MAX1246BEEE-T Maxim Integrated, MAX1246BEEE-T Datasheet

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MAX1246BEEE-T

Manufacturer Part Number
MAX1246BEEE-T
Description
Analog to Digital Converters - ADC 12-Bit 4Ch 133ksps 3.6V Precision ADC
Manufacturer
Maxim Integrated
Datasheet

Specifications of MAX1246BEEE-T

Number Of Channels
4/2
Architecture
SAR
Conversion Rate
133 KSPs
Resolution
12 bit
Input Type
Single-Ended/Differential
Snr
70 dB
Interface Type
4-Wire (SPI, Microwire, QSPI, TMS320)
Operating Supply Voltage
2.7 V to 3.6 V
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
Package / Case
QSOP-16
Maximum Power Dissipation
667 mW
Minimum Operating Temperature
- 40 C
Number Of Converters
1
Voltage Reference
2.5 V
The MAX1246/MAX1247 12-bit data-acquisition systems
combine a 4-channel multiplexer, high-bandwidth
track/hold, and serial interface with high conversion
speed and low power consumption. The MAX1246 oper-
ates from a single +2.7V to +3.6V supply; the MAX1247
operates from a single +2.7V to +5.25V supply. Both
devices’ analog inputs are software configurable for
unipolar/bipolar and single-ended/differential operation.
The 4-wire serial interface connects directly to SPI™/
QSPI™ and MICROWIRE™ devices without external
logic. A serial strobe output allows direct connection to
TMS320-family digital signal processors. The MAX1246/
MAX1247 use either the internal clock or an external seri-
al-interface clock to perform successive-approximation
analog-to-digital conversions.
The MAX1246 has an internal 2.5V reference, while the
MAX1247 requires an external reference. Both parts have
a reference-buffer amplifier with a ±1.5% voltage-
adjustment range. These devices provide a hard-wired
SHDN pin and a software-selectable power-down, and
can be programmed to automatically shut down at the
end of a conversion. Accessing the serial interface auto-
matically powers up the MAX1246/MAX1247, and the
quick turn-on time allows them to be shut down between
all conversions. This technique can cut supply current to
under 60µA at reduced sampling rates. The MAX1246/
MAX1247 are available in a 16-pin DIP and a small QSOP
that occupies the same board area as an 8-pin SO.
For 8-channel versions of these devices, see the
MAX146/MAX147 data sheet.
Pin Configuration appears at end of data sheet.
________________________Applications
19-1071; Rev 2; 10/01
SPI and QSPI are registered trademarks of Motorola, Inc.
MICROWIRE is a registered trademark of National
Semiconductor Corp.
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.
Portable Data Logging
Medical Instruments
Pen Digitizers
Data Acquisition
Battery-Powered Instruments
Process Control
________________________________________________________________ Maxim Integrated Products
General Description
Serial 12-Bit ADCs in QSOP-16
+2.7V, Low-Power, 4-Channel,
o 4-Channel Single-Ended or 2-Channel
o Single-Supply Operation:
o Internal 2.5V Reference (MAX1246)
o Low Power: 1.2mA (133ksps, 3V supply)
o SPI/QSPI/MICROWIRE/TMS320-Compatible
o Software-Configurable Unipolar or Bipolar Inputs
o 16-Pin QSOP Package (same area as 8-pin SO)
Ordering Information continued at end of data sheet.
__________Typical Operating Circuit
MAX1246ACPE
MAX1246BCPE
MAX1246ACEE
MAX1246BCEE
Differential Inputs
4-Wire Serial Interface
PART
+2.7V to +3.6V (MAX1246)
+2.7V to +5.25V (MAX1247)
ANALOG
INPUTS
0.047µF
0V TO
+2.5V
4.7µF
CH0
CH3
VREF
REFADJ
54µA (1ksps, 3V supply)
1µA (power-down mode)
MAX1246
TEMP RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
Ordering Information
SSTRB
DGND
AGND
SHDN
DOUT
SCLK
COM
V
DIN
CS
DD
16 Plastic DIP
16 Plastic DIP
16 QSOP
16 QSOP
PIN-PACKAGE
+3V
0.1µF
SCK (SK)
MOSI (SO)
MISO (SI)
V
I/O
DD
CPU
V
Features
SS
(LSB)
±1/2
±1
±1/2
±1
INL
1

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MAX1246BEEE-T Summary of contents

Page 1

... Pin Configuration appears at end of data sheet. SPI and QSPI are registered trademarks of Motorola, Inc. MICROWIRE is a registered trademark of National Semiconductor Corp. ________________________________________________________________ Maxim Integrated Products 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. +2.7V, Low-Power, 4-Channel, ...

Page 2

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 ABSOLUTE MAXIMUM RATINGS V to AGND, DGND................................................. -0. AGND to DGND ...................................................... -0.3V to 0.3V CH0–CH3, COM to AGND, DGND ............ -0. VREF to AGND........................................... -0.3V to ...

Page 3

ELECTRICAL CHARACTERISTICS (continued +2.7V to +3.6V (MAX1246 clocks/conversion cycle (133ksps); MAX1246—4.7µF capacitor at VREF pin; MAX1247—external reference, VREF = 2.5V applied to VREF pin unless otherwise noted.) A ...

Page 4

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 ELECTRICAL CHARACTERISTICS (continued +2.7V to +3.6V (MAX1246 +2.7V to +5.25V (MAX1247); COM = 0V clocks/conversion cycle (133ksps); MAX1246—4.7µF capacitor at VREF pin; MAX1247—external reference, ...

