LC101N

LC101N SANKEN | Alldatasheet

Document overview

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Technical content

Datasheet sections

• 11.3 Current Balance Operation -------------------------------- -------------------------------- -------
• 11.4 Operable voltage of LC101N -------------------------------- -------------------------------- ------
• 11.5 Overcurrent Protection (OCP) -------------------------------- -------------------------------- ---
• 11.6 Thermal Shutdown (TSD) -------------------------------- -------------------------------- ---------
• 12.1 External Components -------------------------------- -------------------------------- --------------
• 12.1.1 LED current setup resistor, R1 -------------------------------- -----------------------------
• 12.2.1 PCB Trace Layout and Component Placement -------------------------------- -------
• 12.2.2 Pattern Layout Example -------------------------------- -------------------------------- ---
• 12.2.3 Land Pattern Example -------------------------------- -------------------------------- -----
• 14.1 Emboss and Carrier Tape Specification -------------------------------- ----------------------

Features

• Maximum current is 150 mA
• Low input-output voltage difference design is achieved by low saturation voltage; VDIF(max.)＝0.35 V (Io = 150 mA)
• Reference voltage of 200 mV reduces the sense resistor loss
• Optimal balance operation can be realise in parallel connection of multiple LED strings
• Protections Overcurrent Protection (OCP): Foldback Thermal Shutdown (TSD): Auto-restart Typical Application ICONST LO FB IN LED LC101N R1ILED1 LO FB IN LED LC101N R2ILED2 Package DFN 8 *Not to scale

Electrical Characteristics

• Maximum input voltage: 35 V
• Maximum output current: 150 mA
• Reference voltage for the constant current control: 200 mV
• Power Dissipation: 1.3 W

Applications

• LED Lightings
• Back light system for LCD-Touch-panels,etc. 余白上 35mm ヘッター1 線 長さ 174 mm 下方向 33mm 右方向-2mm ヘッター1 線 長さ 174 mm 下方向 33mm 右方向-2mm

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 3 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015 1. Absolute Maximum Ratings

• Unless otherwise specified TA = 25 °C, the LO pin is reference voltage level. Parameter Symbol Rating Units Notes DC input voltage VIN 35 V LED pin voltage VLED VIN V FB pin voltage VFB 5 V Allowable Power Dissipation PD 1.3 W Reference layout pattern mounting on the FR4 double-sided PCB . Refer to Section 12.2.2. Junction Temperature Tj − 40 to 125 °C Storage Temperature Tstg − 40to 80 °C * When the junction temperature of the IC becomes 110 °C (min.) or more, the thermal shutdown (TSD) activates. 2. Recommended Operating Conditions
• Unless otherwise specified TA = 25 °C, the LO pin is reference voltage level. Parameter Symbol Min. Max. Units Notes IN－LO Voltage VIN 2.4 * V Output Current ILED 15 150* mA Operating Ambient Temperature TOP − 20 + 80 °C * Since the between V IN and ILED has following relationship, the value of V IN is different by condition. Allowable power dissipation, PD is calculated by Figure 5-1. PD(MAX) = (VIN − VLED) × ILED(MAX) (1) 3. Electrical Characteristics
• Unless otherwise specified TA = 25 °C, the LO pin is reference voltage level. Parameter Symbol Conditions Min. Typ. Max. Units Reference Voltage VFB VIN = 4 V, ILED = 15 mA 0.194 0.200 0.206 V Reference Voltage Temperature Coefficient (1) ΔVFB/TA Tj = 25 °C to 100 °C -0.02 mV/°C Voltage Difference between Input and Output (2) ΔVDIF ILED ≤ 50 mA 0.18 V ILED ≤ 150 mA 0.35 V Overcurrent protection threshold Current IS1 VIN = 4V, VLED = 90 % 160 mA Thermal Shutdown Temperature(1) TSD 110 130 °C (1) Design assurance. (2) The saturation voltage between the IN pin and the LED pin. 4. Thermal Resistance
• Unless otherwise specified TA = 25 °C, the LO pin is reference voltage level. Parameter Symbol Rating Units Notes Junction to Ambient Thermal Resistance θj-A 65 °C/W Junction to Case Thermal Resistance θj-TOP 27 °C/W Marking surface

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 5 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015 6. Block Diagram IN

1 LED

1. Pin Configuration Definitions IN NC NC LED LO NC NC FB Pin Name Descriptions

1 IN Constant current source input

2 NC Not connected

3 NC Not connected

4 LED Output pin to LED

5 FB LED current detection signal input (positive side)

6 NC Not connected

7 NC Not connected

8 LO LED current detection signal input (negative side)

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 6 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015 8. Typical Application ICONST LO FB IN LED LC101N R1ILED1 LO FB IN LED LC101N R2ILED2 R1 and R2 are set up resistor of ILED

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 7 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015 9. External Dimensions

