MAX15003 Datasheet, PDF (11/32 Pages) Maxim Integrated Products – Triple-Output Buck Controller with Tracking/Sequencing

Triple-Output Buck Controller with
Tracking/Sequencing
Pin Description (continued)
PIN
NAME
FUNCTION
16
FB1
Controller 1 Feedback Regulation Point. Connect to the center tap of a resistive divider from the converter
output to SGND to set the output voltage. The FB1 voltage regulates to V_FB (0.6V).
17
PGOOD1 ^{Controller 1 Power-Good Output. Open-drain PGOOD1 output goes high impedance (releases) when FB1 is}
above 0.925 x V_FB = 0.555V.
Controller 2 Power Ground Connection. Connect the input filter capacitor’s negative terminal, the source of
18
PGND2 the synchronous MOSFET, and the output filter capacitor’s return to PGND2. Connect externally to SGND at
a single point near the input capacitor return terminal.
19
DL2
Controller 2 Low-Side Gate Driver Output. DL2 is the gate driver output for the synchronous MOSFET.
20
DREG2
Controller 2 Low-Side Gate Driver Supply. Connect externally to REG and the anode of the boost diode.
Connect at minimum, a 0.1µF ceramic capacitor from DREG2 to PGND2.
21
LX2
Controller 2 High-Side MOSFET Source Connection/Synchronous MOSFET Drain Connection. Connect the
inductor and the negative side of the boost capacitor to LX2.
22
DH2
Controller 2 High-Side Gate Driver Output. DH2 drives the gate of the high-side MOSFET.
23
BST2
Controller 2 High-Side Gate Driver Supply. Connect BST2 to the cathode of the boost diode and to the
positive terminal of the boost capacitor.
Controller 2 Negative Current-Sense Input. Connect CSN2 to the synchronous MOSFET drain (connected to
24
CSN2
LX2). When using a current-sense resistor, connect CSN2 to the junction of the low-side MOSFET’s source
and the current-sense resistor. See Figure 11.
Controller 2 Positive Current-Sense Input. Connect CSP2 to the synchronous MOSFET source (connected to
25
CSP2
PGND2). When using a current-sense resistor, connect CSP2 to the PGND2 end of the current-sense
resistor.
Controller 2 Valley Current-Limit Set Output. Connect a 25kΩ to 150kΩ resistor, R_ILIM2, from ILIM2 to SGND
26
ILIM2
to program the valley current-limit threshold from 50mV to 300mV. ILIM2 sources 20µA out to R_ILIM2. The
resulting voltage divided by 10 is the valley current-limit threshold. When using a precision current-sense
resistor, connect a resistive divider from REG to ILIM2 to SGND to set the valley current limit. See Figure 11.
27
COMP2
Controller 2 Error Transconductance Amplifier Output. Connect COMP2 to the compensation feedback
network.
Controller 2 Enable/Tracking Input. See Figure 2.
When sequencing, EN/TRACK2 must be above 1.24V for the PWM controller 2 to start.
28 EN/TRACK2 Coincident tracking—connect the same resistive divider used for FB2, from Output 1 to EN/TRACK2 to
SGND.
Ratiometric tracking—connect EN/TRACK2 to analog ground.
29
FB2
Controller 2 Feedback Regulation Point. Connect to the center tap of a resistive divider from the converter
output to SGND to set the output voltage. The FB2 voltage regulates to V_FB (0.6V).
30
PGOOD2 ^{Controller 2 Power-Good Output. Open-drain PGOOD2 output goes high impedance (releases) when FB2 is}
above 0.925 x V_FB = 0.555V.
31
PGOOD3 ^{Controller 3 Power-Good Output. Open-drain PGOOD3 output goes high impedance (releases) when FB3 is}
above 0.925 x V_FB = 0.555V.
32
FB3
Controller 3 Feedback Regulation Point. Connect to the center tap of a resistive divider from the converter
output to SGND to set the output voltage. The FB3 voltage regulates to V_FB (0.6V).
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