Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - hot swap controller Multi-purpose SO 8 Surface-mount

VOUT

VIN

FLT

ISET

GND

SET

(A)

OUT

(A)

VIN

Optional: To

System Monitor

4 5 6

3Vto20VIN

OUT

TPS2421-1

TPS2421-2

www.ti.com

SLUS907G –JANUARY 2009–REVISED MAY 2013

3-V to 20-V Integrated FET Hot Swap

Check for Samples: TPS2421-1, TPS2421-2

FEATURES

DESCRIPTION

The TPS2421 provides highly integrated hot swap

• Integrated Pass MOSFET

power management and superior protection in

• 3.3-V to 20-V Bus Operation

applications where the load is powered by voltages

• Programmable Fault Current

between 3 V and 20 V. These devices are very

effective in systems where a voltage bus must be

• Current Limit Proportionally Larger than Fault

protected to prevent shorts from interrupting or

Current

damaging the unit. The TPS2421 is an easy to use

• Programmable Fault Timer

devices in an 8-pin PowerPad™ SO-8 package.

• Internal MOSFET Power Limiting

The TPS2421 has multiple programmable protection

• Latch-Off on Fault (-1) and Retry (-2) Versions

features. Load protection is accomplished by a non-

• SO-8 PowerPad™ Package

current limiting fault threshold, a hard current limit,

and a fault timer. The current dual thresholds allow

• –40°C to 125°C Junction Temperature Range

the system to draw short high current pulses, while

• UL Listed - File Number E169910

the fault timer is running, without causing a voltage

droop at the load. An example of this is a disk drive

APPLICATIONS

startup. This technique is ideal for loads that

experience brief high demand, but benefit from

• RAID Arrays

protection levels in-line with their average current

• Telecommunications

draw.

• Plug-In Circuit Boards

Hotswap MOSFET protection is provided by power

• Disk Drive

limit circuitry which protects the internal MOSFET

against SOA related failures.

The TPS2421 is available in latch-off on fault (-1) and

retry on fault (-2).

Typical Application

A. Required only in systems with lead and/or load inductance.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2PowerPad is a trademark of Texas Instruments.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (26 pages)