• DFN8 NOTES:
• Dimension is in millimeters
• Pb-free. Device composition compliant with the RoHS directive
• Width of 1 pin is 0.375 mm, the others are 0.3mm
• In order to release temperrature The heat slug of the back surface should heat dissipation to the pattern of PCB. 10. Marking Diagram

8 Abbreviated product number (LC101N)

Y = Last Digit of Year (0~9) M = Month (1~9, O, N or D) D = Period of days (1~9 or A~Z without B, I, O and Q)

1 Y M D

<Top View> <Bottom View> <Side View>

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 8 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015 11. Operational Description

11.1 Basic operation

The current control of the LC101N is quite simple. The both end voltage of the setup resistor R1 which is connected between the FB terminal and the LO pin. So that it becomes constant, the emitter -collector voltage of the internal PNP -transistor is linear -controlled by the error amplifier. Figure 11-1 shows the basic circuit of LC101N. ICONST LO FB IN LED LC101N R1ILED1 LO FB IN LED LC101N R2ILED2 Constant current source LED string A LED1 LED2VF1 VF2 VF1×n VF2×n LED string B Figure 11-1 LC101N basic circuit LED current, ILED is calculated by Equation (3). (3) From Equation (3), the setup resistor, R1 is calculated by Equation (4). (4) The r eference voltage , VFB for the c onstant current control is 200 mV. The both end vol tage of R1 is controlled to become equal to VFB. The loss of R1, PR1 is calculated by Equation (5). (5) Table 11-1 shows the calculation result of relationship of ILED, R1, and PR1. Table 11-1 The loss of R1, PR1 ILED (mA) R1 (Ω) PR1 (mW) 50 4 10 100 2 20 150 1.33 30 In addition, the loss of the IC , PD is calculated by Equation (6). (6) where, VIN is the voltage between the IN pin and the LO pin, and VLED is the voltage between the LED pin and LO pin.

11.2 Power Supply

The power supply should be use the constant-current source. If the constant-voltage source is used, the voltage difference between input and output that does not require for LED becomes the loss of the IC. Though it will operate with the constant-voltage source, if the input-output voltage difference becomes larger than necessary, and all of surplus will be loss in this IC The ability of power supply, PIN is required to satisfy following equation. (7) where, N is number of LED in series, VF is forward voltage of LED, and ICONST is the constant current of power supply. For example, LED current is set to 50 mA in Figure 11-1. The constant current of power supply, ICONST, is set fewer than the total current value of LED -strings A and B (100mA), because the drooping characteristic of constant-current source is considered. In this case, ICONST is set 95 mA. If VF = 3V and n = 7, PIN becomes as follows:

11.3 Current Balance Operation

If All LEDs have same VF, and the same current flows to LED-string A and B, the power loss of IC becomes minimum because the circuit is controlled by the constant-current source, ICONST and the internal transistor is a saturated condition. However, the complete equilibrium state is impossible by characteristic variations of VF. If each VF2 of LED string B is smaller than VF1 of LED string A by 0.1 V.

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 9 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015 In this case, is applied to between the IN pin and the LED pin of LC101N. Since the LED string B current, ILED2, is controlled to constant by R2, the loss of LC101N of LED string B side is following value, and is enough acceptable value. If it is operated in the constant current source, the voltage applied to the LED string, it becomes the minimum requirement value of the LED-string with the highest VF. When the constant current source is used, the necessary voltage for LED string with the highest total VF is supplied. Thus, LC101N reduces the current concentration by VF fluctuation and, the brightness unevenness.

11.4 Operable voltage of LC101N

Operating conditions of LC101N are as follows:

• The minimum difference voltage between the IN pin and thr LED pin is higher than the ΔVDIF.
• The voltage of the IN pin is higher than 2.4V(min.) against the LO pin. One LED is added to the LED pin and setup resistor as shown in Figure 11-1 in order to have enough voltage between the IN pin and the LO pin.

11.5 Overcurrent Protection (OCP)

The LC101N have the fold-back characteristics in overcurrent protection (OCP) as shown in Figure 13-2. The short circuit current does not return to completely 0 A, because start-up characteristics is considered. Thus, be careful to heat generation. When OCP is activated, the LED pin voltage decreases. Then, the difference voltage between input and output is increased, and the temperature of IC increases. In this case, Thermal shutdown might activate (refer to Section 11.6).

11.6 Thermal Shutdown (TSD)

LC101N has the Thermal Shutdown (TSD). The junction temperature of the IC chip, Tj, is detected. When Tj is increase to TSD = 130 °C (typ.), the drive current of the internal PNP transistor is limited. Since the minimum activation temperature of the TSD is 110 °C, Tj should be set less than 110 °C in thermal design. TSD does not have hysteresis. When Tj decreases to TSD or less, the IC returns to normal operation automatically. When TSD is activated under the overcurrent condition, following condition is repeated and output voltage waveform, VLED, becomes intermittent oscillation (refer to Figure 13-4). Overcurrent condition −> VLED decreases −> ILED decreases −> junction temperature Tj decreases −> automatically restart −> Overcurrent condition….

