MAX1510_11 Datasheet, PDF (10/13 Pages) Maxim Integrated Products – Low-Voltage DDR Linear Regulator Thermal Fault Protection

Low-Voltage DDR Linear Regulators
SHDN
200μs
CURRENT LIMIT
POWER-GOOD
WINDOW
OUTPUT OVERLOAD
CONDITION
OUT
PGOOD
2ms STARTUP
DELAY
10μs
PROPAGATION
DELAY
10μs
PROPAGATION
DELAY
Figure 3. MAX1510/MAX17510 PGOOD and Soft-Start Waveforms
Power-Good (PGOOD)
The MAX1510/MAX17510 provide an open-drain
PGOOD output that goes high 2ms (typ) after the out-
put initially reaches regulation during startup as shown
in Figure 3. PGOOD transitions low 10µs after the out-
put goes out of regulation by ±150mV, or when the
device enters shutdown. Connect a pullup resistor from
PGOOD to V_CC for a logic-level output. Use a 100kΩ
resistor to minimize current consumption.
Applications Information
Dynamic Output-Voltage Transitions
By changing the voltage at REFIN, the MAX1510/
MAX17510 can be used in applications that require
dynamic output-voltage changes between two set
points (graphics processors). Figure 4 shows a dynam-
ically 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 voltage at REFIN. The two output
voltages are determined by the following equations:
V_OUT(LOW)
=
V_REF
⎛ _R2 ⎞
⎝⎜ ^{R1 + R2}⎠⎟
V_OUT(HIGH)
=
V_REF
⎡ _{(R2 +R3)} ⎤
⎢
⎣⎢^R1
+
(^R2
+
R3₎
⎥
⎦⎥
REFERENCE
VOLTAGE
(V_REF)
R1
C_REFIN
R2
MAX1510
MAX17510
REFIN
V_OUT(LOW)
V_OUT(HIGH)
R3
( )^R2
V_OUT(LOW) = V_{REF R1 + R2}
(R2 + R3)
V_OUT(HIGH) = VREF _{R1 + (R2 + R3)}
Figure 4. Dynamic Output-Voltage Change
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