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ACE752D
120KHz 3.5A Buck DC-DC Converter
Description The ACE752D is a high efficiency step down DC-DC converter with adjustable current limit in compact SOP-8/ESOP-8 packages, including an error amplifier, ramp generator, current comparator, slope compensation, current sense and logic driver. It also integrates a current error amplifier to have a constant voltage and constant current control. Peak current mode PWM control with external adjustable compensation provides a stable and high efficient operation over a wide range of load currents. By means of an on board current sense resistor and the availability of the current sense pins, a current limit programming is very simple and accurate.The internal robust DMOS transistor with a typical of 150 mΩ assures high efficiency even at high output current level. The internal limiting current of typical value of 3.5 A, output short and over temperature protection, protect the device from accidental damage. The internal fixed switching frequency of 120 kHz, and the SOP-8/ESOP-8 packages pin allow building an ultra compact DC/ DC converter with a minimum board space.
Features
• Up to 2.1A/2.4Aoutput current • Input Under Voltage Lockout • Operating voltage can be up to 40V • 120 kHz Internal Jitter Frequency for lower EMI • Patent-Technique Constant Voltage and Constant Current Control. • Patent-Technique Output Voltage Compensation • Adjustable current limit • Over Temperature Protection • Small SOP-8/ESOP-8 Packages
Application
• Car Charger/Adaptor • Rechargeable Portable Devices • General-purpose step-down converters with adjustable current limit
VER 1.1 1
ACE752D
120KHz 3.5A Buck DC-DC Converter
Absolute Maximum Ratings (Tamb=25°C)
Parameter VIN Supply Voltage SW Voltage BS Voltage COMP Voltage FB Voltage CS+ Voltage CS- Voltage Operating Temperature Range Storage Temperature Range
Symbol VIN VSW VBS
VCOMP VFB VCS+ VCSTLEAD TSTG
Max +40 -0.3 ~VIN+0.3 VSW+8 +5 +5 -0.3~+8 -0.3~+8 -20~+85 -40 to125
Unit V V V V V V V OC OC
Packaging Type
Pin No. 1 2 3 4 5 6 7 8 EP
Pin Name
VIN
FB
COMP
GND CSCS+ BS SW Exposed PAD
I/O P Input Voltage.
Pin Description
I Feedback Input Pin.
I/O Compensation pin, resistor and capacitor connected.
G Ground.
I Current sense Pins, current limit resistor connected
I Current sense Pins, current limit resistor connected
I/O Bootstrap, a 10nF capacitor is connected between BS and SW.
O Switch Pin.
G Heatsink, connected to ground.
VER 1.1 2
Ordering information
ACE752D XX + H
Halogen - free Pb - free
FM :SOP-8(2.1A) IM:ESOP-8(2.4A)
ACE752D
120KHz 3.5A Buck DC-DC Converter
Functional Block Diagram
VER 1.1 3
ACE752D
120KHz 3.5A Buck DC-DC Converter
Electrical Characteristics (Tamb=25°C, VIN=12V, VOUT=5V, Load Current=0, unless otherwise specified)
Parameter
Input Voltage Range Feedback Reference Voltage Feedback Current
Quiescent Current (Switch Off) Current Sense Offset Voltage Switching Frequency NMOS Switch On Resistance NMOS Switch Leakage Current NMOS Current Limit UVLO Input Rising Voltage UVLO o Voltage Hysteresis Thermal Shutdown Temperature Thermal Shutdown Hysteresis SoftStart Time
Symbol
VIN VFB IFB
Iswitch off VCS FS RON IIeak ILMIT
VIN(rising) VIN(hyst)
Tj(sd) Thyst TSS
Conditions
VIN pin voltage
VFB=0.81V VFB=1V
VFB=0.6V VSW=0V
Min
10 0.815
Typ
0.835 -0.1
Max
40 0.855
0.75 1 70 75 80 96 120 144
0.15 10 104
3 3.5 89
2 150 20 16
Unit
V V μA
μA mA KHz Ω μA A V V °C °C mS
FUNCTION DESCRIPTION The ACE752D is a complete and simple step down DC-DC converter with adjustable current Limit. By
means of an on board current sense resistor and the availability of the current sense pins, a current limit programming is very simple and accurate.
Moreover, constant current control can be used to charge batteries. The device can be used as a standard DC-DC converter with adjustable current limit (set by using the external sense resistor).
The internal robust N-channel MOS transistor with a typical value of 150 mΩ assures high efficiency and a minimum dropout even at high output current level. The internal limiting current of typical value of 3.5 A protects the device from accidental overload avoiding dangerous loads damage.
When overload or output short, the main switch is turned on and off periodically to limit the current delivered to the load, protect the load and the device itself. When output short is removed or the load decrease to normal, the output voltage recovers.
If the temperature of the chip goes higher than a fixed internal threshold (150 °C with 20°C hysteresis), the device is turned off.
The internal fixed switching frequency of 120 kHz, and the small SOP-8/ESOP-8 packages allow building an ultra compact DC-DC converter with a minimum board space.
VER 1.1 4
ACE752D
120KHz 3.5A Buck DC-DC Converter
APPLICATIONS INFORMATION Output Voltage and Feedback Loop Settings
Refer to the figure 1, the output voltage of the switching regulator (VOUT) can be set with Equation following:
VOUT = (1+
R3 R4
.