Page 5

ELECTRICAL CHARACTERISTICS (continued +2.7V to +3.6V (MAX1246 clocks/conversion cycle (133ksps); MAX1246—4.7µF capacitor at VREF pin; MAX1247—external reference, VREF = 2.5V applied to VREF pin unless otherwise noted.) A ...

Page 6

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 TIMING CHARACTERISTICS (V = +2.7V to +3.6V (MAX1246 +2.7V to +5.25V (MAX1247 PARAMETER SYMBOL Acquisition Time t ACQ DIN to SCLK Setup t DIN to SCLK Hold ...

Page 7

Operating Characteristics (continued 3V, VREF = 2.5V 2MHz SCLK SUPPLY CURRENT vs. SUPPLY VOLTAGE 2.00 = ∞ CODE = 101010100000 C = 50pF LOAD 1.75 1.50 MAX1246 1.25 1. ...

Page 8

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 ____________________________Typical Operating Characteristics (continued 3V, VREF = 2.5V 2MHz SCLK OFFSET vs. SUPPLY VOLTAGE 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 2.25 ...

Page 9

Description PIN NAME 1 V Positive Supply Voltage DD 2–5 CH0–CH3 Sampling Analog Inputs Ground reference for analog inputs. COM sets zero-code voltage in single-ended mode. Must be 6 COM stable to ±0.5LSB. Three-Level Shutdown Input. Pulling SHDN low ...

Page 10

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 _______________Detailed Description The MAX1246/MAX1247 analog-to-digital converters (ADCs) use a successive-approximation conversion technique and input track/hold (T/H) circuitry to convert an analog signal to a 12-bit digital output. A flexible seri- al interface ...

Page 11

Table 1. Control-Byte Format BIT 7 BIT 6 BIT 5 (MSB) START SEL2 SEL1 BIT NAME DESCRIPTION The first logic “1” bit after CS goes low defines the beginning of the control byte. 7(MSB) START 6 SEL2 These three bits ...

Page 12

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 Table 2. Channel Selection in Single-Ended Mode (SGL SEL2 SEL1 SEL0 Table 3. ...

Page 13

CS SCLK 1 4 UNI/ SGL/ DIN SEL2 SEL1 SEL0 BIP DIF START SSTRB RB1 DOUT ACQUISITION A/D STATE IDLE (f SCLK Figure 5. 24-Clock External Clock Mode Conversion Timing (Microwire and SPI Compatible, QSPI Compatible with ...

Page 14

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 • • • SDV SSTRB • • • SCLK • • • • Figure 7. External Clock Mode SSTRB Detailed Timing CS SCLK UNI/ DIN ...

Page 15

The fastest the MAX1246/MAX1247 can run with CS held low between conversions is 15 clocks per conversion. Figure 10a shows the serial-interface timing necessary to perform a conversion every 15 SCLK cycles in external clock mode tied ...

Page 16

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 __________ Applications Information Power-On Reset When power is first applied, and if SHDN is not pulled low, internal power-on reset circuitry activates the MAX1246/MAX1247 in internal clock mode, ready to convert with ...

Page 17

CLOCK MODE SHDN SETS EXTERNAL CLOCK MODE DIN DOUT 12 DATA BITS POWERED UP MODE Figure 11a. Timing Diagram Power-Down Modes, External Clock CLOCK MODE SETS INTERNAL CLOCK MODE DIN S X ...

Page 18

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 Power-Down Sequencing The MAX1246/MAX1247 auto power-down modes can save considerable power when operating at less than maximum sample rates. Figures 12, 13a, and 13b show the average supply current as a function ...

Page 19

DIN FULLPD 1.21V REFADJ 0V 2.50V VREF 0V Figure 14. MAX1246 FULLPD/FASTPD Power-Up Sequence Lowest Power at Higher Throughputs Figure 13b shows the power consumption with external-reference compensation in fast power-down, with one and four channels ...

Page 20

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 At VREF, the DC input resistance is a minimum of 18kΩ. During conversion, an external reference at VREF must deliver up to 350µA DC load current and have 10Ω or less output ...

Page 21

OUTPUT CODE FS = VREF + COM 011 . . . 111 2 011 . . . 110 ZS = COM -VREF - COM 000 . . . 010 2 VREF 000 . . . 001 1LSB = ...

Page 22

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP- 0.1µF 2 CH0 MAX1246 3 CH1 MAX1247 ANALOG INPUTS 4 CH2 5 CH3 6 COM 7 SHDN +2.5V 8 VREF 0.1µF Figure 19. MAX1246/MAX1247 QSPI Connections, External Reference CS ...

Page 23

... PIN-PACKAGE MAX1246AEPE -40°C to +85°C 16 Plastic DIP MAX1246BEPE -40°C to +85°C 16 Plastic DIP MAX1246AEEE -40°C to +85°C 16 QSOP MAX1246BEEE -40°C to +85°C 16 QSOP MAX1246AMJE -55°C to +125°C 16 CERDIP* MAX1246BMJE -55°C to +125°C 16 CERDIP* MAX1247ACPE 0°C to +70°C 16 Plastic DIP MAX1247BCPE 0°C to +70°C ...

Page 24

Low-Power, 4-Channel, Serial 12-Bit ADCs in QSOP-16 ________________________________________________________Package Information 24 ______________________________________________________________________________________ ...

Page 25

... 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 ____________________ 25 © 2001 Maxim Integrated Products +2 ...

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