TPS65251-1RHAR

TPS65251-1, TPS65251-2, TPS65251-3 SLVSC70B – JANUARY 2015 – REVISED JANUARY 2022 TPS65251-x 4.5-V to 18-V Input, High Current, Synchronous Step Down Three Buck Switchers With Integrated FET divider to any value between 0.8 V and close to the input supply. Each converter features an enable pin that allows a delayed start-up for sequencing purposes, soft-start pin that allows adjustable softstart time by choosing the soft-start capacitor, and a current limit (RLIMx) pin that enables the designer to adjust current limit by selecting an external resistor and optimize the choice of inductor. The current mode control allows a simple RC compensation. 1 Features • • • • • • • • • • • • • Wide input supply voltage range (4.5 to 18 V) Output range: 0.8 V to VIN – 1 V Continuous loading: 3 A (buck 1), 2 A (buck 2 and 3) Maximum current: 3.5 A (buck 1), 2.5 A (buck 2 and 3) Adjustable switching frequency 300 kHz to 2.2 MHz set by external resistor Dedicated enable for each buck External synchronization pin for oscillator Adjustable current limit set by external resistor Soft-start pins Current-mode control with simple compensation circuit Power good Automatic PFM/PWM operation VQFN package, 40-pin 6-mm × 6-mm RHA The switching frequency of the converters can either be set with an external resistor connected to ROSC pin or can be synchronized to an external clock connected to the SYNC pin if needed. The switching regulators are designed to operate from 300 kHz to 2.2 MHz. 180° out-of-phase operation between Buck 1 and Buck 2, 3 (Buck 2 and 3 run in phase) minimizes the input filter requirements. TPS65251-x features a supervisor circuit that monitors each converter output. The PGOOD pin is asserted when sequencing is done, all PG signals are reported and a selectable end of reset time lapses. The polarity of the PGOOD signal is active high. 2 Applications • • • • • • Set top boxes Blu-ray™ DVD DVR DTV Car audio/video Security camera All converters feature an automatic low-power pulse PFM skipping mode, which improves efficiency during light loads and standby operation, while ensuring a very-low output ripple, allowing for a value of less than 2% at low output voltages. 3 Description The TPS65251-x features three synchronous wideinput range, high-efficiency buck converters. The converters are designed to simplify its application while giving the designer the option to optimize their usage according to the target application. Device Information TPS65251-1 The converters can operate in 5-, 9-, 12- or 15-V systems and have integrated power transistors. The output voltage can be set externally using a resistor (1) PART NUMBER TPS65251-2 PACKAGE(1) VQFN (40) BODY SIZE (NOM) 6.00 mm × 6.00 mm TPS65251-3 For all available packages, see the orderable addendum at the end of the data sheet. CMP2 SS2 RLIM2 GND LOW_P FB2 V3V V7V PGOOD AGND FB2 GND FB2 EN2 BST2 VIN VIN VIN VIN SS1 RLIM1 CMP1 EN1 V1 VIN1 FB1 FB1 FB3 FB3 LX1 VIN1 BST1 SYNC ROSC FB1 VIN3 BST3 EN3 V2 LX2 LX2 LX1 TPS65251-X GND LX3 LX3 RLIM3 VIN3 VIN2 SS3 CMP3 FB3 V3 VIN2 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. TPS65251-1, TPS65251-2, TPS65251-3 www.ti.com SLVSC70B – JANUARY 2015 – REVISED JANUARY 2022 Table of Contents 1 Features............................................................................1 2 Applications..................................................................... 1 3 Description.......................................................................1 4 Revision History.............................................................. 2 5 Pin Configuration and Functions...................................3 6 Specifications.................................................................. 5 6.1 Absolute Maximum Ratings........................................ 5 6.2 ESD Ratings............................................................... 