LMP93601 Low-Noise, High Gain, 3-Channel AFE for Thermopile Sensors

1 Features

High Gain, Programmable up to 4096
Low Gain Error Drift, <10 ppm/°C
Low Offset Voltage and Drift; 1 uV, 50 nV/°C
Low Input Bias Current, 1.3 nA
Low Input Offset Current, 120 pA
VCM Output Signal for Level Shifting, AVDD/3
Three Differential EMI Hardened Inputs
16-bit Δ∑ Analog-to-Digital Converter
Low Noise Performance, ENOB 15.3 bits
Four Output Data Rates, up to 1.3 kSPS
Internal Voltage Reference for ADC
SPI Interface Transfer Rate, 20 MHz
Brown-Out Detect
PGA Over-Range Detect
Separate Analog and Digital Supplies, 2.7 to 5.5 V
Low Current Consumption, 1.1 mA
Low Power Shutdown Mode, < 0.1µA
Operating Temp. –25 to 85 °C

2 Applications

Thermopile Array Measurement
Thermopile Flow Measurements
Bridge Sensor Interface
Gesture Recognition

3 Description

The LMP93601 is an optimized Analog-Front-End (AFE) for occupancy detecting thermopile arrays up to 16 x 16 and thermopile mass flow sensors. The AFE combines excellent noise performance, low offset voltage, high gain, and low-power consumption at sampling rates ideal for monitoring thermopile sensors.

The LMP93601 is a precision, 16-bit, analog-to-digital converter (ADC) offered in a leadless WQFN-24 package. The device features three differential EMI hardened inputs, a low-noise, high-gain programmable gain amplifier (PGA), a level shifting voltage source, an internal reference, and a programmable sampling rate. The many integrated features and the simple control of the LMP93601 through an SPI-compatible interface ease precision measurements of thermopile sensor signals.

Device Information

PART NUMBER	PACKAGE	BODY SIZE
LMP93601	WQFN (24)	5.00 mm x 4.00 mm

For all available packages, see the orderable addendum at the end of the datasheet.

4 Simplified Thermopile Array System Diagram

Analog Supply Vs. Offset Voltage Plot

5 Revision History

Changes from * Revision (March 2014) to A Revision

Added application curves Go
Changed Handling Ratings format Go

6 Pin Configuration and Functions

LMP93601

24 Pin

Top View

Pin Functions

PIN⁽²⁾		TYPE(I/O)⁽¹⁾	DESCRIPTION
NAME	NUMBER	TYPE(I/O)⁽¹⁾	DESCRIPTION
VCM	1	Analog in/output	Sensor common mode bias voltage
INP1	2	Analog input	Input signal positive pin
INN1	3	Analog input	Input signal negative pin
INP2	4	Analog input	Input signal positive pin
INN2	5	Analog input	Input signal negative pin
INP3	6	Analog input	Input signal positive pin
INN3	7	Analog input	Input signal negative pin
AGND	8	Analog ground
PWDNB	9	Digital input	Enable, active low
RSTB	10	Digital input	Master reset, active low
SYNC	11	Digital input	Sync, active high
XCLK	12	Digital input	External clock source
DRDYB	13	Digital output	Data ready signal, active low, push-pull
SDI	14	Digital input	Serial data input
CSB	15	Digital input	Chip select, active low
IOGND	16	Digital IO ground
SCLK	17	Digital input	Serial interface clock
SDO	18	Digital output	Serial data output; push-pull
IOVDD	19	Digital IO supply rail
DGND	20	Digital ground
AGND	21	Analog ground
XCAP2	22	Digital LDO	External Cap2
XCAP1	23	Analog	External Cap1
AVDD	24	Analog	Analog supply rail

(1) There is no pull-up/-down for any digital I/O

(2) For best performance, it is recommended that the DAP is connected to AGND (refer to Mechanical, Packaging and Orderable Information ). All three “GND” connections (AGND, DGND and IOGND) must be connected to system ground and cannot be left floating.