Datasheet

© 2010 Microchip Technology Inc. DS22075B-page 5
MCP1790/MCP1791
Short Circuit Foldback Voltage Corner V
FOLDBACK
—4.2— VV
R
= 5.0V
Falling V
OUT,
R
LOAD
<0.1Ω
—3.0— VV
R
= 3.3V
Falling V
OUT,
R
LOAD
<0.1Ω
—2.7— VV
R
= 3.0V
Falling V
OUT,
R
LOAD
<0.1Ω
Short Circuit Foldback Current — 105 — mA V
OUT
~= 0V,
R
LOAD
<0.1Ω,
V
R
= 5.0V (Note 2)
—99—mAV
R
= 3.3V (Note 2)
—99—mAV
R
= 3.0V (Note 2)
Startup Voltage Overshoot V
OVER
—0.10—% V
OUT
V
IN
= 0V to 6.0V
Dropout Voltage V
DROPOUT
— 700 1300 mV I
OUT
= 70 mA, (Note 6)
Dropout Current
I
OUT
= 0 mA
I
DO
— 130 — µA V
R
= 5.0V, V
IN
= 4.500V
—75—µAV
R
= 3.3V, V
IN
= 4.500V
—75—µAV
R
= 3.0V, V
IN
= 4.500V
Shutdown Input
Logic High Input V
SHDN-HIGH
2.4 —V
IN(MAX)
V—
Logic Low Input V
SHDN-LOW
0—0.8 V—
Shutdown Input Leakage Current SHDN
ILK
—
—
0.100
3.0
0.500
5.0
µA SHDN = GND
SHDN
= 6V
Power Good Characteristics
PWRGD Input Voltage Operating
Range
V
PWRGD_VIN
2.8 ——V—
PWRGD Threshold Voltage
(Referenced to V
OUT
)
V
PWRGD_TH
88 90 92 %V
OUT
Falling Edge of V
OUT
PWRGD Threshold Hysteresis V
PWRGD_HYS
1.0 2.0 3.0 %V
OUT
Rising Edge of V
OUT
PWRGD Output Voltage LOW V
PWRGD_L
—0.20.4 VI
PWRGD SINK
= 5.0 mA,
V
OUT
= 0V
PWRGD Output Sink Current I
PWRGD_L
5.0 — — mA V
PWRGD
<= 0.4V
PWRGD Leakage I
PWRGD
_
LK
—1.0—nAV
PWRGD
= V
IN
= 6.0V
PWRGD Time Delay T
PG
— 30 — µs Rising Edge
AC/DC CHARACTERISTICS (CONTINUED)
Electrical Specifications: Unless otherwise noted, V
IN
= V
OUT(MAX)
+ V
DROPOUT(MAX),
(Note 1), I
OUT
= 1 mA,
C
OUT
= 4.7 µF (X7R Ceramic), C
IN
= 4.7 µF (X7R Ceramic), T
A
= +25°C, SHDN > 2.4V.
Boldface type applies for junction temperatures, T
J
(Note 5) of -40°C to +125°C.
Parameters Symbol Min Typ Max Units Conditions
Note 1: The minimum V
IN
, V
IN(MIN)
must meet two conditions: V
IN
≥ 6.0V and V
IN
≥ V
OUT(MAX)
+ V
DROPOUT(MAX).
2: V
R
is the nominal regulator output voltage.
3: Load regulation is measured at a constant junction temperature using low duty cycle pulse testing. Load regulation is
tested over a load range from 1 mA to the maximum specified output current.
4: The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction
temperature and the thermal resistance from junction to air. (i.e., T
A
, T
J
, θ
JA
). Exceeding the maximum allowable power
dissipation will cause the device operating junction temperature to exceed the maximum 165°C rating. Sustained
junction temperatures above 165°C can impact the device reliability.
5: The junction temperature is approximated by soaking the device under test at an ambient temperature equal to the
desired Junction temperature. The test time is small enough such that the rise in the Junction temperature over the
ambient temperature is not significant.
6: Dropout voltage is defined as the input-to-output voltage differential at which the output voltage drops 2% below its
nominal value that was measured with an input voltage of V
IN
= V
R
+ V
DROPOUT(MAX)
.
7: Sustained junction temperatures above 165°C can impact the device reliability.
8: The Short Circuit Recovery Time test is done by placing the device into a short circuit condition and then removing the
short circuit condition before the device die temperature reaches 125 °C. If the device goes into thermal shutdown, then
the Short Circuit Recovery Time will depend upon the thermal dissipation properties of the package and circuit board.
9: TCV
OUT
= (V
OUT-HIGH
- V
OUT-LOW
) *10^6/(V
R
* ΔTemperature), V
OUT-HIGH
= highest voltage measured over the temperature
range. V
OUT-LOW
= lowest voltage measured over the temperature range.