MBI5028 Preliminary Datasheet Macroblock 16-bit Constant Current LED Sink Driver with Gain Control Features · 16 constant-current output channels · Output current adjustable through an external resistor · Output current gain programmable for White Balance · Constant output current range: 5-90 mA · Excellent output current accuracy: between channels: ±3% (max.), and between ICs: ±6% (max.) · Constant output current invariant to load voltage change · Fast response of output current, OE (min.): 200 ns · 25MHz clock frequency · Schmitt trigger input · 5V supply voltage MBI5028CNS MBI5016CNS MBI5016CF MBI5028CF MBI5028CP MBI5016CP Current Accuracy Between Channels Between ICs < ±3% < ±6% Conditions IOUT = 10 mA ~ 60 mA ÓMacroblock, Inc. 2003 Floor 6-4, No.18, Pu-Ting Rd., Hsinchu, Taiwan 30077, ROC. TEL: +886-3-579-0068, FAX: +886-3-579-7534 E-mail: [email protected] -1- MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Product Description MBI5028 succeeds MBI5026 and is designed for LED displays with Gain Control extension. MBI5028 exploits PrecisionDrive™ technology to enhance its output characteristics. MBI5028 contains a serial buffer and data latches, which convert serial input data into parallel output format. At MBI5028 output stage, sixteen regulated current ports are designed to provide constant current sinks for driving LEDs within a wide range of Vf variations. MBI5028 provides users with great flexibility and device performance while using MBI5028 in their LED panel system design. Users may adjust the output current from 5 mA to 90 mA through an external resistor Rext, which gives users flexibility in controlling the light intensity of LEDs. MBI5028 guarantees to endure maximum 17V at the output port. The high clock frequency, 25 MHz, also satisfies the system requirements of high volume data transmission. MBI5028 also exploits Share-I-O™ technology and is backward compatible with MBI5026 in both electrical characteristics and package aspect. To utilize the Current Adjust feature with Share-I-O™ technology, users may not need to change the printed circuit board originally for MBI5026. To enter a special function mode- Current Adjust mode, users just need to set a sequence of signals on LE(CA1), OE (CA2) and CLK input pins. Normally, the output current can be regulated only through an external resistor. In addition, in the Current Adjust mode, the output current can be software-programmable by a system controller. The system controller adjusts the output current by sending a 7-bit Current Adjust code to 16-bit Configuration Latch through MBI5028 SDI pin. The code will be latched and effective to control the output current regulator. A fine adjustment of the output current could be achieved by a gain ranging from 0.5 to 2 with 128 fine steps. By setting another sequence of signals on LE(CA1), OE (CA2) and CLK input pins, MBI5028 may resume to a Normal mode and perform as MBI5026. The Shift Register, with SDI, SDO, and CLK, carries the image data as usual. A Share-I-O™ technique is specifically applied to MBI5028. By means of the Share-I-O™ technique, an additionally effective function, Current Gain, can be added to LED drivers, however, without any extra pins. Thus, MBI5028 could be a drop-in replacement of MBI5026. The printed circuit board originally designed for MBI5026 may be also applicable for MBI5028. For MBI5028, the pin 4, LE(CA1), and the pin 21, OE (CA2), can be acted as different functions as follows: Pin Device Name MBI5028 Function Description of Pin 4 LE + Current Adjust (CA1) Function Description of Pin 21 OE + Current Adjust (CA2) -2- April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Block Diagram OUT1 OUT0 OUT14 OUT15 IO Regulator R-EXT VDD OE (CA2) Control Logic 16-bit Output Driver LE(CA1) 7 GND 16-bit Configuration Latch 16 CLK 16 16-bit Output Latch 16 16-bit Shift Register SDI Pin Configuration Terminal Description Pin No. Pin Name 1 GND Ground terminal for control logic and current sink 2 SDI Serial-data input to the Shift Register 3 CLK Clock input terminal for data shift on rising edge Function Data strobe input terminal 4 LE(CA1) Serial data is transferred to the respective latch when LE(CA1) is high. The data is latched when LE(CA1) goes low. Also, a control signal input for Current Adjust mode (See Timing Diagram) 5~20 SDO GND SDI CLK LE(CA1) OUT0 OUT1 OUT2 OUT3 OUT4 OUT5 OUT6 OUT7 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 VDD R-EXT SDO OE(CA2) OUT15 OUT14 OUT13 OUT12 OUT11 OUT10 OUT9 OUT8 OUT0 ~ OUT15 Constant current output terminals Output enable terminal 21 OE (CA2) When (active) low, the output drivers are enabled; when high, all output drivers are turned OFF (blanked). Also, a second control signal input for Current Adjust mode (See Timing Diagram) 22 SDO 23 R-EXT 24 VDD Serial-data output to the following SDI of next driver IC Input terminal used to connect an external resister for setting up all output current 5V supply voltage terminal -3- April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Equivalent Circuits of Inputs and Outputs OE (CA2) terminal LE(CA1) terminal VDD IN VDD IN CLK, SDI terminal SDO terminal VDD VDD OUT IN -4- April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Timing Diagram Normal Mode N=0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 CLK SDI LE(CA1) OE (CA2) OFF OUT0 ON OFF OUT1 ON OFF OUT2 ON OFF OUT3 ON OFF OUT15 ON SDO : don’t care Truth Table (In Normal Mode) CLK LE OE SDI OUT0 … OUT 7 … OUT15 SDO H L Dn Dn ….. Dn - 7 …. Dn - 15 Dn-15 L L Dn+1 No Change Dn-14 H L Dn+2 Dn + 2 …. Dn - 5 …. Dn - 13 Dn-13 X L Dn+3 Dn + 2 …. Dn - 5 …. Dn - 13 Dn-13 X H Dn+3 Off Dn-13 -5- April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Entering Current Adjust Mode 1 2 3 4 5 OE (CA2) 1 0 1 1 1 LE(CA1) 0 0 0 1 0 CLK The signal sequence makes MBI5028 enter a Current Adjust mode. Writing Configuration Code N=0 1 2 3 4 5 12 13 14 15 Bit3 Bit2 Bit1 Bit0 CLK LE(CA1) SDI 16-Bit Configuration Code Bit15 Bit14 Bit13 Bit12 Bit11 Bit10 Note: Pin OE (CA2) always enables the output port no matter MBI5028 enters a Current Adjust mode or not. When entering the Current Adjust mode, by sending the positive pulse of LE(CA1), the content of the Shift Register, a Current Adjust code, will be written to the 16-Bit Configuration Latch. Resuming to Normal Mode 1 2 3 4 5 OE (CA2) 1 0 1 1 1 LE(CA1) 0 0 0 0 0 CLK Voltage “Low” The signal sequence makes MBI5028 resume to a Normal mode. Note: If users want to know the whole process, that is how to enter a Current Adjust mode, write Current Adjust codes and resume to a Normal mode, please refer to the contents in Application Information. -6- April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Maximum Ratings Characteristic Symbol Rating Unit Supply Voltage VDD 0~7.0 V Input Voltage VIN -0.4~VDD + 0.4 V Output Current IOUT +90 mA Output Voltage VDS -0.5~+20.0 V Clock Frequency FCLK 25 MHz GND Terminal Current IGND 1440 mA CNS – type Power Dissipation (On PCB, Ta=25°C) Thermal Resistance (On PCB, Ta=25°C) 1.52 PD CF – type 1.30 CP – type 1.11 CNS – type 82 