[worklog] LED check, color sensor introduction

1.       TCS3414

   TCS3414 digital color light sensors are designed to accurately derive the color chromaticity and illuminance (intensity) of ambient light and provide a digital output with 16-bits of resolution. The devices include an 8 × 2 array of filtered photodiodes, analog-to-digital converters, and control functions on a single monolithic CMOS integrated circuit. Of the 16 photodiodes, 4 have red filters, 4 have green filters, 4 have blue filters, and 4 have no filter (clear). With the advanced patent pending in-package trim capability, device-to-device and system-to-system tolerance can be minimized allowing very precise repeatability to be attained.

2.       TSL252R

TSL252R are light-to-voltage optical sensors, each combining a photodiode and a transimpedance amplifier (feedback resistor = 16 MΩ, 8 MΩ, and 2.8 MΩ respectively) on a single monolithic IC. Output voltage is directly proportional to the light intensity (irradiance) on the photodiode. These devices have improved amplifier offset-voltage stability and low power consumption and are supplied in a 3-lead clear plastic sidelooker package with an integral lens. When supplied in the lead (Pb) free package, the device is RoHS compliant.

3.       TSL237T

The TSL237T light-to-frequency converter combines a silicon photodiode and a current-to-frequency converter on a single monolithic CMOS integrated circuit. Output is a square wave (50% duty cycle) with frequency directly proportional to light intensity (irradiance) on the photodiode. The digital output allows direct interface to a microcontroller or other logic circuitry. Output enable (OE) places the output in a high-impedance state for multiple-unit sharing of a microcontroller input line. The device has been temperature compensated for the ultraviolet-to-visible light range of 320 nm to 700 nm and responds over the light range of 320 nm to 1050 nm. The TSL237T is characterized for operation over the temperature range of -40°C to 85°C and is supplied in a compact 4-lead surface-mount package.

4.       BH1621FVC

BH1621FVC is an analog current output ambient light sensor. This IC is the most suitable to obtain the ambient light data for adjusting LCD and Keypad backlight of mobile phone for power saving. It is always used to check LED.

5.       OPT101

    The OPT101 is a monolithic photodiode with on-chip Tran impedance amplifier. Output voltage increases linearly with light intensity. The amplifier is designed for single or dual power-supply operation, making it ideal for battery operated equipment. The integrated combination of photodiode and Tran impedance amplifier on a single chip eliminates the problems commonly encountered in discrete designs such as leakage current errors, noise pick-up, and gain peaking due to stray capacitance. The 0.09 x 0.09 inch photodiode is operated in the photoconductive mode for excellent linearity and low dark current. The OPT101 operates from +2.7V to +36V supplies and quiescent current is only 120μA. It is available in clear plastic 8-pin DIP, and J-formed DIP for surface mounting. Temperature range is 0°C to +70°C.

[work log] U1 (C8051F501) reprogramming failure analysis report (upload figure)

U1(C8051F501) reprogramming failure analysis report

1. Failed phenomena:

  U1 has F/W inside. Function of board is OK. The device (U1) can not been reprogram F/W, the programmer can't detect this device.

2. Fail Rate

  More than 1.5%, total ~80 pcs, verify ~40 pcs by ourself.

3. 1^st level analysis by repair team

  Action1: use 1 pcs new IC to replace the failed one on the board, then pass;

  Action2: heat up this IC, can resume programming function, but still failed when cold down.

4. Repeat the 1^st level analysis action and verify

  Take 2 pcs failed sample for example, S/N: L12A008354 and L12A008367, result is as below:

  4.1 Heat U1 (NG: L12A008354), can connect to programmer and reprogram F/W, but after the temperature of U1 is down,still failed (can't connect to programmer and reprogram F/W).

  4.2 Heat U2(NG:L12A008367), still failed. Retry to heat 1 time, failed again.

  4.3 Change 1 pcs new IC on NG board, then pass

5. 2^nd level analysis based on board/circuit diagram, check the basic working condition

  The U1 is a microcontroller, so the basic working condition is power supply and oscillator. After measure the frequency and voltage by Osc, the basic condition can meet U1 requirement.

6. 3^rd level analysis, signal check

  6.1 Measure and compare the signal of P1 that uses to connect to programmer.

 

	Good Board		NG Board
PIN#	Connected	Disconnected	Connected	Disconnected
#1	3.3	3.3	3.3	3.3
#2	0	0	0	0
#3	0	0	0	0
#4	5	5	5	5
#5	2.5	2.5	2.5	2.5
#6	2.5	2.5	2.5	2.5
#7	5	5	0~0.999	5
#8	0	0	0	0
#9	0	0	0	0
#10	5	-3.3	5	-3.3
	Measure the voltage between GND by DMM

PIN7 of P1 connector connect to PIN12 of U1 directly. Pin12 is the reset signal and low voltage is active. But when NG board connect to programmer, this signal keep "0" all the time, but disconnect to programmer, the signal is OK.

