19-2465; Rev 0; 4/02
14-Bit ADCs, 150ksps, 3.3V Single Supply
General Description
The MAX1144/MAX1145 are 150ksps, 14-bit ADCs.
These serially interfaced ADCs connect directly to
SPI™, QSPI™, and MICROWIRE™ devices without
external logic. They combine an input scaling network,
internal track/hold, clock, and three general-purpose
digital output pins (for external multiplexer or PGA con-
trol) in a 20-pin SSOP package. The excellent dynamic
performance (THD
≥
90dB), high speed (150ksps in
bipolar mode), and low power (8.0mA) of these ADCs
make them ideal for applications such as industrial
process control, instrumentation, and medical applica-
tions.
The MAX1144 accepts input signals of 0 to +6V (unipo-
lar) or ±6V (bipolar), while the MAX1145 accepts input
signals of 0 to +2.048V (unipolar) or ±2.048V (bipolar).
Operating from a single 3.135V to 3.465V analog digital
supply, powerdown modes reduce current consump-
tion to 0.15mA at 10ksps and further reduce supply
current to less than 20µA slower data rates.
A serial strobe output (SSTRB) allows direct connection
to the TMS320 family digital-signal processors. The
MAX1144/MAX1145 user can select either the internal
clock or an external serial-interface clock for the ADC to
perform analog-to-digital conversions.
The MAX1144/MAX1145 feature internal calibration cir-
cuitry to correct linearity and offset errors. On-demand
calibration allows the user to optimize performance.
Three user-programmable logic outputs are provided
for the control of an 8-channel mux or PGA.
The MAX1144/MAX1145 are available in a 20-pin SSOP
package and are fully specified over the -40°C to
+85°C temperature range.
Features
o
150ksps (Bipolar) and 125ksps (Unipolar)
Sampling ADC
o
14 Bits, No Missing Codes
o
1LSB INL Guaranteed
o
-100dB THD
o
3.3V Single-Supply Operation
o
Low-Power Operation
5mA typ (Unipolar Mode)
o
1.2µA Shutdown Mode
o
Software-Configurable Unipolar and Bipolar Input
Ranges
0 to +6V and ±6V (MAX1144)
0 to +2.048V and ±2.048V (MAX1145)
o
Internal or External Clock
o
SPI/QSPI/MICROWIRE TMS320-Compatible Serial
Interface
o
Three User-Programmable Logic Outputs
o
Small 20-Pin SSOP Package
MAX1144/MAX1145
Ordering Information
PART
MAX1144ACAP
MAX1144BCAP
MAX1144AEAP
MAX1144BEAP
TEMP
RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
20 SSOP
20 SSOP
20 SSOP
20 SSOP
INL
(LSB)
±1
±2
±1
±2
Ordering Information continued at end of data sheet.
Applications
Industrial Process Control
Industrial I/O Modules
Data-Acquisition Systems
Medical Instruments
Portable and Battery-Powered Equipment
Functional Diagram and Typical Application Circuit appear
at end of data sheet.
TOP VIEW
REF 1
AV
DD
2
AGND 3
AV
DD
4
DGND 5
SHDN 6
P2 7
P1 8
PO 9
Pin Configuration
20 AIN
19 AGND
18 CREF
17 CS
MAX1144
MAX1145
16 DIN
15 DV
DD
14 DGND
13 SCLK
12 RST
11 DOUT
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor, Corp.
SSTRB 10
SSOP
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
14-Bit ADCs, 150ksps, 3.3V Single Supply
MAX1144/MAX1145
ABSOLUTE MAXIMUM RATINGS
AV
DD
to AGND, DV
DD
to DGND ..............................-0.3V to +6V
AGND to DGND.....................................................-0.3V to +0.3V
AIN to AGND ....................................................................±16.5V
CREF, REF to AGND ................................-0.3V to (AV
DD
+ 0.3V)
Digital Inputs to DGND.............................................-0.3V to +6V
Digital Outputs to DGND .........................-0.3V to (DV
DD
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
20-Pin SSOP (derate 8.00mW/°C above +70°C) .........640mW
Operating Temperature Ranges
MAX114_ _CAP...................................................0°C to +70°C
MAX114_ _EAP ................................................-40°C to +85°C
Storage Temperature Range .............................-60°C to +150°C
Junction Temperature ......................................................+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
(AV
DD
= DV
DD
= 3.3V ±5%, f
SCLK
= 3.6MHz, external clock (50% duty cycle), 24 clocks/conversion (150ksps), bipolar input, V
REF
=
2.048V, C
REF
= 4.7µF, C
CREF
= 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC ACCURACY (Note 1)
Resolution
Relative Accuracy
No Missing Codes
Differential Nonlinearity
Transition Noise
Offset Error
Gain Error (Note 3)
Offset Drift (Bipolar and Unipolar)
Gain Drift (Bipolar and Unipolar)
Unipolar
Bipolar
Unipolar
Bipolar
Excluding reference drift
Excluding reference drift
±1
±4
DNL
Bipolar mode
MAX114_A
MAX114_B
INL
Bipolar mode (Note 2)
MAX114_A
MAX114_B
14
-1
-1.00
0.47
±4
±6
±0.2
±0.3
+1
+1.75
14
±1
±2
Bits
LSB
Bits
LSB
LSB
RMS
mV
%FSR
ppm/°C
ppm/°C
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DYNAMIC SPECIFICATIONS (5kHz SINE-WAVE INPUT, 150ksps, 3.6MHZ CLOCK, BIPOLAR INPUT MODE. MAX1144, 12V
P-P
. MAX1145,
4.096V
P-P
.)
