7.7 Buck Converters SW1, SW2
Unless otherwise noted, VIN = 3.6 V, CIN = 10 µF, COUT = 10 µF, LOUT = 2.2-µH ceramic, and TJ = 25°C.(1)(2)(3)(4)(5)(6)
PARAMETER |
TEST CONDITIONS |
MIN |
TYP |
MAX |
UNIT |
VFB
|
Feedback voltage |
|
–3%(7)
|
|
3%(7)
|
|
VOUT
|
Line regulation |
2.8 V < VIN< 5.5 V
IOUT = 10 mA |
|
0.089 |
|
%/V |
Load regulation |
100 mA < IOUT < IMAX
|
|
0.0013 |
|
%/mA |
Eff |
Efficiency |
Load current = 250 mA |
|
96% |
|
|
ISHDN
|
Shutdown supply current |
EN is de-asserted |
|
0.01 |
|
µA |
ƒOSC
|
Internal oscillator frequency |
|
1.7(7)
|
2.1 |
|
MHz |
IPEAK
|
Buck1 peak switching current limit |
|
|
1.5 |
|
A |
Buck2 peak switching current limit |
|
|
1 |
|
IQ(8)
|
Quiescent current “on” |
No load PFM mode |
|
33 |
|
µA |
RDSON (P) |
Pin-pin resistance PFET |
|
|
200 |
|
mΩ |
RDSON (N) |
Pin-pin resistance NFET |
|
|
180 |
|
mΩ |
TON
|
Turnon time |
Start up from shutdown |
|
500 |
|
µs |
CIN
|
Input capacitor |
Capacitance for stability |
10 |
|
|
µF |
COUT
|
Output capacitor |
Capacitance for stability |
10 |
|
|
µF |
(1) All voltages are with respect to the potential at the GND pin.
(2) Minimum (Min) and Maximum (Max) limits are ensured by design, test, or statistical analysis. Typical numbers are not ensured, but do represent the most likely norm.
(3) CIN, COUT: Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics.
(4) The device maintains a stable, regulated output voltage without a load.
(5) Quiescent current is defined here as the difference in current between the input voltage source and the load at VOUT.
(6) Buck VIN ≥ VOUT + 1 V.
(7) Limits apply over the entire junction temperature range for operation, −40°C to +125°C.
(8) The IQ can be defined as the standing current of the LP3907 when the I2C bus is active and all other power blocks have been disabled with the I2C bus, or it can be defined as the I2C bus active, and the other power blocks are active under no load condition. These two values can be used by the system designer when the device is powered using a battery.