Datasheet

LTC4020
3
4020fd
For more information www.linear.com/LTC4020
elecTrical characTerisTics
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). PV
IN
= SENSVIN = CSP = CSN = BAT = 20V, SHDN = 2V,
C
(TG1, BG1, TG2, BG2)
= 1000pF, V
RNG/SS
= 2V.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
INTV
CC
Boost Refresh Supply Voltage I
LOAD
= 5mA
l
4.85 5.0 5.15 V
Boost Refresh Supply Dropout PV
IN
= 4.5V; I
INTVCC
= 5mA 4.46 V
Boost Refresh Supply Short-Circuit Current
Limit
V
INTVCC
= 0V
l
85 150 mA
I
PVIN
PV
IN
Operating Current Note 3; ITH = 0V
l
1.6 3 mA
Shutdown Current V
SHDN
= 0
l
3 6 µA
I
SENSVIN
SENSEVIN Operating Current
l
0.25 0.5 mA
Shutdown Current V
SHDN
= 0
l
25 60 µA
I
SENSTOP
SENSETOP Operating Current 32.5 µA
Shutdown Current V
SHDN
= 0 0.1 µA
V
FBMAX
DC/DC Converter Reference Charging Terminated
l
2.7 2.75 2.8 V
SHDN IC Enable Threshold (Rising)
Threshold Hysteresis
l
1.175 1.225
100
1.275 V
mV
SHDN Pin Bias Current 10 nA
V
SENS
DC/DC Converter Inductor Current Limit
(Average Value)
V
SENSVIN
– V
SENSTOP
;
V
SENSGND
– V
SENSBOT
l
45 50 60 mV
Reverse Current Inhibit
(Average Value)
V
ITH
Falling (TG2 Disabled)
V
ITH
Rising (TG2 Enabled)
l
0 2
6
mV
mV
I
LIMIT
Inductor Current Limit Programming V
ILIMIT
= 0.5V; V
ILIMIT
/V
SENS(MAX)
20 V/V
I
LIMIT
Pin Bias Current
l
47.5 50 52.5 µA
ITH Error Amp Current Limit V
FBMAX
= 0, V
ITH
= 1.3V 8 µA
Error Amp Transconductance V
FBMAX
= 2.75V; V
ITH
= 1.3V 95 umho
VC High Side Current Sense Transconductance (V
SENSVIN
– V
SENSETOP
) to I
VC
V
C
= 1.8V
200 umho
Low Side Current Sense Transconductance (V
SENSGND
– V
SENSEBOT
) to I
VC
V
C
= 1.8V
200 umho
DC
MAX
Maximum Duty Cycle BG2: t
ON
• f
O
l
70 80 %
f
O
Switching Frequency R
RT
= 100k
R
RT
= 50k
R
RT
= 250k
l
235 250
500
100
265 kHz
kHz
kHz
t
ON
Minimum On Time BG2
l
150 250 ns
t
OFF
Minimum Off Time TG1
l
300 500 ns
t
TR
Gate Drive Transition Time TG1, BG1, TG2, BG2 5 ns
t
NOL
Gate Drive Non-Overlap time (TG1 – SW1) to BG1,
(TG2 – SW2) to BG2
75 ns
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