Signal-to-Noise Plus Distortion
(SINAD)
Signal-to-Noise Ratio
(SNR)
Total Harmonic Distortion
(THD)
Spurious-Free-Dynamic Range
(SFDR)
ANALOG INPUT
MAX1144
Input Range
MAX1145
Unipolar
Bipolar
Unipolar
Bipolar
0
-6
0
-2.048
+6
+6
+2.048
+2.048
V
f
IN
= 5kHz
f
IN
= 75kHz
f
IN
= 5kHz
f
IN
= 75kHz
f
IN
= 5kHz
f
IN
= 75kHz
f
IN
= 5kHz
f
IN
= 75kHz
92
78
78
82
81
82
81
-100
-94
105
98
-90
dB
dB
dB
dB
2
_______________________________________________________________________________________
14-Bit ADCs, 150ksps, 3.3V Single Supply
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= 3.3V ±5%, f
SCLK
= 3.6MHz, external clock (50% duty cycle), 24 clocks/conversion (150ksps), bipolar input, V
REF
=
2.048V, C
REF
= 4.7µF, C
CREF
= 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
MAX1144
Input Impedance
MAX1145
Input Capacitance
CONVERSION RATE
Internal Clock Frequency
Aperture Delay
Aperture Jitter
t
AD
t
AJ
Unipolar
Bipolar
Unipolar
Bipolar
0.1
0.1
4.17
4.17
8
6.7
3
10
50
3.0
3.6
125
150
240
µs
240
MHz
ns
ps
CONDITIONS
Unipolar
Bipolar
Unipolar
Bipolar
MIN
7.5
5.9
100
3.4
TYP
10.5
8.4
1000
5.3
32
pF
kΩ
MAX
UNITS
MAX1144/MAX1145
MODE 1 (24 EXTERNAL CLOCK CYCLES PER CONVERSION)
External Clock Frequency
Sample Rate
f
SCLK
f
S
=
f
SCLK
/ 24
MHz
ksps
Conversion Time (Note 4)
MODE 2 (INTERNAL CLOCK)
External Clock Frequency
(Data Transfer Only)
Conversion Time
Acquisition Time (Note 5)
t
CONV+ACQ
Unipolar
= 24 / f
SCLK
Bipolar
4
(SSTRB low pulse width)
Unipolar
Bipolar
f
SCLK
f
S
=
f
SCLK
/ 32
Unipolar or bipolar
Unipolar or bipolar
1.67
1.39
0.1
3.125
3.6
112
5.3
7
MHz
µs
µs
MODE 3 (32 EXTERNAL CLOCK CYCLES PER CONVERSION)
External Clock Frequency
Sample Rate
MHz
ksps
Conversion Time (Note 4)
EXTERNAL REFERENCE
Input Range
Input Current
DIGITAL INPUTS
Input High Voltage
Input Low Voltage
Input Leakage
t
CONV+ACQ
Unipolar or bipolar
= 32 / f
SCLK
8.89
320
µs
(Notes 6, 7)
V
REF
= 2.048V, f
SCLK
= 3.6MHz
V
REF
= 2.048V, f
SCLK
= 0
In power-down, f
SCLK
= 0
V
IH
V
IL
I
IN
V
IN
= 0 or DV
DD
1.9
2.048
110
100
0.1
2.2
V
µA
2.4
0.8
-1
+1
V
V
µA
_______________________________________________________________________________________
3
14-Bit ADCs, 150ksps, 3.3V Single Supply
MAX1144/MAX1145
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= 3.3V ±5%, f
SCLK
= 3.6MHz, external clock (50% duty cycle), 24 clocks/conversion (150ksps), bipolar input, V
REF
=
2.048V, C
REF
= 4.7µF, C
CREF
= 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Input Hysteresis
Input Capacitance
DIGITAL OUTPUTS
Output High Voltage
Output Low Voltage
Three-State Leakage Current
Three-State Output Capacitance
POWER SUPPLIES
Analog Supply
Digital Supply
Analog Supply Current
AV
DD
DV
DD
Unipolar mode
I
ANALOG
Bipolar mode
SHDN
= 0, or software power-down mode
Digital Supply Current
Power-Supply Rejection Ratio
(Note 8)
I
DIGITAL
PSRR
Unipolar or bipolar mode
SHDN
= 0, or software power-down mode
AV
DD
= DV
DD
= 3.135V to 3.465V
3.135
3.135
3.3
3.3
3.9
7
0.1
1
1.1
65
3.465
3.465
8
11
10
2
10
V
V
mA
µA
mA
µA
dB
V
OH
V
OL
I
L
I
SOURCE
= 0.5mA
I
SINK
