RSC102
Unified Multi-Channel/Multi-Mode Readout IC
1. Features
Highly integrated multi-channel ROIC
4-channel inputs
Internal 16-bit ADC
OTP (One Time Programmable Devices)
Multi-mode sensing operations
Unified sensing modes for voltage, current, resistance, and capacitance
Power control and calibration functions
Embedded power control for sensors
Baseline/sensitivity calibrations
Low power consumption
Less than 20 mW
2. Applications
Home appliance
Automotive equipment parts
Industry/office ventilation systems
IoT devices
3. Description
3.1 Device information
The RSC102 is a readout-IC (ROIC) which is designed to have multi-channel/multi-mode operations for various sensor applications. It has four input channels to cooperate with multiple sensors, and each input can also accept different types of signals from the sensor such as voltage, current, resistance, or capacitance.
It has an input common-mode range from 0.1 V to 0.8 V, and has a variable voltage gain from 0 dB to 41.5 dB in order to compensate the drift or deviation in the response of the sensors. Also, the embedded power control block is activated depending on the types of applied sensors.
The RSC102 supports a unified sensing interface for different kinds of the sensors and embedded calibration functions with memory devices. The ROIC is also suitable for battery-powered IT devices since it has a small size and a low power consumption.
Part No.
Package
Body size
RSC102
QFN (40)
6.0 x 6.0 mm
3.2 Functional block diagram of RSC102
4. Pin configuration and functions
Note.
A. External capacitors are required on 16,33, and 34 pins (must be over 1 uF with low ESR). B. External resistors are required on 13, 14, 36, and 37 pins (close to 10-times of heater’s resistance is recommended). C. External oscillator (XTAL or TCXO) is required on 17 and 18 pins.
Pin functions Note: I=input, O=output, I/O=input and output, P=power supply
Name
Pin No.
I/O
Function
A1
1
I/O
Sensing in CH1
A2
2
I/O
Heater power in CH1
A3
3
I/O
Sensing in CH2
A4
4
I/O
Heater power in CH2
VCCA
5
P
External supply voltage (2.6 V ≤ VCCA ≤ 3.6 V)
A5
6
I/O
Sensing in CH3
A6
7
I/O
Heater power in CH3
A7
8
I/O
Sensing in CH4
VCCA
9
P
External supply voltage
A8
10
I/O
Heater power in CH4
NC
11
---
NC
NC
12
---
NC
B1
13
I/O
Monitoring heater power in CH3
B2
14
I/O
Monitoring heater power in CH4
VCCA
15
P
External supply voltage
B3
16
I/O
Supply voltage of SPI
B4
17
I/O
External reference CLK (16 MHz)
B5
18
I/O
External reference CLKB
B6
19
I/O
Reset signal (Active low)
NC
20
---
NC
VCCA
21
P
External supply voltage
VOTP
22
P
External supply voltage for OTP (6.5 V)
C7
23
I/O
Serial input data
C6
24
I/O
Serial input CLK (≤ 1 MHz)
C5
25
I/O
Slave select (Active low)
C4
26
I/O
Serial output data
C3
27
I/O
Chip enable
VCCA
28
P
External supply voltage
C2
29
I/O
Analog negative output
C1
30
I/O
Analog positive output
NC
31
---
NC
NC
32
---
NC
D4
33
I/O
Supply voltage of ADC
D3
34
I/O
Supply voltage of ROIC
VCCA
35
P
External supply voltage
D2
36
I/O
Monitoring heater power in CH2
D1
37
I/O
Monitoring heater power in CH1
VCCA
38
P
External supply voltage
NC
39
---
NC
NC
40
---
NC
5. Specifications
INPUT Signal type - Voltage (V)/current (I)/resistance (R)/capacitance (C)
Items
Unit
Min.
Typ.
Max.
Input DC voltage
V
0.0
0.4
0.8
Sensing resistance
K-ohm
---
---
80
Sensing capacitance
pF
---
---
---
Gain tuning range
dB
0.0
---
41.5
Gain step
dB
0.5
---
6.0
Input-referred noise *
nV/Hz
1.24
---
1.52
Heater power control range
V
0.9
---
2.7
Current consumption
mA
7.11
7.16
7.22
Input-referred noise* It is integrated from 1 Hz to 100 Hz at Rsense=1 Gohm (VCCA=3.3 V, temp=–40℃ to 90℃)
5.1 Absolute maximum ratings *
Symbol
Description
Unit
Min.
Max.
VCCA
Supply voltage range
V
0.0
4.7
Io *
Continuous current through VCCA or GND
mA
0.0
14.8
ESD
Human body model
V
-2,000
2,000
ESD
Machine model
V
N/A
N/A
ESD
Charged device model
V
N/A
N/A
Absolute maximum ratings * Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions are not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
Io * The maximum current is determined as one-channel is activated with the maximum supply voltage.
5.2 Recommended operating conditions
Temperature = 27 C
Symbol
Description
Unit
Min.
Max.
VCCA
Supply voltage range
V
2.6
3.7
Vo
Output DC voltage range
V
1.21
1.21
Io
Continuous current through VCCA or GND
mA
6.56
7.54
5.3 Typical characteristics
6. Application guidance
The RSC102 can process the various types of the signal in the form of voltage, current, resistance, and capacitance. Thus, the external elements of the ROIC are changed depending on the sensing modes.
6.1 Voltage / Current sensing
For the voltage signal, the RSC102 gives very high input impedance and wide gain dynamic range to obtain high SNR. In the current sensing mode, the shut resistor is required to convert the current to voltage.
6.2 Resistance sensing
Some gas sensor shows the concentration of the gas by its resistance variation. The RSC102 generates the current, Itest, which measures the resistance of the sensor, Rsensor, as follows :
6.3 Capacitance sensing
The RSC102 has the tunable oscillator circuits depending on the external sensing capacitance. However, the sensing capacitance can be easily affected by the parasitic effects such as coupling capacitance between PCB lines, package, connectors. The detailed calibration is described in the application notes.
6.4 LDO monitoring
In order to measure the output current of the LDO, the reference current is produced and changed in the ROIC. By the external resistor, Rtemp, the reference current converts to the reference voltage as follows :
7. Outline dimensions
Quad-Flat Non-leaded Package (unit: mm)
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