Datasheet

MCP1790/MCP1791
DS22075B-page 6 © 2010 Microchip Technology Inc.
Detect Threshold to PWRGD Active
Time Delay
TV
DET-PWRG
D
— 235 — µs V
OUT
= V
PWRGD_TH
+
100 mV to V
PWRGD_TH
-
100 mV
AC Performance
Output Delay from SHDN
T
OR
— 200 — µs SHDN = GND to V
IN,
V
OUT
= GND to 95% V
R,
C
OUT
= 1.0 µF
PWRGD Delay from SHDN
T
SHDN_PG
— 400 — ns SHDN = V
IN
to GND
,
C
OUT
= 1.0 µF
Output Noise e
N
—1.2—(µV/√Hz) I
OUT
= 50 mA, f = 1 kHz
Power Supply Ripple Rejection Ratio PSRR dB V
IN
= 7.0V, CIN = 0 µF,
I
OUT
= 10 mA,
V
INAC
= 400 mVpp
— 90 — f = 100 Hz
— 75 — f = 1 kHz, V
R
= 5.0V
— 80 — f = 1 kHz, V
R
= < 5.0V
Thermal Shutdown Temperature T
SD
— 157 — °C Rising Temperature
Thermal Shutdown Hysteresis ΔT
SD
— 20 — °C Falling Temperature
Short Circuit Recovery Time t
THERM
—0—ms(Note 8)
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.