Refer to datasheet of C8051F501 

    6.2 Check the interface (C2) and the key signal from U1 (C8051F501)

  C2 Interface: C8051F50x-F51x devices include an on-chip Silicon Labs 2-Wire (C2) debug interface to allow Flash programming and in-system debugging with the production part installed in the end application. The C2 interface uses a clock signal (C2CK) and a bi-directional C2 data signal (C2D) to transfer information between the device and a host system. See the C2 Interface Specification for details on the C2 protocol. (Refer to section 28 of datasheet)

The result is as below:

Item	Sample #	U1 Signal Pin	Picture name#	Status
1	OK(L12A008367)	PIN12	ALL0000/ALL0001	Connected
2	OK(L12A008367)	PIN11	ALL0002/ALL0003	Connected
3	OK(L12A008367)	PIN11	ALL0004	Disconnected
4	NG(L12A008354)	PIN12	ALL0005	Connected
5	NG(L12A008354)	PIN11	ALL0006/ALL0007/ALL0008/ALL0009	Connected
6	NG(E13A021033)	PIN12	ALL0010/ALL0011	Connected
7	NG(E13A021033)	PIN11	ALL0012	Connected

  (Pin12 Good board) Vs. (Pin12 NG board)    

 

 (Pin11 Good board) Vs. (Pin11 NG board)

7. Conclusion and next action

  7.1 Conclusion is that raw material is bad.

  7.2 Send the failed chip samples to supplier for further failure analysis on chip level.

[work log]U1 (C8051F501) reprogramming failure analysis report

U1(C8051F501) reprogramming failure analysis report

1. Failed phenomena:

  U1 has F/W inside. Function of board is OK. The device (U1) can not been reprogram F/W, the programmer can't detect this device.

2. Fail Rate

  More than 1.5%, total ~80 pcs, verify ~40 pcs by ourself.

3. 1^st level analysis by repair team

  Action1: use 1 pcs new IC to replace the failed one on the board, then pass;

  Action2: heat up this IC, can resume programming function, but still failed when cold down.

4. Repeat the 1^st level analysis action and verify

  Take 2 pcs failed sample for example, S/N: L12A008354 and L12A008367, result is as below:

  4.1 Heat U1 (NG: L12A008354), can connect to programmer and reprogram F/W, but after the temperature of U1 is down,still failed (can't connect to programmer and reprogram F/W).

  4.2 Heat U2(NG:L12A008367), still failed. Retry to heat 1 time, failed again.

  4.3 Change 1 pcs new IC on NG board, then pass

5. 2^nd level analysis based on board/circuit diagram, check the basic working condition

  The U1 is a microcontroller, so the basic working condition is power supply and oscillator. After measure the frequency and voltage by Osc, the basic condition can meet U1 requirement.

6. 3^rd level analysis, signal check

  6.1 Measure and compare the signal of P1 that uses to connect to programmer.

 

	Good Board		NG Board
PIN#	Connected	Disconnected	Connected	Disconnected
#1	3.3	3.3	3.3	3.3
#2	0	0	0	0
#3	0	0	0	0
#4	5	5	5	5
#5	2.5	2.5	2.5	2.5
#6	2.5	2.5	2.5	2.5
#7	5	5	0~0.999	5
#8	0	0	0	0
#9	0	0	0	0
#10	5	-3.3	5	-3.3
	Measure the voltage between GND by DMM

PIN7 of P1 connector connect to PIN12 of U1 directly. Pin12 is the reset signal and low voltage is active. But when NG board connect to programmer, this signal keep "0" all the time, but disconnect to programmer, the signal is OK.

Refer to datasheet of C8051F501

  6.2 Check the interface (C2) and the key signal from U1

  C2 Interface: C8051F50x-F51x devices include an on-chip Silicon Labs 2-Wire (C2) debug interface to allow Flash programming and in-system debugging with the production part installed in the end application. The C2 interface uses a clock signal (C2CK) and a bi-directional C2 data signal (C2D) to transfer information between the device and a host system. See the C2 Interface Specification for details on the C2 protocol. (Refer to section 28 of datasheet)

The result is as below:

Item	Sample #	U1 Signal Pin	Picture #	Status
1	OK(L12A008367)	PIN12(Reset/clk)	ALL0000/ALL0001	Connected
2	OK(L12A008367)	PIN11(Data)	ALL0002/ALL0003	Connected
3	OK(L12A008367)	PIN11	ALL0004	Disconnected
4	NG(L12A008354)	PIN12	ALL0005	Connected
5	NG(L12A008354)	PIN11	ALL0006/ALL0007/ALL0008/ALL0009	Connected
6	NG(E13A021033)	PIN12	ALL0010/ALL0011	Connected
7	NG(E13A021033)	PIN11	ALL0012	Connected

 

      (Pin12 Good board) Vs. (Pin12 NG board)

(Pin11 Good board) Vs. (Pin11 NG board)

7. Conclusion and next action

  7.1 Conclusion is that raw material is bad.

  7.2 Send the failed chip samples to supplier for further failure analysis on chip level.

PCBA FCT Basic Introduction--Annual Training (MS PowerPoint)

Ø

Topic

1. ØType of Test 
2. ØBasic Test Methodology 
3. ØFCT Basic Architecture 
4. ØHardware Platform 
5. ØVI-Virtual Instrument 
6. ØDMM Introduction 
7. ØDAQ Introduction 
8. ØReference  

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