EV1340QI-E Datasheet, PDF (9/10 Pages) Altera Corporation – 40V, Low Quiescent Current, 50mA Linear Regulator

Page 9
Output Voltage Setting
The output voltage is programmed using an external resistor divider, as shown in Figure 11.
CIN
0.1µF
VIN
VOUT
R1
EN
VFB
EY1602SI-ADJ
R2
GND
COUT
10µF
FIGURE 11. SETTING OUTPUT VOLTAGE
The output voltage is calculated using Equation 1:
V_OUT
=
1.223 V



R_-----1_--
R2
+
1_
(EQ. 1)
Power Dissipation
The junction temperature must not exceed the range specified in “Recommended Operating Conditions” on page 3.
The power dissipation can be calculated using Equation 2:
P_D = V_IN – V_OUT  I_OUT + V_IN  I_GND
(EQ. 2)
The maximum allowable junction temperature, T_J(MAX) and the maximum expected ambient temperature, T_A(MAX) will
determine the maximum allowable junction temperature rise (T_J), as shown in Equation 3:
T_J = T_{JMAX} – T_{AMAX}
(EQ. 3)
To calculate the maximum ambient operating temperature, use the junction-to-ambient thermal resistance (_JA), as
shown in Equation 4:
T_{JMAX} = P_{DMAX} x _JA + T_A
(EQ. 4)
Board Layout Recommendations
A good PCB layout is important to achieve expected performance. Consideration should be taken when placing the
components and routing the trace to minimize the ground impedance, and keep the parasitic inductance low. The
input and output capacitors should have a good ground connection and be placed as close to the IC as possible. The
VFB feedback trace should be away from other noisy traces. Connect the exposed pad to the ground plane for better
heat dissipation. Thermal vias on the PAD increases heat dissipation.
Document Revision History
The table lists the revision history for this document.
Date
February 2014
Version
1.0 Initial release.
Changes
February 2014 Altera Corporation
09618
EY1602 40V, Low Quiescent Current, 50mA Linear Regulator
March 14, 2014
Rev A