MAX1531EVKIT Datasheet MAX1531EVKIT | P7-P9

Positive Charge Pump

The positive charge pump of the MAX1531 EV kit pow-

ers the GON linear regulator and features an option to

cascade up to two charge-pump stages. The charge

pump’s first stage can be connected to PIN or VOUT,

and the charge pump’s second stage can be connect-

ed to PIN or the previous stage. Jumpers JU12 and

JU13 configure the number of stages and select the

voltage source for the positive charge pump on the

MAX1531 EV kit. Tables 8 and 9 list the jumper options.

The default configuration of the positive charge pump

of the MAX1531 EV kit is a two-stage charge pump

powered from PIN as indicated in Tables 8 and 9.

Since the positive charge pump powers the GON linear

regulator, ensure that the combination of the charge-

pump configuration and the input voltage range (PIN)

does not over stress the GON linear regulator’s external

pass transistor. The V

CEO

maximum rating of the

MMBT3904 used on this EV kit is 40V. If the input volt-

age (PIN) exceeds +13.2V, either reconfigure the

charge pump (using JU12 and JU13) as a two-stage

charge pump from VOUT or a one-stage charge pump

from PIN, as appropriate, or select a higher-voltage-

rated transistor for Q3. Also, if higher charge-pump

voltages are required, ensure that Q6 and C15 are not

over stressed. Refer to the Charge Pumps section of

the MAX1531 data sheet for more information on select-

ing a charge-pump configuration.

Evaluates: MAX1530/MAX1531

MAX1531 Evaluation Kit

_______________________________________________________________________________________ 7

JU7 SHUNT

LOCATION

JU11 SHUNT

LOCATION

ONL5 PIN SEQUENCING MODE

1-2 Don’t Care

Connected to VL

through R42

GOFF linear regulator enabled immediately if JU3 is removed

(SEQ = high) and step-down switching regulator soft-start is

finished. Sequence not used.

1-4 Don’t Care

Connected to

GND

GOFF linear regulator disabled.

1-2 Connected to R14

GOFF linear regulator soft-starts about 6ms after sequence block

enabled.

1-3 Connected to R15

GOFF linear regulator soft-starts about 9ms after sequence block

enabled.

1-4

(Default)

Connected to R16

GOFF linear regulator soft-starts about 12ms after sequence

block enabled.

1-3

(Default)

1-5 Connected to C11

GOFF linear regulator soft-starts about 15ms after sequence

block enabled.

Table 7. ONL5 Setting (JU7 and JU11)

SHUNT

LOCATION

1ST STAGE

POSITIVE

CHARGE

PUMP

OPERATING MODE

1-2

(Default)

Connected to

First stage of a two-stage

charge pump connected to

PIN.

2-3

Connected to

VOUT

First stage of a two-stage

charge pump connected to

VOUT.

None Not used

The first stage is not used for

one-stage charge pumps.

Table 8. Jumper JU12 Functions

SHUNT

LOCATION

2ND STAGE

POSITIVE

CHARGE

PUMP

OPERATING MODE

1-2

Connected to

One-stage charge pump

connected to PIN.

2-3

(Default)

Connected to

previous stage

charge-pump

output

Last stage of a two-stage

charge pump.

None Not used Charge pump not used.

Table 9. Jumper JU13 Functions

Evaluates: MAX1530/MAX1531

VGAM Power Supply

The power supply for the VGAM linear regulator can be

connected to PIN or STEP_UP. PIN is the input voltage

for the EV kit. STEP_UP is the output of the MAX1522

step-up switching regulator circuit on the EV kit.

Jumper JU14 selects the power supply for the VGAM

linear regulator on the MAX1531 EV kit. Table 10 lists

the jumper options.

VSRC Power Supply

The power supply for the VSRC linear regulator can be

connected to PIN or STEP_UP. PIN is the input voltage

for the EV kit. STEP_UP is the output of the MAX1522

step-up switching regulator circuit on the EV kit.

Jumper JU15 selects the power supply for the VSRC

linear regulator on the MAX1531 EV kit. Table 11 lists

the jumper options.

The MAX1522 Step-Up Circuit

The MAX1531 EV kit includes a MAX1522 step-up

switching regulator. This regulator is not generally

needed, but is provided as a convenience for applica-

tions where the input voltage (PIN) can be less than

VSRC. If the step-up is needed, enable the MAX1522

using JU16 and set JU14 and JU15 so that VGAM and

VSRC use the step-up’s output.

Output Voltage Selection

Step-Down Switching-Regulator Output

Voltage (V

OUT

)

The MAX1531 EV kit’s step-down switching-regulator

output (VOUT) is set to +3.3V by feedback resistors R1

and R2. To generate output voltages other than +3.3V

(from +1.24V up to 0.6 x V

), select different external

voltage-divider resistors (R1, R2). Output capacitor C7

is rated to +6.3V. To set the output voltage greater than

+6.3V, use a higher-voltage-rated capacitor. Refer to

the Main Step-Down Regulator Output Voltage

Selection section in the MAX1531 data sheet for

instructions on selecting the resistors.