5 6.3 Recommended Operating Conditions.........................5 6.4 Thermal Information....................................................5 6.5 Electrical Characteristics.............................................6 6.6 Typical Characteristics for Buck 1...............................8 6.7 Typical Characteristics for Buck 2...............................9 6.8 Typical Characteristics for Buck 3.............................10 7 Detailed Description...................................................... 11 7.1 Overview................................................................... 11 7.2 Functional Block Diagram......................................... 11 7.3 Feature Description...................................................12 7.4 Device Functional Modes..........................................15 8 Application and Implementation.................................. 16 8.1 Application Information............................................. 16 8.2 Typical Application.................................................... 16 9 Power Supply Recommendations................................29 10 Layout...........................................................................30 10.1 Layout Guidelines................................................... 30 10.2 Layout Example...................................................... 31 11 Device and Documentation Support..........................32 11.1 Receiving Notification of Documentation Updates.. 32 11.2 Support Resources................................................. 32 11.3 Trademarks............................................................. 32 11.4 Electrostatic Discharge Caution.............................. 32 11.5 Glossary.................................................................. 32 12 Mechanical, Packaging, and Orderable Information.................................................................... 32 4 Revision History Changes from Revision A (January 2015) to Revision B (January 2022) Page • Updated the numbering format for tables, figures, and cross-references throughout the document. ................1 • Change VIN1, VIN2, VIN3, LX1, LX2, and LX3 maximum rating voltage from 18 V to 20 V..............................5 • Change LX1, LX2, and LX3 minimum rating voltage from –1 V to –3 V.............................................................5 Changes from Revision * (January 2015) to Revision A (January 2015) Page • Updated device status to production data ......................................................................................................... 1 2 Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: TPS65251-1 TPS65251-2 TPS65251-3 TPS65251-1, TPS65251-2, TPS65251-3 www.ti.com SLVSC70B – JANUARY 2015 – REVISED JANUARY 2022 5 Pin Configuration and Functions GND LOW_P 26 25 RLIM2 PGOOD 27 SS2 V7V 28 FB2 V3V 29 COMP2 AGND 30 24 23 22 21 GND 31 20 VIN 32 19 BST2 VIN 33 18 VIN2 VIN 34 17 LX2 GND 35 16 LX2 LX3 36 15 LX1 LX3 37 14 LX1 VIN3 38 13 VIN1 BST3 39 12 BST1 EN3 40 11 EN1 FB3 7 8 9 10 RLIM1 CMP3 6 SS1 SS3 5 CMP1 4 FB1 3 SYNC 2 ROSC 1 RLIM3 QFN RHA40 (power pad connected to ground) EN2 Table 5-1. Pin Functions PIN NAME NO. I/O DESCRIPTION RLIM3 1 I Current limit setting for Buck 3. Fit a resistor from this pin to ground to set the peak current limit on the output inductor. SS3 2 I Soft-start pin for Buck 3. Fit a small ceramic capacitor to this pin to set the converter soft-start time. COMP3 3 O Compensation for Buck 3. Fit a series RC circuit to this pin to complete the compensation circuit of this converter. FB3 4 I Feedback input for Buck 3. Connect a divider set to 0.8 V from the output of the converter to ground. SYNC 5 I Synchronous clock input. If there is a sync clock in the system, connect to the pin. When not used, connect to GND. ROSC 6 I Oscillator set. This resistor sets the frequency of the internal autonomous clock. If external synchronization is used, the resistor should be fitted and set to about 70% of external clock