).
Note 4:
The output-voltage full-scale ranges must be satisfied to ensure the device meets its accuracy and linearity specifications.
Only applies to current DAC operation, not power-supply tracking operation.
Note 5:
Temperature drift excludes drift caused by external resistors.
Note 6:
Differential linearity is defined as the difference between the expected incremental current increase with respect to position
and the actual increase. The expected incremental increase is the full-scale range divided by 127.
Note 7:
Integral linearity is defined as the difference between the expected value as a function of the setting and the actual value.
The expected value is a straight line between the zero and the full-scale values proportional to the setting.
Note 8:
Timing shown is for fast-mode operation (400kHz). This device is also backward-compatible with I
2
C standard-mode timing.
Note 9:
C
B
—Total capacitance of one bus line in pF.
4
_______________________________________________________________________________________
Quad-Channel, I
2
C-Margining IDACs with
Three Channels of Power-Supply Tracking
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
DS4426
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
DS4426 toc01
SUPPLY CURRENT
vs. TEMPERATURE
DS4426 toc02
VOLTCO (SOURCE)
40kΩ LOAD ON FS[3:0].
V
CC
= +5.5V
-175
I
OUT
(μA)
DS4426 toc03
600
575
SUPPLY CURRENT (μA)
550
525
500
475
450
425
400
SDA = SCL = THR[3:1] = V
CC
GAIN[3:1] = FS[3:0] = OUT[3:0] = OPEN
INP[3:1] = INN[3:1] = GND
600
575
SUPPLY CURRENT (μA)
550
525
500
475
V
CC
= +2.7V
450
425
400
SDA = SCL = THR[3:1] = V
CC
GAIN[3:1] = FS[3:0] = OUT[3:0] = OPEN
INP[3:1] = INN[3:1] = GND
-40
-20
0
20
40
60
80
V
CC
= +5.5V
V
CC
= +3.3V
-150
-200
-225
SDA = SCL = THR[3:1] = V
CC
GAIN[3:1] = OPEN
INP[3:1] = INN[3:1] = GND
-250
0
1
2
V
OUT
(V)
3
4
5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
VOLTCO (SINK)
DS4426 toc04
TEMPERATURE COEFFICIENT
vs. SETTING (SOURCE)
DS4426 toc05
TEMPERATURE COEFFICIENT
vs. SETTING (SINK)
TEMPERATURE COEFFICIENT (°C/ppm)
550
450
350
250
150
50
-50
-150
-250
0
25
50
75
100
125
+25°C TO +85°C
+25°C TO -40°C
RANGE FOR THE 50μA TO 200μA
CURRENT SINK RANGE
DS4426 toc06
250
40kΩ LOAD ON FS[3:0].
V
CC
= +5.5V
225
I
OUT
(μA)
300
TEMPERATURE COEFFICIENT (°C/ppm)
250
200
150
+25°C TO -40°C
100
50
0
-50
+25°C TO +85°C
0
25
50
75
100
125
RANGE FOR THE 50μA TO 200μA
CURRENT SOURCE RANGE
650
200
175
SDA = SCL = THR[3:1] = V
CC
GAIN[3:1] = OPEN
INP[3:1] = INN[3:1] = GND
150
0
0.5
1.0
1.5
2.0
V
OUT
(V)
2.5
3.0
3.5
4.0
SETTING (DEC)
SETTING (DEC)
INTEGRAL LINEARITY
DS4426 toc07
DIFFERENTIAL LINEARITY
0.8
0.6
0.4
DNL (LSB)
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
RANGE FOR THE 50μA TO 200μA
CURRENT SOURCE AND SINK RANGE
DS4426 toc08
1.0
0.8
0.6
0.4
INL (LSB)
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
0
25
50
75
100
RANGE FOR THE 50μA TO 200μA
CURRENT SOURCE AND SINK RANGE
1.0
125
0
25
50
75
100
125
SETTING (DEC)
SETTING (DEC)
_______________________________________________________________________________________
5
京公网安备 11010802033920号
EEWORLD
