19-2380; Rev 0; 4/02
MAX5040 Evaluation Kit
General Description
The MAX5040 evaluation kit (EV kit) is a complete, fully
assembled and tested voltage-tracking controller circuit
that demonstrates the capability of the MAX5040. The
MAX5040 controls the output voltage of two power sup-
plies, VI/O and VCORE, during power-up and power-
down. The device ensures that the two supplies rise or
fall at the same rate, limiting the voltage difference
between them to under 200mV. The EV kit board comes
with two step-down switching power supplies pro-
grammed to 3.3V and 1.8V output voltages that allow
for an easy evaluation of the featured voltage-tracking
controller. The EV kit board operates from a 5V supply
capable of supplying up to 4A.
Features
o
On-Board Power Supplies Set at 3.3V and 1.8V
o
Voltage Tracking of Dual Power Supplies During
Power-Up and Power-Down
o
Core Voltage Range Configurable from 0.8V to 4V
o
I/O Voltage Range Configurable from VCORE to 4V
o
Detects Short Circuit on VCORE and VI/O
o
Disables Both Power Supplies During Short-
Circuit Condition
o
Output Undervoltage Monitoring and Power-OK
(POK) Status
o
Surface-Mount Construction
o
Fully Assembled and Tested
Evaluates: MAX5040
Ordering Information
PART
MAX5040EVKIT
TEMP RANGE
0°C to +70°C
IC PACKAGE
10 µMAX
Component List
DESIGNATION
QTY
DESCRIPTION
1.0µF ±10%, 25V X7R ceramic
capacitor (1206)
TDK C3216X7R1E105KT or
Taiyo Yuden TMK316BJ105KL
0.1µF ±10%, 50V X7R ceramic
capacitors (0805)
TDK C2012X7R1H104KT or
Taiyo Yuden UMK212BJ104KG
Not installed capacitor (HC)
1500pF ±10%, 50V X7R ceramic
capacitor (0603)
Taiyo Yuden UMK107BJ152KZ
10µF ±20%, 10V X5R ceramic
capacitors (1206)
TDK C3216X5R1A106M
2.2µF ±10%, 10V X5R ceramic
capacitors (0805)
TDK C2012X5R1A225KT or
Taiyo Yuden LMK212BJ225KG
0.01µF ±10%, 50V X7R ceramic
capacitor (0603)
TDK C1608X7R1H103KT or
Taiyo Yuden UMK107B103KZ
DESIGNATION
C13
QTY
1
DESCRIPTION
0.022µF ±10%, 50V X7R ceramic
capacitor (0603)
TDK C1608X7R1H223KT
470pF ±10%, 50V, X7R ceramic
capacitors (0603)
TDK C1608X7R1H471KT
1.0µF ±10%, 10V X5R ceramic
capacitors (0603)
TDK C1608X5R1A105K
Not installed capacitor (0603)
100µF, 6.3V low-ESR capacitors (C)
Sanyo 6TPC100M (POSCAP)
Not installed capacitor (A)
1A 30V Schottky diode (SOD123)
Nihon EP10QY03 or
Toshiba CRS02
2-pin headers
3-pin headers
2.2µH, 3.8A inductors
Sumida CDRH6D28 4762-TO54
C1
1
C14, C15
2
C2, C3, C6
3
C4, C5
C7
0
1
C16, C17
C18
C19, C20
C21, C22
D1
JU1, JU2, JU3
JU4, JU5
L1, L2
2
0
2
0
1
3
2
2
C8, C9
2
C10, C11
2
C12
1
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
MAX5040 Evaluation Kit
Evaluates: MAX5040
Component List (continued)
DESIGNATION
N1
N2
N3
QTY
1
0
0
DESCRIPTION
6A, 20V N-channel MOSFET
(8-pin SO) Vishay Si9428DY
Not installed N-channel MOSFET
(DPAK)
Not installed N-channel MOSFET
(D
2
PAK)
1.8A, 30V N-channel MOSFET (3-pin
SOT23)
Fairchild FDN361AN
261kΩ ±1% resistor (0805)
100kΩ ±1% resistors (0805)
10kΩ ±1% resistors (0805)
143kΩ ±1% resistor (0805)
20kΩ ±5% resistors (0603)
Not installed resistor (0603)
10Ω ±5% resistors (0603)
DESIGNATION
R13
R14
R15
R16
R17, R18, R19
R20
R21
U1
U2, U3
VI/O, VCORE,
GND
None
None
None
None
QTY
1
1
1
1
3
1
1
1
2
3
5
1
1
1
DESCRIPTION
39.2kΩ ±1% resistor (0603)
75kΩ ±1% resistor (0603)
100kΩ ±1% resistor (0603)
49.9kΩ ±1% resistor (0603)
10kΩ ±5% resistors (0603)
10kΩ ±5% resistor (0805)
51Ω ±5% resistor (1206)
MAX5040EUB (10-pin µMax)
MAX1842EEE (16-pin QSOP)
Noninsulated banana jack
connectors
Shunts (JU1–JU5)
MAX5040 PC board
MAX5040 data sheet
MAX5040 EV kit data sheet
N4
R1
R2, R6
R3, R4
R5
R7, R8
R9, R10
R11, R12
1
1
2
2
1
2
0