frequency. FB1 7 I Feedback pin for Buck 1. Connect a divider set to 0.8 V from the output of the converter to ground. COMP1 8 O Compensation pin for Buck 1. Fit a series RC circuit to this pin to complete the compensation circuit of this converter. SS1 9 I Soft-start pin for Buck 1. Fit a small ceramic capacitor to this pin to set the converter soft-start time. RLIM1 10 I Current limit setting pin for Buck 1. Fit a resistor from this pin to ground to set the peak current limit on the output inductor. EN1 11 I Enable pin for Buck 1. A low-level signal on this pin disables it. If pin is left open, a weak internal pull-up to V3V allows for automatic enable. For a delayed start-up, add a small ceramic capacitor from this pin to ground. BST1 12 I Bootstrap capacitor for Buck 1. Fit a 47-nF ceramic capacitor from this pin to the switching node. VIN1 13 I Input supply for Buck 1. Fit a 10-µF ceramic capacitor close to this pin. O Switching node for Buck 1 O Switching node for Buck 2 LX1 LX2 14 15 16 17 VIN2 18 I Input supply for Buck 2. Fit a 10-µF ceramic capacitor close to this pin. BST2 19 I Bootstrap capacitor for Buck 2. Fit a 47-nF ceramic capacitor from this pin to the switching node. Copyright © 2022 Texas Instruments Incorporated Product Folder Links: TPS65251-1 TPS65251-2 TPS65251-3 Submit Document Feedback 3 TPS65251-1, TPS65251-2, TPS65251-3 www.ti.com SLVSC70B – JANUARY 2015 – REVISED JANUARY 2022 Table 5-1. Pin Functions (continued) PIN NAME NO. I/O DESCRIPTION EN2 20 I Enable pin for Buck 2. A low-level signal on this pin disables it. If pin is left open, a weak internal pull-up to V3V allows for automatic enable. For a delayed start-up, add a small ceramic capacitor from this pin to ground. RLIM2 21 I Current limit setting for Buck 2. Fit a resistor from this pin to ground to set the peak current limit on the output inductor. SS2 22 I Soft-start pin for Buck 2. Fit a small ceramic capacitor to this pin to set the converter soft-start time. COMP2 23 O Compensation pin for Buck 2. Fit a series RC circuit to this pin to complete the compensation circuit of this converter FB2 24 I Feedback input for Buck 2. Connect a divider set to 0.8 V from the output of the converter to ground. LOW_P 25 I Low-power operation mode (active-high) input for TPS65251 GND 26 PGOOD 27 O Power good. Open-drain output asserted after all converters are sequenced and within regulation. Polarity is factory selectable (active-high default). V7V 28 O Internal supply. Connect a 10-μF ceramic capacitor from this pin to ground. V3V 29 O Internal supply. Connect a 3.3- to 10-μF ceramic capacitor from this pin to ground. AGND 30 Analog ground. Connect all GND pins and the power pad together. GND 31 Ground pin Ground pin 32 VIN 33 I Input supply 34 GND LX3 4 35 36 37 Ground pin O Switching node for Buck 3 VIN3 38 Input supply for Buck 3. Fit a 10-µF ceramic capacitor close to this pin. BST3 39 I Bootstrap capacitor for Buck 3. Fit a 47-nF ceramic capacitor from this pin to the switching node. EN3 40 I Enable pin for Buck 3. A low-level signal on this pin disables it. If pin is left open, a weak internal pull-up to V3V allows for automatic enable. For a delayed start-up, add a small ceramic capacitor from this pin to ground. PAD — — Power pad. Connect to ground. Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: TPS65251-1 TPS65251-2 TPS65251-3 TPS65251-1, TPS65251-2, TPS65251-3 www.ti.com SLVSC70B – JANUARY 2015 – REVISED JANUARY 2022 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted)(1) MIN MAX UNIT –0.3 20 V –3 23 V BST1, BST2, BST3, referenced to Lx pin –0.3 7 V V7V –0.3 7 V V3V, RLIM1, RLIM2, RLIM3, EN1, EN2, EN3, SS1, SS2,SS3, FB1, FB2, FB3, PGOOD, SYNC, ROSC, RST_IN, LOW_P, COMP1, COMP2, COMP3 –0.3 3.6 V AGND, GND –0.3 0.3 V TJ Operating virtual junction temperature –40 125 °C Tstg Storage temperature –55 150 °C VIN1,VIN2, VIN3, LX1, LX2, LX3 LX1, LX2, LX3 (maximum withstand voltage transient