IFX81481ELV
10 A synchronous DC/DC Step-Down Controller
Data Sheet
Rev. 1.0, 2013-09-02
Standard Power
10 A synchronous DC/DC Step-Down Controller
IFX81481ELV
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Overview
10 A synchronous step down Controller
Current limitation adjustable with Shunt resistor or Rdson
Adjustable output voltage
± 2% output voltage tolerance
External power transistors
Integrated bootstrap diode
PWM regulation
Very Low Dropout Operation: max Duty Cycle higher than 99%
Input voltage range from 4.75V to 45V
Adjustable switching frequency from 100 to 700 kHz
Synchronization input
Very low shutdown current consumption (<2µA)
Soft-start function
Input undervoltage lockout
Suited for industrial applications:
T
j
= -40°C to +125°C
Green Product (RoHS compliant)
PG-SSOP-14
The
IFX81481ELV
is not qualified and manufactured according to the requirements of Infineon Technologies with
regards to automotive and/or transportation applications. For automotive applications please refer to the Infineon
TLx (TLE, TLS, TLF.....) voltage regulator products.
Description
The IFX81481ELV is a PWM step-down DC/DC controller with external power switches, packaged in a small PG-
SSOP-14 with exposed pad. The controller is capable to drive external power MOSFETs for load currents up to
10 A. A current limitation feature is provided, which can be implemented either in Rdson configuration, measuring
the voltage over the high-side switch while it is closed, or in a shunt configuration where a shunt resistor above
the high-side switch is used to measure the voltage.
Type
IFX81481ELV
Package
PG-SSOP-14
Marking
81481ELV
Data Sheet
2
Rev. 1.0, 2013-09-02
IFX81481ELV
Block Diagram
2
Block Diagram
IVCC
sensehigh
VS
LDO
senselow
V_ls
EN
GND
Enable
Softstart
BTS
Temp . D
S
UG
SYNC/
FREQ
Osc
Sync
Step Down
BUO
V_ls
LG
COMP
Regulator
FB
IFX81481 ELV
Figure 1
Block Diagram
PGND
Data Sheet
3
Rev. 1.0, 2013-09-02
IFX81481ELV
Pin Configuration
3
3.1
Pin Configuration
Pin Assignment
IVCC
VS
EN
GND
SYNC/FREQ
COMP
FB
1
2
3
4
5
6
7
14 sensehigh
13 senselow
12 BTS
11 UG
10 BUO
9
8
LG
PGND
IFX81481 ELV
SSOP_14_PIN.vsd
Figure 2
Pin Configuration
3.2
Pin
1
Pin Definitions and Functions
Symbol Function
IVCC
Internal Voltage Supply
Output of the internal linear regulator, supply for low-side driver and through internal bootstrap
diode to high-side driver,
connect a capacitor between this pin and GND
Input Voltage
Connect to input voltage for internal power supply
Enable Input
Active-high enable input with integrated pull down resistor
Ground
Connect to ground plane
Synchronization and Oscillator frequency set Input
Connect to an external clock signal in order to synchronize/adjust the switching frequency
(SYNC-mode). Connect an external resistor to set the frequency (FREQ-mode)
Compensation Input
Frequency compensation for regulation loop stability
Connect to compensation network
Feedback Input
Connect via voltage divider to output capacitor
Power Ground
Connect to Ground plane
Low-side MOSFET driver output
Driving output for the low-side external power MOSFET, connect to gate
Buck Switch Out
Connect this point between the switching transistors,
floating ground for high-side driver
2
3
4
5
VS
EN
GND
SYNC/
FREQ
COMP
6
7
8
9
10
FB
PGND
LG
BUO
Data Sheet
4
Rev. 1.0, 2013-09-02
IFX81481ELV
Pin Configuration
Pin
11
12
13
Symbol Function
UG
BTS
sense
low
sense
high
Up-side MOSFET driver output
Driving output for the high-side external power MOSFET, connect to gate
Buck Driver Supply Input
Connect the bootstrap capacitor between this pin and pin BUO
Current sensing (low-side) input
For Shunt-configuration connect a shunt resistor from senselow to input/battery voltage, for
Rdson-configuration connect to source of the high-side MOSFET
Current sensing (high-side) input
Connect a resistor between battery and this pin to adjust the current threshold for both Rdson
and Shunt configurations
Connect to heatsink area and GND by low inductance wiring
14
Exposed Pad
Data Sheet
5
Rev. 1.0, 2013-09-02
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