Specification
- Input voltage: from 2 V to 16 V
- Maximum output current: 1.5 A
- Resting current: 1 mA
- Output voltage: 5 V (can be changed to 6 V using SEL pin)
- Short-circuit and overtemperature protection
- Under-voltage cut-off: selectable voltage
- Dimensions: 15 x 13 x 6 mm
- Weight: 0.8 g (without connectors)
Product description: S9V11F5S6CMA - step-up/step-down converter - 5V 1,5A - with low voltage cut-off - Pololu 2870
The converteris used to supply circuits operating at 5 V. The circuit has a wide range of input voltages, which makes it ideal for battery-powered designs. Application of S9V11F5S6CMA ensuresstability of power supplyduring the entire cycle of battery discharge. In order to increase reliability, the module is equipped with short-circuit protection and automatic power cut-off when the permissible operating temperature or minimum voltage is exceeded.
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The set includes goldpins for individual soldering.
How to use
The module is very simple to use, it has three basic leads:
- VIN- input voltage from 2 V to 16 V. With lower voltage module will not turn on, higher can damage the chip.
- GND- Ground of the system.
- VOUT- output voltage of 5 V.
Additional pins:
- EN- Enable input. It switches the system on after applying voltage above 0,8 V. It is connected via 12-step potentiometer withVIN, so it cuts off the power when VIN voltage is below the set value.
- PG- Voltage Quality Indicator. An open-drain type output, it sets low when power drops below 90% of nominal voltage, also when theENpin is in the low state. Returns to the high state when the mod 95 % is exceeded. Has high impedance, requires a pull-up resistor.
- SEL- output can be driven from 1.1 V to 16 V to change theVOUToutput to 6 V. SettingSELlow or unconnected setsVOUTto 5 V. To permanently set 6 V, solder a wire as shown in the following figure.
The allowable input voltage range is from 2 V to 16 V. At a lower value the regulator will not turn on. A higher voltage may damage the circuit.
The connectors are properly signed on the board.The pinout is 2.54 mm (goldpin connectors). The module can be clipped into thecontactboard, connected withwiresor soldered to a dedicated PCB.
Setting the cut-off voltage
Too low VIN voltage which should cause power cut-off is controlled by potentiometer and EN pin. When the voltage on EN drops below 0.7 V, the chip sets itself to a low power state - sleep mode. When 0.8 V is received at the EN pin, the chip returns to operation. Turning the potentiometer clockwise increases the cutoff voltage. This voltage can be set by measuring VIN and EN and adjusting the potentiometer according to a formula:
For example, if a 3.7 volt battery is connected to VIN and the cutoff voltage is to be 3.0 volts, the formula will be as follows:
EN is equal to 0.86 V, so spin the potentiometer until this is the voltage you can measure on the EN pin.
Note that the cutoff level includes hysteresis. The regulator will shut down at 0.7 V, but you must apply about 0.8 V to get it to start up again. The VIN voltage must be equal to approximately 114% of the cutoff voltage to restart (3.43 V in the above case).
Output current
The maximum current that can flow through the circuit depends on the value of the input voltage. This relationship is shown in the graph below:
Maximum output current as a function of input voltage.
Efficiency
This parameter is especially important with battery power supply, when it is important for the system to work as long as possible on a single charge. The efficiency of the converter depends on the current flowing and the input voltage (graph below). On average, it is between 85% and 95%, which allows to use practically the maximum energy from the battery.
The efficiency of the converter depending on the current consumed.
Voltage jumps (pins)
In electronic circuits, the starting current may cause so-called spikes, sudden voltage jumps to a value above a set level. If the amplitude of the spikes exceeds the regulator's allowable value, the regulator can be destroyed. Therefore, if the circuit will be supplied with voltage above 9 V or the load will have high inductance, we recommend soldering a capacitor of 33 µF / 20 V or higher as close as possible to the circuit between VIN and GND.
Miniature DC/DC converter with huge possibilities
The Pololu 2870 is a step-up/step-down converter module based on an integrated controller with a built-in transistor key. Thanks to such a solution, the designers of the module managed to achieve extremely small dimensions of the whole - the PCB has dimensions of only 15.2 x 12.7 mm.
S9V11F5S6CMA - step-up/step-down converter - 5V 1.5A - with low-voltage cut-off function - Pololu 2870can operate with input voltages from 2 V to 16 V, and resting current consumption is only 1 mA.
Application notes for the inverter
In addition to three power lines (Vin - input, Vout - output, GND - ground), the chip also offers three control and indicator lines that can be used in more advanced applications. The SEL pin allows to change the output voltage from 5 V to 6 V.
The EN input allows to switch off the inverter with a low state, and additionally allows to set the inputcut-off voltage -thanks to a precise rotary potentiometer, a user can independently determine the minimum value of the supply voltage, below which the inverter switches off. An additional PG pin informs the external electronic circuit when the output voltage drops below 90% of the nominal value.
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