• Notice of TSD The purpose of the TSD is the protection of IC from temporary heat generation. TSD does not guarantee the operation including reliabilities under the continuous heat generation conditions, such as short circuit for a long time. Since the temperature of LC101N which is connected to the LED depends on the mounting location (distance) and the wiring method, TSD might be activated by the thermal of LEDs. 12. Design Notes

12.1 External Components

All components are required for matching to the condition of use.

12.1.1 LED current setup resistor, R1

Reference voltage of LC101N, VFB, controls the LED current, is 200 mV. The IC controls so that the VFB and both end voltage of setup resistor R1 is equal. Because the VFB is low voltage, the resistor should not be selected wirewound resistors to prevent malfunction in transient state including start/stop operation. In addition, lead of the resistor of through hole type should be short to reduce the back electromotive voltage by the parasitic inductance. R1 is recommended surface device, and should be as close to LC101N as possible. If the problem occurs at the open-short test of resistor, please considering the series-parallel connection of the resistor. R1 setup is as shown in Table 11-1.

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 10 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015

12.2 Pattern Layout

12.2.1 PCB Trace Layout and Component

• Setup resistance, R1, should be as close to the FB pin and the LO pin as possible as shown in Figure 12-1.
• The layout between the FB pin and the LED string should be avoided to parallel with switching trace. Noise is superimposed to the FB pin by induction, the LC101N might be malfunction. LO FB IN 8 5 LED LC101N constant-current source LED string R1 should be as close to the FB pin and the LO pin. LED1 Figure 12-1 Important locations of the pattern layout

12.2.2 Pattern Layout Example

Figure 12-2 shows the pattern layout example, and Table 12-1 shows this PCB information. Table 12-1 PCB information of pattern layout example Items Information PCB type double-sided Size(Outline) 40 mm × 40 mm Substrate thickness t = 1.6 mm Copper foil thickness 35 μm (A) Top View (B) Bottom View Figure 12-2 Pattern layout example LED LED LED LED IN Lo Lo FB LC101N Power supply (+) *Ground of power supply is LO pin 1pin→ LED

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 11 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015

12.2.3 Land Pattern Example

0.15 0.65 0.30 1.50 0.60 0.50 3.00 0.375 2.30 Figure 12-3 Land pattern example (not to scale) 13. Typical Performance Curves Figure 13-1 Saturation voltage characteristic Figure 13-2 Overcurrent characteristic Figure 13-3 LO Pin Current Figure 13-4 Thermal shutdown characteristic 0.05 0.1 0.15 0.2 0.25 0.3 0 50 100 150 LED Current mA (1)入出力電圧差 Doropout Voltage 0.5 1.5 2.5 3.5 4.5 0 0.1 0.2 0.3 0.4 LED Current A (2)過電流保護 Over current protection 0 2 4 6 8 10 12 Input Voltage V (3)Lo 端子電流 ＊VLED=3.8v Setting Lo Terminal Current 0.5 1.5 2.5 3.5 4.5 0 50 100 150 Junction Temperature ℃ (4)過熱保護特性 Thermal protection Saturation voltage, ΔVDEF (V) ILED (mA) ILED (mA) VIN=4V VIN=6V VLED (V) Junction temperature, Tj (°C) VLED (V) VIN = 4.5 V TA = 25 °C Input Voltage VIN (V) LO Pin Current ILO (mA) ILED=150mA ILED=100mA ILED=100mA VLED = 3.8 V

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 12 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015 14. Packing Specifications

14.1 Emboss and Carrier Tape Specification

Figure 14-1 Emboss and carrier tape dimensions The direction of tape drawer The direction of tape drawer Units：mm Taping direction Empty seal part IC receipt part Empty seal part 160 mm(min.) Trailer part 5000 pcs (5000 pockets) Cover tape↓ 200 mm(min.) Leader part 600 mm(min.)

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 13 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015

14.2 Reel Specifications

Figure 14-2 Reel dimensions 9 ± 0.3 11.4 ± 1.0 Material：PS (Polystyrene) Color：Black Quantity/Reel: 5000 pcs. Units：mm

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 14 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015 15. Recommended Reflow Temperature Profile Figure 15-1 Recommended reflow temperature profile 90 ± 30 s 30 ± 10 s 250 °C (peak) 230 °C 180 °C 150 °C 250 200 150 Solder joint temperature (°C) *Reflow is limited to twice.

LC101N-DSE Rev.1.0 SANKEN ELECTRIC CO.,LTD 15 Nov.19, 2015 http://www.sanken-ele.co.jp/en/ © SANKEN ELECTRIC CO.,LTD. 2015 IMPORTANT NOTES

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