Wide Input Range / Step Down onverter The NT3875 is a step down PWM converter with driving a output current up to 2A (NT3875A) and 1A (NT3875B) without additional transistor. It is designed to allow for operating a wide supply voltage range from 8 to 40. The external shutdown function can be controlled by logic level to pull MP/EN pin down, and then comes into standby mode. The external compensation makes feedback control have good line and load regulation with flexible external design. The NT3875 features a programmable / mode control functions. The mode (constant voltage) function provides a regulated voltage output and the mode (constant current) function provides a current limitation function. The current value is set by external resister during current sense amplifier input stage. The NT3875 is suitable for the D/D switching power applications when requested the current limit function. The devices are available in SP8L and PSP8L packages and require very few external devices for operation. ar harger Portable harger Devices HighBrightness Lighting General Description Applications IN perate with 8 ~ 40 Supply oltage UT Accuracy (ref =1.2) +1.0% ver Line oltage / Mode ontrol (onstant urrent and onstant oltage) +/ 5% urrent Limit Accuracy utput Short ircuit Protection utput ver oltage Protection (~120%) ver Temperature Protection Internal Soft Start ~ 7ms Fixed Frequency 120 KHz UL Protection (min=6, typ=7, max=8) Duty ycle Range (0~90%) Single Pin to External ompensation and Shutdown ontrol Integrated Power NMSFET Rds_on=150m ohm for NT3875A Rds_on=240m ohm for NT3875B (P)SP 8L Package Features rdering Information GeneralPurpose D/D onverters with urrent Limit rder Number NT3875ASA8 Package SP8L Remark utput urrent = 2A NT3875ASW8 PSP8L utput urrent = 2A NT3875BSA8 SP8L utput urrent = 1A Note: NT products are compatible with the current IP/ JEDE JSTD020 requirement. They are halogenfree, RoHS compliant and 100% matte tin (Sn) plating that are suitable for use in SnPb or Pbfree soldering processes. Pin onfiguration 1 8 LX FB 2 7 BST MP/EN 3 6 ISEN GND 4 5 SP8L/ PSP8L ISEN+ Rev. 30, File Name: NT3875DS3000 1
Typical Application ircuit IN BST LX RS UT R3 MP/EN ISEN+ ISEN 0R 0R R1 GND FB R2 Functional Pin Description No. Pin Name 1 2 FB Pin Function Power Supply Input. Bypass this pin with a 10uF ceramic capacitor to GND, placed as close to the I as possible. Feedback Pin. The voltage at this pin is regulated between output and GND to set the output voltage. to 1.2. onnect to the resistor divider 3 MP/EN 4 GND Error Amplifier utput. This is the output of the error amplifier (EA) and the noninverting input of the PWM comparator. Use this pin in combination with the SEN pin to compensate the voltage control feedback loop of the converter. Pulling MP/EN to a level below 0.4 nominal disables the controller, causes the oscillator to stop, and makes the UGATE and LGATE outputs held low. Ground. onnect this pin to a large PB copper area for best heat dissipation, Return SEN, and MP to this GND and connect this GND to power GND at a single point for best noise immunity. 5 I SEN+ The urrent Sense Input (+) Pin. 6 I SEN The urrent Sense Input () Pin. 7 BST Bootstrap Pin. T his provides power to the internal higher MSFET gate driver. onnect a 10nF capacitor from BST pin to LX pin. 8 L X Power Switching utput to External Inductor. Rev. 30, File Name: NT3875DS3000 2
Functional Block Diagram 5 Internal Regulator urrent Sense Amplifier PR P 5 ISEN+ 120% P Enable Fault Logics BST REF FB 25% REF UP ver Temperature Protection Slope ompensator Gate ontrol Driver LX MP/EN 0.4 REF Error Amp. Enable able omp ramp scillator 120KHz Driver 5 urrent Sense Amplifier GND 0.6 control loop ISEN+ ISEN Rev. 30, File Name: NT3875DS3000 3
