LM2612 National Semiconductor Corporation, LM2612 Datasheet - Page 4

• Manufacturer Part Number: LM2612
• Description: LM2612 - Miniature, Programmable, Step-down DC-DC Converter For Ultra Low-voltage Circuits, Package: Microsmd, Pin Nb=10
• Manufacturer: National Semiconductor Corporation

www.national.com
I
f
F
T
VID
sync
Electrical Characteristics
Specifications with standard typeface are for T
perature Range (T
0V.
OSC
min
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings are conditions for which the device is intended
to be functional, but parameter specifications may not be guaranteed. For guaranteed specifications and associated test conditions, see the Min and Max limits and
Conditions in the Electrical Characteristics table. Electrical Characteristics table limits are guaranteed by production testing, design or correlation using standard
Statistical Quality Control methods. Typical (Typ) specifications are mean or average values from characterization at 25C and are not guaranteed.
Note 2: In PWM mode, Thermal shutdown will occur if the junction temperature exceeds the 150˚C maximum junction temperature of the device.
Note 3: Thermal resistance specified with 2 layer PCB(0.5/0.5 oz. cu).
Note 4: Thermal resistance specified with 3 layer PCB (2/1/1 oz. cu) and 12 vias 0.33mm diameter (see Application Note AN-1187).
Note 5: The LM2612 is designed for cell phone applications where turn-on after power-up is controlled by the system processor and internal UVLO (Under Voltage
LockOut) circuitry is unecessary. The LM2612 has no UVLO circuitry and should be kept in shutdown by holding the EN pin low until the input voltage exceeds 2.8V.
Although the LM2612 exhibited safe behavior during pre-production evaluation while enabled at low input voltages, this is not guaranteed.
Note 6: The feedback voltage is trimmed at the 1.5V output setting. The other output voltages result from the pin selection of the internal DAC’s divider ratios. The
precision for the feedback voltages is
if trimming at other voltages is desired.
Note 7: : The hysteresis voltage is the minimum voltage swing on FB that causes the internal feedback and control circuitry to turn the internal PFET switch on and
then off, during PFM mode.
Note 8: Current limit is built-in, fixed, and not adjustable. If the current limit is reached while the output is pulled below about 0.7V, the internal PFET switch turns
off for 2.5 µs to allow the inductor current to diminish.
Note 9: EN is a CMOS Schmitt trigger digital input with logic thresholds that scale with the supply voltage at the VDD pin. The nominal logic thresholds are
approximately 0.71VDD and 0.55VDD for the high and low thresholds respectively.
Note 10: SYNC driven with an external clock switching between V
external clock frequency. The LM2612 synchronizes to the rising edge of the external clock.
Symbol
VID1, VID0 Pull Down
Current
SYNC/MODE Clock
Frequency Range
(Note 10)
Internal Oscillator
Frequency
Minimum ON-Time of P FET
Switch in PWM Mode
Load Transient Response in
PWM Mode
Line Transient Response in
PFM Mode
A
= T
Parameter
J
= −25˚C to +85˚C). Unless otherwise specified, PVIN = VDD = EN = SYNC = 3.6V, VID0 = VID1 =
±
2%, except for the 1.05V setting, which is 5%. Contact the Portable Power Applications group at National Semiconductor,
(Continued)
VID1, VID0 = 3.6V
LM2612ABP, PWM Mode
(SYNC = VIN)
LM2612BBP, PWM Mode
(SYNC = VIN)
Circuit of Figure 1
I
Circuit of Figure 1
V
t
A
OUT
r
IN
= t
= T
= 3.0V to 3.6V Step
p
= 20mA to 200mA Step
J
IN
= 10 µs
= 25˚C, and those in bold face type apply over the full Operating Tem-
and GND. When an external clock is present at SYNC, the IC is forced to PWM mode at the
Conditions
4
Min
500
468
450
Typ
±
600
600
200
1.8
±
25
3
1000
Max
732
750
Units
kHz
kHz
mV
mV
µA
ns