PM8851 STMICROELECTRONICS | Alldatasheet
Document overview
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Technical content
Features
Low-side MOSFET driver 1 A sink and 0.8 A source capability Complementary outputs for source and sink driving Ext. reference for input threshold Wide supply voltage range (10 V ÷ 18 V) Input and output pull-down resistors Short propagation delays Input and output UVLO Wide operating temperature range: -40 °C to 125 °C SOT23-6L package
Applications
SMPS Digital lighting Wireless battery chargers Digitally controlled MOSFETs
Description
The PM8851 device is a high frequency single channel low-side MOSFET driver specifically designed to work with digital power conversion microcontrollers, such as the STMicroelectronics STLUX™ family of products. The PM8851 has complementary output pins to differentiate sink and source driving with a current capability of respectively 1 A and 0.8 A. The input levels of the driver are derived by the voltage present at the IN_TH pin (between 2 V and 5.5 V). This pin is typically connected at the same voltage of the microcontroller supply voltage. The PM8851 includes both input and output pull- down resistors. UVLO circuitry for input and output stages is present preventing the IC from driving external MOSFET in unsafe condition. SOT23-6L Table 1. Device summary
1 Block diagram
Figure 1. Block diagram
2 Pin connection
Figure 2. Pin connection Table 2. Pinning between this pin and GND to supply the IC. GND 2 Reference voltage connection. IN 3 Digital input signal for driver. It is internally pulled down to GND with a 100 k (typ.) equivalent resistor. SNK 5 MOSFET gate drive sinking output controlled by the IN pin. A pull-down equivalent resistor [100 k (typ.)] is present. SRC 6 MOSFET gate drive sourcing output controlled by the IN pin. A pull-down equivalent resistor [100 k (typ.)] is present.
3 Maximum ratings
Table 3. Thermal data Table 4. Absolute maximum ratings
4 Electrical characteristics
(VCC = 12 V, VIN_TH = 3.3 V, TJ = - 40 ÷ 125 °C, unless otherwise specified). Table 5. Electrical characteristics
- Not tested in production.
- Overlapping prevent by hysteresis V IN_Hyst.
5 Typical applications
Figure 7. Test circuit Figure 8. Digitally controlled PFC boost converter
6 Application guidelines
6.1 Power supply
applied to the IN pin, or it can be derived by the VCC pin, eventually using a voltage divider. It is mainly suggested to provide IN_TH voltage starting from VCC voltage. pin to bypass the current's spikes absorbed by VCC during the gate charging. when long traces are used to supply it; when derived by VCC a lighter filtering is allowed.
6.2 Layout suggestions
current running between the OUT pin and the MOSFET's gate pin. Figure 11. Shared supply configuration Figure 12. Independent supply configuration
6.3 Driving switches
The IN pin truth table is reported in Table 6. deviation between theoretical and practical behaviors. for the resistances placed between the MOSFET's gate and the SRC and SNK pins. delay (typ. 300 ns) after the falling edge of the input signal.
6.4 Power dissipation
required by the device to supply internal structures and pull-downs resistors. can be considered equal to VCC. Table 6. PM8851 truth table (levels refer to unloaded condition of SNK and SRC)
7 Package information
In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available at: www.st.com. ECOPACK is an ST trademark.
Figure 13. SOT23-6L package outline Table 7. SOT23-6L package mechanical data
- Dimensions per JEDEC MO178AB.
8 Revision history
Table 8. Document revision history 23-Oct-2014 1 In itial release.