= 5mA
I
SINK
= 16mA
CS
= DV
DD
CS
= DV
DD
-10
10
DV
DD
-
0.5
0.4
0.8
+10
V
V
µA
pF
SYMBOL
V
HYST
C
IN
CONDITIONS
MIN
TYP
0.2
10
MAX
UNITS
V
pF
TIMING CHARACTERISTICS (Figures 5 and 6)
(AV
DD
= DV
DD
= 3.3V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
DIN to SCLK Setup
DIN to SCLK Hold
SCLK to DOUT Valid
CS
Fall to DOUT Enable
CS
Rise to DOUT Disable
CS
to SCLK Rise Setup
CS
to SCLK Rise Hold
SCLK High Pulse Width
SCLK Low Pulse Width
SCLK Fall to SSTRB
CS
Fall to SSTRB Enable
CS
Rise to SSTRB Disable
SSTRB Rise to SCLK Rise
RST
Pulse Width
SYMBOL
t
DS
t
DH
t
DO
t
DV
t
TR
t
CSS
t
CSH
t
CH
t
CL
t
SSTRB
t
SDV
t
STR
t
SCK
t
RS
C
LOAD
= 50pF
C
LOAD
= 50pF, external clock mode
C
LOAD
= 50pF, external clock mode
Internal clock mode
0
278
70
C
LOAD
= 50pF
C
LOAD
= 50pF
100
0
120
120
80
80
80
CONDITIONS
MIN
50
0
70
80
80
TYP
MAX
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
4
_______________________________________________________________________________________
14-Bit ADCs, 150ksps, 3.3V Single Supply
TIMING CHARACTERISTICS (Figures 5 and 6) (continued)
(AV
DD
= DV
DD
= 3.3V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
Note 1:
Tested at AV
DD
= DV
DD
= 3.3V, bipolar input mode.
Note 2:
Relative accuracy is the deviation of the analog value at any code from its theoretical value after the gain error and offset
error have been nullified.
Note 3:
Offset nullified.
Note 4:
Conversion time is defined as the number of clock cycles multiplied by the clock period; clock has 50% duty cycle. Includes
the acquisition time.
Note 5:
Acquisition time is 5 clock cycles in short acquisition mode and 13 clock cycles in long acquisition mode.
Note 6:
Performance is limited by the converter’s noise floor, typically 300µV
P-P
.
Note 7:
When an external reference has a different voltage than the specified typical value, the full scale of the ADC scales propor-
tionally.
Note 8:
Defined as the change in positive full scale caused by a ±5% variation in the nominal supply voltage.
MAX1144/MAX1145
Typical Operating Characteristics
(MAX1144/MAX1145, AV
DD
= DV
DD
= 3.3V, f
SCLK
= 3.6MHz, external clock (50% duty cycle), 24 clocks/conversion (150ksps),
bipolar input, REF = 2.048V, 4.7µF on REF, 1µF on CREF, T
A
= +25°C, unless otherwise noted.)
INTEGRAL NONLINEARITY
vs. DIGITAL OUTPUT CODE
MAX1144/45 toc01
DIFFERENTIAL NONLINEARITY
vs. DIGITAL OUTPUT CODE
MAX1144/45 toc02
TOTAL SUPPLY CURRENT
vs. TEMPERATURE
8.9
TOTAL SUPPLY CURRENT (mA)
8.8
8.7
8.6
8.5
8.4
8.3
8.2
8.1
8.0
A
C
B
A: AV
DD
, DV
DD
= 3.135V
B: AV
DD
, DV
DD
= 3.3V
C: AV
DD
, DV
DD
= 3.465V
MAX1144/45 toc03
1.0
0.8
INTEGRAL NONLINEARITY (LSB)
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
1
1707
3413
5119
6825
1.0
DIFFERENTIAL NONLINEARITY (LSB)
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
9.0
10237
13649
8531
11943
15355
1
1707
3413
5119
6825
10237
13649
8531
11943
15355
-40
-20
0
20
40
60
80
DIGITAL OUTPUT CODE
DIGITAL OUTPUT CODE
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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