MAX1510 Maxim Integrated Products, MAX1510 Datasheet - Page 10

• Manufacturer Part Number: MAX1510
• Description: Low-Voltage DDR Linear Regulator
• Manufacturer: Maxim Integrated Products

Low-Voltage DDR Linear Regulator
The MAX1510 provides an open-drain PGOOD output
that goes high 2ms (typ) after the output initially reach-
es regulation during startup. PGOOD transitions low
10µs after the output goes out of regulation by ±150mV,
or when the device enters shutdown. Connect a pullup
resistor from PGOOD to V
Use a 100kΩ resistor to minimize current consumption.
By changing the voltage at REFIN, the MAX1510 can
be used in applications that require dynamic output-
voltage changes between two set points (graphics
processors). Figure 4 shows a dynamically adjustable
resistive voltage-divider network at REFIN. Using an
external signal MOSFET, a resistor can be switched in
and out of the REFIN resistor-divider, changing the volt-
age at REFIN. The two output voltages are determined
by the following equations:
Figure 3. MAX1510 PGOOD and Soft-Start Waveforms
V
V
Dynamic Output-Voltage Transitions
CURRENT LIMIT
OUT LOW
OUT HIGH
POWER-GOOD
WINDOW
(
(
PGOOD
SHDN
Applications Information
OUT
)
)
=
=
V
V
REF
REF
CC
200µs
Power-Good (PGOOD)







R
R
for a logic-level output.
2ms STARTUP
1
1
R
(
DELAY
+
+
R
2
2
R
(
R
2
+
2



R
+
3
)
R
3
)




PROPAGATION
DELAY
10µs
Figure 4. Dynamic Output-Voltage Change
V
V
OUTPUT OVERLOAD
CONDITION
OUT(LOW)
OUT(HIGH)
V
OUT(HIGH)
= V
=
V
REF
REF
10µs
PROPAGATION
DELAY
( )
V
R1 + (R2 + R3)
R1 + R2
OUT(LOW)
R2
(R2 + R3)
C
REFIN
REFERENCE
R1
R2
R3
VOLTAGE
(V
REF
)
REFIN
MAX1510