Absolute Maximum Rating Supply Input oltage, (Note1) 0.3 to +45 BST to LX 0.3 to +7 LX to GND D 1 to +IN+1 BST to GND D SW0.3 to SW+7 FB, MP to GND D 0.3 to +7 ISEN, ISEN+ to GND D 0.3 to +9 Storage Temperature Range 65 to +150 Junction Temperature 20 to +150 Lead Temperature Range(Soldering 10sec) 260 ESD Rating (Note2) HBM(Human Body Mode)2K MM(Mechine Mode)200 Thermal Information Package Thermal Resistance (Note 3) SP8L θ JA 160 /W SP8L θ J 39 /W PSP8L θ JA 50 /W PSP8L θ J 5 /W Power Dissipation, PD @ TA = 25 SP8L 0.63W PSP8L 2W Note 1. Stresses listed as the above Absolute Maximum Ratings may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note 2. Devices are ESD sensitive. Handling precaution recommended. Note 3. θ JA is measured in the natural convection at T A = 25 on a high effective thermal conductivity test board of JEDE 517 thermal measurement standard. Note 4. The device is not guaranteed to function outside its operating conditions. Rev. 30, File Name: NT3875DS3000 4
( = 12, T A = +25 unless otherwise specified.) onceptual Electrical haracteristics Parameter Supply Input Supply oltage Range Supply Input urrent PWERNRESET Symbol Test onditions Min Typ Max Units 8 40 I Q PR Threshold RTH PR Threshold FT H SILLATR Normal PWM Frequency F S Minimum ntime T NMIN Duty ycle REFERENE Range Reference oltage EF MP/EN = GND 0. 3 0. 5 ma I 5 10 ma Rising. 7 7. 7 8 Falling 6 6. 7 7 120 KHz T A = 25 to 80 102 138 Hz 200 ns Duty 0 90 % R 1. 2 Reference oltage Tolerance 1 + 1 % REF Load ompensator Δ ISEN = 115m 2. 5 % PWM ERRR AMPLIFIER FB Input urrent I B F MP High oltage MP_ H MP Low oltage MP_ L MP Shutdown Threshold oltage FB = 1.2 0. 1 1 ua 5. 5 0. 8 0. 4 MP Source urrent = 1 42 ua MP MP_ H MP Sink urrent = 1 42 ua MP URRENT SENSE AMPLIFIER Difference oltage between ISEN and ISEN+ PRTETIN Δ ISEN 115 m FB ver oltage Level P Recent of REF 120 % FB Under oltage Level UP urrent Limit Recent of 5 REF I LIM. 5 2 % 4 A ver Temperature Shutdown 160 ver Temperature Hysteresis 40 Soft Start Soft Start Time Ts s 7 ms Recycle Time 260 ms Rev. 30, File Name: NT3875DS3000 5
Typical peration haracteristics This page is intentionally left blank and will be updated later. Rev. 30, File Name: NT3875DS3000 6
0.70 ± 0. 10 1.27 ± 0. 10 onceptual 1.50 ± 0. 10 SP8L 4.80 5.00 Package Information 3.80 4.00 5.80 6.20 4.00 ±0. 10 5.50 ± 0. 10 7.00 ± 0. 10 1.27 BS 0.32 0.52 Recommended Solder Pad Layout 0.18 0.25 1.75 MAX 1.45 1.60 0.10 0.25 0.41 0.89 3.81 BS Note 1.Package utline Unit Description: BS: Basic. Represents theoretical exact dimension or dimension target MIN: Minimum dimension specified. MAX: Maximum dimension specified. REF: Reference. Represents dimension for reference use only. This value is not a device specification. TYP. Typical. Provided as a general value. This value is not a device specification. 2.Dimensions in Millimeters. 3.Drawing not to scale. 4.These dimensions do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15mm. Rev. 30, File Name: NT3875DS3000 7
PSP8L Package Information 0.70 ± 0. 10 1.27 ± 0. 10 3.20 ± 0. 10 1.50 ± 0. 10 4.80 5.00 2.60 3.40 1.90 2.45 3.80 4.00 5.80 6.20 4.00 ±0. 10 2.30 ± 0. 10 5.50 ± 0. 10 7.00 ± 0. 10 1.27 BS 0.32 0.52 Recommended Solder Pad Layout 0.18 0.25 1.45 1.60 1.75 MAX 0.05 0.15 0.40 0.90 3.81 BS Note 1.Package utline Unit Description: BS: Basic. Represents theoretical exact dimension or dimension target MIN: Minimum dimension specified. MAX: Maximum dimension specified. REF: Reference. Represents dimension for reference use only. This value is not a device specification. TYP. Typical. Provided as a general value. This value is not a device specification. 2.Dimensions in Millimeters. 3.Drawing not to scale. 4.These dimensions do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15mm. Rev. 30, File Name: NT3875DS3000 8