lm5118mhx National Semiconductor Corporation, lm5118mhx Datasheet - Page 2

• Manufacturer Part Number: lm5118mhx
• Description: Wide Voltage Range Buck-boost Controller
• Manufacturer: National Semiconductor Corporation

www.national.com
LM5118MH
LM5118MHX
Connection Diagram
Ordering Information
Pin Descriptions
Pin
10
11
12
13
14
15
Ordering Number
1
2
3
4
5
6
7
8
9
COMP
RAMP
AGND
VOUT
SYNC
PGND
Name
UVLO
CSG
VIN
EN
CS
RT
SS
FB
LO
Description
Input supply voltage.
If the UVLO pin is below 1.23V, the regulator will be in standby mode (VCC regulator running, switching
regulator disabled). When the UVLO pin exceeds 1.23V, the regulator enters the normal operating mode. An
external voltage divider can be used to set an under-voltage shutdown threshold. A fixed 5 µA current is sourced
out of the EN pin. If a current limit condition exists for 256 consecutive switching cycles, an internal switch pulls
the UVLO pin to ground and then releases.
The internal oscillator frequency is set with a single resistor between this pin and the AGND pin. The
recommended frequency range is 50 kHz to 500 kHz.
If the EN pin is below 0.5V, the regulator will be in a low power state drawing less than 10 µA from VIN. EN
must be raised above 3V for normal operation.
Ramp control signal. An external capacitor connected between this pin and the AGND pin sets the ramp slope
used for emulated current mode control.
Analog ground.
Soft-Start. An external capacitor and an internal 10 µA current source set the rise time of the error amp
reference. The SS pin is held low when VCC is less than the VCC under-voltage threshold (< 3.7V), when the
UVLO pin is low (< 1.23V), when EN is low (< 0.5V) or when thermal shutdown is active.
Feedback signal from the regulated output. Connect to the inverting input of the internal error amplifier.
Output of the internal error amplifier. The loop compensation network should be connected between COMP
and the FB pin.
Output voltage monitor for emulated current mode control. Connect this pin directly to the regulated output.
Sync input for switching regulator synchronization to an external clock.
Current sense input. Connect to the diode side of the current sense resistor.
Current sense ground input. Connect to the ground side of the current sense resistor.
Power Ground.
Boost MOSFET gate drive output. Connect to the gate of the external boost MOSFET.
Package Type
TSSOP-20EP
TSSOP-20EP
See NS Package Numbers MXA20A
NSC Package Drawing
Top View
2
MXA20A
MXA20A
30058502
2500 units shipped as Tape & Reel
73 Units Per Anti-Static Tube
Supplied As