Rth(j-a) CF – type CP – type 96 W °C/W 112 Operating Temperature Topr -40~+85 °C Storage Temperature Tstg -55~+150 °C -7- April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Recommended Operating Conditions Characteristic Symbol Condition Min. Typ. Max. Unit Supply Voltage VDD - 4.5 5.0 5.5 V Output Voltage VDS OUT0 ~ OUT15 - - 17.0 V IOUT DC Test Circuit 5 - 60 mA IOH SDO - - -1.0 mA IOL SDO - - 1.0 mA VIH CLK, OE (CA2), LE(CA1) and SDI CLK, OE (CA2), LE(CA1) and SDI 0.8VDD - VDD+0.3 V -0.3 - 0.3VDD V tw(L) 40 - - ns OE (CA2) Pulse Width tw(OE) 200 - - ns CLK Pulse Width tw(CLK) 20 - - ns 5 - - ns Output Current Input Voltage VIL LE(CA1) Pulse Width Normal Mode VDD=4.5~5.5V Setup Time for SDI tsu(D) Hold Time for SDI th(D) 10 - - ns Setup Time for LE(CA1) tsu(L) 15 - - ns Hold Time for LE(CA1) th(L) 15 - - ns CLK Pulse Width tw(CLK) 20 - - ns Setup Time for LE(CA1) tsu(CA1) 5 - - ns 10 - - ns Current Adjust Mode VDD=4.5~5.5V Hold Time for LE(CA1) th(CA1) Setup Time for OE (CA2) tsu(CA2) 5 - - ns Hold Time for OE (CA2) th(CA2) 10 - - ns Cascade Operation - - 25.0 MHz Ta=85°C (CNS type) - - 0.79 Ta=85°C (CF type) - - 0.67 Ta=85°C (CP type) - - 0.57 Clock Frequency Power Dissipation FCLK PD -8- W April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Electrical Characteristics Characteristic Input Voltage Symbol Condition Min. Typ. Max. Unit “H” level VIH Ta = -40~85ºC 0.8VDD - VDD V “L” level VIL Ta = -40~85ºC GND - 0.3VDD V IOH VOH=17.0V - - 0.5 μA VOL IOL=+1.0mA - - 0.4 V VOH IOH=-1.0mA 4.6 - - V Output Leakage Current Output Voltage SDO Output Current 1 IOUT1 VDS=0.6V Rext=720 Ω - 25.0 - mA Current Skew dIOUT1 IOL=25mA VDS=0.6V Rext=720 Ω - ±1 ±3 % Output Current 2 IOUT2 VDS=0.8V Rext=360 Ω - 50.0 - mA Current Skew dIOUT2 IOL=50mA VDS=0.8V Rext=360 Ω - ±1 ±3 % Output Current vs. Output Voltage Regulation %/dVDS VDS within 1.0V and 3.0V - ±0.1 - %/V Output Current vs. Supply Voltage Regulation %/dVDD VDD within 4.5V and 5.5V - ±1 - %/V RIN(up) OE (CA2) 250 500 800 KΩ RIN(down) LE(CA1) 250 500 800 KΩ IDD(off) 1 Rext=Open, OUT0 ~ OUT15 =Off - 9 - IDD(off) 2 Rext=720 Ω, OUT0 ~ OUT15 =Off - 11 - IDD(off) 3 Rext=360 Ω, OUT0 ~ OUT15 =Off - 14 - IDD(on) 1 Rext=720 Ω, OUT0 ~ OUT15 =On - 11 - IDD(on) 2 Rext=360 Ω, OUT0 ~ OUT15 =On - 14 - Pull-up Resister Pull-down Resister “OFF” Supply Current “ON” mA Test Circuit for Electrical Characteristics IDD VDD OE(CA2) IIH, IIL CLK LE(CA1) IOUT .. .. OUT0 OUT15 SDI R - EXT GND SDO VIH, VIL Iref -9- April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Switching Characteristics Characteristic Propagation Delay Time (“L” to “H”) Symbol Condition Min. Typ. Max. Unit CLK - OUTn tpLH1 - 50 100 ns LE(CA1) - OUTn tpLH2 - 50 100 ns OE (CA2)- OUTn tpLH3 - 20 100 ns CLK - SDO tpLH 15 20 - ns - 100 150 ns - 100 150 ns - 50 150 ns 15 20 - ns 20 - - ns 20 - - ns VDD=5.0 V VDS=0.8 V VIH=VDD VIL=GND Rext=300 Ω VL=4.0 V RL=52 Ω CL=10 pF CLK - OUTn tpHL1 LE(CA1) - OUTn tpHL2 OE (CA2)- OUTn tpHL3 CLK - SDO tpHL CLK tw(CLK) LE(CA1) tw(L) OE (CA2) tw(OE) 200 - - ns Hold Time for LE(CA1) th(L) 5 - - ns Setup Time for LE(CA1) tsu(L) 5 - - ns Maximum CLK Rise Time tr** - - 500 ns Maximum CLK Fall Time tf** - - 500 ns Output Rise Time of Iout tor - 70 200 ns Output Fall Time of Iout tof - 40 120 ns Propagation Delay Time (“H” to “L”) Pulse Width **If the devices are connected in cascade and tr or tf is large, it may be critical to achieve the timing required for data transfer between two cascaded devices. Test Circuit for Switching Characteristics IDD VIH, VIL Function