Terminal Functions
TC74VHC157FT (DIGITAL : IC745)
TPS563200 (DIGITAL : IC751 - IC753)
Terminal Functions
PIN
DESCRIPTION
NAME
NUMBER
GND
1
Ground pin Source terminal of low-side power NFET as well as the ground ter-
minal for controller circuit. Connect sensitive VFB to this GND at a single point.
SW
2
Switch node connection between high-side NFET and low-side NFET.
VIN
3
Input voltage supply pin. The drain terminal of high-side power NFET.
VFB
4
Converter feedback input. Connect to output voltage with feedback resistor
divider.
EN
5
Enable input control. Active high and must be pulled up to enable the device.
VBST
6
Supply input for the high-side NFET gate drive circuit. Connect a 0.1 μ F ca-
pacitor between VBST and SW pins.
Block diagram
TC74VHC157F/FN/FT/FK
2007-10-01
2
Pin Assignment
IEC Logic Symbol
Truth Table
Inputs
ST SELECT A B
Output
H
X
X X
L
L
L
L X
L
L
L
H X
H
L
H
X L
L
L
H
X H
H
X: Don’t care
(1)
(15)
(2)
(5)
(3)
1A
2A
1B
(6)
(10)
3A
2B
(4)
(9)
1Y
3Y
(7)
(12)
2Y
4Y
EN
SELECT
ST
3B
(14)
(13)
4A
4B
G1
(11)
1 MUX
1
4A
VCC
16
4B
15
14
13
12
11
10
1
2
3
4
5
6
7
1Y
2A
2B
2Y
GND
4Y
8
3Y
9
3A
3B
(top view)
1A
1B
SELECT
ST
A S G
B
A
Y
B
A Y
B
A
Y
B
Y
SW
VBST
VFB
GND
2
3
1
EN
4
6
5
VIN
TPS562200, TPS563200
DDC (SOT) Package
Top View
2 SW
ZC
XCON
PWM
Control Logic
+
+
+
UVP
OVP
3
VIN
Ton
One-Shot
6 VBST
+
4
VFB
OCL
+
+
Soft Start
5
EN
HS
LS
1 GND
SS
Voltage
Reference
Ref
Hiccup
V
UVP
V
OVP
OCL
threshold
Regulator
UVLO
VREG5
VREG5
TSD
Before Servicing
This Unit
Electrical
Mechanical
Repair Information
Updating
42
