MAX146/MAX147
19-0465; Rev 2; 10/01
+2.7V, Low-Power, 8-Channel,
Serial 12-Bit ADCs
General Description ____________________________Features
The MAX146/MAX147 12-bit data-acquisition systems
8-Channel Single-Ended or 4-Channel
combine an 8-channel multiplexer, high-bandwidth
Differential Inputs
track/hold, and serial interface with high conversion
Single-Supply Operation
speed and low power consumption. The MAX146 oper-
+2.7V to +3.6V (MAX146)
ates from a single +2.7V to +3.6V supply; the MAX147
+2.7V to +5.25V (MAX147)
operates from a single +2.7V to +5.25V supply. Both
devices analog inputs are software configurable for
Internal 2.5V Reference (MAX146)
unipolar/bipolar and single-ended/differential operation.
Low Power
The 4-wire serial interface connects directly to SPI/
1.2mA (133ksps, 3V supply)
QSPI and MICROWIRE devices without external
54A (1ksps, 3V supply)
logic. A serial strobe output allows direct connection to
1A (power-down mode)
TMS320-family digital signal processors. The
SPI/QSPI/MICROWIRE/TMS320-Compatible
MAX146/MAX147 use either the internal clock or an exter-
4-Wire Serial Interface
nal serial-interface clock to perform successive-approxi-
mation analog-to-digital conversions.
Software-Configurable Unipolar or Bipolar Inputs
The MAX146 has an internal 2.5V reference, while the
20-Pin DIP/SSOP Packages
MAX147 requires an external reference. Both parts have
a reference-buffer amplifier with a 1.5% voltage- Ordering Information
adjustment range.
INL
These devices provide a hard-wired SHDN pin and a PART TEMP RANGE PIN-PACKAGE
(LSB)
software-selectable power-down, and can be pro-
MAX146ACPP 0C to +70C 20 Plastic DIP 1/2
grammed to automatically shut down at the end of a con-
version. Accessing the serial interface automatically MAX146BCPP 0C to +70C 20 Plastic DIP 1
powers up the MAX146/MAX147, and the quick turn-on
MAX146ACAP 0C to +70C 20 SSOP 1/2
time allows them to be shut down between all conver-
MAX146BCAP 0C to +70C 20 SSOP 1
sions. This technique can cut supply current to under
MAX146BC/D 0C to +70C Dice* 1
60A at reduced sampling rates.
Ordering Information continued at end of data sheet.
The MAX146/MAX147 are available in 20-pin DIP and
*Dice are specified at T = +25C, DC parameters only.
A
SSOP packages.
For 4-channel versions of these devices, see the
MAX1246/MAX1247 data sheet.
Typical Operating Circuit
________________________Applications
+3V
Portable Data Logging Data Acquisition
V
CH0 V DD
DD
0.1 F
Medical Instruments Battery-Powered Instruments
0V TO
DGND
+2.5V
ANALOG
Pen Digitizers Process Control
MAX146
INPUTS
AGND
CPU
CH7 COM
I/O
VREF CS
4.7 F
SCLK
SCK (SK)
DIN MOSI (SO)
Pin Configuration appears at end of data sheet.
DOUT MISO (SI)
REFADJ
0.047 F
SSTRB
V
SS
SHDN
SPI and QSPI are registered trademarks of Motorola, Inc.
MICROWIRE is a registered trademark of National Semiconductor
Corp.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxims website at www.maxim-ic.com.
EVALUATION KIT
AVAILABLE+2.7V, Low-Power, 8-Channel,
Serial 12-Bit ADCs
ABSOLUTE MAXIMUM RATINGS
V to AGND, DGND................................................. -0.3V to 6V Continuous Power Dissipation (T = +70C)
DD A
AGND to DGND...................................................... -0.3V to 0.3V Plastic DIP (derate 11.11mW/C above +70C) ......... 889mW
CH0CH7, COM to AGND, DGND ............ -0.3V to (V + 0.3V) SSOP (derate 8.00mW/C above +70C) ................... 640mW
DD
VREF, REFADJ to AGND ........................... -0.3V to (V + 0.3V) CERDIP (derate 11.11mW/C above +70C).............. 889mW
DD
Digital Inputs to DGND .............................................. -0.3V to 6V Operating Temperature Ranges
Digital Outputs to DGND ........................... -0.3V to (V + 0.3V) MAX146_C_P/MAX147_C_P .............................. 0C to +70C
DD
Digital Output Sink Current .................................................25mA MAX146_E_P/MAX147_E_P............................ -40C to +85C
MAX146_MJP/MAX147_MJP ........................ -55C to +125C
Storage Temperature Range ............................ -60C to +150C
Lead Temperature (soldering, 10s) ................................ +300C
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
(V = +2.7V to +3.6V (MAX146); V = +2.7V to +5.25V (MAX147); COM = 0; f = 2.0MHz; external clock (50% duty cycle); 15
DD DD SCLK
clocks/conversion cycle (133ksps); MAX1464.7F capacitor at VREF pin; MAX147external reference, VREF = 2.500V applied to
VREF pin; T = T to T ; unless otherwise noted.)
A MIN MAX
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
)
DC ACCURACY (Note 1
Resolution 12 Bits
MAX14_A 0.5
MAX14_B 1.0
Relative Accuracy (Note 2) INL LSB
MAX147C 2.0
No Missing Codes NMC 12 Bits
MAX14_A/MAX14_B 1.0
Differential Nonlinearity DNL LSB
MAX147C 0.8
MAX14_A 0.5 3
Offset Error LSB
MAX14_B/MAX147C 0.5 4
Gain Error (Note 3) 0.5 4 LSB
Gain Temperature Coefficient 0.25 ppm/C
Channel-to-Channel Offset
0.25 LSB
Matching
DYNAMIC SPECIFICATIONS (10kHz sine-wave input, 0V to 2.500Vp-p, 133ksps, 2.0MHz external clock, bipolar input mode)
MAX14_A/MAX14_B 70 73
Signal-to-Noise + Distortion Ratio SINAD dB
MAX147C 73
MAX14_A/MAX14_B -88 -80
Up to the 5th
Total Harmonic Distortion THD dB
harmonic
MAX147C -88
MAX14_A/MAX14_B 80 90
Spurious-Free Dynamic Range SFDR dB
MAX147C 90
Channel-to-Channel Crosstalk 65kHz, 2.500V (Note 4) -85 dB
p-p
Small-Signal Bandwidth -3dB rolloff 2.25 MHz
Full-Power Bandwidth 1.0 MHz
CONVERSION RATE
Internal clock, SHDN = FLOAT 5.5 7.5
Conversion Time (Note 5) t s
Internal clock, SHDN = V 35 65
CONV DD
External clock = 2MHz, 12 clocks/conversion 6
2 _______________________________________________________________________________________
MAX146/MAX147