Generator VDD OE(CA2) CLK LE(CA1) IOUT .. .. OUT0 OUT15 RL SDI R - EXT GND SDO CL Logic input waveform VIH = 5V VL CL Iref VIL = 0V tr = tf = 10 ns - 10 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Timing Waveform Normal Mode tW(CLK) tsu(D) SDI 50% 50% CLK 50% 50% th(D) 50% SDO 50% tW(L) tpLH, tpHL LE(CA1) 50% 50% th(L) OE (CA2) tsu(L) LOW = OUTPUTS ENABLED HIGH = OUTPUT OFF 50% OUTn tpLH1, tpHL1 LOW = OUTPUT ON tpLH2, tpHL2 tW(OE) 50% OE (CA2) 50% tpLH3 tpHL3 90% 50% 10% OUTn tof - 11 - 90% 50% 10% tor April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Entering Current Adjust Mode tW(CLK) 50% 50% CLK 50% 50% 50% tsu(CA2) th(CA2) OE (CA2) 50% 50% tsu(CA1) LE(CA1) 50% th(CA1) 50% 2 CLK - 12 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Application Information Constant Current To design LED displays, MBI5028 provides nearly no variations in current from channel to channel and from IC to IC. This can be achieved by: 1) The maximum current variation between channels is less than ±3%, and that between ICs is less than ±6%. 2) In addition, the current characteristic of output stage is flat and users can refer to the figure as shown below. The output current can be kept constant regardless of the variations of LED forward voltages (Vf). This performs as a perfection of load regulation. 100.00 90.00 Iout (mA) 80.00 70.00 60.00 50.00 40.00 30.00 20.00 10.00 0.00 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 2 2.5 VDS (V) - 13 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Adjusting Output Current The output current of each channel (IOUT) is set by an external resistor, Rext. After a power-on status, the relationship between Iout and Rext is shown in the following figure. IOUT (mA) 100 90 80 70 VDS = 1.0V 60 50 40 30 20 10 0 0 500 1000 1500 2000 2500 3000 3500 4000 Resistance of the external resistor, Rext, in Ω Also, the output current in milliamps can be calculated from the equation: IOUT is (625/ Rext) x 14.4 x G, approximately, where Rext, in Ω, is the resistance of the external resistor connected to R-EXT terminal. Conceptually, G is the digital current gain. After a power-on status, the default value of G is 1.984. Based on IOUT = (625/ Rext) x 14.4 x G, thus, IOUT is (625/ Rext) x 28.8 The magnitude of current is around 50mA at 360Ω and 25mA at 720Ω. - 14 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Entering Current Adjust Mode 1 2 3 4 5 OE (CA2) 1 0 1 1 1 LE(CA1) 0 0 0 1 0 CLK Each time the system controller sends the sequence patterns shown above, MBI5028 can enter the Current Adjust mode. During this phase, the system controller can still send data through SDI pin. The state of OE (CA2) and LE(CA1) is sampled by the rising edge of each CLK. We use “0” and “1” to represent the state of “Voltage Low” and “Voltage High” respectively. The states of the successive five OE (CA2) and LE(CA1) are (1, 0), (0, 0), (1, 0), (1, 1) and (1, 0). Writing Configuration Code N=0 1 2 3 4 5 12 13 14 15 Bit3 Bit2 Bit1 Bit0 CLK LE(CA1) SDI 16-Bit Configuration Code Bit15 Bit14 Bit13 Bit12 Bit11 Bit10 : don’t care After entering the Current Adjust mode, the system controller sends a 7-bit Current Adjust code to 16-bit Shift Register through MBI5028 SDI pin. Then sending LE(CA1) will transfer the contents in the Shift Register to a 16-bit Configuration Latch rather than the 16-bit Output Latch in a Normal mode. The 7-bit Current Adjust code in the Configuration Latch will directly affect the IO Regulator by a gain, G. The output current resulted by the gain values will be then defined as: (625/ Rext) x 14.4 x G - 15 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Current Gain … Gain = 1+(63/64) 64 steps …. …. Gain = 1 …. …. 