Evaluating Other Output Voltages

The MAX5035 step-down DC-DC switching regulator

output is set to 5V by feedback resistors R1 and R2. To

generate output voltages other than 5V (1.25V to 12V),

select different external voltage-divider resistors for R1

and R2. Refer to the Setting the Output Voltage section

in the MAX5035 data sheet for instructions on selecting

the resistors. The minimum input voltage for a given

output voltage is maximum duty-cycle dependent for

that input voltage. Refer to the MAX5035 data sheet for

additional information.

Startup Delays/

Sequencing Two DC-DC Converters

The MAX5035 EV kit can be configured for various

startup delays. To evaluate a startup delay, cut open

the PCB trace shorting resistor R4 and install the

desired surface-mount resistor (0805 case). Capacitor

C5 (0805 case) must also be selected and installed.

Refer to the MAX5035 data sheet’s Shutdown Mode

and Undervoltage Lockout (UVLO) sections to select

values for resistor R4 and capacitor C5.

The MAX5035 EV kit’s startup delay can also be utilized

to sequence two MAX5035 EV kits. Components

the startup delay between the two EV kits. The following

equation can be used to select values for R4 and C5:

where Time_delay is the desired startup delay time,

pad on the EV kit and 1.69V (typ) is the on/off threshold

voltage of the MAX5035.

C

Time delay

Rx

V

5

41

169

=









































−−

_

ln

.

_

MAX5035 Evaluation Kit

_______________________________________________________________________________________

3

JU1

1

2

3

R4

SHORT

PC TRACE

R3

130k

Ω

1%

VIN

SHDN

R5

45.3k

Ω

1%

C5

OPEN

VIN

GND

C1

68

µF

100V

C6

0.22

µF

100V

C4

0.1

µF

R2

13.3k

Ω

1%

MAX5035

U1

SHDN

SGND

VD

GND

BST

FB

LX

1

4

8

6

5

3

7

2

GND

VOUT

R1

41.2k

Ω

1%

C3

0.1

µF

L1

100

µH

D1

C2

68

µF

10V

Figure 1. MAX5035 EV Kit Schematic