74LS191 Datasheet – Synchronous 4-Bit Up/Down Counter

Part Number : 74LS191

Function : Synchronous 4-Bit Up/Down Counters With Up/Down Mode Control

Pakcage : DIP, SOP 16 Pin

Manufacturers : Texas Instruments


74LS191 Counter


Description :

The ‘190, ‘LS190, ‘191, and ‘LS191 are synchronous, reversible up/down counters having a complexity of 8 equivalent gates. The ‘191 and ‘LS191 are 4-bit binary counters and the ‘190 and ‘LS190 are BCD counters. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when so instructed by the steering logic. This mode of operation eliminates the output counting spikes normally associated with asynchronous (ripple clock) counters.

Pinouts :

74LS191 datasheet

The outputs of the four master-slave flip-flops are triggered on a low-to-high transition of the clock input if the enable input is low. A high at the enable input inhibits counting. Level changes at the enable input should be made only when the clock input is high. The direction of the count is determined by the level of the down/up input. When low, the counter count up and when high, it counts down. A false clock may occur if the down/up input changes while the clock is low. A false ripple carry may occur if both the clock and enable are low and the down/up input is high during a load pulse.


1. Counts 8-4-2-1 BCD or Binary
2. Single Down/Up Count Control Line
3. Count Enable Control Input
4. Ripple Clock Output for Cascading
5. Asynchronously Presettable with Load Control
6. Parallel Outputs
7. Cascadable for n-Bit Applications


74LS191 Datasheet PDF Download

74LS191 pdf

Other data sheets within the file : 74190, 74191, 74LS190, 74LS191, SN54190

SY8208AQNC Datasheet – Synchronous Step Down Regulator

This post explains for the semiconductor SY8208AQNC.

The Part Number is SY8208AQNC.

The Package is QFN3x3-10.

The function of this semiconductor is Synchronous Step Down Regulator.

Manufacturers : Silergy

Images :

SY8208AQNC Regulator

Description :

The SY8208AQNC develops a high efficiency synchronous step-down DC-DC regulator capable of delivering 8A continuous, 16A peak current. The SY8208A operates over a wide input voltage range from 4V to 28V and integrates main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss.

The SY8208AQNC adopts the instant PWM architecture to achieve fast transient responses for high step down applications and high efficiency at light loads. In addition, it operates at pseudo-constant frequency of 800kHz under continuous conduction mode to minimize the size of inductor and capacitor. […]


SY8208AQNC pinout

· Low RDS(ON) for internal switches (top/bottom): 20/10 mΩ
· Wide input voltage range: 4-28V
· Instant PWM architecture to achieve fast transient responses
· Internal 400uS softstart limits the inrush current
· Pseudo-constant frequency: 800kHz.
· 8A continuous/16A peak output current capability
· ±1.5% 0.6V reference
· Programmable peak current limit
· Power good indicator
· Output discharge function
· Short circuit latch off protection
· Over voltage latch off protection
· Input UVLO
· Over temperature protection
· RoHS Compliant and Halogen Free


· Set Top Box
· Notebook
· High Power AP

SY8208AQNC Datasheet