64 steps Gain = 1/2 (1,0,0,0,0,0,0) (0,0,0,0,0,0,0) (1,1,1,1,1,1,1) (0,0,0,0,0,0,1) (0,0,0,0,0,1,0) 16-Bit Configuration Code Meaning Default Value Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 HC CC0 CC1 CC2 CC3 CC4 CC5 - 1 1 1 1 1 1 1 Bit 8 - Bit 9 Bit 10 Bit 11 Bit 12 Bit 13 Bit 14 Bit 15 - - - - - - - 7-bit Current Adjust Code Binary Representation of the Current Adjust Code =｛HC, CC〔0:5〕｝ Gain, G = (1 + HC) x (1 + D/64)/2 where HC is 1 or 0 (HC=0 : Low current band; HC=1 : High current band) and D = CC0 x 25+ CC1 x 24+ CC2 x 23+ CC3 x 22+ CC4 x 21+ CC5 x 20; So, the Current Adjust Code is a floating number with one bit exponent HC and 6-bit mantissa. - 16 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control For example, when the Current Adjust Code is (1,1,1,1,1,1,1) Gain, G = (1+1) x (1+ 63/64)/2 = 1.984 when the Current Adjust Code is (1,0,0,0,0,0,0) Gain, G = (1+1) x (1+ 0/64)/2 = 1 when the Current Adjust Code is (0,0,0,0,0,0,0) Gain, G = (1+0) x (1+ 0/64)/2 = 0.5 After power on, the default value of Current Adjust Code is (1,1,1,1,1,1,1). Thus, G is 1.984. Typically, the output current resulted by the digital current gain, G, is shown as the figure below. Iout vs. Gain (Rext = 720Ω) 30 Iout (mA) 25 20 15 10 5 0 0.5 0.65 0.8 0.95 1.1 1.25 1.4 1.55 1.7 1.85 2 Gain Resuming to Normal Mode 1 2 3 4 5 OE (CA2) 1 0 1 1 1 LE(CA1) 0 0 0 0 0 CLK Voltage “Low” Each time the system controller sends the sequence patterns shown above, MBI5028 can resume to a Normal mode. During this phase, the system controller can still send data through SDI pin. The state of OE (CA2) and LE(CA1) is sampled by the rising edge of each CLK. We use “0” and “1” to represent the state of “Voltage Low” and “Voltage High” respectively. The states of the successive five OE (CA2) and LE(CA1) are (1, 0), (0, 0), (1, 0), (1, 0) and (1, 0). After resuming to the Normal mode, the Shift Register is again merely used for conveying the image data sent from the system controller. The gain will always be effective until power off or the Configuration Latch is re-written. - 17 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Timing Chart for Current Adjust Mode (An Example) N x MBI5028 are connected in cascade, ie, SDO, k --> SDI, k+1. And, all MBI5028 ICs are connected to the same CLK, LE(CA1) and OE (CA2) sources. SDO, 0 SDI, 1 SDO, 1 SDI, 0 CLK LE(CA1) OE (CA2) 1 2 3 4 MBI5028, 1 MBI5028, 0 SDO, 2 SDO, N-1 MBI5028, N-2 MBI5028, 2 5 MBI5028, N-1 1 N x 16 CLK Pulses (Note 1) 2 3 4 5 CLK SDI, 0 - - - - - - - CC5 CC4 CC3 CC2 CC1 CC0 CC HC - - - - - - - - CC5 CC4 CC3 CC2 CC1 CC0 HC - Configuration Codes (Note 1) (Note2) For MBI5028, 0 For MBI5028, N -1 LE(CA1) OE (CA2) LE(CA1) Pulse (Note 3) Writing the Configuration Codes, Code k, k = 0… (N x 16 –1) A Entering Current Adjust Mode B Note 1: N x 16 CLK pulses before the next LE(CA1) shift the configuration codes. N 16-bit Configuration Codes are required, although only 7 bits are significant. C Note 2: Gain G = (1+ HC) x (1 + D/64)/2 D = CC0 x 25+ CC1 x 24 + CC2 x 23 + CC3 x 22 + CC4 x 21 + CC5 x 20 . - 18 - Note 3: The LE(CA1) pulse writes the Configuration Codes to each MBI5028. Resuming to Normal Mode April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Package Power Dissipation (PD) The maximum allowable package power dissipation is determined as PD(max) = (Tj – Ta) / Rth(j-a). When 16 channels are