2
Component Suppliers
SUPPLIER
Fairchild
Nihon
Sanyo
Sumida
Taiyo Yuden
TDK
Toshiba
Vishay
PHONE
888-522-5372
81-33343-3411
619-661-6322
847-545-6700
800-348-2496
847-803-6100
949-455-2000
203-268-6261
FAX
408-522-5372
81-33342-5407
619-661-1055
847-545-6720
847-925-0899
847-390-4498
949-859-3963
203-452-5670
WEBSITE
www.fairchildsemi.com
www.niec.co.jp
www.sanyo.com
www.sumida.com
www.t-yuden.com
www.component.tdk.com
www.toshiba.com/taec/
www.vishay.com
Note:
Please indicate that you are using the MAX5040 when contacting these component suppliers.
Quick Start
The MAX5040 EV kit is a fully assembled and tested
surface-mount board. Follow the steps below for simple
board operation.
Do not turn on the power supply
until all connections are completed.
1) Verify that a shunt is connected across jumpers JU1,
JU2, and JU3.
2) Verify that a shunt is connected across pins 1 and 2
of jumpers JU4 and JU5.
3) Connect the positive terminal of the 5V power sup-
ply to the VIN pad. Connect the ground terminal of
the 5V power supply to the GND pad. Leave the
VCC pad open circuit; it is connected to VIN
through jumper JU3.
2
4) Connect voltmeters or an oscilloscope to pads
SDO
and POK to analyze the functionality of the MAX5040
voltage-tracking controller during power-up.
5) Connect an oscilloscope at V
IN
, VI/O, and VCORE
to observe voltage tracking during power-up and
power-down. Set the oscilloscope to trigger on the
rising edge of VIN.
6) Turn on the 5.0VDC power supply.
7) Verify that VI/O is 3.3V and VCORE is 1.8V.
Note:
Connect the ground terminals of the voltmeters
connected to
SDO
and POK to the AGND pad.
_______________________________________________________________________________________
MAX5040 Evaluation Kit
Detailed Description
The MAX5040 EV kit is a complete, fully assembled and
tested circuit that demonstrates the capability of the
MAX5040 voltage-tracking controller. The MAX5040 pro-
vides intelligent control to power systems where two sup-
ply voltages need to be tracked. The device limits the
voltage difference between the two supply voltages dur-
ing power-up and power-down. The controller generates
logic signals that can be used to shut down the power
sources or other devices when a fault is detected.
The EV kit board comes with two MAX1842 step-down
switching power supplies preset to 3.3V (VI/O), 1.8V
(VCORE), and operates from a 5V supply voltage capa-
ble of supplying up to 4A. The MAX5040 controller
turns on the N-channel MOSFET (N1) when VI/O is
below VCORE or when VCORE is below 1.6V. The
undervoltage lockout threshold for the MAX5040 con-
troller is set to 4.5V.
Note:
A 33µF capacitor is recommended to stabilize
the VI/O and VCORE inputs if a lab power supply is
connected to the EV kit through long wires or if it has a
poor transient response. For further information on the
MAX1842 power supplies, refer to the MAX1742/
MAX1842 EV kit or data sheets.
Evaluates: MAX5040
Output Voltage Delays
The VCORE and VI/O power supplies have an external
RC signal delay of 2ms at their respective shutdown pins.
If the delay is used in one of the power supplies, its start-
up is delayed by 2ms with respect to the other power
supply. VI/O and VCORE power supplies also have differ-
ent soft-start capacitor values causing VCORE to rise
slower than VI/O. The delay can be used to evaluate how
the MAX5040 functions when one of the two tracking volt-
ages lags behind the other during system startup. The
delay can be bypassed by placing a shunt across pins 1
and 2 of jumpers JU4 and JU5. See Table 1 for jumper
JU4, JU5 configurations and functions.
