MAX16930 Datasheet, PDF (19/29 Pages) Maxim Integrated Products – 2MHz, 36V, Dual Buck with Preboost and 20μA Quiescent Current

MAX16930/MAX16931
2MHz, 36V, Dual Buck with Preboost and
20µA Quiescent Current
The input voltage ripple is composed of DV_Q (caused by
the capacitor discharge) and DV_ESR (caused by the ESR
of the input capacitor). The total voltage ripple is the sum
of DV_Q and DV_ESR that peaks at the end of an on-cycle.
Calculate the input capacitance and ESR required for a
specific ripple using the following equation:
ESR[Ω] =
∆V_ESR

I_{LOAD (MAX )}
+
∆I_{P − P}
2


C_IN
[µF]
=
I_{LOAD (MAX )}
(∆V_Q x
x



V_OUT
V_IN
f_SW )



where:
∆I_P−P
= ^{(VIN − VOUT ) x VOUT}
V_IN x f_SW x L
I_LOAD(MAX) is the maximum output current in A, DI_P-P is
the peak-to-peak inductor current in A, f_SW is the switch-
ing frequency in MHz, and L is the inductor value in µH.
The internal 5V linear regulator (BIAS) includes an output
UVLO with hysteresis to avoid unintentional chattering
during turn-on. Use additional bulk capacitance if the
input source impedance is high. At lower input voltage,
additional input capacitance helps avoid possible under-
shoot below the undervoltage lockout threshold during
transient loading.
MAX16930/
MAX16931
NH
DH_
LX_
NL
DL_
GND
INPUT (VIN)
CIN
L
RSENSE
CS_
OUT_
A) OUTPUT SERIES RESISTOR SENSING
MAX16930/
MAX16931
NH
DH_
LX_
NL
DL_
GND
INPUT (VIN)
CIN
INDUCTOR
L
DCR
R1
R2
CEQ
CS_
OUT_
B) LOSSLESS INDUCTOR SENSING
Figure 1. Current-Sense Configurartions
Maxim Integrated
COUT
COUT
( )^R2
R_CSHL = _{R1 + R2} R_DCR
[ ] ^L
RDCR = _CEQ
1+1
R1 R2
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