ACE1085G Datasheet, PDF (4/8 Pages) ACE Technology Co., LTD. – 3A Low Dropout Linear Regulator

ACE1085G
Thermal Resistance
Junction–to-Ambient
(No heat sink ;No air
flow)
Thermal Resistance
Junction-to-Case
3A Low Dropout Linear Regulator
98
℃/W
Control Circuitry / Power Transistor
15
℃/W
Note 1: See thermal regulation specifications for changes in output voltage due to heating effects. Line and load regulation are
measured at a constant junction Temperature by low duty cycle pulse testing. Load regulation is measured at the output
lead =1/18” from the package.
Note 2: Line and load regulation are guaranteed up to the maximum power dissipation of 15W. Power dissipation is determined by
the difference in input and output and the output current. Guaranteed maximum power dissipation will not be available
over the full input/output range.
Functional Description
Introduction
The ACE1085G adjustable or fixed-mode Low Dropout (LDO) regulator is a 3 terminal device which can
easily be programmed by internal mask change to any voltage within the range of 1.25 to Vin-1.4V. The
ACE1085G only needs 1.4V differential between Vin and Vout to maintain output regulation, in addition,
the output voltage tolerances are also extremely tight and they include the transient response as port of the
specification. For example, Intel VRE specification calls for a total of ±100mV including initial tolerance,
load regulation and 0 to 3A load step. The ACE1085G is specifically designed to meet the fast current
transient needs as well as providing an accurate initial voltage, reducing the overall system cost with the
need for fewer output capacitors.
Load Regulation
Since the ACE1085G is only a 3 terminal device, it is not possible to provide true remote sensing of the
output voltage at the load. But it can supply good load regulation by internal feedback bypass the external
loss such as adjustable mode.
Stability
The ACE1085G requires the use of an output capacitor as part of the frequency compensation in order to
make the regulator stable .For most applications a minimum of 10uF aluminum electrolytic capacitor
insures both stability and good transient response.
Thermal Design
The ACE1085G incorporates an internal shutdown that protects the device when the junction
temperature exceeds the maximum allowable junction temperatures. Although this device can operate
with junction temperatures in the range of 150℃, it is recommended that the selected heat sink be chosen
such that during maximum continuous load operation the junction temperature is kept below the
temperature.
Layout Consideration
The output capacitors must be located as close to the Vout terminal of the device as possible .It is
recommended to use a section of a layer of the PC board as a plane to connect the Vout pin to the output
capacitors to prevent any high frequency oscillation that may result due to excessive trace inductance.
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