MIC2155_0911 Datasheet, PDF (5/35 Pages) Micrel Semiconductor – Two-Phase, Single-Output, PWM Synchronous Buck Control IC

Micrel, Inc.
MIC2155/2156
Pin Description cont.
Pin Number
16
Pin Name
PGOOD
17
EA2+
18
FB2
19
COMP2
20
VOUT
21
VIN2
22
N/C
23
SW2
24
HSD2
25
BST2
26
PGND2
27
LSD2
VDD
28
29
30
31
32
EPAD
EN1
VIN1
LSD1
PGND1
EP
Pin Function
Power Good (Output): Asserts high when voltage on the FB pin rises above
Power Good threshold.
(input) Positive input to Channel 2 (current sharing) Error Amplifier. Connect to
Channel 1 current sense.
Negative Input to Channel 2 (current sharing) Error Amplifier (Input). Connect to
Channel 2 current sense.
Compensation 2 (Input): Pin for external compensation of Channel 2.
Output Sense (input): Connect to output side of inductors. Used for current
sharing.
Supply Voltage for Channel 2 (Input). Used for Channel 2 UVLO circuit.
No Connect
Switch node 2 (Output): Return for HSD2.
High-Side Drive 2 (Output): High-current output-driver for the high-side
MOSFET.
Boost 2 (Input): Provides voltage for high-side MOSFET driver in Channel 2. The
gate drive voltage is higher than the source voltage by V_DD minus a diode drop.
Power Ground 2. High current return for low-side driver 2.
Low-Side Drive 2 (Output): High-current driver output for Channel 2 low-side
external MOSFET.
5V Internal Linear Regulator from V_IN1 (Output): V_DD is the ext. MOSFET gate
drive supply voltage and an internal supply bus for the IC. When V_IN1 is <5V, this
regulator operates in drop-out mode. Connect external bypass capacitor.
Enable 1 (Input): Output enable. Turns off both sides. Pull high to enable. Pull
low to disable.
Supply voltage Channel 1 (Input): Used for UVLO and V_DD circuits.
Low-Side Drive 1 (Output): High-current driver output for Channel 1 low-side
external MOSFET.
Power Ground 1. High current return for low-side driver 1.
Exposed Pad (Power): Must make a full connection to the GND plane to
maximize thermal performance of the package.
November 2009
5
M9999-111209-B