ALLEGRO APM81911 Evaluation Board Module User Guide

June 10, 2024
ALLEGRO

ALLEGRO APM81911 Evaluation Board Module

ALLEGRO-APM81911-Evaluation-Board-Module-FIG-1

Product Information

The APM81911 Evaluation Board is an electronic device designed to help system designers evaluate the operation and performance of the APM81911 synchronous buck regulator ClearPower module. It allows for the configuration of output voltage with a jumper for either 5 V or 3.3 V. The evaluation board has six configuration jumpers that enable different operating modes of the APM81911.

Features

  • Input Operating Voltage: 3.5 V to 36 V
  • *Output Current:** 0 A to 3 A
  • Switching Frequency and SYNCIN Frequency: 1 MHz to 2.15 MHz
  • Output voltage selectable with jumper for either 5 V or 3.3 V
    *Note: Maximum output current may be lower due to thermal limitations of the APM81911 and the APM81911 Evaluation Board at certain operating conditions.

Product Usage Instructions

To use the APM81911 Evaluation Board, follow the steps below:

  1. Connect a power supply using banana cables to the VIN and GND through hole banana jack or with test leads to the VIN and GND test points for power input.
  2. Install all configuration jumpers prior to power-on, unless using an external EN signal or SYNCIN signal where jumper J1 or J5 must be uninstalled, respectively. Refer to Table 3 for jumper descriptions.
  3. The APM81911 datasheet contains detailed information on the use and functionality of each pin and should be consulted for more detailed information than is contained in this user guide.
  4. To select the output voltage, install the jumper at 5V for 5 V output or uninstall/install at 3.3V for 3.3 V output.
    Note: For more detailed information on the connections and configuration options of the APM81911 Evaluation Board, refer to Figure 2 and Table 4 for test point descriptions in the user manual.

DESCRIPTION

The APM81911 Evaluation Board is designed to help system designers evaluate the operation and performance of the APM81911 synchronous buck regulator ClearPower module. The APM81911 evaluation board output voltage can be configured with a jumper for 5 V or 3.3 V.

FEATURES

  • APM81911 buck converter power module
  • User-selectable output voltage, switching frequency, lowpower mode, soft-start time, clock source, and output clock state
  • Banana jacks for input and output power

APM81911 Evaluation Board Configurations

Table 1: APM81911 Evaluation Board Configurations

Configuration Name Part Number Output Voltage
APM81911 APEK81911KNB-01 Selectable (3.3 V or 5 V)

Table 2: General Specifications

Specification Min. Nom. Max. Units
Input Operating Voltage 3.5 36 V
Output Current* 0 3 A
Switching Frequency and SYNCIN Frequency 1 2.15 MHz

*Maximum output current may be lower due to thermal limitations of the APM81911 and the APM81911 Evaluation Board at certain
operating conditions.

USING THE EVALUATION BOARD

This section provides an overview of the connections and configuration options of the APM81911 Evaluation Board. Each group of
connections highlighted in Figure 2 has a detail section below. The default jumper positions are highlighted in green. The APM81911
datasheet contains detailed information on the use and functionality of each pin and should be consulted for more detailed information
than is contained in this user guide.

ALLEGRO-APM81911-Evaluation-Board-Module-FIG-3

Power Input
Connect a power supply using banana cables to the VIN and GND through hole banana jack or with test leads to the VIN and GND
test points.

Device Configuration
There are six configuration jumpers on the evaluation board to exercise different operating modes of the APM81911. All configuration jumpers must be installed prior to power-on, unless using an external EN signal or SYNCIN signal where jumper J1 or J5 must be
uninstalled, respectively.
Table 3: Jumper Descriptions

Jumper Name Description
J1 EN Install to tie EN to VIN and enable the APM81911 when VIN is above

UVLO. Uninstall to control EN through an external signal at the EN test point.
J2| SS| Soft-start select. Install at “Internal” to use internal soft-start or “External” to use the external 47 nF soft-start capacitor.
J3| PWM/AUTO| Low-power mode select. Install at “Auto LP” to allow the part to enter low-power mode under light loads. Install at “Force PWM” to always stay in PWM switching mode.
J4| FSET| Frequency Set select. Install at “2.15 MHz” or “1 MHz”. The “2.15 MHz” option ties FSET to VCC and the “1 MHz” option ties FSET to GND through a resistor.
J5| SYNCIN| Clock synchronization input. Install from center pin to top “Internal Clock” pin to use the internal clock and enable the CLKOUT pin. Install from center pin to the bottom “Int Clock + No CLKOUT” to use the internal clock and disable the CLKOUT signal. Leave the jumper open to apply a synchronization clock at the SYNCIN test point.
J6| VOUT| Output voltage select. Install at “5V” for 5 V output. Uninstall or install at “3.3V” for 3.3 V output.

Table 4: Test Point Descriptions

Test Point Description
VIN Positive terminal for input voltage connection or sensing.
VOUT Positive terminal for output voltage connection or sensing.
GND Negative terminal for voltage input/output or sensing.
VCC VCC pin voltage monitor test point.
EN EN pin voltage monitor or external logic input. Uninstall J1 to use an

external enable signal on the EN test point.
SS| Soft-start pin voltage monitor test point.
FSET| FSET voltage monitor test point.
PWMAUTO| PWM/AUTO voltage monitor test point.
SYNCIN| SYNCIN test point for connecting external PWM signal for clock synchronization.
CLKOUT| Clock monitor test point for CLKOUT signal if SYNCIN jumper is configured to enable CLKOUT.
PGOOD| PGOOD monitor test point. This pin is pulled up to VCC and asserts low to indicate the output is out of regulation.

