Micrel, Inc.

MIC2870

September 5, 2013

3

Revision 1.0

Pin Description (Continued)

Pin Number

Pin Name

Pin Function

7, 15

PGND

Power Ground. PGND is used for the switching NMOS and PMOS of boost converter, and power

ground for LED current sinks.

8

TRSET

Torch-Mode Current Level Programming. Connect a resistor from TRSET to AGND to set the

maximum current in the torch m

ode. For example, a 10kΩ resistor sets the LED sink current to its

maximum value of 187.5mA per channel. TRSET can be grounded if the default maximum torch-

mode current (187.5mA) is desired. TRSET, however, cannot be left floating and the maximum

resistance is limited to 80kΩ.

9

LED2

Channel 2 LED Current Sink. Connect the LED anode to OUT and cathode to LED2.

10

LED1

Channel 1 LED Current Sink. Connect the LED anode to OUT and cathode to LED1.

11

TEN

Torch-Mode Enable. Initiates torch mode when TEN is HIGH. If TEN is left floating, it is pulled-

down internally by a built-in 1µA current source when the device is enabled.

12

OUT

Boost Converter Output.

13

EN

Enable (IC). The MIC2870 is in standby mode when EN is asserted HIGH. If EN is driven low for

more than 1s, the IC is shut down. Alternatively, the I

enabling/disabling the IC through the master control/status register. EN is pulled down by an

internal resistor.

14

SW

Inductor Connection. It is connected to the internal power MOSFETs.

16

SDA

High-Speed Mode (3.4MHz) I²C Data Input/Output.

EP

ePad

Exposed Heat Sink Pad. Connect to PGND ground plane for best thermal performance. This pin

is internally connected to PGND.