MAX1540 Datasheet, PDF (20/49 Pages) Maxim Integrated Products – Dual Step-Down Controllers with Saturation Protection, Dynamic Output, and Linear Regulator

Dual Step-Down Controllers with Saturation
Protection, Dynamic Output, and Linear Regulator
PIN
MAX1540 MAX1541
31
39
32
40
Pin Description (continued)
NAME
ON2
ON1
FUNCTION
OUT2 Enable Input. Pull ON2 to GND to shut down controller 2 (OUT2). Connect to
V_CC for normal operation. When discharge mode is enabled by OVP/UVP, the output
is discharged through a 10Ω resistor between OUT2 and GND, and DL2 is forced
high after V_OUT2 drops below 0.3V. When discharge mode is disabled by OVP/UVP,
OUT2 remains a high-impedance input and DL2 is forced low so LX2 also appears as
a high impedance. A rising edge on ON1 or ON2 clears the fault-protection latch.
OUT1 Enable Input. Pull ON1 to GND to shut down controller 1 (OUT1). Connect to
V_CC for normal operation. When discharge mode is enabled by OVP/UVP, the output
is discharged through a 10Ω resistor between OUT1 and GND, and DL1 is forced
high after V_OUT1 drops below 0.3V. When discharge mode is disabled by OVP/UVP,
OUT1 remains a high-impedance input and DL1 is forced low so LX1 also appears as
high impedance. A rising edge on ON1 or ON2 clears the fault-protection latch.
Table 1. Component Selection for Standard Applications
COMPONENT
Input Voltage (V_IN)
Output Voltage (V_OUT_)
Load Current (I_OUT_)
Switching Frequency
( f_{S W}_)
Input Capacitor (C_IN)
PWM1
7V to 24V
1.8V
4A
MAX1540
PWM2
7V to 24V
2.5V
8A
TON = REF (485kHz)
TON = REF (355kHz)
(2) 10µF, 25V
Taiyo Yuden TMK432BJ106KM
PWM1
7V to 24V
1.0V/1.5V
4A
MAX1541
PWM2
7V to 24V
2.5V
4A
TON = REF (485kHz)
TON = REF (355kHz)
(2) 4.7µF, 25V
Taiyo Yuden TMK325BJ475KM
Output Capacitor
(C_OUT_)
220µF, 6.3V, 12mΩ
Sanyo POSCAP
6TPD220M
330µF, 4V, 12mΩ
Sanyo POSCAP
4TPD330M
470µF, 4V, 10mΩ
Sanyo POSCAP
4TPD470M
220µF, 6.3V, 12mΩ
Sanyo POSCAP
6TPD220M
High-Side MOSFET
(N_H_)
Low-Side MOSFET
(N_L_)
Low-Side Schottky
(D_L_)
(if needed)
35mΩ, 30V
Fairchild 1/2 FDS6982S
22mΩ, 30V
Fairchild 1/2 FDS6982S
1A, 30V Schottky
Nihon EP10QS03L
20mΩ, 30V
Fairchild FDS6690
12.5mΩ, 30V
Fairchild FDS6670S
1A, 30V Schottky
Nihon EP10QS03L
35mΩ, 30V
Fairchild 1/2 FDS6982S
22mΩ, 30V
Fairchild 1/2 FDS6982S
35mΩ, 30V
Fairchild 1/2 FDS6982S
22mΩ, 30V
Fairchild 1/2 FDS6982S
1A, 30V Schottky
Nihon EP10QS03L
1A, 30V Schottky
Nihon EP10QS03L
Inductor (L_)
2.5µH, 6.2A, 15mΩ
Sumida
CDEP105(H)-2R5
2.2µH, 10A, 4.4mΩ
Sumida
CDEP105(L)-2R2
1.8µH, 9.0A, 6.2mΩ
Sumida
CDEP105(S)-1R8
4.3µH, 6.8A, 8.7mΩ
Sumida
CDEP105(L)-4R3
R_{SENSE_}
15mΩ ±1%, 0.5W
5mΩ ±1%, 0.5W
15mΩ ±1%, 0.5W
15mΩ ±1%, 0.5W
IRC LR2010-01-R015F IRC LR2010-01-R005F IRC LR2010-01-R015F IRC LR2010-01-R015F
or Dale WSL-2010-R015F or Dale WSL-2010-R005F or Dale WSL-2010-R015F or Dale WSL-2010-R015F
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