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SLVS485 − AUGUST 2003

  

FEATURES

D Step-Down Controller for Applications With

up to 95% Efficiency

D 1.8-V to 6.5-V Operating Input Voltage Range

D Adjustable Output Voltage Range From 1.2 V

to V

D High Efficiency Over a Wide Load Current

Range

D 100% Maximum Duty Cycle for Lowest

Dropout

D Internal Softstart

D 20-µA Quiescent Current (Typical)

D Overcurrent Protected

D Available in a SOT23 Package

APPLICATIONS

D USB Powered Peripherals

D Organizers, PDAs, and Handheld PCs

D Low Power DSP Supply

D Digital Cameras

D Hard Disk Drives

D Portable Audio Players

DESCRIPTION

The TPS6420x are nonsynchronous step-down

controllers that are ideally suited for systems powered

from a 5-V or 3.3-V bus or for applications powered from

a 1-cell Li-Ion battery or from a 2- to 4-cell NiCd, NiMH, or

alkaline battery. These step-down controllers drive an

external P-channel MOSFET allowing design flexibility. To

achieve highest efficiency over a wide load current range,

this controller uses a minimum on time, minimum off time

control scheme and consumes only 20-µA quiescent

current. The minimum on time of typically 600 ns

(TPS64203) allows the use of small inductors and

capacitors. When disabled, the current consumption is

reduced to less than 1 µA. The TPS6420x is available in

the 6-pin SOT23 (DBV) package and operates over a free

air temperature range of −40°C to 85°C.

TYPICAL APPLICATION CIRCUIT

TPS64200

Si5447DC

ZHCS2000

GND

VIN

ISENSE

= 33 mΩ

10 µH

3.3 V / 2 A

47 µF

PosCap

6TPA47M

620 kΩ

360 kΩ

10 µF

5 V

100

0.0001 0.001 0.01 0.1 1 10

= 25°C,

= 3.3 V

TPS64200

EFFICIENCY

LOAD CURRENT

− Load Current − A

Efficiency − %

= 4.2 V

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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.

www.ti.com

Summary of content (29 pages)

