Datasheet

MAX1870A
Step-Up/Step-Down
Li+ Battery Charger
______________________________________________________________________________________ 11
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V
DCIN
= 16V, CELLS = REFIN, V
CLS =
V
REF
, V
ICTL
= V
REFIN
= 3.3V, T
A
= +25°C, unless otherwise noted.)
REF LOAD REGULATION
MAX1870A toc16
LOAD CURRENT (μA)
V
REF
(V)
20001000500 1500
4.04
4.05
4.06
4.08
4.07
4.10
4.09
4.11
4.03
02500
REFERENCE ERROR vs. TEMPERATURE
MAX1870Atoc17
TEMPERATURE (°C)
REFERENCE ERROR (%)
806020 400-20
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0
-40 100
LDO LOAD REGULATION
MAX1870A toc18
LOAD (mA)
V
LDO
(V)
403010 20
5.26
5.32
5.28
5.36
5.30
5.34
5.38
5.24
050
V
IN
= 28V
V
IN
= 16V
V
IN
= 9V
LDO vs. TEMPERATURE
MAX1870A toc19
TEMPERATURE (°C)
LDO VOLTAGE ERROR (%)
8040-20 06020
-0.2
0.2
0.6
0
0.4
0.8
-0.4
-40 100
OUTPUT VOLTAGE RIPPLE
vs. BATTERY VOLTAGE
MAX1870Atoc20
V
BATT
(V)
RMS OUTPUT RIPPLE (mV)
15105
20
40
60
80
100
120
140
160
180
0
020
STEP-UP/STEP-DOWN
SWITCHING WAVEFORM
MAX1870Atoc21
0V
D4
10V
0V
CATHODE
D3 ANODE
INDUCTOR CURRENT
4A
V
BATT
(AC-COUPLED)
200mV/div
2A
10V
20V
2.00μs
V
IN
= 16V
V
BATT
= 16V
STEP-DOWN
SWITCHING WAVEFORM
MAX1870Atoc22
0V
D4
10V
0V
CATHODE
D3 ANODE
INDUCTOR CURRENT
4A
V
BATT
(AC-COUPLED)
10mV/div
2A
10V
20V
2.00μs
V
IN
= 16V
V
BATT
= 12V