PERFORMANCE DATA

Startup and Shutdown

ALLEGRO-APM81911-Evaluation-Board-Module-FIG-4

Load Transient Response

ALLEGRO-APM81911-Evaluation-Board-Module-FIG-5

Efficiency

ALLEGRO-APM81911-Evaluation-Board-Module-FIG-6

Thermal Performance
The following figure shows the thermal performance of the APM81911 Evaluation Board after five minutes of continuous operation
with ambient temperature near 25°C.

ALLEGRO-APM81911-Evaluation-Board-Module-FIG-7
ALLEGRO-APM81911-Evaluation-Board-Module-FIG-8

SCHEMATIC

ALLEGRO-APM81911-Evaluation-Board-Module-FIG-9

PCB LAYOUT

ALLEGRO-APM81911-Evaluation-Board-Module-FIG-10

BILL OF MATERIALS

Table 5: APEK81911 Bill of Materials

Designator| Description| Quan- tity| Manufacturer| Manufacturer Part Number
---|---|---|---|---
Electrical
C1| Capacitor, Electrolytic, 47 µF, 50 V, 8 mm| 1| Nichicon| UUX1H470MNL6GS
C3, C4| CAP CER 4.7 µF, 50 V, X7S 0805| 2| Murata| GRM21BC71H475KE11L
C5, C6| CAP CER 22 µF, 25 V, X5R 1206| 2| TDK| C3216X5R1E226M160AB
C8| CAP CER 10 pF, 50 V, NP0 0402| 1| TDK| C1005NP01H100D050BA
C9| CAP CER 4.7 µF, 10 V, X5R 0603| 1| KEMET| C0603C475M8PACTU
C10| CAP CER 0.047 µF, 16 V, X7R 0402| 1| Murata| GRM155R71C473KA01D
C12| CAP CER 1000 pF, 50 V, NP0 0402| 1| Murata| GRM1555C1H102GA01D
R1| Resistor, 20.0 kΩ,1/16 W, 1%, 0402| 1| Yageo| RC0402FR-0720KL
R3| Resistor, 34.0 kΩ,1/16 W, 1%, 0402| 1| Yageo| RC0402FR-0734KL
R4| Resistor, 13.3 kΩ,1/16 W, 1%, 0402| 1| Yageo| RC0402FR-0713K3L
R5| Resistor, 0 Ω,1/10 W, Jumper, 0603| 1| Yageo| RC0603JR-070RL
R6| Resistor, 100 kΩ,1/16 W, 1%, 0402| 1| Yageo| RC0402FR-07100KL
R7| Resistor, 49.9 Ω,1/16 W, 1%, 0402| 1| Yageo| RT0402FRE0749R9L
R8| Resistor, 732 kΩ,1/16 W, 1%, 0402| 1| Yageo| RC0402FR-07732KL
R9| Resistor, 95.3 kΩ,1/16 W, 1%, 0402| 1| Yageo| RC0402FR-0795K3L
R10| Resistor, 137 kΩ,1/16 W, 1%, 0402| 1| Yageo| RC0402FR-07137KL
U1| APM81911 in QFN 4 mm × 6 mm| 1| Allegro MicroSystems| APM81911KNBATR
Mechanical
CN1, CN2, CN3, CN4| Banana Jack- Non-Insulated 0.218″ Length| 4| Keystone Electronics| 575-4
J1| CONN HEADER VERT 2 POS 2.54 mm| 1| Wurth Electronics| 61300211121
J2, J3, J4, J5, J6| CONN HEADER VERT 3 POS 2.54 mm| 5| Wurth Electronics| 61300311121
MS1, MS2, MS3, MS4| PAN HEAD SCREW_M 3 × 8 mm CROSS SL| 4| Wurth Electronics| 97790803111
STND1, STND2, STND3, STND4| Standoffs & Spacers 5.0 HEX 15.0 mm NYLON| 4| Keystone Electronics| 25512
BIAS, ACINJ| Test Point, SMT, 105 mil × 40 mil| 2| Keystone Electronics| 5015
VIN, VOUT, EN, VCC| Test Point, Red, Through Hole Mount, 1.6 mm| 4| Keystone Electronics| 5010
GND| Test Point, Black, Through Hole Mount, 1.6 mm| 2| Keystone Electronics| 5011
SS, PGOOD, CLKOUT, PWMAUTO, FSET, SYNCIN| Test Point, Yellow, Through Hole Mount, 1.6 mm| 6| Keystone Electronics| 5014
Not Fitted
C2| CAP CER 4.7 µF, 50 V, X7S 0805| 0| Murata| GRM21BC71H475KE11L
C7| CAP CER 22 µF, 25 V, X5R 1206| 0| TDK| C3216X5R1E226M160AB
C11| CAP CER 0.1 pF, 25 V, NP0 0402| 0| Murata| GRM1555C1ER10WA01D
R2| Resistor,100 kΩ, 1/16 W, 1%, 0402| 0| Yageo| RC0402FR-07100KL

Copyright 2023, Allegro MicroSystems.

  • Allegro MicroSystems reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current.
  • Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.
  • The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use.
  • Copies of this document are considered uncontrolled documents.

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References

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