AMC3202 Datasheet, PDF (3/11 Pages) ADDtek Corp – 1.5A 280kHz BOOST REGULATORS

AMC3202
Pin
Number
Pin Name
1
COMP
2
FB
3
SS
4
EN
5
VCC
6
AGND
7
PGND
8
V_SW
Exposed ^{Heat Pad}
Pad _(PGND)
PIN DESCRIPTION
Pin Function
Loop compensation pin. This pin is the output of the error amplifier and is used for loop
compensation. Loop compensation can be implemented by a simple RC network.
Feedback pin. Sense the output voltage and referenced to 1.276V. When the voltage at this
pin falls below 0.4V, chip switching-frequency reduces to a much lower frequency.
Soft Start pin. Left this pin floating if soft start function is not used.
Enable pin. A TTL low will shut down the chip and high enable the chip. This pin may
also be used to synchronize the part to nearly twice the base frequency. If synchronization
is not used, this pin should be either tied high or left floating for normal operation.
Input power supply pin. Supply power to the IC and should have a bypass capacitor
connected to AGND.
Analog ground. Provide a clean ground for the controller circuitry and should not be in
the path of large currents. This pin is connected to the IC substrate.
Power ground. This pin is the ground connection for the emitter of the power switching
transistor. Connection to a good ground plane is essential.
High current switch pin. Connect to the collector of the internal power switch. The open
voltage across the power switch can be as high as 40V. To minimize radiation, use a trace
as short as practical.
Heat pad. Connect to power ground. Must be soldered to electrical ground on PCB.
THERMAL DATA
Thermal Resistance from Junction to Ambient, θ _JA
Junction Temperature Calculation: T_J = T_A + (P_D × θ _JA).
The θ_JA numbers are guidelines for the thermal performance of the device/pc-board system.
Connect the ground pin to ground using a large pad or ground plane for better heat dissipation.
All of the above assume no ambient airflow.
Maximum Power Calculation:
P_D(MAX)=
T_J(MAX) – T_A(MAX)
θ_JA
T_J (°C): ^{Maximum recommended junction temperature}
T_A (°C): ^{Ambient temperature of the application}
θ_JA (°^OC /W): ^{Junction-to-Ambient thermal resistance of the package, and other heat dissipating materials.}
The maximum power dissipation for a single-output regulator is:
P_D(MAX) = [(V_IN(MAX) - V_OUT(NOM))] × I_OUT(NOM) + V_IN(MAX) × I_Q
Where:
Then
V_OUT(NOM) = the nominal output voltage
I_OUT(NOM) = the nominal output current, and
I_Q = the quiescent current the regulator consumes at I_OUT(MAX)
V_IN(MAX) = the maximum input voltage
θ_JA = (+150 ^OC – T_A)/P_D
165°C /W
Copyright © 2006 ADDtek Corp.
3
DD074_B -- AUGUST 2006