Datasheet

3
LT1571 Series
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C.
V
CC
= 16V (LT1571-1, LT1571-2), V
CC
= 10V (LT1571-5), V
BAT
= 8V (LT1571-1,LT1571-2), V
BAT
= 4V (LT1571-5), no load on any
outputs unless otherwise noted. (Note 6)
ELECTRICAL CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
Overall
Supply Current V
PROG
= 2.7V ● 5.2 7 mA
DC Battery Charging Current, I
BAT
8V ≤ V
CC
≤ 26V, 0V ≤ V
BAT
≤ 20V (LT1571-1)
R
PROG
= 4.93k ● 0.93 1.0 1.07 A
R
PROG
= 4.93k, T
J
< 0°C 0.91 1.09 A
R
PROG
= 3.28k ● 1.35 1.5 1.65 A
R
PROG
= 49.3k 75 100 125 mA
R
PROG
= 49.3k, T
J
< 0°C 70 130 mA
Shutdown
Auto Shutdown, Reverse Current from Battery V
BAT
≤ 20V, 0°C ≤ T
J
≤ 70°C (LT1571-1) 5 15 µA
(When Adapter in Figure 1 Circuit is Removed)
Shutdown Threshold at V
C
Pin 40 80 mV
When V
CC
is Connected
Shutdown Supply Current V
C
≤ 40mV 0.15 0.3 mA
Reference
Reference Voltage (LT1571-1) R
PROG
= 4.93k. Measured at V
FB
, with VA
Supplying I
PROG
and Switch Off
8V ≤ V
CC
≤ 26V, 0°C ≤ T
J
≤ 70°C 2.446 2.465 2.480 V
8V ≤ V
CC
≤ 26V, 0°C ≤ T
J
≤ 125°C 2.441 2.465 2.489 V
8V ≤ V
CC
≤ 26V, T
J
< 0°C (Note 5) 2.430 2.465 2.480 V
Preset Battery Voltage
LT1571-2: 8.2V/8.4V R
PROG
= 4.93k. Measured at BAT2 Pin
LT1571-5: 4.1V/4.2V T
J
= 25°C 0.5 %
8V ≤ V
CC
≤ 26V, 0°C ≤ T
J
≤ 125°C–11%
Voltage Setting Resistors Tolerance (R4, R5) Absolute Value, Not Matching –40 40 %
BAT2 Pin Input Current (LT1571-2, LT1571-5) V
BAT2
= V
PRESET
– 1V ● 6 µA
Charge Completion Flag (Comparator E6)
Charge Completion Threshold (Note 8) R
PROG
= 4.93k 0.14 0.20 0.28 A
R
PROG
= 4.93k, R
CAP
= 65.6k 0.05 0.085 0.13 A
Threshold on CAP Pin Low-to-High Threshold 4 4.5 V
High-to-Low Threshold 0.6 V
FLAG (Open Collector) Output Low V
CAP
= 4.5V, I
FLAG
≤ 1mA ● 0.3 V
FLAG Pin Leakage Current V
CAP
= 0.6V, V
CC
= 26V ● 3 µA
Voltage Amplifier VA
Transconductance Output Current from 100µA to 500µA 0.3 0.6 2.5 mho
Output Source Current V
PROG
= V
REF
, V
FB
= V
REF
+ 10mV 1.3 mA
V
FB
Input Bias Current (LT1571-1) At 0.75mA Output Current ● ±3 ±15 nA
Overall
Minimum Input Operating Voltage Undervoltage Lockout ● 6.2 7 7.8 V
Boost Pin Current V
CC
– V
BOOST
≤ 20V ● 0.10 20 µA
20V < V
CC
– V
BOOST
≤ 26V ● 0.25 30 µA
2V ≤ V
BOOST
– V
CC
≤ 8V (Switch ON) ● 611 mA
8V < V
BOOST
– V
CC
≤ 20V (Switch ON) (LT1571-1) ● 814 mA