MAX191 Datasheet, PDF (1/24 Pages) Maxim Integrated Products – Low-Power, 12-Bit Sampling ADC with Internal Reference and Power-Down

19-4506; Rev 4; 2/97
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Low-Power, 12-Bit Sampling ADC
with Internal Reference and Power-Down
General Description
The MAX191 is a monolithic, CMOS, 12-bit analog-to-
digital converter (ADC) featuring differential inputs,
track/hold (T/H), internal voltage reference, internal or
external clock, and parallel or serial µP interface. The
MAX191 has a 7.5µs conversion time, a 2µs acquisition
time, and a guaranteed 100ksps sample rate.
The MAX191 operates from a single +5V supply or from
dual ±5V supplies, allowing ground-referenced bipolar
input signals. The device features a logic power-down
input, which reduces the 3mA V_DD supply current to
50µA max, including the internal-reference current.
Decoupling capacitors are the only external compo-
nents needed for the power supply and reference. This
ADC operates with either an external reference, or an
internal reference that features an adjustment input for
trimming system gain errors.
The MAX191 provides three interface modes: two 8-bit
parallel modes, and a serial interface mode that is com-
patible with SPI^TM, QSPI^TM, and MICROWIRE^TM serial-
interface standards.
________________________Applications
Battery-Powered Data Logging
PC Pen Digitizers
High-Accuracy Process Control
Electromechanical Systems
Data-Acquisition Boards for PCs
Automatic Testing Systems
Telecommunications
Digital Signal Processing (DSP)
Functional Diagram
VREF ⁵
REFADJ ⁶
V_DD
24
2.46V
REF
AIN + ³
AIN - ⁴
MAX191
7
12
AGND DGND
CLK/SCLK
23
OSC _3-STATE
OUTPUT
8-BIT
BUS
AND
12 ^SERIAL
I/O
IN REF OUT
12-BIT
SAR ADC
2
V_SS
CONTROL
LOGIC
1 22 8
PD _PAR BIP
18 _D7/DOUT
17
16 ^D6/SCLKOUT
D5/SSTRB
15
D4
14 _D3/D11
13 _D2/D10
11
D1/D9
10 _D0/D8
20 _CS
19
9
21
RD
BUSY
HBEN
____________________________Features
o 12-Bit Resolution, 1/2LSB Linearity
o +5V or ±5V Operation
o Built-In Track/Hold
o Internal Reference with Adjustment Capability
o Low Power: 3mA Operating Mode
20µA Power-Down Mode
o 100ksps Tested Sampling Rate
o Serial and 8-Bit Parallel µP Interface
o 24-Pin Narrow DIP and Wide SO Packages
Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
ERROR
(LSB)
MAX191ACNG 0°C to +70°C 24 Narrow Plastic DIP ±1/2
MAX191BCNG 0°C to +70°C 24 Narrow Plastic DIP ±1
MAX191ACWG 0°C to +70°C 24 Wide SO
±1/2
MAX191BCWG 0°C to +70°C 24 Wide SO
±1
MAX191BC/D
0°C to +70°C Dice*
±1
MAX191AENG -40°C to +85°C 24 Narrow Plastic DIP ±1/2
MAX191BENG -40°C to +85°C 24 Narrow Plastic DIP ±1
MAX191AEWG -40°C to +85°C 24 Wide SO
±1/2
MAX191BEWG -40°C to +85°C 24 Wide SO
±1
MAX191AMRG -55°C to +125°C 24 Narrow CERDIP** ±1/2
MAX191BMRG -55°C to +125°C 24 Narrow CERDIP** ±1
* Dice are specified at T_A = +25°C, DC parameters only.
** Contact factory for availability and processing to MIL-STD-883.
Pin Configuration
TOP VIEW
PD ₁
V_{SS 2}
AIN+ ₃
AIN- ₄
VREF ₅
REFADJ 6
AGND ₇
BIP ₈
BUSY ₉
D0/D8 ₁₀
D1/D9 ₁₁
DGND ₁₂
MAX191
24 ^VDD
23 ^CLK/SCLK
22 ^PAR
21 HBEN
20 CS
19 RD
18 D7/DOUT
17 D6/SCLKOUT
16 D5/SSTRB
15 D4
14 D3/D11
13 D2/D10
DIP/SO
SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp.
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