NCP3123 ON Semiconductor, NCP3123 Datasheet
NCP3123
Available stocks
Related parts for NCP3123
NCP3123 Summary of contents
Page 1
... The NCP3123 is a dual buck converter designed for low voltage applications requiring high efficiency. This device is capable of producing an output voltage as low as 0.8 V. The NCP3123 provides dual 3.0 A switching regulators with an adjustable 200 kHz − 2200 kHz switching frequency. The switching frequency is set by an external resistor. The NCP3123 also incorporates an auto− ...
Page 2
COMP 1 Error Amplifier FB 1 EOTA Soft Start & Tracking Control (MUX1) TRACK 1 RT ref (0.8 V) SEQ1 Power EN 1 Sequencing 1 Power EN 2 Sequencing 2 SEQ 2 SS2 ...
Page 3
... Soft−start/stop control input for Channel 1. An internal current source charges an external capacitor con- nected to this pin to set the soft−start time. 30 GND1 Power ground for Channel 1. Exposed Pad The exposed pad at the bottom of the package is the electrical ground connection of the NCP3123. This (GND) node must be tied to ground. Description http://onsemi.com 3 ...
Page 4
MAXIMUM RATINGS Characteristics Power Supply Voltage Input Signal Supply Voltage Input SW Pin Voltage EN Pin Voltage Input SEQ Pin Voltage Output PG Pin Voltage All Other Pins Thermal Resistance, Junction−to−Ambient (Note 1) Storage Temperature Range Junction Operating Temperature (Note ...
Page 5
ELECTRICAL CHARACTERISTICS noted open kW) T Characteristic RECOMMENDED OPERATING CONDITIONS Input Voltage Range SUPPLY CURRENT Quiescent Supply Current Shutdown Supply Current UNDERVOLTAGE LOCKOUT UVLO Threshold UVLO Hysteresis SWITCHING REGULATOR Minimum Duty Cycle Maximum Duty Cycle High Side MOSFET ...
Page 6
ELECTRICAL CHARACTERISTICS noted open kW) T Characteristic TRACK Tracking Voltage Range Tracking Voltage Offset Track Bias Current POWER GOOD PG Threshold PG Shutdown Mode PG Delay PG Low Level Voltage PG Hysteresis PG Leakage Current ENABLE/POWER SEQUENCING Enable ...
Page 7
TYPICAL OPERATING CHARACTERISTICS 0.813 0.808 0.803 0.798 0.793 0.788 0.783 −50 − TEMPERATURE (°C) Figure 3. Feedback Voltage vs. Temperature 216 211 206 RT = open 201 196 191 186 −50 − TEMPERATURE (°C) ...
Page 8
TYPICAL OPERATING CHARACTERISTICS 100 −50 − TEMPERATURE (°C) Figure 7. Shutdown Supply Current vs. Temperature 4.50 4.45 4.40 4.35 4.30 4.25 4.20 −50 − ...
Page 9
TYPICAL OPERATING CHARACTERISTICS 9.9 9.4 8.9 8.4 7.9 7.4 6.9 −50 − TEMPERATURE (°C) Figure 13. Soft−Start Discharge Current vs. Temperature 0.6 V TRACK −5 −10 −15 −50 − ...
Page 10
... Figure 22. SEQ Internal Pull−down Current vs. 3.318 3.315 3.312 3.309 3.306 3.303 3 0.5 Figure 24. NCP3123 Load Regulation http://onsemi.com 10 www.DataSheet4U.com 100 125 TEMPERATURE (°C) Temperature 100 125 TEMPERATURE (°C) Temperature ...
Page 11
... Figure 30. Minimum Input Voltage vs. Operating Frequency, 3A, 3.3 Vout http://onsemi.com 11 www.DataSheet4U.com 12 V 500 kHz 750 kHz 1400 kHz 2200 kHz 1.0 1.5 2.0 2.5 I (A) out Figure 26. NCP3123 Efficiency 255C in out 800 1000 1200 1400 1600 1800 2000 ...
Page 12
TYPICAL OPERATING CHARACTERISTICS 5.7 5.6 5.5 5.4 5.3 5.2 5.1 5.0 4.9 200 400 600 800 1000 1200 1400 FREQUENCY (kHz) Figure 31. Minimum Input Voltage vs. Operating Frequency, 3A, 1.8 Vout 6 0.1 A 0.5 A 1.0 A 1.5 ...