Logic-Voltage-Supply Linear Regulator

Output Voltage (VLOG)

The MAX1531 EV kit’s logic-voltage-supply linear regu-

lator output (VLOG) is set to +2.5V by feedback resis-

tors R9 and R10. To generate output voltages other

than +2.5V (from +1.24V up to VOUT) select different

external voltage-divider resistors (R9, R10). Output

capacitor C9 is rated to +6.3V. To set the output volt-

age greater than +6.3V, use a higher-voltage-rated

capacitor. Refer to the Linear-Regulator Controllers

Output Voltage Selection section in the MAX1531 data

sheet for instructions on selecting the resistors.

Gamma-Reference Linear Regulator

Output Voltage (VGAM)

The MAX1531 EV kit’s gamma-reference linear regula-

tor output (VGAM) is set to +9.7V by feedback resistors

R18 and R19. To generate output voltages other than

+9.7V (from +1.24V up to its input voltage) select differ-

ent external voltage-divider resistors (R18, R19). Output

capacitor C12 is rated to +16V. To set the output volt-

age greater than +16V, use a higher-voltage-rated

capacitor. Refer to the Linear-Regulator Controllers

Output Voltage Selection section in the MAX1531 data

sheet for instructions on selecting the resistors.

MAX1531 Evaluation Kit

8 _______________________________________________________________________________________

SHUNT

LOCATION

VGAM

POWER

SUPPLY

OPERATING MODE

1-2

Connected to

STEP_UP

VGAM powered from the

output of the MAX1522 step-

up regulator.

2-3

(Default)

Connected to

VGAM powered from PIN.

None Not used VGAM not used.

Table 10. Jumper JU14 Functions

SHUNT

LOCATION

VSRC

POWER

SUPPLY

OPERATING MODE

1-2

Connected to

STEP_UP

VSRC powered from the

output of the MAX1522 step-

up regulator.

2-3

(Default)

Connected to

VSRC powered from PIN.

None Not used VSRC not used.

Table 11. Jumper JU15 Functions

SHUNT

LOCATION

MAX1522

SHDN PIN

MAX1522

OPERATING MODE

1-2

Connected to

VOUT

Enabled

2-3

(Default)

Connected to

GND

Disabled

Table 12. Jumper JU16 Functions

Gate-On Linear Regulator Output

Voltage (GON)

The MAX1531 EV kit’s gate-on linear regulator output

(GON) is set to +25V by feedback resistors R25 and

R26. To generate output voltages other than +25V (from

+1.24V up to the linear regulator’s input, which is the

output of the positive charge pump), select different

external voltage-divider resistors (R25, R26). Take care

not to exceed either the pnp pass transistor’s V

CEO

rat-

ing (40V) or the output capacitor’s (C16) +50V rating.

Before GON is enabled, Q3 is off and the positive

charge pump’s full output voltage is present across Q3.

If the input voltage (PIN) exceeds 13.2V, do not power

the EV kit with the charge pump configured as a two-

stage charge pump powered from PIN, as Q3’s 40V

rating will be exceeded. Configure JU12 and JU13 for a

two-stage charge pump powered from VOUT or as a

one-stage charge pump powered from PIN, whichever

is appropriate. Alternatively, select a different transistor

for Q3 and possibly Q6, which must withstand the

same voltage, minus V

. If V

exceeds +20V, even

a one-stage charge pump will exceed +40V, so either

change Q3 or disable the charge pump entirely and

power the linear regulator directly from PIN, whichever

is appropriate.

Refer to the Linear-Regulator Controllers Output

Voltage Selection section in the MAX1531 data sheet

for instruction on selecting the voltage-divider resistors.

Also, refer to the Charge Pumps section for more infor-

mation about configuring the positive charge pump.

Source-Supply Linear Regulator Output

Voltage (VSRC)

The MAX1531 EV kit’s source-supply linear regulator

output (VSRC) is set to +10V by feedback resistors R22

and R23. To generate output voltages other than +10V

(from +1.24V up to its input voltage) select different

external voltage-divider resistors (R22, R23). Output

capacitor C13 is rated to +16V. To set the output volt-

age greater than +16V, use a higher-voltage-rated

capacitor. Refer to the Linear-Regulator Controllers

Output Voltage Selection section in the MAX1531 data

sheet for instructions on selecting the resistors.

Gate-Off Linear Regulator Output

Voltage (GOFF)

The MAX1531 EV kit’s negative linear regulator output

(GOFF) is set to -9V by feedback resistors R28 and

R29. To generate output voltages other than -9V (0V

down to its input voltage), select different external volt-

age-divider resistors (R28, R29). Output capacitor C19

is rated to -16V. To set the output voltage below -16V,

use a higher-voltage-rated capacitor. Refer to the

Linear-Regulator Controllers Output Voltage Selection

and Charge Pumps sections in the MAX1531 data

sheet for instructions on selecting the resistors.

Evaluating the MAX1530

The MAX1531 EV kit can also evaluate the MAX1530.

To evaluate the MAX1530, replace U1 with the

MAX1530. Refer to the MAX1530/MAX1531 data sheets

for additional information.

Evaluates: MAX1530/MAX1531

MAX1531 Evaluation Kit

_______________________________________________________________________________________ 9

P1-P3 P4-P6 P7-P9 P10-P12 P13-P13

MAX1531EVKIT

Mfr. #:

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Manufacturer:

Maxim Integrated

Description:

Power Management IC Development Tools MAX1530/1 Eval Kit

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