MAX8664EVKIT+ Maxim Integrated Products, MAX8664EVKIT+ Datasheet - Page 18

• Manufacturer Part Number: MAX8664EVKIT+
• Description: KIT EVAL FOR MAX8664
• Manufacturer: Maxim Integrated Products

Specifications of MAX8664EVKIT+

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 2, Non-Isolated
• Voltage - Input: 4.5 ~ 28V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: MAX8664
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Output: -
• Power - Output: -
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Table 5. Component List for Figure 5
The MAX8664 features an OSC/EN12 input that is used
both for setting the switching frequency and as an
enable input for both controllers. A resistor from
OSC/EN12 to GND sets the switching frequency, and
when OSC/EN12 is high impedance, both controllers
enter low-power shutdown mode. This is easily
achieved with a transistor between the resistor and
GND. Figure 6a shows the startup configuration with
independent outputs. With REFIN2 connected to V
both controllers use the internal reference.
Low-Cost, Dual-Output, Step-Down
Controller with Fast Transient Response
Figure 6a. Two Independent Output Startup and Shutdown Waveforms
18
C2, C3, C14, C15
DESIGNATION
C10, C19
C11, C20
C1, C13
C7, C16
C8, C17
C9, C18
______________________________________________________________________________________
C12
C5
C6
QTY
2
4
1
1
2
2
2
2
2
1
Power-Up and Sequencing
0.01µF, 10V X7R ceramic
capacitors
10µF, 25V X5R ceramic capacitors
1µF, 25V X5R ceramic capacitor
1µF, 10V X5R ceramic capacitor
0.22µF, 10V X7R ceramic
capacitors
4700pF, 10V X7R ceramic
capacitors
470µF/2.5V POSCAP capacitors
Sanyo 2R5TPD470M6
10µF, 6.3V X5R ceramic capacitors
1000pF, 25V X7R ceramic
capacitors
4.7µF, 10V X5R ceramic capacitor
DESCRIPTION
CC
,
ENABLE
PWRGD
CHIP
V
For tracking applications, connect REFIN2 to the center
of a resistive voltage-divider between the output of con-
troller 1 and GND. See Figure 6b. In this application,
the output of regulator 2 tracks the output voltage of
controller 1. The voltage-divider resistors set the
V
the VTT supply of DDR memory.
Figure 6c shows one method of sequencing the out-
puts. Output 1 rises first. When PWRGD goes high, the
transistors allow the external reference to drive REFIN2
and output 2 rises. The circuit in Figure 6d functions
similarly, except the enable signal is supplied externally
instead of being driven by the PWRGD signal.
V
OUT1
OUT2
OUT2
DESIGNATION
R3, R11
R5, R10
N1–N4
L1, L2
/V
R12
N5
R1
R2
R4
R6
R7
R8
R9
OFF
OUT1
ENABLE
ON
CHIP
ratio. A typical tracking application is for
QTY
2
4
1
1
1
2
1
2
1
1
1
1
1
1.43µH, 4.52mΩ inductors
Panasonic ETQP3H1E4BFA
n-channel MOSFETs
IRF7821 (8-pin SOs)
n-channel MOSFET
2N7002 (SOT23)
2.87kΩ ±1% resistor (0402 or 0603)
40.2kΩ ±1% resistor (0402 or 0603)
10kΩ ±1% resistors (0402 or 0603)
5.36kΩ ±1% resistor (0402 or 0603)
2.0Ω ±5% resistors (1206)
2.26kΩ ±1% resistor (0402 or 0603)
10kΩ ±5% resistor (0402 or 0603)
75kΩ ±1% resistor (0402 or 0603)
25.5kΩ ±1% resistor (0402 or 0603)
9.53kΩ ±1% resistor (0402 or 0603)
V
REFIN2
OSC/EN12
CC
DESCRIPTION
MAX8664