Page 13
... SEQ pin have to be pulled high or connected directly to V (max 8 V). in Note: For proper operation of the NCP3123 circuit, no voltage may be pulled high on the output pins. The output capacitors should be discharged. If this condition is not observed when NCP3123 is enabled, the regulator does not start switching ...
Page 14
... The current through each channel is continuously monitored. The current limit is set to allow Thermal Shutdown The NCP3123 has a thermal shutdown feature to protect the device from overheating when the die temperature exceeds 160°C (typically). If the chip temperature exceeds the overtemperature shutdown trip point, the fault signal is activated ...
Page 15
Inductor The output inductor may be the most critical component in the converter because it will directly affect the choice of other components and dictate both the steady state and transient performance of the converter. When choosing inductors, one might ...
Page 16
... The peak reverse voltage is equal to the maximum input voltage. The peak conducting current is clamped by the current limit of the NCP3123. Use of Schottky barrier diodes reduces diode reverse recovery input current spikes. For switching regulators operating at low duty cycles beneficial to use rectifying diodes with somewhat higher RMS current ratings (thus lower forward voltages) ...
Page 17
Table 3. Schottky Diode Example Part Number Description MBRA340T3G Schottky Rectifier MBRS340T3G Schottky Rectifier MBRS330T3G Schottky Rectifier The worst case of the diode average current occurs during maximum ...
Page 18
Output Voltage Programming The controller will maintain 0 the feedback pin. Thus resistor divider circuit is placed across the Table 4. Output Voltage Setting V [V] 8 7.5 OUT R [kW] 180 360 1 R [kW] ...
Page 19
... In that case, the signal processors require multiple power supplies generating different voltage levels for core and I/O peripherals over time. NCP3123 offers ratiometric sequencing, sequential sequencing and tracking sections to manage the output voltages behavior during start−up and power−down. Basically, the DSP, FPGA, and PLD ...
Page 20
EN1/SEQ1 & EN2/SEQ2 SS1 & SS2 0.8V 90% V FB1 (min) VOUT1 & VOUT2 90% V FB2 (min) PG1 & PG2 Figure 41. Typical Behavior of Ratiometric Sequencing Mode Figure 42. Ratiometric Mode − Power−up Figure 44. Ratiometric Mode − ...
Page 21
... Figure 46 shows the NCP3123’s configuration and standard waveforms. The rising slope of both voltages can be selected independently by the soft−start capacitors’ values (C12, C22). When the ...
Page 22
... Vout1 Vout2 Vout3 Vout4 Figure 47. Simplified Drawing of Daisy−chained NCP3123’s When the first voltage rail has reached a specific voltage level, the next voltage rail is enabled and its rise is monitored until it has reached the power good trip point. At this point, the next voltage rail is enabled. This continues until all soft− ...
Page 23
EN1 & SEQ2 SS1 90 (min) VOUT1 Internal PG1 90 VOUT2 (min) Internal PG2 SEQ1 & EN2 SS2 VOUT1 & VOUT2 PG1 PG2 Figure 48. Typical Behavior of Sequential Mode 0.8V 4V 0.8V 4V http://onsemi.com 23 ...
Page 24
Figure 49. Sequential Mode − Power−up Figure 51. Sequential Mode − Power−down Figure 52. Daisy Chain of Four Outputs Figure 50. Sequential Mode − Power−down Figure 53. OLM of the 3rd Output in Daisy http://onsemi.com 24 www.DataSheet4U.com Chain ...
Page 25
... Track pins must be tied high in the normal operation (except in the tracking mode). The output voltage during tracking can be calculated with the following equation OUT C3 C13 R8 Cmaster SW1 VIN VIN VIN NCP3123 VIN VIN VIN SW2 R11 GND GND R7 C4 GND C master Figure 54. Tracking Configuration http://onsemi.com 25 www ...
Page 26
EN1/SEQ1 & EN2/SEQ2 SS1 0.8V 90 (min) VOUT1 & SS2 TRACK2 0. (min) VOUT1 90 & VOUT2 (min) PG1 PG2 Figure 55. Typical Behavior of Tracking Configuration 4V http://onsemi.com 26 ...
Page 27
Figure 56. Tracking Mode − Power−up Figure 58. Tracking Mode of Four Outputs − Power−up When hiccup overload mode is detected on the slave channel only, the output voltage of the 2nd channel (slave) decreases. After the overload condition ends, ...
