MIC2829 datasheet(32/52 Pages) MICREL

32 / 52 page

Micrel Inc.

MIC2829

May 2010

M9999-051410-B

FB5 and FB6

The feedback pin (FB5, FB6) allows DC5 and DC6

output voltage to be set by applying an external resistor

network. The internal reference voltage is 1V and the

recommended value of RBOTTOM is 20kΩ or below. A

feed-forward capacitor (CFF) of 120pF should be placed

parallel to RTOP to improve stability and transient

response. This does not impact the output voltage

setting. The output voltage is calculated from the

equation below.

⎟

⎠

⎞

⎜

⎝

⎛

kΩ

TOP

OUT

RBOTTOM

RTOP

CFF

VOUT

Figure 2. Feedback Resistor Network

The switch pin (SW1 to SW6) connects directly to one

end of the inductor and provides the current path during

switching cycles. The other end of the inductor is

connected to the output of the buck regulator. Due to the

high speed switching on this pin, the switch node should

be routed away from sensitive nodes whenever possible.

VSC2

The voltage scaling pin (VSC2) is used to switch the

output of DC2 between two different voltage levels. A

high on the VSC2 pin will set the output voltage of DC2

to the higher voltage. A low on the VSC2 pin will set the

output voltage to the lower voltage. Do not leave floating.

LSPWR

The level shifter input supply pin (LSPWR) provides

power to the level shifter. A minimum 1µF input capacitor

with a minimum voltage rating of 6.3V placed close to

LSPWR and ground (AGND1, AGND2) is required.

Refer to the layout recommendations for details.

SIMPWR

SIM power (SIMPWR) provides power to the SIM Card.

A minimum 1µF input capacitor with a minimum voltage

rating of 6.3V to ground (AGND1, AGND2) is required.

Refer to the layout recommendations for details.

VSLS

VSLS selects the level shifted voltage for the SIM Card.

A high logic voltage on VSLS selects the level shifter to

3V. A low logic voltage on VSLS selects the level shifter

to 1.8V. Do not leave floating.

RSTIN, SIMRST

RSTIN is the digital reset input for the SIM Card and

translates to SIMRST through the digital level shifter. It is

one directional. If VSLS is low, then the input at RSTIN

will be level shifted to 1.8V at the SIMRST output. If

VSLS is high, then the input at RSTIN will be level

shifted to 3V at the SIMRST output.

CLKIN, SIMCLK

CLKIN is the digital input clock for SIM card. The CLKIN

translates to SIMCLK and is one directional. If VSLS is

low, then the input at CLKIN will be level shifted to 1.8V

at the SIMCLK output. If VSLS is high, then the input at

CLKIN will be level shifted to 3V at the SIMCLK output.

DATA, SIMIO

DATA is the digital data for the SIM Card. The DATA

translate to SIMIO through the digital level shifter and is

bi-directional using internal pull ups. If VSLS is low, then

the level shifted output is 1.8V at the SIMIO output. If

VSLS is high, then the level shifted output is 3V at the

SIMIO output. Since DATA and SIMIO are bi-directional,

the input at SIMIO is level shifted to equal the LSPWR

voltage at the DATA output.

G1 – G9

The G1 through G9 pins are not internally connected.

They serve as thermal relief and should be connected to

ground

(AGND1,

AGND2)

maximize

the

heat

dissipation. See layout recommendations for details.

MIC2829 数据表(PDF) 32 Page - Micrel Semiconductor

MIC2829 数据表(HTML) 32 Page - Micrel Semiconductor

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

数据表下载