PAGE 1
www.ti.com SLVS485 − AUGUST 2003 FEATURES D Step-Down Controller for Applications With up to 95% Efficiency D 1.8-V to 6.5-V Operating Input Voltage Range D Adjustable Output Voltage Range From 1.
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www.ti.com SLVS485 − AUGUST 2003 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. ORDERING INFORMATION PLASTIC SOT23-6(1) (2) (DBV) OUTPUT VOLTAGE MINIMUM ON-TIME MINIMUM OFF-TIME MARKING Adjustable 1.2 V to VI Adjustable 1.2 V to VI ON time = 1.
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www.ti.com SLVS485 − AUGUST 2003 ELECTRICAL CHARACTERISTICS VIN = 3.8 V, VO = 3.3 V, EN = VIN, TA = −40°C to 85°C (unless otherwise noted) SUPPLY CURRENT PARAMETER VI I(Q) Operating quiescent current I(SD) Shutdown current OUTPUT/CURRENT LIMIT VO VFB TEST CONDITIONS Input voltage range MIN IO = 0 mA EN = VI Adjustable output voltage range MAX V 20 35 µA 0.1 1 µA VI V 0.01 0.2 µA +2 % 105 120 mV 0.01 0.2 µA 1.
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www.ti.com SLVS485 − AUGUST 2003 PIN ASSIGNMENTS DBV PACKAGE (TOP VIEW) EN 1 6 SW GND 2 5 VIN FB 3 4 ISENSE Terminal Functions TERMINAL NAME NO. I/O DESCRIPTION EN 1 I Enable. A logic low enables the converter, logic high forces the device into shutdown mode reducing the supply current to less than 1 µA. FB 3 I Feedback pin. Connect an external voltage divider to this pin to set the output voltage.
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www.ti.com SLVS485 − AUGUST 2003 TYPICAL CHARACTERISTICS All graphs were generated using the circuit as shown unless otherwise noted. For output voltages other than 3.3 V, the output voltage divider was changed accordingly. Graphs for the TPS64203 were taken using the application circuit shown in Figure 25. VI R(ISENSE) = 33 mΩ CI 10 µF X7R TPS6420x 1 2 3 EN SW GND VIN FB ISENSE 6 Si5447DC 5 CDRH 103R−100 4 VO 10 µH MBRM120LT3 R1 620 kΩ Cff 4.
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www.ti.com SLVS485 − AUGUST 2003 100 TPS64200 TPS64201 EFFICIENCY vs LOAD CURRENT EFFICIENCY vs LOAD CURRENT 100 VI = 3.6 V VI = 4.2 V 80 Efficiency − % Efficiency − % 70 60 50 40 VI = 6 V 50 40 30 20 20 TA = 25°C, VO = 3.3 V 0.001 0.01 0.1 IO − Load Current − A 1 VI = 5 V 60 30 10 VI = 4.2 V 80 VI = 5 V VI = 6 V 70 0 0.0001 VI = 3.6 V 90 90 TA = 25°C, VO = 3.3 V 10 0 0.0001 10 0.
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www.ti.com SLVS485 − AUGUST 2003 TPS64200 TPS64201 OUTPUT VOLTAGE vs OUTPUT CURRENT OUTPUT VOLTAGE vs OUTPUT CURRENT 3.40 3.40 TA = 25°C, VO = 3.3 V 3.38 VO − Output Voltage − V VI = 4.2 V VI = 6 V 3.34 3.32 3.30 VI = 3.6 V 3.28 3.26 10 VI = 3.6 V 3.28 3.26 3.22 1 VI = 4.2 V 3.30 3.22 0.01 0.1 IO − Output Current − A VI = 5 V 3.32 3.24 0.001 VI = 6 V 3.34 3.24 3.20 0.0001 TA = 25°C, VO = 3.3 V 3.36 VI = 5 V 3.
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www.ti.com SLVS485 − AUGUST 2003 TPS64200 TPS64201 SWITCHING FREQUENCY vs OUTPUT CURRENT SWITCHING FREQUENCY vs OUTPUT CURRENT 500 400 VO = 3.3 V VO = 3.3 V VI = 5 V 450 350 400 250 f − Frequency − kHz f − Frequency − kHz 300 VO = 1.2 V 200 150 VI = 5 V 350 300 250 VO = 1.2 V 200 150 100 100 50 50 0 0.001 0.01 0.1 1 0 0.001 10 IO − Output Current − A 0.
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www.ti.com SLVS485 − AUGUST 2003 TPS642000 OPERATING QUIESCENT CURRENT vs INPUT VOLTAGE TPS64200 OUTPUT VOLTAGE RIPPLE VI = 3.8 V, VO = 1.2 V, RL = 1.2 Ω, TA = 25°C 35 TA = 25°C TA = 85°C 20 mV/Div 30 TA = −40°C 25 VO 20 I(coil) 15 10 5 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 2 ms/Div VI − Input Voltage − V Figure 14 Figure 15 TPS64200 TPS64203 LINE TRANSIENT RESPONSE LOAD TRANSIENT RESPONSE VI = 3.8 V to 5 V, VO = 1.2 V, RL = 1.
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www.ti.com SLVS485 − AUGUST 2003 TPS64200 STARTUP TIMING EN VO II I(Inductor) VI = 3.8 V, VO = 3.3 V, RL = 1.66 Ω, TA = 25°C 100 ms/Div Figure 18 DETAILED DESCRIPTION Operation The TPS6420x is a nonsynchronous step-down controller which is operating with a minimum on-time/minimum off-time control. An external PMOS is turned on until the output voltage reaches its nominal value or the current limit is exceeded.
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www.ti.com SLVS485 − AUGUST 2003 Soft Start The TPS6420x has an internal soft start circuit that limits the inrush current during start up. This prevents possible voltage drops of the input voltage in case a battery or a high impedance power source is connected to the input of the TPS6420x. During soft start the current limit is increased from 25% of its maximum to the maximum within about 250 µs.
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www.ti.com SLVS485 − AUGUST 2003 THEORY OF OPERATION The basic application circuit for the TPS64200 is shown in Figure 1. External component selection is driven by the load requirement. It begins with the selection of the current sense resistor R(ISENSE) followed by the output diode, the inductor L, and the output and input capacitors. The inductor is chosen based on the desired amount of ripple current and switching frequency.