Input Voltage
The MAX5040 EV kit requires an input voltage of 4.5V
to 5.5V for normal operation. The MAX5040 controller
starts to function at an input voltage of 2.5V but it holds
the VI/O and VCORE power supplies in shutdown mode
until the 4.5V undervoltage lockout threshold has been
exceeded. Once the input voltage exceeds this thresh-
old, the controller enables the VI/O and VCORE sup-
plies. The EV kit has a maximum input voltage limit of
5.5V. See the
Monitoring External Power Sources
sec-
tion for instructions to disconnect the power supplies
Table 1. Power Supplies Shutdown and
Signal Delay (Shunt on JU2 Is Installed)
JUMPER
SHUNT
POSITION
1 and 2
SHDN
PIN
Connected to
SDO
Connected to
ground
Connected to
SDO
pin
through the
RC filter
FUNCTION
Bypasses the 2ms
signal delay on the
shutdown pin of VI/O
VI/O in shutdown
mode
VI/O shutdown pin
has a 2ms delay
On-Board Power Supplies
The MAX5040 EV kit includes two MAX1842 step-down
switching power supplies that allow the user to evaluate
the MAX5040 under conditions similar to a real system
application. The first power supply (VI/O) is set to an
output voltage of 3.3V and provides 2.5A of current.
The VI/O supply is used to simulate a power source to
an I/O bus in a system.
The second power supply (VCORE) is set to an output
voltage of 1.8V and provides 2.5A of current. The
VCORE supply is used to simulate a power source to
the main core processor in a system. The VI/O and
VCORE power supplies require a 3.3V to 5.5V input
voltage at VIN. However, VI/O and VCORE do not start
up until VIN reaches 4.5V. The MAX5040 controller’s
undervoltage lockout threshold is set to 4.5V and the
controller holds VI/O and VCORE in shutdown mode
until VIN is greater than 4.5V. VI/O and VCORE can be
manually shut down by placing a shunt across pins 2
and 3 of jumpers JU4 and JU5. See Table 1 for jumper
JU4 and JU5 configurations.
JU4
2 and 3
None
1 and 2
Connected to
SDO
Bypasses the 2ms
signal delay on the
shutdown pin of
VCORE
VCORE in
shutdown mode
VCORE shutdown
pin has a 2ms
delay
JU5
2 and 3
Connected to
ground
Connected to
SDO
pin
through the
RC filter
None
_______________________________________________________________________________________
3
MAX5040 Evaluation Kit
Evaluates: MAX5040
Voltage Thresholds
The MAX5040 EV kit voltage-monitoring thresholds are
programmed with external resistors as indicated in
Table 2. Refer to the MAX5039/MAX5040 data sheet to
select new resistor values.
thresholds within 15ms, the controller pulls
SDO
and
POK low, shutting the voltage regulators and signaling
a fault in the system. If VI/O and VCORE are above their
thresholds within 15ms, the controller enters normal
operation mode. See Table 3 for the complete startup
sequence of the EV kit that also includes voltage condi-
tions and EV kit outputs.
Note:
SDO is the inverted signal of
SDO
that can be
used for active-high shutdown pins.
SDO
and SDO
high state is V
IN
. POK high state is VI/O.
Table 2. Threshold Settings
SOURCE
THRESHOLD
(V)
4.5
EV KIT
FUNCTIONS
Voltage below
which
SDO
goes low
VCORE
threshold/
regulation
voltage
Voltage below
which POK
goes low
FEEDBACK
RESISTORS
R1, R2
VCC
Normal Mode
In normal operation, the controller attempts to keep
VCORE from falling below 1.6V. If V
IN
falls below 4.5V,
the controller shuts down the power supplies by pulling
SDO
low. If VCORE falls below 1.6V, the controller dri-
ves the NDRV pin high, which turns on the MOSFET
connected across VCORE and VI/O, sourcing current
from the VI/O rail to raise VCORE to 1.6V. The controller
also drives the NDRV pin high if VI/O voltage falls
below VCORE to source current in the opposite direc-
tion. POK is always pulled low when any fault is detect-
ed. See Table 4 for fault conditions.
