TPS51125_16 Datasheet, PDF (1/33 Pages) Texas Instruments – Dual-Synchronous, Step-Down Controller With Out-of-Audio Operation and 100-mA LDOS for Notebook System Power

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TPS51125
SLUS786H – OCTOBER 2007 – REVISED JANUARY 2015
TPS51125 Dual-Synchronous, Step-Down Controller With Out-of-Audio™ Operation and
100-mA LDOS for Notebook System Power
1 Features
•1 Wide Input Voltage Range: 5.5 V to 28 V
• Output Voltage Range: 2 V to 5.5 V
• Built-In 100-mA, 5-V and 3.3-V LDO With
Switches
• Built-In 1% 2-V Reference Output
• With or Without Out-of-Audio™ Mode Selectable
Light-Load and PWM-Only Operation
• Internal 1.6-ms Voltage Servo Soft-Start
• Adaptive On-Time Control Architecture With Four
Selectable Frequency Setting
• 4500 ppm/°C R_DS(on) Current Sensing
• Built-In Output Discharge
• Powergood Output
• Built-In OVP/UVP/OCP
• Thermal Shutdown (Nonlatch)
• QFN, 24-Pin (RGE)
2 Applications
• Notebook Computers
• I/O Supplies
• System Power Supplies
3 Description
The TPS51125 is a cost-effective, dual-synchronous
buck controller targeted for notebook system power
supply solutions. The device provides 5-V and 3.3-V
LDOs and requires few external components. The
270-kHz VCLK output can be used to drive an
external charge pump, thus generating gate drive
voltage for the load switches without reducing the
efficiency of the main converter. The TPS51125
supports high-efficiency, fast-transient response and
provides a combined power-good signal. Out-of-
Audio mode light-load operation enables low acoustic
noise at much higher efficiency than conventional
forced PWM operation. Adaptive on-time D-CAP™
control provides convenient and efficient operation.
The part operates with supply input voltages ranging
from 5.5 V to 28 V and supports output voltages from
2 V to 5.5 V. The TPS51125 is available in a 24-pin
QFN package and is specified from -40°C to 85°C
ambient temperature range.
Device Information⁽¹⁾
PART NUMBER
PACKAGE
BODY SIZE (NOM)
TPS51125
VQFN (24)
4.00 mm x 4.00 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Simplified Schematic
VIN
10mF x 2
VO2
3.3 V
330mF
3.3mH
13 kW
20 kW
130 kW
20 kW
220 nF
30 kW
130 kW
654321
VIN
10mF x 2
10mF
0.1mF
7 VO2
8 VREG3
9 VBST2
5.1W
10 DRVH2
TPS51125RGE
VO1 24
100 kW
PGOOD 23
VREG5
VBST1 22
5.1W
DRVH1 21
0.1mF
11 LL2 PowerPAD
LL1 20
12 DRVL2
DRVL1 19
3.3mH
330mF
VIN
5.5 V
to
28 V
VO1
5V
EN0
620 kW
13 14 15 16 17 18
VREG5
VREF
VIN
33mF _VO1
100 nF
100 nF
100 nF
100 nF
1mF
15 V
UDG-09019
1
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.