MAX11156ETC+ Maxim Integrated, MAX11156ETC+ Datasheet - Page 11

• Manufacturer Part Number: MAX11156ETC+
• Description: Analog to Digital Converters - ADC 18Bit 500ksps 5V SAR ADC w/Internal Ref
• Manufacturer: Maxim Integrated

Specifications of MAX11156ETC+

• Rohs: yes
• Number Of Channels: 1
• Architecture: SAR
• Conversion Rate: 500 KSPs
• Resolution: 18 bit
• Input Type: Pseudo-Differential
• Snr: 94.6 dB
• Interface Type: SPI
• Operating Supply Voltage: 2.3 V to 5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: TDFN-12
• Maximum Power Dissipation: 38.5 W
• Minimum Operating Temperature: - 40 C
• Number Of Converters: 1

MAX11156
Functional Diagram
Detailed Description
The MAX11156 is an 18-bit single-channel, pseudo-differ-
ential ADC with a maximum throughput rates of 500ksps.
This ADC includes a precision internal reference that
allows for measuring a bipolar input voltage range of Q5V.
An external reference can also be applied for input ranges
between Q3.05V and Q5.19V. Both inputs (AIN+ and AIN-)
are sampled with a pseudo-differential on-chip track-and-
hold exhibiting no pipeline delay or latency, making these
ADCs ideal for multiplexed applications.
The MAX11156 measures a true bipolar voltage of Q5V
(10V
overrange current. This ADC is powered from a 4.75V to
5.25V analog supply (V
digital supply (OVDD). The MAX11156 requires 500ns to
acquire the input sample on an internal track-and-hold
and then convert the sampled signal to 18 bits of accuracy
using an internally clocked converter.
Analog Inputs
The MAX11156 ADC consists of a true sampling pseudo-
differential input stage with high-impedance, capacitive
inputs. The internal T/H circuitry feature a small-signal
bandwidth of about 6MHz to provide 18-bit accurate
sampling in 500ns. This allows for accurate sampling of
www.maximintegrated.com
AGNDS
REFIO
AIN+
AIN-
P-P
) and the inputs are protected for up to Q20mA of
REFERENCE
INTERNAL
18-BIT ADC
DD
10k
MAX11156
) and a separate 2.3V to 5.25V
Ω
SW1
CONFIGURATION REGISTER
REF
BUF
AND CONTROL
INTERFACE
SW2
a number of scanned channels through an external mul-
tiplexer.
The MAX11156 can thus convert input signals on AIN+ in
the range of -(K O V
where K = 5.000/4.096. AIN+ should also be limited to
±(V
input range of -0.1V to +0.1V and should be connected
to the ground reference of the input signal source. The
MAX11156 performs a true differential sample on inputs
between AIN+ and AIN- with good common-mode rejec-
tion (see the
improved sampling of remote transducer inputs.
Many traditional ADCs with single supplies that mea-
sure bipolar input signals use resistive divider networks
directly on the analog inputs. These networks increase
the complexity of the input signal conditioning. However,
the MAX11156 includes a patented input switch architec-
ture which allows direct sampling onto the input sample
and hold capacitor without the use of scaling resistor net-
works. This results in zero source loading errors when the
sample and hold is allowed to fully settle. This architec-
ture requires a minimum sample rate of 10Hz to maintain
accurate conversions over the designed temperature and
supply ranges.
DD
DIN
SCLK
DOUT
CNVST
V
OVDD
GND
REF
+ 0.1V) for accurate conversions. AIN- has an
DD
with Internal Reference in TDFN
18-Bit, 500ksps, ±5V SAR ADC
Typical Operating
CONFIGURATION
B5
REGISTER
0
0
1
1
REF
+ AIN-) to +(K O V
B4
0
1
0
1
REFERENCE
MODE
Circuit). This allows for
0
1
2
3
Maxim Integrated │ 11
REFERENCE SWITCH
CLOSED
CLOSED
OPEN
OPEN
SW2
STATE
REF
CLOSED
CLOSED
OPEN
OPEN
SW1
+ AIN-)