UC2845AM Microsemi Analog Mixed Signal Group, UC2845AM Datasheet - Page 4

• Manufacturer Part Number: UC2845AM
• Description: IC CTRLR PWM CURRENT MODE 8DIP
• Manufacturer: Microsemi Analog Mixed Signal Group

Specifications of UC2845AM

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 500kHz
• Duty Cycle: 50%
• Voltage - Supply: 8.2 V ~ 25 V
• Buck: Yes
• Boost: Yes
• Flyback: Yes
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-DIP
• Frequency-max: 500kHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: UC2845AMR; UC2845AMR

UC184xA/284xA/384xA
4
Notes: 2. These parameters, although guaranteed, are not 100% tested in
CURRENT SENSE
Under-Voltage Lockout Section
Start Threshold
Min. Operation Voltage After Turn-On
PWM Section
Maximum Duty Cycle
Minimum Duty Cycle
Total Standby Section
Start-Up Current
Operating Supply Current
Zener Voltage
*** - Toggle flip flop used only in x844A and x845A series.
** - POWER GROUND and GROUND are internally connected for 8 pin packages.
* - V
GROUND
3. Parameter measured at trip point of latch with V
4. Gain defined as: A
5. Adjust V
6. Output frequency equals oscillator frequency for the UC1842A
CC
production.
and UC1843A. Output frequency is one half oscillator frequency
for the UC1844A and UC1845A.
COMP
and V
R
V
Parameter
T
/C
CC
V
**
FB
*
C
T
CC
are internally connected for 8 pin packages.
above the start threshold before setting at 15V.
VOL
8.4V (1843A/5A)
16V (1842A/4A)
34V
=
Oscillator
UVLO
Error Amp
V
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
V
2.5V
ISENSE
COMP
E L E C T R I C A L C H A R A C T E R I S T I C S
Symbol
C
I
; 0
V
CC
U R R E N T
Z
P
0.8V (1843A/5A)
UVLO
6V (1842A/4A)
R O D U C T I O N
V
Hysteresis
x842A/4A
x842A/4A
x843A/5A
x843A/5A
x842A/3A
x844A/5A
I
ISENSE
CC
2R
= 25mA
R
VFB
0.8V.
B L O C K D I A G R A M
M
= 0.
S / R
Good Logic
O D E
Test Conditions
V
1V
REF
Ref
5V
P W M C
D
7. "Temperature stability, sometimes referred to as average temperature
Current Sense
Comparator
***
A T A
coefficient, is described by the equation:
V
voltage measured over the appropriate temperature range. Note that
the extremes in voltage do not necessarily occur at the extremes in
temperature."
REF
(max.) & V
O N T R O L L E R
Temp Stability =
S
R
S
Internal
H E E T
T
Bias
PWM
Latch
REF
(min.) are the maximum & minimum reference
(Con't.)
Min. Typ. Max. Min. Typ. Max.
UC184xA/284xA
7.8
7.0
15
94
47
30
9
V
REF
T
J
8.4
7.6
0.3
16
10
96
48
11
35
(max.) - V
(max.) - T
100
9.0
8.2
0.5
17
11
50
17
0
J
REF
(min.)
14.5
7.8
8.5
7.0
94
47
30
(min.)
UC384xA
8.4
7.6
0.3
16
10
96
48
11
35
V
5.0V
50mA
V
OUTPUT
POWER GROUND
17.5
11.5
100
9.0
8.2
0.5
50
17
REF
C
0
*
Copyright © 1995
Rev. 1.2a 10/25
Units
mA
mA
%
%
%
V
V
V
V
V
**