EY1603 Datasheet, PDF (8/10 Pages) Altera Corporation – 40V, Low Quiescent Current, 150mA Linear Regulator

Page 8
Functional Description
Functional Overview
The EY1603 is a high performance, high voltage, low-dropout regulator (LDO) with 150mA sourcing capability. The
part is rated to operate over the -40°C to +125°C temperature range. Featuring ultra-low quiescent current, it is an ideal
choice for “always-on” applications. It works well under a “load dump condition” where the input voltage could rise
up to 40V. This LDO device also features current limit and thermal shutdown protection.
Enable Control
The EY1603 has an enable pin, which turns the device on when pulled high. When EN is low, the IC goes into
shutdown mode and draws less than 2µA. In “always-on” applications, EN can be tied to IN.
Current Limit Protection
The EY1603 has internal current limiting functionality to protect the regulator during fault conditions. During current
limit, the output sources a fixed amount of current largely independent of the output voltage. If the short or overload
is removed from V_OUT, the output returns to normal voltage regulation mode.
Thermal Fault Protection
In the event that the die temperature exceeds a typical value of +165°C, the output of the LDO will shut down until the
die temperature cools down to a typical +145°C. The level of power dissipated, combined with the ambient
temperature and the thermal impedance of the package, determines if the junction temperature exceeds the thermal
shutdown temperature. See the “Power Dissipation” section on page 8 for more details.
Application Information
Input and Output Capacitors
A minimum 0.1µF ceramic capacitor is recommended at the input for proper operation. For the output, a ceramic
capacitor with a capacitance of 10µF is recommended for the EY1603 to maintain stability. The ground connection of
the output capacitor should be routed directly to the GND pin of the device and also placed close to the IC.
Output Voltage Setting
The EY1603TI-ADJ output voltage is programmed using an external resistor divider as shown in Figure 11.
CIN
0.1µF
VIN
VOUT
R1
EN
VFB
R2
GND
COUT
10µF
FIGURE 11. OUTPUT VOLTAGE SETTING
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:
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 2:
T_J = T_{JMAX} – T_{AMAX}
(EQ. 2)
EY1603 40V, Low Quiescent Current, 150mA Linear Regulator
09619
March 14, 2014
February 2014 Altera Corporation
Rev A