High-Speed, Adjustable, Synchronous Step-Down

Controllers with Integrated Voltage Positioning

______________________________________________________________________________________

13

Pin Description (continued)

PIN

NAME

FUNCTION

21

SKIP

Connect to GND to enable pulse-skipping operation. Low-noise forced-PWM mode causes inductor

current recirculation at light loads and suppresses pulse-skipping operation. Normal operation

prevents current recirculation. SKIP can also be used to disable both overvoltage and undervoltage

protection circuits and clear the fault latch (see No-Fault Test Mode). Do not leave

SKIP floating.

22

BST

Boost Flying-Capacitor Connection. Connect to an external capacitor and diode according to the

standard application circuit (Figure 1).

23

LX

External Inductor Connection. Connect LX to the switched side of the inductor. LX serves as the

lower supply rail for the DH high-side gate driver. LX does not connect to the current-limit

comparator.

24

CS

threshold is set by ILIM. If the current-sense signal (Inductor Current

current-limit threshold, the MAX1716/MAX1854/MAX1855 will not initiate a new cycle.

COMPONENT

CIRCUIT 1

(FIGURE 1)

CIRCUIT 2

(FIGURE 11)

CIRCUIT 3

(FIGURE 12)

CIRCUIT 4

(FIGURE 13)

Output Voltage

1.6V

1.3V

1.0V

1.6V

Input Voltage Range

7V to 24V

7V to 24V

7V to 24V

7V to 24V

Maximum Load Current

18A

12A

12A

18A

Inductor

0.68

µH

Sumida

CDEP134H-0R6

or Panasonic

ETQP6F0R6BFA

1

µH

Sumida

CEP125-1R0MC

or Panasonic

ETQP6FIRIBFA

0.68

µH

Sumida

CDEP134H-0R6

or Panasonic

ETQP6F0R6BFA

0.47

µH

Sumitomo

CXE-R47

TON Level

Float

Float

REF

GND

Frequency

300kHz

300kHz

400kHz

550kHz

High-Side MOSFET

International Rectifier

(2) IRF7811

International Rectifier

IRF7811

International Rectifier

IRF7811

International Rectifier

(2) IRF7811

Low-Side MOSFET

Fairchild (2) FDS7764A

Or International

Rectifier (2) IRF7811

Fairchild (2) FDS7764A

Or International

Rectifier (2) IRF7811

Fairchild (2) FDS7764A

Or International

Rectifier (2) IRF7811

Fairchild (2) FDS7764A

Or International

Rectifier (2) IRF7811

Input Capacitor

(5) 10

µF

Taiyo Yuden

TMK432BJ106

(4) 10

µF

Taiyo Yuden

TMK432BJ106

(4) 10

µF

Taiyo Yuden

TMK432BJ106

(5) 10

µF

Taiyo Yuden

TMK432BJ106

Output Capacitor

(5) 220

µF

Panasonic

EEFUE0E221R

(4) 220

µF

Panasonic

EEFUE0E221R

(4) 220

µF

Panasonic

EEFUE0E221R

(8) 47

µF

Taiyo Yuden

JMK432BJ476MM

or TDK

C4532X5ROJ476M

Current-Sense Resistor

3m

Ω

3.5m

Ω

3.5m

Ω

3m

Ω

ILIM Level

Voltage-Positioning

Resistor Ratio

1:1 (0.5x)

1:2 (0.66x)

1:2 (0.66x)

1:1 (0.5x)

Table 1. Component Selection for Standard Applications