AS2954
(Continued)
Parameter
Conditions
Typical
AS2954A
AS2954
Min Max
AS2954B
Min Max
Units
(Note 2)
Min
Max
Applies for AS2954YT5-X, AS2954YU5-X and AS2954YS-X
Error Comparator
Output Leakage Current
V
OH = 30V
0.01
150
100
2.00
250
400
100
100
A
µ
2.00
250
400
2.00
250
400
Output Low Voltage
VIN = 4.5V
IOL = 400 A
mV
µ
Upper Threshold Voltage
Lower Threshold Voltage
Hysteresis
(Note 8)
(Note 8)
(Note 8)
240
350
60
-320
-380
-450
-640
-150
-100
230
-320
-380
-450
-640
-150
-100
230
-320
-150
-100
230
mV
mV
mV
-380
-450
-640
160
160
160
Shutdown Input
VSD
Output Turn-On
Threshold Voltage
1.155
1.140
1.305
1.320
1.155
1.140
1.305
1.320
1.155
1.140
1.305
1.320
V
mV
Hysteresis(HYST)
6
Input Bias Current(IB)
VIN(SD) = 0V to 5V
10
-30
-50
-30
-50
-30
-50
-30
-50
-30
-50
-30
-50
nA
Note 1: Output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range.
Note 2: Unless otherwise specified all limits are guaranteed for TJ = 25°C, VIN = 6V, IL = 100 µA and CL = 1µF. Additional conditions for the 8-pin versions are
feedback tied to 5V tap and output tied to output sense (VOUT = 5V) and VSHUTDOWN ≤ 0.8V.
Note 3: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are
covered under the specification for thermal regulation.
Note 4: Line regulation for the AS2954 is tested at 150°C for IL = 1 mA. For IL = 100µA and TJ = 125°C, line regulation is guaranteed by design to 0.2%. See typical
performance characteristics for line regulation versus temperature and load current.
Note 5: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below its nominal value measured at 1V differential at
very low values of programmed output voltage, the minimum input supply voltage of 2V (2.3V over temperature) must be taken into account.
Note 6: VREF ≤VOUT ≤ (VIN - 1V), 2.3 ≤VIN≤30V, 100µA≤IL≤ 250 mA, TJ ≤ TJMAX
.
Note 7: Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the nominal reference voltage measured at 6V input. To
express these thresholds in terms of output voltage change, multiply by the error amplifier gain = VOUT/VREF = (R1 + R2)/R2. For example, at a programmed output
voltage of 5V, the ERROR output is guaranteed to go low when the output drops by 95 mV x 5V/1.235 = 384 mV. Thresholds remain constant as a percent of VOUT as
V
OUT is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed.
Note 8: VSHUTDOWN ≥ 2V, VIN ≤ 30V, VOUT =0, feedback pin tied to 5V Tap.
Note 9: The junction -to-ambient thermal resistance of the TO-92 package is 180°C/ W with 0.4” leads and 160°C/ W with 0.25” leads to a PC board.
The thermal resistance of the 8-Pin DIP package is 105°C/W junction-to-ambient when soldered directly to a PC board. Junction-to-ambient thermal resistance for the
SOIC (S) package is 160°C/W.
UNREGULATED DC
VO
5V @ 250mA
1
7
8
MAX
+
INPUT
FEEDBACK
OUTPUT
2
SENSE
Ω
180k
..
+
_
6
ERROR
3
FROM
CMOS OR
TTL
AMPLIFIER
Ω
5V TAP
330k ..
SHUTDOWN
+
Ω
60k ..
5
µ
1
F..
+
______
ERROR
+
_
60 mV
ERROR
TO CMOS OR
TTL
COMPARATOR
+
1.23V
4
REFERENCE
GROUND
AS2954 Block Diagram
Rev.9/29/00
SIPEX [ SIPEX CORPORATION ]
