MAX187CEWE-T Maxim Integrated, MAX187CEWE-T Datasheet - Page 7

• Manufacturer Part Number: MAX187CEWE-T
• Description: Analog to Digital Converters - ADC
• Manufacturer: Maxim Integrated

Specifications of MAX187CEWE-T

• Number Of Channels: 1
• Architecture: SAR
• Conversion Rate: 75 KSPs
• Resolution: 12 bit
• Input Type: Single-Ended
• Snr: Yes
• Interface Type: QSPI, Serial (SPI, Microwire)
• Operating Supply Voltage: 4.75 V to 5.25 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-16 Wide
• Maximum Power Dissipation: 500 mW
• Minimum Operating Temperature: - 40 C
• Number Of Converters: 1
• Voltage Reference: 4.096 V

The MAX187/MAX189 use input track/hold (T/H) and suc-
cessive approximation register (SAR) circuitry to convert
an analog input signal to a digital 12-bit output. No exter-
nal hold capacitor is needed for the T/H. Figures 3a and
3b show the MAX187/MAX189 in their simplest configu-
ration. The MAX187/MAX189 convert input signals in the
0V to V
The MAX187’s internal reference is trimmed to 4.096V,
while the MAX189 requires an external reference. Both
devices accept external reference voltages from +2.5V to
V
SCLK, CS, and DOUT, and provides easy interface to
microprocessors (µPs).
Both converters have two modes: normal and shutdown.
Pulling SHDN low shuts the device down and reduces
supply current to below 10µA, while pulling SHDN high or
leaving it floating puts the device into the operational mode.
Figure 1. Load Circuits for DOUT Enable Time
Figure 2. Load Circuits for DOUT Disable Time
Maxim Integrated
DD
. The serial interface requires only three digital lines,
REF
range in 10µs, including T/H acquisition time.
DOUT
DOUT
Detailed Description#
3kI
3kI
A. HIGH-Z TO V OH AND V OL TO V OH
Converter Operation
DGND
DGND
A. V OH TO HIGH-Z
+5V, Low-Power, 12-Bit Serial ADCs
C
C
LOAD
LOAD
= 100pF
= 100pF
A conversion is initiated by CS falling. The conversion result
is available at DOUT in unipolar serial format. A high bit,
signaling the end of conversion (EOC), followed by the data
bits (MSB first), make up the serial data stream.
The MAX187 operates in one of two states: (1) internal
reference and (2) external reference. Select internal
reference operation by forcing SHDN high, and external
reference operation by floating SHDN.
Figure 4 illustrates the sampling architecture of the
ADC’s analog comparator. The full-scale input voltage
depends on the voltage at REF.
For specified accuracy, the external reference voltage
range spans from +2.5V to V
Internal Reference
(MAX187 only)
External Reference
REFERENCE
DOUT
B. HIGH-Z TO V OL AND V OH TO V OL
DOUT
MAX187/MAX189
B. V OL TO HIGH-Z
ZERO SCALE
+5V
+5V
3kI
3kI
C
DGND
C
DGND
0V
0V
DD
LOAD
LOAD
.
= 100pF
= 100pF
Analog Input
FuLL SCALE
+4.096V
V
REF
7