SM72485MMX/NOPB

Manufacturer Part NumberSM72485MMX/NOPB
DescriptionLow Dropout Controllers - LDO SolarMagic 100V 150mA Buck Swtch Reg
ManufacturerTexas Instruments
SM72485MMX/NOPB datasheet
 


Specifications of SM72485MMX/NOPB

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100V, 150 mA Constant On-Time Buck Switching Regulator
FEATURES
1
Renewable Energy Grade
2
Operating Input Voltage Range: 6V to 95V
Integrated 100V, N-Channel Buck Switch
Internal Start-Up Regulator
No Loop Compensation Required
Ultra-Fast Transient Response
On Time Varies Inversely With Input Voltage
Operating Frequency Remains Constant With
Varying Line Voltage and Load Current
Adjustable Output Voltage From 2.5V
Highly Efficient Operation
Precision Internal Reference
Low Bias Current
Intelligent Current Limit
Thermal Shutdown
Package
– VSSOP
– WSON (4mm x 4mm)
Typical Application, Basic Step-Down Regulator
6V - 95V
Input
V
IN
C1
R
T
GND
SHUTDOWN
R
CL
1
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.
All trademarks are the property of their respective owners.
2
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.
Check for Samples:
SM72485
APPLICATIONS
PV Panel Smart Junction Boxes
Non-Isolated Telecommunication Buck
Regulator
Secondary High Voltage Post Regulator
+42V Automotive Systems
DESCRIPTION
The SM72485 Step Down Switching Regulator
features all of the functions needed to implement a
low cost, efficient, Buck bias regulator. This high
voltage regulator contains an 100 V N-Channel Buck
Switch. The device is easy to implement and is
provided in the VSSOP and the thermally enhanced
WSON package. The regulator is based on a control
scheme using an ON time inversely proportional to
V
. This feature allows the operating frequency to
IN
remain relatively constant. The control scheme
requires no loop compensation. An intelligent current
limit is implemented with forced OFF time, which is
inversely proportional to Vout. This scheme ensures
short
circuit
foldback. Other features include: Thermal Shutdown,
V
under-voltage lockout, Gate drive under-voltage
CC
lockout, Max Duty Cycle limiter, and a pre-charge
switch.
VIN
VCC
SM72485
BST
RT/SD
SW
RCL
RTN
FB
SM72485
SNVS697C – JANUARY 2011 – REVISED MAY 2011
control
while
providing
minimum
C3
C4
L1
V
OUT
D1
R3
R
FB2
C2
GND
R
FB1
Copyright © 2011, Texas Instruments Incorporated

SM72485MMX/NOPB Summary of contents

  • Page 1

    ... CL 1 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. All trademarks are the property of their respective owners. 2 PRODUCTION DATA information is current as of publication date. ...

  • Page 2

    ... Input operating range 95V. The exposed pad has no electrical contact. Connect to system ground plane for reduced thermal resistance. Product Folder Links: SM72485 www.ti.com VIN VCC RT/ Figure 2. Top View 8-Lead VSSOP IN Copyright © 2011, Texas Instruments Incorporated . ...

  • Page 3

    ... All limits are guaranteed. All electrical characteristics having room temperature limits are tested during production with T All hot and cold limits are guaranteed by correlating the electrical characteristics to process and temperature variations and applying statistical process control. Copyright © 2011, Texas Instruments Incorporated Human Body Model = 25°C, and those with boldface type apply over full Operating Junction ...

  • Page 4

    ... Trip point for switch OFF WSON Package VSSOP Package Product Folder Links: SM72485 www.ti.com Typ Max Units 0.8 V 150 ns 0.3 0.36 A 350 ns 35 µs 2.56 µs 2.77 3.5 µs 300 420 ns 0.70 1. 300 ns 2.5 2.550 V 2.875 V 100 nA 165 °C 25 °C 40 °C/W 200 Copyright © 2011, Texas Instruments Incorporated ...

  • Page 5

    ... Efficiency vs. Load Current and V (Circuit of Figure Figure 3. ON-Time vs Input Voltage and R Figure 5. Maximum Frequency vs. V Figure 7. Copyright © 2011, Texas Instruments Incorporated Typical Performance Characteristics IN 12) T and V OUT IN Product Folder Links: SM72485 SM72485 SNVS697C – JANUARY 2011 – REVISED MAY 2011 VCC vs ...

  • Page 6

    ... Gate drive under-voltage CC Product Folder Links: SM72485 www.ti.com VCC C3 BST Vin SD C4 DRIVER OUT D1 PRE - CHARGE BUCK R FB2 FB1 . The control scheme requires no loop IN OUT ). Following the ON period the T Copyright © 2011, Texas Instruments Incorporated . This (1) ...

