LM3687 Datasheet, PDF (15/35 Pages) National Semiconductor (TI) – Step-Down DC-DC Converter with Integrated Low Dropout Regulator and Startup Mode

LM3687
www.ti.com
SNVS473A – DECEMBER 2007 – REVISED JULY 2008
Typical Performance Characteristics
Unless otherwise specified, typical application (post regulation), V_BATT = 3.6V, T_A = 25°C, enable pins tied to V_BATT, V_{OUT_DCDC}
= 1.8V, V_{OUT_LIN} = 1.2V
I_{Q_VBATT}
vs.
I_{Q_VBATT}
vs.
V_BATT, LDO disabled
V_BATT, both enabled
40
T_A = 125°C
35
30
T_A = 25°C
25
20
15
T_A = -30°C
10
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
SUPPLY VOLTAGE V_BATT (V)
V_{OUT_DCDC}
vs.
I_{OUT_DCDC}
1.830 _{PFM Mode}
1.825
1.820
1.815
1.810
1.805
PWM Mode
1.800
1.795
1.790
0 100 200 300 400 500 600 700 800
OUTPUT CURRENT DC-DC (mA)
T_A = 125°C
90
85
80
75
70
65
T_A = 25°C
60
55
50
45
40
T_A = -30°C
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
SUPPLY VOLTAGE V_BATT (V)
V_{OUT_LIN}
vs.
I_{OUT_LIN}
1.205
1.204
1.203
1.202
1.201
1.200
1.199
1.198
1.197
1.196
0
50 100 150 200 250 300 350
OUTPUT CURRENT LDO (mA)
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