Switching Regulator. LM25005 Datasheet

LM25005 Regulator. Datasheet pdf. Equivalent

LM25005 Datasheet
Recommendation LM25005 Datasheet
Part LM25005
Description 2.5A Step-Down Switching Regulator
Feature LM25005; LM25005 www.ti.com SNVS411C – JANUARY 2006 – REVISED MARCH 2013 LM25005 42V, 2.5A Step-Down Switc.
Manufacture etcTI
Datasheet
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Texas Instruments LM25005
LM25005
www.ti.com
SNVS411C – JANUARY 2006 – REVISED MARCH 2013
LM25005 42V, 2.5A Step-Down Switching Regulator
Check for Samples: LM25005
FEATURES
1
2 Integrated 42V, 160mN-Channel MOSFET
• Ultra-Wide Input Voltage Range from 7V to 42V
• Internal Bias Regulator
• Adjustable Output Voltage from 1.225V
• 1.5% Feedback Reference Accuracy
• Current Mode Control with Emulated Inductor
Current Ramp
• Single Resistor Oscillator Frequency Setting
• Oscillator Synchronization Input
• Programmable Soft-Start
• Shutdown / Standby Input
• Wide Bandwidth Error Amplifier
• Thermal Shutdown
DESCRIPTION
The LM25005 switching regulator features all of the
functions necessary to implement an efficient, high
voltage buck regulator using a minimum of external
components. This easy to use regulator includes a
42V, 160m, N-channel MOSFET, with an output
current capability of 2.5 Amps. The regulator control
method is based upon current mode control utilizing
an emulated current ramp. Current mode control
provides inherent line voltage feed-forward, cycle-by-
cycle current limiting and ease of loop compensation.
The use of an emulated control ramp reduces noise
sensitivity of the pulse-width modulation circuit,
allowing reliable control of very small duty cycles
necessary in high input voltage applications. The
operating frequency is programmable from 50kHz to
500kHz. An oscillator synchronization pin allows
multiple LM25005 regulators to self-synchronize or to
be synchronized to an external clock. Additional
protection features include: current limit, thermal
shutdown and remote shutdown capability. The
device is available in a power enhanced HTSSOP
package featuring an exposed die attach pad to aid
thermal dissipation.
Package
• HTSSOP (Exposed Pad)
Simplified Application Schematic
VIN
LM25005 BST
VIN
SD
SW
SYNC
COMP
IS
GND
VOUT
FB
OUT
RAMP RT SS VCC
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.
Copyright © 2006–2013, Texas Instruments Incorporated



Texas Instruments LM25005
LM25005
SNVS411C – JANUARY 2006 – REVISED MARCH 2013
Connection Diagram
www.ti.com
1
VCC
2
SD
3
VIN
4
VIN
5
SYNC
6
COMP
7
FB
8
RT
9
RAMP
10 AGND
20
BST
19
PRE
18
SW
17
SW
16
IS
15
IS
14
PGND
13
PGND
12
OUT
11
SS
Pin(S)
1
2
3, 4
5
6
7
8
9
10
11
12
13, 14
Figure 1. Top View
20-Lead HTSSOP
Name
VCC
SD
Vin
SYNC
COMP
FB
RT
RAMP
AGND
SS
OUT
PGND
PIN DESCRIPTIONS
Description
Application Information
Output of the bias regulator
Vcc tracks Vin up to 9V. Beyond 9V, Vcc is regulated to 7 Volts.
A 0.1uF to 1uF ceramic decoupling capacitor is required. An
external voltage (7.5V – 14V) can be applied to this pin to
reduce internal power dissipation.
Shutdown or UVLO input
If the SD pin voltage is below 0.7V the regulator will be in a low
power state. If the SD pin voltage is between 0.7V and 1.225V
the regulator will be in standby mode. If the SD pin voltage is
above 1.225V the regulator will be operational. An external
voltage divider can be used to set a line undervoltage shutdown
threshold. If the SD pin is left open circuit, a 5µA pull-up current
source configures the regulator fully operational.
Input supply voltage
Nominal operating range: 7V to 42V
Oscillator synchronization input or output
The internal oscillator can be synchronized to an external clock
with an external pull-down device. Multiple LM25005 devices
can be synchronized together by connection of their SYNC pins.
Output of the internal error amplifier
The loop compensation network should be connected between
this pin and the FB pin.
Feedback signal from the regulated output
This pin is connected to the inverting input of the internal error
amplifier. The regulation threshold is 1.225V.
Internal oscillator frequency set input
The internal oscillator is set with a single resistor, connected
between this pin and the AGND pin. The recommended
frequency range is 50KHz to 500KHz.
Ramp control signal
An external capacitor connected between this pin and the AGND
pin sets the ramp slope used for current mode control.
Recommended capacitor range 50pF to 2000pF.
Analog ground
Internal reference for the regulator control functions
Soft-start
An external capacitor and an internal 10µA current source set
the time constant for the rise of the error amp reference. The SS
pin is held low during standby, Vcc UVLO and thermal
shutdown.
Output voltage connection
Connect directly to the regulated output voltage.
Power ground
Low side reference for the PRE switch and the IS sense resistor.
2
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Copyright © 2006–2013, Texas Instruments Incorporated



Texas Instruments LM25005
LM25005
www.ti.com
Pin(S)
15, 16
17, 18
19
20
NA
Name
IS
SW
PRE
BST
EP
SNVS411C – JANUARY 2006 – REVISED MARCH 2013
PIN DESCRIPTIONS (continued)
Description
Current sense
Switching node
Pre-charge assist for the bootstrap
capacitor
Boost input for bootstrap capacitor
Exposed Pad
Application Information
Current measurement connection for the re-circulating diode. An
internal sense resistor and a sample/hold circuit sense the diode
current near the conclusion of the off-time. This current
measurement provides the DC level of the emulated current
ramp.
The source terminal of the internal buck switch. The SW pin
should be connected to the external Schottky diode and to the
buck inductor.
This open drain output can be connected to SW pin to aid
charging the bootstrap capacitor during very light load conditions
or in applications where the output may be pre-charged before
the LM25005 is enabled. An internal pre-charge MOSFET is
turned on for 250ns each cycle just prior to the on-time interval
of the buck switch.
An external capacitor is required between the BST and the SW
pins. A 0.022µF ceramic capacitor is recommended. The
capacitor is charged from Vcc via an internal diode during the
off-time of the buck switch.
Exposed metal pad on the underside of the device. It is
recommended to connect this pad to the PWB ground plane, in
order to aid in heat dissipation.
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.
Absolute Maximum Ratings(1)(2)
VIN to GND
BST to GND
PRE to GND
SW to GND (Steady State)
BST to VCC
VCC to GND
BST to SW
OUT to GND
SD, SYNC, SS, FB to GND
ESD Rating(3)
Storage Temperature Range
Human Body Model
45V
60V
45V
-1.5V
45V
14V
14V
Limited to Vin
7V
2kV
-65°C to +150°C
(1) Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which
operation of the device is intended to be functional. For ensured specifications and test conditions, see the Electrical Characteristics .
(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and
specifications.
(3) The human body model is a 100pF capacitor discharged through a 1.5kresistor into each pin.
Operating Ratings(1)
VIN
Operation Junction Temperature
7V to 42V
40°C to + 125°C
(1) Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which
operation of the device is intended to be functional. For ensured specifications and test conditions, see the Electrical Characteristics .
Copyright © 2006–2013, Texas Instruments Incorporated
Product Folder Links: LM25005
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