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www.ti.com SLVS485 − AUGUST 2003 For a first approximation use: L = 10 µH V(ripple) = 150 mV (verify in the application) Selecting the Inductor Value The main parameters when choosing the inductor are current rating and inductance. The inductance mainly determines the inductor current ripple. The TPS6420x operates with a wide range of inductor values. Values between 4.7 µH and 47 µH work in most applications.
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www.ti.com SLVS485 − AUGUST 2003 Selecting the External PMOS An external PMOS must be used for a step-down converter with the TPS64200. The selection criteria for the PMOS are threshold voltage, rDS(on), gate charge and current and voltage rating. Since the TPS64200 can operate down to 1.8 V, the external PMOS must have a VGS(th) much lower than that if it is operated with such a low voltage.
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www.ti.com SLVS485 − AUGUST 2003 Selecting the Output Capacitor The value of the output capacitor depends on the output voltage ripple requirements as well as the maximum voltage deviation during a load transient. The TPS6420x require a certain ESR value for proper operation. Low ESR tantalum capacitors or PosCap work best in the application. A ceramic capacitor with up 1 µF may be used in parallel for filtering short spikes.
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www.ti.com SLVS485 − AUGUST 2003 APPLICATION INFORMATION Li-lon 3.3 V to 4.2 V R(ISENSE) = 33 mΩ CIN 10 µF TPS64202 1 2 3 EN SW GND VIN FB ISENSE 6 Si5475DC 5 CDRH6D28-5R0 4 3.3 V / 2 A 5 µH MBRM120LT3 R1 620 kΩ Cff 4.7 pF Co 47 mF PosCap 6TPA47M R2 360 kΩ Figure 19. Application For a Li-Ion to 3.
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www.ti.com SLVS485 − AUGUST 2003 DESIGN EXAMPLE FOR AN APPLICATION USING A LI-ION CELL (3.3 V TO 4.2 V) TO GENERATE 3.3 V/500 mA 1. Calculate the sense resistor for the current limit: V R (ISENSE) v min (ISENSE) + 90 mV + 138 mW 1.3 I 1.3 0.5 A O (18) Choose the next lower standard value : R(ISENSE) = 120 mΩ. Verify the inductor current ripple after the inductor has been determined in step 5.
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www.ti.com SLVS485 − AUGUST 2003 DI + ǒVO ) V(SCHOTTKY) ) RRL I O Ǔ t off , min L + 110 mA (24) The current rating for the inductor must be: I, inductor u I O ) DI + 555 mA 2 (25) 6. Select the input and output capacitor The output capacitor is selected for an output voltage ripple of less than 20 mVpp. With ESR, max [ DV pp 1.1 DI + 1.1 0.02 V + 165 mW 0.11 A (26) A 47-µF PosCap with an ESR of 100 mΩ was selected to meet the ripple requirements.
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www.ti.com SLVS485 − AUGUST 2003 5V R(ISENSE) = 33 mΩ 10 µF TPS64200 1 2 3 EN SW GND VIN FB ISENSE 6 Si5447DC 5 CDRH103R-100 4 3.3 V / 2 A 10 µH ZHCS200 R1 620 kΩ 47 mF PosCap 6TPA47M R2 360 kΩ Figure 22. Application For a 5-V to 3.3-V / 2-A Conversion Inverter Using TPS64200 VI 2.7 V to 4.2 V R(ISENSE) = 33 mΩ 10 µF TPS64200 1 EN 6 SW 2 GND 3 FB ISENSE Si2301DS 5 VIN MBR0530T1 4 −5 V / 0.
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www.ti.com SLVS485 − AUGUST 2003 The TPS6420x can be used for an inverter. Only one additional operational amplifier is required for this application. When the PMOS is switched on, the current in the inductor ramps up to its maximum, set by Rs. Then the PMOS is switched off, the energy stored in the inductor is transferred to the output. The output voltage and the maximum output current can be calculated using: V + R1 O R2 V FB I O V max [ 0.
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www.ti.com SLVS485 − AUGUST 2003 5V 10 µF X5R TPS64203 1 2 3 EN SW GND VIN FB ISENSE 6 Si2323DS 5 Wurth 744052006 4 1.2 V / 1.2 A 6.2 µH MBRM120LT3 100 µF/6.3 V B45294-R1107-M40 Figure 25. Application For a 5-V to 1.2-V / 1.2-A Conversion 5V R(ISENSE) = 20 mΩ CIN 22 µF TPS64202 1 2 3 EN SW GND VIN FB ISENSE 6 Si5475DC 5 4 DO3316P−472 3.3 V / 3 A 4.7 µH B320 R1 620 kΩ Cff 4.7 pF R2 360 kΩ Co 100 mF PosCap 6TPC100M Figure 26.
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www.ti.com SLVS485 − AUGUST 2003 Ceramic Output Capacitor 5V R(ISENSE) = 33 mΩ CI 10 µF TPS64203 1 EN SW 6 2 GND VIN 5 3 4 FB ISENSE R(GATE) 10 Ω Si5475DC CDRH6D28-100 MBRM120LT3 10 µH R1a 680 kΩ R1b 2.2 MΩ 3.3 V / 2 A Cff 82 pF R2 300 kΩ Co 22 µF X5R 6.3 V Figure 27.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device.
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PACKAGE MATERIALS INFORMATION www.ti.com 5-Mar-2014 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) TPS64200DBVR SOT-23 DBV 6 3000 178.0 9.0 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 3.23 3.17 1.37 4.0 8.0 Q3 TPS64200DBVT SOT-23 DBV 6 250 178.0 9.0 3.23 3.17 1.37 4.0 8.0 Q3 TPS64201DBVR SOT-23 DBV 6 3000 179.0 8.4 3.2 3.2 1.4 4.0 8.
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PACKAGE MATERIALS INFORMATION www.ti.com 5-Mar-2014 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS64200DBVR SOT-23 DBV 6 3000 180.0 180.0 18.0 TPS64200DBVT SOT-23 DBV 6 250 180.0 180.0 18.0 TPS64201DBVR SOT-23 DBV 6 3000 203.0 203.0 35.0 TPS64201DBVR SOT-23 DBV 6 3000 180.0 180.0 18.0 TPS64201DBVT SOT-23 DBV 6 250 180.0 180.0 18.0 TPS64201DBVT SOT-23 DBV 6 250 203.0 203.0 35.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.