PAGE 1
TPS2421-1 TPS2421-2 www.ti.com SLUS907G – JANUARY 2009 – REVISED MAY 2013 3-V to 20-V Integrated FET Hot Swap Check for Samples: TPS2421-1, TPS2421-2 FEATURES DESCRIPTION • • • • The TPS2421 provides highly integrated hot swap power management and superior protection in applications where the load is powered by voltages between 3 V and 20 V. These devices are very effective in systems where a voltage bus must be protected to prevent shorts from interrupting or damaging the unit.
PAGE 2
TPS2421-1 TPS2421-2 SLUS907G – JANUARY 2009 – REVISED MAY 2013 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
PAGE 3
TPS2421-1 TPS2421-2 www.ti.com SLUS907G – JANUARY 2009 – REVISED MAY 2013 ELECTRICAL CHARACTERISTICS Unless otherwise noted: 3 V ≤ VVIN ≤ 18 V, EN = 0 V, PG = FLT = open, ROUT = open, RRSET = 49.9 kΩ, –40°C ≤ TJ ≤ 125°C, No external capacitor connected to VOUT PARAMETER TEST CONDITIONS MIN TYP MAX 2.6 2.85 2.9 UNIT VIN UVLO VIN rising Hysteresis Bias current 150 V mV EN = 2.4V 25 100 μA EN = 0V 3.9 5 mA 33 50 mΩ 5 7.5 0.77 1.
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TPS2421-1 TPS2421-2 SLUS907G – JANUARY 2009 – REVISED MAY 2013 www.ti.com ELECTRICAL CHARACTERISTICS (continued) Unless otherwise noted: 3 V ≤ VVIN ≤ 18 V, EN = 0 V, PG = FLT = open, ROUT = open, RRSET = 49.9 kΩ, –40°C ≤ TJ ≤ 125°C, No external capacitor connected to VOUT PARAMETER TEST CONDITIONS MIN TYP MAX UNIT EN Threshold voltage Input bias current V EN falling 0.8 1.0 1.5 V Hysteresis 20 150 250 mV VEN = 2.4 V –2.0 0 0.5 VEN = 0.2 V –3.0 1 0.
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TPS2421-1 TPS2421-2 www.ti.com SLUS907G – JANUARY 2009 – REVISED MAY 2013 BLOCK DIAGRAM Block Diagram I(D) Detector IVOUT VIN 3 7 VOUT V(DS) Detector + 6 10 uA Q Pump Internal Rail GND 4 8 LCA + Constant Power Engine ILIM VIN -500mV PLIM 1 FLT 1.6uILIM + Fast Trip Comparator 1.5uISET 1.0V + ISET 5 k: u + ISET 2.85 V / 2.7 V 1VyRSET EN PG + 2 + VIN + 1.15 V / 1.00 V 100Ÿ THERMAL SHUTDOWN 16.80Ÿ S Q R Q VIN LATCH -1 RETRY -2 FACTORY SET 50NŸ 1.4V 35 uA CT + 0.
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TPS2421-1 TPS2421-2 SLUS907G – JANUARY 2009 – REVISED MAY 2013 www.ti.com PINOUT DIAGRAM TPS2421-x 1 FLT PG 8 2 EN VOUT 7 CT 6 ISET 5 3 VIN 4 GND Table 1. TERMINAL FUNCTIONS FUNCTION PIN NO.
PAGE 7
TPS2421-1 TPS2421-2 www.ti.com SLUS907G – JANUARY 2009 – REVISED MAY 2013 The internal MOSFET actively limits current if IVIN reaches the current limit set point. The fault timer operation is the same in this mode as described previously. The fault current value is programmed as shown in Equation 3: 200kW RRSET = ISET (3) EN: When this pin is pulled low, the device is enabled. The input threshold is hysteretic, allowing the user to program a startup delay with an external RC circuit.
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TPS2421-1 TPS2421-2 SLUS907G – JANUARY 2009 – REVISED MAY 2013 www.ti.com TYPICAL CHARACTERISTICS FAULT TIMER THRESHOLD VOLTAGE vs JUNCTION TEMPERATURE FAULT CURRENT vs JUNCTION TEMPERATURE 1.50 RSET = 100 kW 2.15 IFAULT – Fault Current – A VTHRESH – Fault Timer Threshold Voltage -– V 2.20 2.10 2.50 2.00 1.95 1.90 1.85 1.80 –50 0 TJ 50 100 1.45 1.40 1.35 1.30 –50 150 0 TJ – Junction Temperature – °C – Junction Figure 1. 100 150 Temperature – °C Figure 2.
PAGE 9
TPS2421-1 TPS2421-2 www.ti.com SLUS907G – JANUARY 2009 – REVISED MAY 2013 TYPICAL CHARACTERISTICS (continued) PG PG EN VCT 12 V Startup into 15 W, 700 mF Load RSET = 49.9 kW ILOAD Temp capacitive overload, power limit tripped 12-V load at 1.5 A, then 140 mF added to load ILOAD RSET = 49.9 kW VOUT VOUT Figure 5. 12-V Startup Into 15 Ω, 700 μF Load Figure 6.
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TPS2421-1 TPS2421-2 SLUS907G – JANUARY 2009 – REVISED MAY 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) PG PG VCT VCT ILOAD ILOAD Overload, power limit tripped, 12-V load stepped from 3 A to 5.4 A, CLOAD = 700 mF, R SET = 49.9 kW 12-V load at 3.6 A, then short applied to output, RSET = 49.9 kW VOUT VOUT Figure 9. 12-V Firm Overload, 3 A to 5.4 A, Power Limit Tripped Figure 10. 12-V Hard Overload, 3.6-A Load Then Short 12-V PLIM during startup into 60 W, 800 mF RSET = 49.
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TPS2421-1 TPS2421-2 www.ti.com SLUS907G – JANUARY 2009 – REVISED MAY 2013 TYPICAL CHARACTERISTICS (continued) PG PG VCT EN 3 V startup into 3.2 A load RSET = 49.9 kW ILOAD 3.3 V overload step from 3.8 A to 5.5 A, RSET = 49.9 kW ILOAD VOUT VOUT Figure 13. 3-V Startup into 1-Ω Load PG Figure 14. 3-V Firm Overload, Load Stepped From 3.8 A to 5.5 A FLT VCT VCT ILOAD ILOAD 3.3 V overload shorted while under 3.5 A load, RSET = 49.9 kW 3.3 V overload step from 3.8 A to 7.1 A, RSET = 49.
