Datasheet

1
VA
2VIN0
3
VIN1
4
VIN2
5
VIN3
6
VIN4
7
VIN5
8
VREFP1
9
VREFN1
10
VIN6/VREFP2
11
12
28
27
26
25
24
23
22
21
20
19
18
17
VIO
D6 / DRDYB
D5
D4
D3
D2
D1
D0
SDO/DRDYB
SDI
SCLK
13
14
LMP900xx
16
15
VIN7/VREFN2
IB2
IB1
XOUT
CSB
GND
XIN/CLK
LMP90080/
LMP90078 only
LMP90080/
LMP90079 only
LMP90077, LMP90078, LMP90079, LMP90080
www.ti.com SNAS521F –JULY 2011–REVISED MARCH 2013
True Continuous Background Calibration
The LMP90080/LMP90079/LMP90078/LMP90077 feature a 16 bit ΣΔ core with continuous background
calibration to compensate for gain and offset errors in the ADC, virtually eliminating any drift with time and
temperature. The calibration is performed in the background without user or ADC input interruption, making it
unique in the industry and eliminating down time associated with field calibration required with other solutions.
Having this continuous calibration improves performance over the entire life span of the end product.
Continuous Background Sensor Diagnostics
Sensor diagnostics are also performed in the background, without interfering with signal path performance,
allowing the detection of sensor shorts, opens, and out-of-range signals, which vastly improves system reliability.
In addition, the fully flexible input multiplexer described below allows any input pin to be connected to any ADC
input channel providing additional sensor path diagnostic capability.
Flexible Input MUX Channels
The flexible input MUX allows interfacing to a wide range of sensors such as thermocouples, RTDs, thermistors,
and bridge sensors. The LMP90080/LMP90079’s multiplexer supports 4 differential channels while the
LMP90078/LMP90077 supports 2. Each effective input voltage that is digitized is V
IN
= V
INX
– V
INY
, where x and y
are any input. In addition, the input multiplexer of the LMP90080/LMP90079 also supports 7 single-ended
channels (LMP90078/LMP90077 supports 4), where the common ground is any one of the inputs.
Programmable Gain Amplifiers (FGA & PGA)
The LMP90080/LMP90079/LMP90078/LMP90077 contain an internal 16x fixed gain amplifier (FGA) and a 1x,
2x, 4x, or 8x programmable gain amplifier (PGA). This allows accurate gain settings of 1x, 2x, 4x, 8x, 16x, 32x,
64x, or 128x through configuration of internal registers. Having an internal amplifier eliminates the need for
external amplifiers that are costly, space consuming, and difficult to calibrate.
Excitation Current Sources (IB1 & IB2) - LMP90080/LMP90078
Two matched internal excitation currents, IB1 and IB2, can be used for sourcing currents to a variety of sensors.
The current range is from 100 µA to 1000 µA in steps of 100 µA.
Connection Diagram
Figure 2. 28-pin HTSSOP
See Pin Descriptions table below for specific information regarding options LMP90079, LMP90078, and
LMP90077.
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Product Folder Links: LMP90077 LMP90078 LMP90079 LMP90080