Page 28
Figure 61. Master Voltage − Start of OLM Figure 63. Master Voltage − Start of Augmented OLM Note: If the overload conditions are detected on the master channel only or on both channels together (master + slave), Figure 62. Master ...
Page 29
... PG2 EN1 SEQ1 NCP3123 EN2 SEQ2 TRACK1 TRACK2 R9 GND GND R7 C4 GND C1 C16 R17 C6 R21 PG1 PG2 EN1 SEQ1 NCP3123 EN2 SEQ2 TRACK1 TRACK2 R18 GND GND R16 C2 GND Figure 65. Mixed Mode, Configuration A http://onsemi.com 29 www.DataSheet4U.com VIN GND SW1 L1 VIN ...
Page 30
Figure 66. Mixed Mode of Four Outputs − Power−up Figure 67. Mixed Mode of Four Outputs − Power−down http://onsemi.com 30 www.DataSheet4U.com ...
Page 31
... Out2 EN EN OUT OUT SEQ SEQ NCP3123 NCP3123 TRACK TRACK VOUT1 VOUT2 VOUT3 VOUT4 VOUT5 VOUT6 Figure 68. Mixed Mode, Configuration B Figure 70. Mixed Mode of Six Outputs − http://onsemi.com 31 www.DataSheet4U.com Out5 EN OUT SEQ NCP3123 TRACK Out6 EN OUT SEQ NCP3123 TRACK Power−down ...
Page 32
... EN1 Enable Disable EN2 RT VOUT1 VOUT2 AVIN C13 C3 R13 C12 SW1 PG1 VIN PG2 VIN EN1 VIN SEQ1 NCP3123 VIN EN2 VIN SEQ2 VIN TRACK1 SW2 TRACK2 C22 GND GND R23 C23 GND Figure 71. Normal Operation Configuration http://onsemi.com 32 www.DataSheet4U.com VIN ...
Page 33
EN1/SEQ1 EN2/SEQ2 SS1 0.8V SS2 90%VFB (min) VOUT1 90%VFB (min) VOUT2 PG1 PG2 Figure 72. Typical Application Behavior 4V 0.8V 4V http://onsemi.com 33 www.DataSheet4U.com 0.8V 0.8V hyst + delay hyst + delay ...
Page 34
... Parallel Operation Parallel operation of NCP3123 circuit(s) has several advantages. One of the most important aspects is the capability to deliver a double output current. The major advantage is a reduced output voltage ripple in case of out−of−phase synchronization. The standard configuration is shown in Figure 73. R_TRACK PG1 Enable ...
Page 35
Figure 74. Parallel Operation of Both Outputs http://onsemi.com 35 www.DataSheet4U.com ...
Page 36
... IC. for specific requirements, the COMPCALC design tool is available from ON Semiconductor at no charge. Visit http://www.onsemi.com/pub/Collateral/COMPCALC.ZIP to download the self−extracting program for NCP3123 loop compensation design assistance. There is an Excel design tool for component selection. This design tool is available at http://www.onsemi.com/pub/Collateral/NCP312X%20 DWS ...
Page 37
Layout Diagram Figure 75. Typical Layout Diagram http://onsemi.com 37 www.DataSheet4U.com ...
Page 38
... EN2 EN2 SEQ2 TRACK1 TRACK2 C13 22n C15 NU R13 C3 4.7k RVIN 100n 100 C12 100n SW1 VIN VIN VIN NCP3123 VIN VIN VIN SW2 C22 100n GND R23 4.7k C25 NU C23 22n GND Figure 76. Typical Circuit Diagram http://onsemi.com 38 www.DataSheet4U.com VIN GND OUT1 ...
Page 39
Figure 77. PCB Layout Example − Evaluation Board v 2.11 http://onsemi.com 39 www.DataSheet4U.com ...
Page 40
... MBRS340T3 ORDERING INFORMATION Device NCP3123MNTXG †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D. BOM of the NCP3123 – Evaluation Board v2.11 Scale Ref. Designator Chip NCP3123 Resistors 1206 RV ...
Page 41
... D 5.00 BSC D2 2.950 3.100 3.250 E 5.00 BSC E2 2.950 3.100 3.250 e 0.500 BSC K 0.200 −−− −−− L 0.300 0.400 0.500 5.30 3.20 3.20 5. 0.50 PITCH ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative NCP3123/D ...