PAGE 12
TPS2421-1 TPS2421-2 SLUS907G – JANUARY 2009 – REVISED MAY 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) PG 3.3 V attempting startup into 1 W, 2200 mF load, retry mode - CT = 0.1 mF EN RSET = 49.9 kW VCT VCT ILOAD ILOAD 3.3 V, 1600 mF added while under 3.5 A load, RSET = 49.9 kW VOUT VOUT Figure 17. 3 V, 1600 μF Added To 3.5-A Load Figure 18. 3-V Retry Startup into 1 Ω, 2200-μF Load Figure 19.
PAGE 13
TPS2421-1 TPS2421-2 www.ti.com SLUS907G – JANUARY 2009 – REVISED MAY 2013 APPLICATION INFORMATION Startup Large inrush current occurs when power is applied to discharged capacitors and load. During the inrush period, the TPS2421 operates in power limit (or SOA protect mode) managing the current as VVOUT rises. In SOA protect mode, the internal MOSFET power dissipation ([VVIN – VVOUT] x IVOUT) is regulated at 5W typical while the fault timer starts and CCT ramps up.
PAGE 14
TPS2421-1 TPS2421-2 SLUS907G – JANUARY 2009 – REVISED MAY 2013 www.ti.com 2 4 ´ RMIN ´ PLIM _ MIN > VVIN RLOAD > RMIN = (9) 2 VVIN 4 ´ PLIM _ MIN (10) Enable Pin Considerations 0.56uF 80.6k COUT For the case when EN is simply connected to GND, TPS2421 will start ramping the voltage on VOUT as VIN rises above UVLO (~2.85V typical). If IN does not ramp monotonically, the TPS2421 may momentarily turn off then on during startup if IN falls below ~2.70V.
PAGE 15
TPS2421-1 TPS2421-2 www.ti.com SLUS907G – JANUARY 2009 – REVISED MAY 2013 2V/div FLT 0.5V/div CT 1A/div ILOAD 5V/div VOUT 5ms/div Figure 21. Fault Timer Operation During Start up CCT can be chosen for fault-free start up including expected COUT and CCT capacitance tolerance as shown in Equation 11. (1 + COUT_TOL + CCT_TOL ) ´ t ON CCT = 40000 (11) Normal Operation When load current exceeds ISET during normal operation the fault timer starts.
PAGE 16
TPS2421-1 TPS2421-2 SLUS907G – JANUARY 2009 – REVISED MAY 2013 www.ti.com Programming the Fault (ISET) and Current-limit (ILIM) Thresholds The ISET and ILIM thresholds is user programmable with a single external resistor connected to ISET and the ILIM threshold is internally set according to the ILIM/ISET ratio specified in the electrical characteristics table. The TPS2421 uses an internal regulation loop to provide a regulated voltage on the ISET pin.
PAGE 17
TPS2421-1 TPS2421-2 SLUS907G – JANUARY 2009 – REVISED MAY 2013 0.56uF 80.6k COUT www.ti.com Figure 22. Design Example Schematic 1. Calculate maximum RRSET to ensure that minimum ISET is above maximum operating load current using Equation 15 as shown below in Equation 18. 185.58 = 82.39kW 2.1 + 0.13 RRSET,max = 0.99 ´ (18) ● Choose a standard 1% value below RRSET,max for RRSET = 80.6kΩ ● ISET,min = 2.15A using Equation 12 and will meet the maximum operating current requirement of 2.
PAGE 18
TPS2421-1 TPS2421-2 SLUS907G – JANUARY 2009 – REVISED MAY 2013 www.ti.com The following equation estimates the magnitude of these voltage spikes: VSPIKE(absolute ) = VNOM + ILOAD ´ L C (20) where VNOM is the nominal supply voltage ILOAD is the load current C is the capacitance present at the input or output of the TPS2421 L equals the effective inductance seen looking into the source or the load Calculating the inductance due to a straight length of wire is shown in Equation 21. æ 4´L ö - 0.
PAGE 19
TPS2421-1 TPS2421-2 www.ti.com SLUS907G – JANUARY 2009 – REVISED MAY 2013 REVISION HISTORY Changes from Revision A (March 2009) to Revision B Page • Changed MARKING .............................................................................................................................................................. 2 • Added For the most current package and ordering information, see the Package Option Addendum at the end of this document, or visit the device product folder on www.ti.com. .....
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 18-Oct-2013 Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties.
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PACKAGE MATERIALS INFORMATION www.ti.com 17-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant TPS2421-1DDAR SO Power PAD DDA 8 2500 330.0 12.8 6.4 5.2 2.1 8.0 12.0 Q1 TPS2421-2DDAR SO Power PAD DDA 8 2500 330.0 12.8 6.4 5.2 2.1 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 17-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS2421-1DDAR SO PowerPAD DDA 8 2500 364.0 364.0 27.0 TPS2421-2DDAR SO PowerPAD DDA 8 2500 364.0 364.0 27.
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