Datasheet

SS
FREQ
IN
SW
PGND
COMP
FB
EN
8-PIN4.9mmx3mmx1.1mmMSOP (DGK)
8-PIN6.4mmx3mmx1.2mm TSSOP (PW)
1
2
3
4
8
7
6
5
TPS61085
SLVS859A –JUNE 2008–REVISED APRIL 2012 www.ti.com
PIN ASSIGNMENT
DGK, PW PACKAGES
(TOP VIEW)
PIN FUNCTIONS
PIN
I/O DESCRIPTION
NAME NO.
COMP 1 I/O Compensation pin
FB 2 I Feedback pin
EN 3 I Shutdown control input. Connect this pin to logic high level to enable the device
PGND 4 Power ground
SW 5 Switch pin
IN 6 Input supply pin
FREQ 7 I Frequency select pin. The power switch operates at 650 kHz if FREQ is connected to GND and at 1.2 MHz if
FREQ is connected to IN
SS 8 Soft-start control pin. Connect a capacitor to this pin if soft-start needed. Open = no soft-start
space
TYPICAL CHARACTERISTICS
TABLE OF GRAPHS
FIGURE
vs Input voltage at high frequency (1.2 MHz) Figure 1
I
OUT(max)
Maximum load current
vs Input voltage at low frequency (650 kHz) Figure 2
vs Load current, V
S
= 12 V, V
IN
= 3.3 V Figure 3
η Efficiency
vs Load current, V
S
= 9 V, V
IN
= 3.3 V Figure 4
PWM switching - discontinuous conduction Figure 5
PWM switching - continuous conduction Figure 6
Load transient response at High frequency (1.2 MHz) Figure 7
Load transient response at Low frequency (650 kHz) Figure 8
Soft-start Figure 9
Supply current vs Supply voltage Figure 10
Frequency vs Load current Figure 11
Frequency vs Supply voltage Figure 12
The typical characteristics are measured with the inductors 7447789003 3.3 µH (high frequency) or B82464G4
6.8 µH (low frequency) from Epcos and the rectifier diode SL22.
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