  • Page 7

    ... The inductor current increases to the current limit threshold (I ) and during t2 V LIM intended voltage the average inductor current decreases (t3) to the nominal load current (I Copyright © 2011, Texas Instruments Incorporated 9. However, R3 slightly degrades the load regulation ...

  • Page 8

    ... Vin is varied over its range. The on-time equation for the SM72485 is: - 1.385 Submit Documentation Feedback Figure 10. Startup Sequence resistor, and is inversely proportional to the input voltage T Product Folder Links: SM72485 www.ti.com 7 V Vin (4) Copyright © 2011, Texas Instruments Incorporated ...

  • Page 9

    ... When activated, typically at 165°C, the controller is forced into a low power reset state by disabling the buck switch. This feature prevents catastrophic failures from accidental device overheating. When the junction temperature reduces below 140°C (typical hysteresis = 25°C) normal operation is resumed. Copyright © 2011, Texas Instruments Incorporated ) greater than 400 ns, for proper current limit IN /SD pin to ground ...

  • Page 10

    ... R , and since V = 2.5V, the ratio of R FB2 FB1 FB Equation 2, R calculates to 260 kΩ. A standard value 309 kΩ resistor T Equation 2, resulting in a frequency of 234 kHz. Product Folder Links: SM72485 www.ti.com to R calculates as 3:1. FB2 FB1 (6) (7) Copyright © 2011, Texas Instruments Incorporated ...

  • Page 11

    ... IC to help dissipate the heat. Additionally, the use of wide PC board traces, where possible, can also help conduct heat away from the IC. Judicious positioning of the PC board within the end product, along with use of any available air flow (forced or natural convection) can help reduce the junction temperatures. Copyright © 2011, Texas Instruments Incorporated Equation 5, R calculates to 310 kΩ ...

  • Page 12

    ... SM72485 www.ti.com C3 0. 220 PH 10.0V V OUT FB2 3.3 3.01k C2 R FB1 22 PF 1.0k GND Value 1 µF, 100V 22 µF, 25V 0.47 µF, 50V 0.01 µF, 50V 0.1 µF, 100V 100V, 1A 220 µH 3.01 kΩ 1.0 kΩ 3.3 Ω 309 kΩ 316 kΩ Copyright © 2011, Texas Instruments Incorporated ...

  • Page 13

    ... OUT SW where V is the absolute value of the voltage at the SW pin during the off-time (typically 1V the DC SW voltage at the RA/CA junction, and is used in the next equation. Copyright © 2011, Texas Instruments Incorporated Figure 14. Efficiency vs Figure 15, Cff is added across R FB2 to be reduced to a minimum of 25 mVp-p by reducing R3, since the OUT ...

  • Page 14

    ... Submit Documentation Feedback ) x t /Δ Figure Product Folder Links: SM72485 www.ti.com V OUT C2 FB2 FB1 is the same as that in the Block Diagram, is determined by the OUT FB2 R3 V OUT FB1 C2 Copyright © 2011, Texas Instruments Incorporated (11) ...

  • Page 15

    ... PACKAGING INFORMATION Orderable Device Status Package Type Package (1) SM72485MM/NOPB ACTIVE VSSOP SM72485MME/NOPB ACTIVE VSSOP SM72485MMX/NOPB ACTIVE VSSOP SM72485SD/NOPB ACTIVE WSON SM72485SDE/NOPB ACTIVE WSON SM72485SDX/NOPB ACTIVE WSON (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. ...

  • Page 16

    TI and TI suppliers consider certain information to be proprietary, and thus CAS ...

  • Page 17

    ... TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Type Drawing SM72485MM/NOPB VSSOP DGK SM72485MME/NOPB VSSOP DGK SM72485MMX/NOPB VSSOP DGK SM72485SD/NOPB WSON NGU SM72485SDE/NOPB WSON NGU SM72485SDX/NOPB WSON NGU PACKAGE MATERIALS INFORMATION Pins SPQ Reel Reel A0 Diameter ...

  • Page 18

    ... Device Package Type SM72485MM/NOPB VSSOP SM72485MME/NOPB VSSOP SM72485MMX/NOPB VSSOP SM72485SD/NOPB WSON SM72485SDE/NOPB WSON SM72485SDX/NOPB WSON PACKAGE MATERIALS INFORMATION Package Drawing Pins SPQ Length (mm) DGK 8 1000 DGK 8 250 DGK 8 3500 NGU 8 1000 NGU 8 250 NGU 8 4500 ...

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    NGU0008B www.ti.com MECHANICAL DATA SDC08B (Rev A) ...

  • Page 21

    ... 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. All semiconductor products (also referred to herein as “ ...