VCORE
1.6
R3, R4
VI/O
(Sense)
3.0
R5, R6
Startup Mode
The MAX5040 EV kit starts to function when the system
voltage V
IN
reaches the minimum input voltage of 2.5V
required by the voltage-tracking controller. The con-
troller pulls the
SDO
pin low at an input voltage of 0.9V,
which keeps the VI/O and VCORE supplies in shut-
down. The
SDO
pin is connected to the active-low shut-
down pin of VI/O and VCORE regulators through
jumper JU2. When V
IN
exceeds 4.5V, the
SDO
pin is
pulled HIGH (to V
IN
) to enable VI/O and VCORE. If the
VI/O and VCORE output voltages are not above their
Shutdown
The MAX5040 controller can be forced into shutdown
mode by connecting an external device to the UV_CC
pad and driving it low. When the controller is in shut-
down mode, the controller pulls the
SDO
pin low, forc-
ing VI/O and VCORE into shutdown.
Table 3. Startup Sequence
STEP
1
2
3
4
VCORE <
VI/O < 3.0V
5
≥4.5V
X
<VCORE
≥3.0V
≥1.6V
<1.6V
≥1.6V
≥1.6V
CONDITIONS
VCC
<0.9V
0.9V
≤
V
CC
< 4.5V
≥4.5V
VI/O
X
0V
S
VCORE
X
0V
S
SDO
X
L
H
15ms later
H
L
H
L
H
L
L
L
H
VI/O low forces POK low
Startup fault
Normal operation
EV KIT OUTPUTS
SDO
X
H
L
POK
X
L
L
EV KIT FUNCTIONS
Not operating
Power supplies in
shutdown mode
Power supplies are turned
ON
X = Don’t care.
S = VI/O and VCORE power supplies in startup mode.
4
_______________________________________________________________________________________
MAX5040 Evaluation Kit
Evaluates: MAX5040
Table 4. Fault Conditions
CONDITIONS
VCC
<4.5V
≥4.5V
≥4.5V
≥4.5V
VI/O
≥3.0V
VCORE
≤
VI/O < 3.0V
VI/O < VCORE
After 15ms
X
After 15ms
<1.6V
VCORE
≥1.6V
≥1.6V
≥1.6V
SDO
L
H
H
L
H
L
EV KIT OUTPUTS
SDO
H
L
L
H
L
H
POK
L
L
L
L
L
L
EV KIT FUNCTIONS
Power supplies are turned OFF
VI/O low forces POK low
NDRV pin is driven HIGH
Power supplies are turned OFF
NDRV pin is driven HIGH
Power supplies are turned OFF
X = Don’t care.
Monitoring External Power Sources
The MAX5040 voltage-tracking controller monitors two
MAX1842 step-down switching power supplies that are
set for 3.3V and 1.8V, and can deliver up to 2.5A. The
input voltage range for the EV kit is 2.5V to 5.5V. The
EV kit circuit can be modified to operate with external
power sources set at different output voltages and/or
current capabilities. The two on-board power supplies
must be disabled from the controller circuit when using
external supplies.
To monitor external power supplies:
1) Place a shunt across pins 2 and 3 of jumper JU4
and JU5 to disable the on-board power supplies.
2) Remove the shunt across jumper JU2.
3) Connect the external voltage source to the VI/O
banana jack and the external core source to the
VCORE banana jack. Connect the grounds from the
external voltage sources to the GND banana jack.
4) Connect the shutdown pin of the external supplies
to
SDO
(active-low shutdown) or SDO (active-high
shutdown) pads.
5) Replace the feedback resistor pairs listed in Table
2 if the voltage thresholds or the output voltages are
different from 3.3V and 1.8V.
For higher current capabilities, remove MOSFET N1 on
the EV kit and install a DPAK N-channel MOSFET (N2)
or a D
2
PAK N-channel MOSFET (N3).
None
Jumper JU1
The MAX5040 EV kit circuit features D1 between the
input power connection and the V
CC
pin of the voltage-
tracking controller. D1 and C1 can be used to hold the
supply in the event of a rapid voltage drop by the
power source. Install a 10µF capacitor at C1 to use this
feature. This protection can be bypassed or implement-
ed by reconfiguring jumper JU1. See Table 5 for
jumper JU1 configuration.
Table 5. Jumper JU1 Functions
SHUNT
LOCATION
EV KIT FUNCTIONS
EV kit operates normally when there is a
momentary loss of input power (requires a
10µF capacitor at C1).
Full operation may be disrupted if there is a
momentary loss of input power.
Installed
_______________________________________________________________________________________
5
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