turned on simultaneously, the actual package power dissipation is PD(act) = (IDD x VDD) + (IOUT x Duty x VDS x 16). Therefore, to keep PD(act) ≤ PD(max), the allowable output current as a function of duty cycle is: IOUT = { [ (Tj – Ta) / Rth(j-a) ] – (IDD x VDD) } / VDS / Duty / 16, where Tj = 150°C. (A) Iout = 90mA, VDS = 1.0V, 16 output channels active For CNS type package, the thermal resistance is Rth(j-a) = 82 (°C/W) Ta = 25°C Ta = 55°C 90% 95% 100% 90% 95% 100% 85% 80% 75% 70% 65% 60% 55% 50% 45% 40% 35% 30% 25% 20% 15% 10% Ta = 85°C 5% Iout (mA) Iout vs. Duty Cycle at Rth = 82 (°C/W) 100 90 80 70 60 50 40 30 20 10 0 Duty Cycle For CF type package, the thermal resistance is Rth(j-a) = 96 (°C/W) 100 90 80 70 60 50 40 30 20 10 0 Ta = 25 ℃ Ta = 55 ℃ 85% 80% 75% 70% 65% 60% 55% 50% 45% 40% 35% 30% 25% 20% 15% 10% Ta = 85 ℃ 5% Iout (mA) Iout vs. Duty Cycle at Rth = 96 (°C/W) Duty Cycle - 19 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control For CP type package, the thermal resistance is Rth(j-a) = 112 (°C/W) 100 90 80 70 60 50 40 30 20 10 0 Ta = 25°C Ta = 55°C 100% 95% 90% 85% 80% 75% 70% 65% 60% 55% 50% 45% 40% 35% 30% 25% 20% 15% 10% Ta = 85°C 5% Iout (mA) Iout vs. Duty Cycle at Rth = 112 (°C/W) Duty Cycle (B) Iout = 60mA, VDS = 0.8V, 16 output channels active For CNS type package, the thermal resistance is Rth(j-a) = 82 (°C/W) Iout vs. Duty Cycle at Rth = 82 (°C/W) 70 60 40 Ta = 25°C 30 Ta = 55°C 20 Ta = 85°C 10 100% 95% 90% 85% 80% 75% 70% 65% 60% 55% 50% 45% 40% 35% 30% 25% 20% 15% 10% 0 5% Iout (mA) 50 Duty Cycle - 20 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control For CF type package, the thermal resistance is Rth(j-a) = 96 (°C/W) Iout vs. Duty Cycle at Rth = 96 (°C/W) 70 60 Iout (mA) 50 Ta = 25°C 40 30 Ta = 55°C 20 Ta = 85°C 10 100% 95% 90% 85% 80% 75% 70% 65% 60% 55% 50% 45% 40% 35% 30% 25% 20% 15% 5% 10% 0 Duty Cycle For CP type package, the thermal resistance is Rth(j-a) = 112 (°C/W) Iout vs. Duty Cycle at Rth = 112 (°C/W) 70 60 40 Ta = 25°C 30 Ta = 55°C 20 10 Ta = 85°C 100% 95% 90% 85% 80% 75% 70% 65% 60% 55% 50% 45% 40% 35% 30% 25% 20% 15% 10% 0 5% Iout (mA) 50 Duty Cycle - 21 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control The maximum power dissipation, PD(max) = (Tj-Ta) / Rth(j-a) , decreases as the ambient temperature increases. Max. Power Dissipation at Various Ambient Temperature 1.6 Power Dissipation 1.4 1.2 1 CNS Type: Rth = 82 0.8 CF Type: Rth = 96 0.6 CP Type: Rth = 112 0.4 0.2 0 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 Ambient Temperature Load Supply Voltage (VLED) MBI5028 are designed to operate with VDS ranging from 0.4V to 1.0V considering the package power dissipating limits. VDS may be higher enough to make PD(act) > PD(max) when VLED = 5V and VDS = VLED – Vf, in which VLED is the load supply voltage. In this case, it is recommended to use the lowest possible supply voltage or to set an external voltage reducer (VDROP). A voltage reducer lets VDS = (VLED – Vf) – VDROP. Resisters, or Zener diode can be used in the applications as the following figures. VLED VLED VDROP VDROP Vf Vf VDS VDS MBI5028 MBI5028 - 22 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control Package Outlines MBI5028CNS Outline Drawing SDIP-24-P-300-1.78 Units: mm Weight: 1.11g (typ) MBI5028CF Outline Drawing SOP-24-P-300-1.00 Units: mm Weight: 0.28g (typ) - 23 - April 2003, V0.8-4 MBI5028 16-bit Constant Current LED Sink Driver with Gain Control MBI5028CP Outline Drawing SSOP24-P-150-0.64 Units: mm Weight: 0.11g (typ) - 24 - April 2003, V0.8-4