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.

Figure 1. RSC102

Part No.	Package	Body size
RSC102	QFN (40)	6.0 x 6.0 mm

3.2 Functional block diagram of RSC102

Figure 2. Functional block diagram

Figure 3. Typical application circuit

4. Pin configuration and functions

Figure 4. RSC102 Top view pin map

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

Figure 5. Voltage gain

Figure 6. DC-offset chracteristic

Figure 7. LDO Output (Vout = 1.6 V), Rising time = 4.06us

Figure 8. LDO Output (Vout = 1.6 V), Rising time = 574us

Figure 9. Heater power control range

Figure 10. Gain variation over channel and temperature, G=0 dB

Figure 10. Gain variation over channel and temperature, G=41.5 dB

Figure 11. Test current variation over channel and temperature, Itest=10 uA

Figure 11. Test current variation over channel and temperature, Itest=100 uA

Figure 12. Oscillation frequency variation over channel and temperature, free oscillation

Figure 12. Oscillation frequency variation over channel and temperature, After PCB parasitic calibration

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)

Figure 13. RSC102 Top view

Figure 14. RSC102 Bottom view

Figure 15. RSC102 Side view

780KB

RSC102_Instruction Manual rev.0.1.pdf

PDF

Open